JP4107221B2 - Mode map creation method and hybrid vehicle mode map using the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing a mode map which can select the optimum mode of a power train system capable of achieving various control modes, and a mode map for a hybrid vehicle using the method. <P>SOLUTION: A method of producing a mode map from a control mode selecting step to select a control mode achievable at an operation point, a power income and expense calculating step to calculate the income and expense of power to the quantity of consumed fuel in each selected mode, a power balance calculating step to make the maximum value of each power income and expense the power function to the quantity of consumed fuel, a drive efficiency function calculating step to calculate the drive efficiency function to the quantity of consumed fuel, and a control mode function calculating step to calculate a control mode function capable of obtaining maximum power to the drive efficiency from the above power function and the above drive efficiency function and to calculate a control mode function geared to SOC, based on the relation between the above drive efficiency and the above SOC, is used in the production of the mode map of a hybrid vehicle. <P>COPYRIGHT: (C)2005,JPO&amp;NCIPI

Description

  The present invention relates to a mode map of a hybrid vehicle having a plurality of control modes, and particularly belongs to the technical field of a mode map for determining an optimal control mode by three elements.

There are three elements (for example, an engine and two motor generators) that can be input, and various output states to the drive system (hereinafter referred to as control modes) depending on the engagement states of the plurality of planetary gear mechanisms and the plurality of engagement elements. Patent Document 1 discloses a hybrid vehicle to which a power train system capable of achieving (1) is applied.
Japanese Patent Laid-Open No. 2003-34153.

  The present applicant has developed a power train system capable of achieving various control modes. Here, since the engine and the motor generator using battery power are used as the drive source, the relationship between the state of charge of the battery and the fuel consumption is important as a parameter for selecting the optimum mode. However, it has been difficult to select a control mode that optimizes the state of charge of the battery and the fuel consumption of the engine.

  The present invention has been made paying attention to the above problem, and a mode map creation method capable of selecting an optimum mode of a power train system capable of achieving various control modes, and a hybrid vehicle mode map using the method. The purpose is to provide.

  In order to solve the above-described problems, in the present invention, regardless of the SOC, a control mode selection step for selecting a control mode that can be achieved at a driving point determined by a vehicle speed and a driving force, and a selection by the control mode selection step. A power balance calculating step for calculating a power balance with respect to the fuel consumption in each control mode, and a power function calculating step with the maximum value of each power balance calculated in the power balance calculating step as a power function for the fuel consumption; A drive efficiency function calculation step for calculating a drive efficiency function for fuel consumption from the power function, and a control mode function for obtaining a maximum power for the drive efficiency from the power function and the drive efficiency function, Based on the relationship between the driving efficiency and the SOC, a control mode function calculation function that calculates a control mode function corresponding to the SOC. Tsu and up, using the method to create a mode map from.

  In the mode map creation method of the present invention, the relationship between the power balance and the driving efficiency is derived from the relationship between the fuel consumption and the power balance, and the relationship between the fuel consumption and the driving efficiency. From the relationship between the driving efficiency and the SOC, depending on the SOC. By determining the control mode, it is possible to select a control mode that can achieve the operating point while suppressing fuel consumption.

  Hereinafter, the best mode for realizing a hybrid vehicle of the present invention will be described based on an embodiment shown in the drawings.

  FIG. 1 shows a hybrid transmission according to Embodiment 1 of the present invention. In this embodiment, the following configuration is useful for use as a transaxle for a rear wheel drive vehicle (FR vehicle).

In FIG. 1, the hybrid transmission has an engine ENG, a composite current two-layer motor 3, and three rows of first to third planetary gears 4, 5, 6 arranged coaxially from the left side. The first planetary gear 4 includes a first sun gear S1, a first carrier C1 , and a first ring gear R1. The second planetary gear 5 includes a second sun gear S2, a second carrier C2, and a second ring gear R2. The third planetary gear 6 includes a third sun gear S3, a third carrier C3, and a third ring gear R3.

  The composite current two-layer motor 3 includes an inner rotor 3ri and an annular outer rotor 3ro surrounding the inner rotor 3ri so as to be coaxially and rotatably supported on the rear shaft end in the transmission case 1, and the inner rotor 3ri and A stator 3s made of an annular coil coaxially arranged in an annular space between the outer rotors 3ro is fixed to the transmission case 1.

  In this manner, the annular motor 3s and the outer rotor 3ro constitute a first motor / generator MG1 that is an outer motor / generator. The annular coil 3s and the inner rotor 3ri constitute a second motor / generator MG2 that is an inner motor / generator.

  Here, each of the motor generators MG1 and MG2 is a motor that outputs rotations in individual directions according to the supply current and at individual speeds (including stop) according to the supply current when a composite current is supplied. Functions and functions as a generator that generates electric power according to rotation by external force when composite current is not supplied.

  In the coupling between the composite current two-layer motor 3 and the first to third planetary gears 4, 5, 6, the first sun gear S 1 of the first planetary gear 4 and the second sun gear S 2 of the second planetary gear 5 are used. The second motor / generator MG2 (specifically, the inner rotor 3ri) is coupled to the motor. The first motor / generator MG1 (specifically, the outer rotor 3ro) is coupled to the second ring gear R2 of the second planetary gear 5.

  The first rotating member M1 connects the second carrier C2 and the third ring gear R3. The second rotating member M2 connects the first ring gear R1 and the third sun gear S3.

The engine clutch E / C (second clutch described in claims) directly connects the first rotating member M1 and the engine ENG. The high clutch HC (first clutch described in the claims) connects the first carrier C1, the first sun gear S1, and the second sun gear S2. The low brake LB (first brake described in claims) fixes the first carrier C1 to the transmission case 1. The high / low brake HLB (second brake described in claims) fixes the first motor generator MG1 and the second ring gear R2 to the transmission case 1.

  The rotation output from the engine ENG, the first motor / generator MG1 or the second motor / generator MG2 is output from the third carrier C3 of the third planetary gear 6.

FIG. 2 is a diagram showing a configuration of a hybrid system including a control device.
A hybrid system (hereinafter referred to as an E-iVT system) in the first embodiment includes an integrated controller 10 that integrally controls the entire energy, an engine controller 12 (including an engine clutch controller) that controls the engine, and a hybrid The motor controller 11 controls the MGs 1 and 2 in the transmission, the inverter 13 for supplying electricity to the MG, the battery 14 for storing electric energy, and the hybrid transmission including the MG.

  The integrated controller 10 controls the motor controller 11 so as to realize a driving state (driving point) intended by the driver according to the accelerator opening AP, the engine speed Ne, and the vehicle speed VSP (proportional to the output shaft rotational speed). The target MG torque is commanded to the engine controller 12, and the target engine torque is commanded to the engine controller 12.

  Further, the command value to the motor controller 11 may be the target MG rotation speed instead of the target MG torque, and the motor controller 11 may have a control system that achieves the target MG rotation speed with a PI controller or the like.

(Control mode in FR type E-iVT system)
The FR E-iVT system is broadly divided into EV mode that runs on electric power alone and HEV mode that uses both engine and electric power. Further, in each mode, the following five modes 1) Low mode 2) Low- iVT mode 3) 2nd mode 4) High-iVT mode 5) High mode, ie, 10 modes. FIG. 3 shows combinations of EV mode, HEV mode and the above five modes.

  All the modes shown in FIG. 3 use the first motor / generator MG1 and the second motor / generator MG2. However, the main difference is whether or not the engine (or engine clutch EC) is driven or whether or not the low brake LB, high clutch HC, and high / low brake HLB are used.

  FIG. 4 shows the on / off relationship of the low brake LB, high clutch HC, and high / low brake HLB in the modes 1) to 5). The above modes are not selectable in any driving situation, and can be achieved in a limited control region.

  The control area is composed of a three-dimensional space consisting of three axes. The three axes represent vehicle speed VSP, driving force F, and battery SOC (State of charge). In general, as the SOC decreases, the control area for all modes becomes smaller. Here, the driving force F is a required driving force required to drive the vehicle. The required driving force F is determined from the accelerator pedal opening and the vehicle speed operated by the driver, and the optimum mode is selected from the above 10 modes. In particular, a point determined by the vehicle speed VSP and the driving force F is described as a driving point.

(Collinear diagram of FR type E-iVT system)
Here, the alignment chart of the FR type E-iVT system will be described. FIG. 5A is a collinear diagram when the high clutch HC is OFF, and FIG. 5B is a collinear diagram when the high clutch HC is ON.

  When the high latch HC is OFF, a rigid lever exists in each of the first to third planetary gears 4, 5, and 6. In FIG. 5A, the rigid lever 1 represents the second planetary gear 5, the rigid lever 2 represents the first planetary gear 4, and the rigid lever 3 represents the third planetary gear 6. Note that M2 in FIG. 5A indicates that the rotation of the first ring gear R1 of the first planetary gear 4 and the third sun gear S3 of the third planetary gear 6 becomes the same by the second connecting member M2. That is, because of the connecting member between the planetary gears, it is not involved in torque transmission to the engine, the first and second motor generators MG1, MG2, and the output shaft.

  When the high clutch HC is ON, the first sun gear S1, the first carrier C1, and the first ring gear R1 of the first planetary gear 4 all rotate together. Further, the second sun gear S2 and the third sun gear S3 are connected. Therefore, in FIG. 5B, the rigid lever 1 represents the second planetary gear 5 and the third planetary gear 6 connected by the first member M1 and the second member M2, and the rigid lever 2 is the first planetary gear 4. Represents. The rigid lever 2 moves horizontally because the first planetary gear 4 rotates together.

  As an example, the relationship between the rotational speed and torque of each rotary element when the high clutch HC is ON will be described.

[Rotational speed of rotating elements]
The rotation speed of the first motor generator MG1 is N ₁ , the rotation speed of the second motor generator MG2 is N ₂ , the rotation speed input from the engine (that is, the rotation speed of the first rotation member M1) is Ne, and the rotation of the output shaft Output Set the number to No. Here, assuming that the ratio of the rotational speed Ne input from the engine and the output shaft rotational speed No is 1, these rotational speeds are expressed by the following equations.
(N ₁ −Ne) / (No−N ₂ ) = α / β
Α is the ratio between the first motor generator MG1 and the rotational speed Ne input from the engine, and β is the ratio between the second motor generator MG2 and the output shaft rotational speed No. Similarly, in the rigid lever 2, when the second motor-generator revolution speed N ₂ was 1 the ratio between the rotation speed of the first carrier C1, and the first carrier C1 is the rotational speed ratio between the first ring gear R1 [delta] It is described as.

[Rotating element torque]
When the rigid levers 1 and 2 shown in FIG. 5B are in a steady state, the total torque acting on the rigid lever is 0, and when the rigid lever is not moving in the steady state, the total moment is also 0.

T ₁ the torque of the first motor-generator MG1, T ₂ the torque of the second motor-generator MG2, the torque of the engine Te, the torque of the output shaft To, when the torque of the high low brake HLB and T _HLB,
T ₁ + T _HLB + Te-To + T ₂ = 0
It becomes.
Also, from the relationship of torque moment,
(1 + α) · (T ₁ + T _HLB ) + 1 · Te = β · T ₂
It becomes.

(Each control mode of FR type E-iVT system)
Next, the torque and rotational speed (T ₁ , N ₁ , T ₂ , N ₂ , Te, Ne, To of each of the first motor / generator MG1, the second motor / generator MG2, the engine, and the output shaft Output in each control mode. , No) will be described. Basically, each component has mechanical limit values (for example, battery capacity, maximum torque and maximum speed of the engine, maximum torque and maximum speed of each motor generator, etc.). Thus, each control mode cannot be achieved at all operating points. Based on this point, the controllable region determined by the vehicle speed V including all battery states (SOC) and the required driving force F is shown simultaneously.

[High-iVT mode]
In the High-iVT mode, the engine and the first motor / generator MG1 and the second motor / generator MG2 are used. The high clutch HC is ON, the low brake LB is OFF, and the high / low brake HLB is OFF. FIG. 6 shows the relationship between the rotational speed and torque in the High-iVT mode. The relational expression between rotational speed and torque is shown below.
(Formula 1)
N ₁ = −αNo + (1 + α) Ne
N ₂ = (1 + β) No−βNe
T ₁ = βT ₀ / (1 + α + β) − (1 + β) Te / (1 + α + β)
T ₂ = (1 + α) To / (1 + α + β) −αTe / (1 + α + β)
T _HLB = 0 N _HLB = N ₁
T _LB = 0 N _LB = N ₂

  Based on the relational expression (1), driving force control in the High-iVT mode is executed. FIG. 7 is a diagram illustrating the High-iVT mode controllable region determined by the vehicle speed VSP and the required driving force F. In the control region of the E-iVT system, the control region to which the operating point determined by three inputs (vehicle speed VSP, required driving force F, battery capacity SOC) belongs is determined as the optimum mode. Note that the map shown in FIG. 7 shows an operable region regardless of the SOC.

  The High-iVT mode can be achieved in all vehicle speed ranges and can output driving force from a low driving force range to a medium driving force range.

[High mode]
In High, the engine and the first motor / generator MG1 and the second motor / generator MG2 are used. The high clutch HC is ON, the low brake LB is OFF, and the high / low brake HLB is ON. FIG. 8 shows the relationship between the rotational speed and torque in the High mode. The relational expression between rotational speed and torque is shown below.
(Formula 2)
N ₁ = 0
N ₂ = (1 + α + β) No / (1 + α)
Ne = αNo / (1 + α)
T ₁ = 0
T ₂ = (1 + α) To / (1 + α + β) −αTe / (1 + α + β)
T _HLB = To-Te-T ₁ -T ₂ N _HLB = 0
T _LB = 0 N _LB = N ₂

  Based on the relational expression (2), the driving force control in the High mode is executed. FIG. 9 is a diagram illustrating the High mode controllable region determined by the vehicle speed VSP and the required driving force F. The High mode can be achieved except in the extremely low vehicle speed region, and can output the driving force from the low driving force region to the middle driving force region. However, the upper limit value of the driving force is defined by the maximum driving force of the second motor generator MG2.

[Low-iVT mode]
In the Low-iVT mode, the engine and the first motor / generator MG1 and the second motor / generator MG2 are used. The high clutch HC is OFF, the low brake LB is ON, and the high / low brake HLB is OFF. FIG. 10 shows the relationship between the rotational speed and torque in the Low-iVT mode. The relational expression between rotational speed and torque is shown below. It is assumed that the torque input from the engine to the second carrier C2 is Te ⁽¹⁾ , and the torque input from the engine to the third ring gear R3 is Te ⁽²⁾ . The torque input to the first ring gear R1 connected by the second connecting member M2 is T ′ ₂ ⁽¹⁾ , and the torque input to the third sun gear S3 is T ′ ₂ ⁽²⁾ .

The second connecting member M2 represents the torque relationship according to the following equation, taking into account that the total torque becomes 0 from the relationship of action and reaction.
(Formula 3)
N ₁ = αNo / δ + {δ (1 + α + β) -αβ} Ne / δ (1 + β)
N ₂ =-(1 + β) No / δ + βNe / δ
T ₁ = βTo / (1 + α + β) − (1 + β) Te / (1 + α + β)
T ₂ = {αβ−δ (1 + α + β)} / (1 + β) (1 + α + β)} To−αTe / (1 + α + β)
T _HLB = To-Te-T1-T2 N _HLB = 0
T _LB = 0 N _LB = N ₂
Te ⁽¹⁾ + Te ⁽²⁾ = Te
T ₂ ⁽¹⁾ + T ₂ ⁽²⁾ = T ₂
T ' ₂ ⁽¹⁾ + T' ₂ ⁽²⁾ = T ' ₂ = 0
T ₂ ⁽¹⁾ = δTo / (1 + β) + T ₂
T ₂ ⁽²⁾ = -δTo / (1 + β)
Te ⁽¹⁾ = Te-βTo / (1 + β)
Te ⁽²⁾ = βTo / (1 + β)
T ' ₂ ⁽¹⁾ = -To / (1 + β)
T ' ₂ ⁽²⁾ = To / (1 + β)

  Based on the relational expression (3), driving force control in the Low-iVT mode is executed. FIG. 11 is a diagram illustrating the low-iVT mode controllable region determined by the vehicle speed VSP and the required driving force F. The Low-iVT mode can be achieved from the low vehicle speed range to the medium vehicle speed range, and the upper limit value of the vehicle speed is defined by the maximum rotation speed of the first motor generator MG1.

[Low mode]
In the low mode, the engine and the first motor / generator MG1 and the second motor / generator MG2 are used. The high clutch HC is OFF, the low brake LB is ON, and the high / low brake HLB is ON. FIG. 12 shows the relationship between the rotational speed and torque in the low mode. The relational expression between rotational speed and torque is shown below.
(Formula 4)
N ₁ = 0
N ₂ = (1 + β) (1 + α + β) No / {αβ-δ (1 + α + β)}
N _e = α (1 + β) No / {αβ-δ (1 + α + β)}
T ₁ = 0
T ₂ = {αβ−δ (1 + α + β)} To / (1 + β) (1 + α + β) −αTe / (1 + α + β)
T _HLB = {(δ-β) / (1 + β)} To-Te-T ₁ -T ₂ N _HLB = 0
T _LB = {(1 + δ) / (1 + β)} To N _LB = 0
Te ⁽¹⁾ + Te ⁽²⁾ = Te
T ₂ ⁽¹⁾ + T ₂ ⁽²⁾ = T ₂
T ' ₂ ⁽¹⁾ + T' ₂ ⁽²⁾ = T ' ₂ = 0
T ₂ ⁽¹⁾ = δTo / (1 + β) + T ₂
T ₂ ⁽²⁾ = -δTo / (1 + β)
Te ⁽¹⁾ = Te-βTo / (1 + β)
Te ⁽²⁾ = βTo / (1 + β)
T ' ₂ ⁽¹⁾ = -To / (1 + β)
T ' ₂ ⁽²⁾ = To / (1 + β)

  Based on the relational expression (4), the driving force control in the low mode is executed. FIG. 13 is a diagram illustrating the low mode controllable region determined by the vehicle speed VSP and the required driving force F. The Low mode can be achieved only in the low vehicle speed range excluding the extremely low vehicle speed range, and the upper limit value of the vehicle speed is defined by the maximum rotational speed of the second motor generator MG2. Further, since the engine speed is also proportional to the vehicle speed, the lower limit value of the vehicle speed is defined by the idle speed of the engine.

[2nd mode]
In the 2nd mode, the engine, the first motor / generator MG1, and the second motor / generator MG2 are used. The high clutch HC is ON, the low brake LB is ON, and the high / low brake HLB is OFF. FIG. 14 shows the relationship between the rotational speed and torque in the 2nd mode. The relational expression between rotational speed and torque is shown below.
(Formula 5)
N ₁ = (1 + α + β) No / β
N ₂ = 0
N _e = (1 + β) No / β
T ₁ = βTo / (1 + α + β)-(1 + β) Te / (1 + α + β)
T ₂ = 0
T _HLB = 0 N _HLB = N ₁
T _LB = To-Te-T ₁ -T ₂ N _LB = 0
Te ⁽¹⁾ + Te ⁽²⁾ = Te
T ₂ ⁽¹⁾ + T ₂ ⁽²⁾ = T ₂ = 0
T ' ₂ ⁽¹⁾ + T' ₂ ⁽²⁾ = T ' ₂ = 0
T ₂ ⁽¹⁾ = -T _LB
T ₂ ⁽²⁾ = T ₂ -T ₂ ⁽²⁾

  Based on the relational expression (5), the driving force control in the 2nd mode is executed. FIG. 15 is a diagram illustrating a 2nd mode controllable region determined by the vehicle speed VSP and the required driving force F. The 2nd mode can be achieved from the low vehicle speed range except the extremely low vehicle speed range to the medium vehicle speed range. Defined by number. Further, it can be achieved from the low driving force region to the middle driving force region, and the maximum value of the driving force is defined by the maximum driving force of the first motor generator MG1.

[EV-High-iVT mode]
In the EV-High-iVT mode, only the first motor / generator MG1 and the second motor / generator MG2 are used. The high clutch HC is ON, the low brake LB is OFF, and the high / low brake HLB is OFF. FIG. 16 shows the relationship between the rotational speed and torque in the EV-High-iVT mode. The relational expression between rotational speed and torque is shown below.
(Formula 6)
N ₂ = (1 + α + β) No / (1 + α) -βN ₁ / (1 + α)
T ₁ = βTo / (1 + α + β)
T ₂ = (1 + α) To / (1 + α + β)
T _HLB = 0 N _HLB = N ₁
T _LB = 0 N _LB = N ₂

  Based on the relational expression (6), the driving force control in the EV-High-iVT mode is executed. FIG. 17 is a diagram illustrating an EV-High-iVT mode controllable region determined by the vehicle speed VSP and the required driving force F. The EV-High-iVT mode can be achieved in all vehicle speed ranges, but only in the low driving force range. The upper limit of the driving force is defined by each motor generator MG1, MG2 and battery power.

[EV-High mode]
In the EV-High mode, only the first motor / generator MG1 and the second motor / generator MG2 are used. The high clutch HC is ON, the low brake LB is OFF, and the high / low brake HLB is ON. FIG. 18 shows the relationship between the rotation speed and torque in the EV-High mode. The relational expression between rotational speed and torque is shown below.
(Formula 7)
N ₁ = 0
N ₂ = (1 + α + β) No / (1 + α)
T ₁ = 0
T ₂ = (1 + α) To / (1 + α + β)
T _HLB = To-T ₁ -T ₂ N _HLB = 0
T _LB = 0 N _LB = N ₂

  Based on the relational expression (7), the driving force control in the EV-High mode is executed. FIG. 19 is a diagram illustrating an EV-High mode controllable region determined by the vehicle speed VSP and the required driving force F. The EV-High mode can be achieved at all vehicle speeds, but cannot be achieved at high vehicle speeds in the low driving force range. That is, since the rotation speed of the second motor generator MG2 increases in proportion to the vehicle speed, a low torque cannot be achieved for a high rotation in a high vehicle speed range.

[EV-Low-iVT mode]
In the EV-Low-iVT mode, only the first motor / generator MG1 and the second motor / generator MG2 are used. The high clutch HC is OFF, the low brake LB is ON, and the high / low brake HLB is OFF. FIG. 20 shows the relationship between the rotational speed and torque in the EV-Low-iVT mode. The relational expression between rotational speed and torque is shown below.
(Formula 8)
N ₂ =-(1 + β) (1 + α + β) No / {δ (1 + α + β) -αβ}

+ Β (1 + β) N ₁ / {δ (1 + α + β) -αβ
T ₁ = βTo / (1 + α + β)
T ₂ = {αβ−δ (1 + α + β) To} / (1 + β) (1 + α + β)
T _HLB = 0 N _HLB = N ₁
T _LB = (1 + δ) To / (1 + β) N _LB = N ₂

  Based on the relational expression (8), driving force control in the EV-Low-iVT mode is executed. FIG. 21 is a diagram illustrating an EV-Low-iVT mode controllable region determined by the vehicle speed VSP and the required driving force F. The EV-Low-iVT mode can be achieved in all vehicle speed ranges except for the high vehicle speed range, and the upper limit value of the vehicle speed is defined by the maximum rotation speed of the first motor generator MG1.

[EV-Low mode]
In the EV-Low mode, only the first motor / generator MG1 and the second motor / generator MG2 are used. The high clutch HC is OFF, the low brake LB is ON, and the high / low brake HLB is ON. FIG. 12 shows the relationship between the rotation speed and torque in the EV-Low mode. The relational expression between rotational speed and torque is shown below.
(Formula 9)
N ₁ = 0
N ₂ = (1 + β) (1 + α + β) No / {αβ-δ (1 + α + β)}
T ₁ = 0
T ₂ = {αβ−δ (1 + α + β)} To / (1 + β) (1 + α + β)
T _HLB = {(δ-β) / (1 + β)} To-T ₁ -T ₂ N _HLB = 0
T _LB = {(1 + δ) / (1 + β)} To N _LB = 0
Te ⁽¹⁾ + Te ⁽²⁾ = Te = 0
T ₂ ⁽¹⁾ + T ₂ ⁽²⁾ = T ₂
T ' ₂ ⁽¹⁾ + T' ₂ ⁽²⁾ = T ' ₂ = 0
T ₂ ⁽¹⁾ = δTo / (1 + β) + T ₂
T ₂ ⁽²⁾ = -δTo / (1 + β)
Te ⁽¹⁾ = -βTo / (1 + β)
Te ⁽²⁾ = βTo / (1 + β)
T ' ₂ ⁽¹⁾ = -To / (1 + β)
T ' ₂ ⁽²⁾ = To / (1 + β)

  Based on the relational expression (9), the driving force control in the EV-Low mode is executed. FIG. 23 is a diagram illustrating an EV-Low mode controllable region determined by the vehicle speed VSP and the required driving force F. The EV-Low mode can be achieved only in the low vehicle speed range, and the upper limit value of the vehicle speed is defined by the maximum rotation speed of the second motor generator MG2.

[EV-2nd mode]
In the EV-2nd mode, only the first motor / generator MG1 and the second motor / generator MG2 are used. The high clutch HC is ON, the low brake LB is ON, and the high / low brake HLB is OFF. FIG. 24 shows the relationship between the rotation speed and torque in the 2nd mode. The relational expression between rotational speed and torque is shown below.
(Formula 10)
N ₁ = (1 + α + β) No / β
N ₂ = 0
T ₁ = βTo / (1 + α + β)
T ₂ = 0
T _HLB = 0 N _HLB = N ₁
T _LB = To -T ₁ -T ₂ N _LB = 0
^{Te (1) + Te (2} ) = T 2 = 0
T ₂ ⁽¹⁾ = -T ₁ + To
T ₂ ⁽²⁾ = T ₁ -To + T ₂

  Based on the relational expression (10), driving force control in the EV-2nd mode is executed. FIG. 25 is a diagram illustrating a 2nd mode controllable region determined by the vehicle speed VSP and the required driving force F. The EV-2nd mode can be achieved from low to medium vehicle speeds and outputs a small driving force. The upper limit value of the vehicle speed is defined by the maximum rotational speed of the first motor generator MG1, and the upper limit value of the driving force is defined by the maximum driving force of each motor generator MG1, MG2.

(About control mode configuration)
Hereinafter, the configuration of the optimum mode map and the logic for constructing the optimum mode map will be described. Here, three assumptions are made.
1) In the calculation for constructing the mode map, the engine characteristics are similar regardless of the engine used.
2) In the calculation for constructing the mode map, the motor characteristics are similar regardless of the motor used.
3) In the calculation for constructing the mode map, the battery characteristics are similar regardless of the battery used.

  The above three assumptions are actual assumptions, and no special configuration is used when calculating and constructing the mode map. In other words, the result calculated based on this assumption can be applied to a general FR type E-iVT system.

[Optimum mode map]
The optimum mode map is defined by three elements: vehicle speed VSP, required driving force F, and battery state SOC. As a simplified expression, FIGS. 26, 27, and 28 show mode maps represented by two elements of vehicle speed VSP and required driving force F when SOC is low, during SOC, and when SOC is high. Among the ten modes described above, a plurality of modes overlap at the driving point determined by a certain vehicle speed VSP and the required driving force F. At this time, the mode with the best fuel efficiency is selected from among the selected modes.

(When SOC is low)
FIG. 26 shows an optimum mode map when the SOC is low. When the SOC is low, the amount of power stored in the battery is low. Therefore, the EV mode running with only the battery cannot be used in a wide range and requires battery charging. Therefore, when the SOC is low, the EV mode hardly appears in the optimum mode map, and the HEV mode using the engine occupies most. Of the areas divided by the thick dotted lines in FIG. 26, the high vehicle speed / low driving force area is the EV mode, and the other areas are the HEV mode. The characteristics of the optimum mode map when the SOC is low are described below.
1) The driving force is very large, and the Low mode is used at low vehicle speeds.
2) The driving force is large, and the Low-iVT mode is used from low to medium vehicle speeds.
3) The driving force is large, and the 2nd mode is used in the middle vehicle speed range.
4) The High-iVT mode is used from the low driving force range to the medium driving force range in all vehicle speed ranges.
5) High mode is used in the low driving force range from the middle vehicle speed range to the high vehicle speed range.
6) When braking force is applied, EV-High-iVT mode is used at high vehicle speeds.

(During SOC)
FIG. 27 shows an optimum mode map when the SOC is medium. It can be seen that because the SOC is medium, the area that can be driven in EV mode is larger than when the SOC is low. It can also be seen that the HEV mode has changed significantly. The characteristics of the optimum mode map when the SOC is medium are described below.
1) The driving force is very large, and the Low mode is used at low vehicle speeds.
2) The driving force is large, and the Low-iVT mode is used from low to medium vehicle speeds.
3) The 2nd mode is used in the middle driving force range from the low vehicle speed range to the medium vehicle speed range.
4) The High-iVT mode is used from the low driving force range to the medium driving force range and from the low vehicle speed range to the high vehicle speed range.
5) High mode is used in the low driving force range from the low vehicle speed range to the medium vehicle speed range.
6) The EV-Low mode is used in the extremely low driving speed range and the extremely low vehicle speed range.
7) The EV-Low-iVT mode is used in the extremely low driving speed range and at low vehicle speeds.
8) The EV-High-iVT mode is used in the extremely low driving force range from the low vehicle speed range to the high vehicle speed range.

(When SOC is high)
FIG. 28 is a diagram illustrating an optimum mode map when the SOC is high. Since the SOC is high, the usable area of EV mode is the widest. On the other hand, the HEV mode is used only when the EV mode cannot be selected. The case where the EV mode cannot be selected represents the case where the mechanical limit values (maximum speed, maximum torque, etc.) of each motor generator MG1, MG2 or the maximum capacity of the battery are exceeded. Further, when the SOC is high, the configuration is simpler than the optimum mode map for the SOC from low to medium. The characteristics of the optimum mode map when SOC is high are described below.
1) The low mode is used in a high driving force range and a low vehicle speed range.
2) The Low-iVT mode is used from the middle driving force range to the high driving force range and from the low vehicle speed range to the medium vehicle speed range.
3) High-iVT mode is used in the low to medium driving force range and in the medium vehicle speed range.
4) The EV-Low mode is used in the extremely low vehicle speed range from the extremely low drive force range to the high drive force range.
5) The EV-Low-iVT mode is used in the extremely low driving speed range and at low vehicle speeds.
6) The EV-High-iVT mode is used in the extremely low driving force range from the low vehicle speed range to the high vehicle speed range.

(Optimal mode map construction logic)
Next, the construction logic of the optimum mode map will be described. Here, rather than SOC, a driving efficiency EFF that represents how much driving force per 1 cc of fuel contributes is used. The driving efficiency EFF and SOC have a close relationship. When the SOC is high, the battery does not require charging. At this time, the fuel consumption is low, so the supplied fuel is not used for charging but is used for driving, so the driving efficiency EFF is high. On the other hand, when the SOC is low, the battery needs to be charged, and it is necessary to drive the engine in order to charge the battery. At this time, the fuel consumption increases, so the driving efficiency EFF is low. Using this relationship, the optimum mode map is constructed by reading the relationship between the mode and the driving efficiency and finally the relationship between the mode and the SOC.

(Step 1)
Calculate power E in all possible modes along the fuel consumption axis of the engine. This electric power E corresponds to the electric power balance (electric power and electric power loss (including motor loss and inverter loss)) of the first motor generator MG1 and the second motor generator MG2.

(Step 2)
The power function E = f (fuel) is a function of power according to the fuel consumption. Of the power in each mode calculated in step 1, a mode capable of generating the maximum power for each fuel consumption is selected. That is, an optimum mode function for the fuel consumption amount fuel is obtained. Here, E> 0 represents a state where the battery is charged, and E <0 represents a state where the battery is consuming power.

(Step 3)
From the power function E obtained in step 2, a drive efficiency function EFF = g (fuel) is calculated. The drive efficiency function EFF is the ratio of power to fuel consumption. That is, the power balance {E (i) −E (fuel ₀ )} that increases when the fuel is consumed {fuel (i) −fuel ₀ } further than the fuel consumption amount fuel ₀ when the battery is used to the maximum Can be calculated to see how much the fuel contributed to the improvement of the power balance. That is, the improvement contribution of the power balance represents the driving efficiency EFF indicating how much fuel is used for the driving force.

(Step 4)
The drive efficiency function obtained in step 3 is inversely transformed to calculate a fuel consumption function fuel = h1 (EFF).

(Step 5)
From the calculation results of step 4 and step 2, the mode function Mode = h2 (EFF) is obtained. That is, a control mode corresponding to the estimated driving efficiency EFF is obtained.

  Through the above steps, a three-dimensional optimum mode map based on the vehicle speed VSP, the required driving force F, and the driving efficiency EFF can be constructed. The driving efficiency EFF is obtained from electric power E and fuel consumption fuel as variables. Further, as described above, since SOC and EFF have a close relationship, a three-dimensional optimal mode map based on vehicle speed VSP, required driving force F, and SOC is created using this relationship.

(Optimal mode map construction logic when four modes are selectable)
For example, when the vehicle speed VSP = A (km / h), driving force F = B (N), and SOC = variable, four modes can be selected: Low mode, Low-iVT mode, 2nd mode, and High-iVT mode A case will be described.

  FIG. 29 is a diagram illustrating a calculation result of electric power with respect to the fuel consumption amount fuel in each mode. From this calculation result, the maximum power for the fuel consumption amount fuel is selected in the relationship of the power to the fuel consumption amount shown in FIG. FIG. 30 shows that in a certain fuel consumption, if E <0, the power consumption is minimum, and if E> 0, the charged power is maximum.

Next, the driving efficiency EFF with respect to the fuel consumption is calculated. First, the power function shown in FIG. 30 is differentiated based on the following equation.
dE / dfuel = {E (i) −E (fuel _{0 (n)} )} / {fuel (i) −fuel _{0 (n)} }
Note that fuel _{0 (n)} is a fuel consumption minimum value (for example, a point indicated by fuel _{0 (1)} in FIG. 30 in the first calculation ₎ in consideration of the maximum charge / discharge capacity of the battery. FIG. 31 shows the relationship between the differential value of the power function shown in FIG. 30 and the fuel consumption. In the calculation result of dE / dfuel shown in FIG. 31, fuel (= a) that takes the maximum value (= b) of dE / dfuel is plotted.

Next, after fuel = a, fuel _{0 (2)} = a is set, dE / dfuel is calculated again, and fuel taking the maximum value of dE / dfuel is plotted. By repeating this calculation, a function EFF = g (fuel) of the driving efficiency EFF with respect to the fuel consumption amount fuel is created.

  Next, as shown in FIG. 33, EFF = g (fuel) is converted into a function of fuel = h1 (EFF). The function of mode function Mode = h2 (EFF) is estimated from the function of fuel = h1 (EFF) and E = f (fuel) shown in FIG. 29 described above. Specifically, the fuel consumption fuel at the point where the mode is switched from E = f (fuel) is known. EFF = g (fuel) corresponding to this fuel is the point at which the mode switches. From such a comparison, as shown in FIG. 34, the control mode corresponding to the drive efficiency EFF is specified.

  As described above, since the driving efficiency EFF is closely related to the SOC, the driving efficiency EFF can be read as the SOC, and an optimum mode map corresponding to the SOC can be created.

(Configuration of HEV mode)
FIG. 35 is a diagram summarizing a region with a large mode change and a region with a small mode change according to the SOC as shown in FIGS. 26 to 28 when focusing on the HEV mode. In the HEV mode, it is divided into 10 zones (Z1 to Z10).
Z1: Low vehicle speed, high driving force range
Z2: Low vehicle speed, high driving force range
Z3: Low vehicle speed (higher than Z2), high driving force range
Z4: Low to medium vehicle speed, medium to high driving force range
Z5: Low vehicle speed, medium driving force range
Z6: Medium vehicle speed, medium driving force range
Z7: Low to high vehicle speed, medium driving force range
Z8: Low to medium speed, low driving force range
Z9: High vehicle speed, low driving force range
Z10: All vehicle speeds are divided so that they are above the low driving force range.

Here, Table 1 shows the set modes in each zone corresponding to three SOCs of low SOC, medium SOC, and high SOC. ○ represents the selected mode, and x represents that the mode is not selected. Actually, each mode changes continuously according to the SOC.
(Table 1)

  Basically, five modes are used to cover all vehicle speed ranges. When the vehicle speed VSP increases from 0 to VSPmax, the mode uses the Low mode, Low-iVT mode, 2nd mode, High-iVT mode, and High mode.

Here, the five modes are roughly classified into two types.
1) Mode using fixed gear ratio: Low mode, 2nd mode, High mode 2) Mode using variable gear ratio: Low-iVT mode, High-iVT mode As a general principle, variable in terms of fuel consumption Using the gear ratio provides higher performance because the engine, the first motor generator MG1, and the second motor generator MG2 have a higher degree of freedom of rotation.

For this reason, even if control is performed in the following three modes instead of using the above five modes, the mode map can be greatly simplified without causing much deterioration in fuel consumption.
1) Low mode: This mode is used in the low vehicle speed and high driving force region (Z1).
2) Low-iVT mode: Covers the low to medium vehicle speed range and medium driving force range and corresponds to Z2 to Z6. This area is called ZA.
3) High-iVT mode: Covers all vehicle speed range and low driving force range and corresponds to Z7 to Z10. Let this region be ZB.

  Here, as shown in Table 1, mode transitions (Low-iVT mode and 2nd mode) performed according to the SOC in Z5 and Z6 will be described.

(About operation point 1ST in Z6)
FIG. 36 shows an operating point 1ST (vehicle speed VSP = C, driving force F = D) indicated by x belonging to Z6. This operating point 1ST can be selected from three modes: High-iVT mode, Low-iVT mode, and 2nd mode.

At this time, the optimum mode map construction logic is applied to construct the optimum mode map. FIG. 37 is a diagram illustrating a power function in each mode. FIG. 38 shows a function fuel = h1 (EFF) representing fuel consumption with respect to drive efficiency EFF. From these two functions, the mode for the driving efficiency EFF is determined as shown in FIG.
1) When SOC is low, the optimal mode is the 2nd mode.
2) When SOC is medium, the optimal mode is Low-iVT mode.
3) When SOC is high, the optimum mode is Low-iVT mode.

  Such a mode configuration results from the characteristics of the power function shown in FIG. The power function in each mode is determined by engine characteristics, motor characteristics, gear characteristics, and battery characteristics, respectively. However, each of these characteristics is general. The above mode transition is proved by data analysis.

  Two variables are used for data analysis. One is engine combustion efficiency and one is motor loss. The purpose of this calculation is to select an optimal control mode in order to achieve optimal engine combustion efficiency and motor loss minimization. For this analysis, an engine plane representing the relationship among the engine speed, engine torque, and fuel consumption in each mode is used. On this engine plane, an α ray representing the optimum engine combustion efficiency is shown.

  FIG. 40 is a diagram showing the combustion efficiency (g / kWh), which is the fuel weight g required to obtain 1 (kWh) using the engine plane in the 2nd mode. However, the fuel consumption indicated by the dotted line in the figure is k- <k <k +. In the figure, the combustion efficiency (g / kWh) indicated by the solid line is K- <K <K +. FIG. 41 is a diagram showing a loss kW of the first motor generator MG1 and the second motor generator MG2 using the engine plane in the 2nd mode. However, in the figure, the motor loss kW is S0 <S2 (the motor loss is larger in S2).

  The operating point 1ST is at a position close to the boundary line of the High-iVT mode as shown in FIG. In the High-iVT mode, it is close to the limit values of the maximum torque and maximum rotation speed of the first and second motor generators MG1, MG2. That is, the power when the High-iVT mode is selected is lower than that of the 2nd mode or the Low-iVT mode. Therefore, it is sufficient to consider the 2nd mode and the Low-iVT mode, and consider these two modes.

Since the engine is used in both the 2nd mode and the Low-iVT mode at the operating point 1ST, the engine power Pe (2nd) in the 2nd mode and the engine power Pe (Low-iVT) in the Low-iVT mode are the same. Further, the vehicle speed VSP and the required driving force F are the same, and the power P = No · To output from the output shaft torque takes a constant value. At this time,
Pe (2nd) + P1 (2nd) + P2 (2nd) = Pe (Low-iVT) + P1 (Low-iVT) + P2 (Low-iVT)
The relationship is established. Here, Pe is the engine power, P1 is the first motor generator power, and P2 is the second motor generator power.

At this time,
P1 (2nd) + P2 (2nd) = P1 (Low-iVT) + P2 (Low-iVT)
The relationship is established. Furthermore, as shown in FIG.
E = P1 + P2-Loss
It is expressed. Here, Loss represents motor loss. On the engine plane, the power difference in each mode corresponding to the point of fuel = k + shown in FIG. 37 is calculated.
E (2nd) −E (Low-iVT)
= {P1 (2nd) + P2 (2nd) -Loss (2nd)}-{P1 (Low-iVT) + P2 + (Low-iVT) -Loss (Low-iVT)
= -Loss (2nd) + Loss (Low-iVT)> 0
Get a relationship.

  This relationship is always established as is apparent from FIGS. 41 and 43. Basically, the 2nd mode is considered to be because the second motor generator MG2 is stopped and the motor loss is reduced accordingly. In conclusion, at fuel = k +, the power is always higher in the 2nd mode than in the Low-iVT mode.

  Next, consider the point of fuel = k− shown in FIG. 37 in the engine plane. In the 2nd mode at this operating point, if the output shaft speed No is constant, the engine speed is also constant because the gear ratio is fixed.

On the other hand, in the Low-iVT mode, the engine speed fluctuates if the output shaft speed No is constant because the gear ratio is variable. The fluctuation of the engine speed fluctuates in the vicinity of the α ray, and the maximum power considering the fuel consumption is output. That is,
P = Pe (2nd) + P1 (2nd) + P2 (2nd) = Pe (Low-iVT) + P1 (Low-iVT) + P2 (Low-iVT)
Pe (Low-iVT) −Pe (2nd) = {P1 (2nd) + P2 (2nd)} − {P1 (Low-iVT) + P2 (Low-iVT)}
Get a relationship. Also,
Pe (Low-iVT)> Pe (2nd)
Therefore,
{P1 (2nd) + P2 (2nd)}> {P1 (Low-iVT) + P2 (Low-iVT)}
It becomes.

  In other words, even if the relationship Loss (2nd) <Loss (Low-iVT) is obtained as the power loss Loss, the absolute value of the power consumption of the 2nd mode is greater than the absolute value of the power consumption of the Low-iVT mode. The value is large. Therefore, it represents that the power function E = f (fuel) in the 2nd mode is smaller than the power function E = f (fuel) in the Low-iVT mode.

From the above analysis results, the following became clear.
1) The power in the High-iVT mode is always smaller than the power in the Low-iVT mode.
2) There is an operating point where the fuel consumption is large and the power in the 2nd mode is larger than that in the Low-iVT mode.
3) There is an operating point where the fuel consumption is small and the power in the Low-iVT mode is larger than that in the 2nd mode.

(About operation point 2ND in Z5)
FIG. 44 shows x driving point 2ND belonging to Z5 (vehicle speed VSP = E (<C), driving force F = F (≈D)). The operation point 2ND can be selected from four modes: High-iVT mode, Low-iVT mode, 2nd mode, and Low mode.

At this time, the optimum mode map construction logic is applied to construct the optimum mode map. FIG. 45 is a diagram illustrating a power function in each mode. FIG. 46 shows a function fuel = h1 (EFF) representing fuel consumption with respect to drive efficiency EFF. From these two functions, the mode for the driving efficiency EFF is determined as shown in FIG.
1) When SOC is low, the optimal mode is Low-iVT mode.
2) The optimum mode is the 2nd mode when the SOC is medium.
3) When SOC is high, the optimum mode is Low-iVT mode.

  The operating point 2ND is at a position close to the boundary line of the High-iVT mode as shown in FIG. 7 as described in the operating point 1ST. In the High-iVT mode, it is close to the limit values of the maximum torque and maximum rotation speed of the first and second motor generators MG1, MG2. FIG. 54 is a diagram showing the combustion efficiency on the engine plane in the High-iVT mode. FIG. 55 is a diagram showing motor loss in the engine plane in the High-iVT mode. As shown in FIG. 54, the combustion efficiency is high, but the motor loss is very high as shown in FIG. That is, the power when the High-iVT mode is selected is lower than that of the 2nd mode or the Low-iVT mode. Therefore, the 2nd mode, the Low-iVT mode, and the Low mode may be considered, and three modes will be considered.

The Low mode is set for a low vehicle speed range, the high brake HB is ON, and the first motor generator MG1 is stopped. The rotation of the engine and the second motor generator MG2 is in a proportional relationship, and when the vehicle speed VSP is constant, the second motor generator rotation speed N2 is larger than the engine rotation speed Ne. This relationship is as shown in the above equation (4). As shown in the collinear diagram of FIG. 12, in the low mode, since the rotation speed of the second motor generator MG2 is large, the achievable torque range of the second motor generator MG2 is extremely narrow. That is,
P = Pe + P2 + P1 _{(= 0)} = Ne _{(= cst)} × Te + N _{2 (= cst)} × T ₂
It is expressed. Since the first motor generator MG1 is fixed, a P1 = 0, because it is constant the output shaft speed by the gear ratio fixed, Ne and N ₂ takes a constant value.

  As shown in FIGS. 48 and 49, the range that the Low mode can take is located at a position far away from the α-ray. Therefore, the engine is operated at a low combustion efficiency, and the engine power is low. Furthermore, as shown in FIG. 45, the power is smaller than the power in the Low-iVT mode at the same fuel consumption. From the above points, it can be seen that the 2nd mode and the Low-iVT mode should be studied.

  Here, the point of the fuel consumption amount fuel = l− shown in FIG. 45 will be considered. FIG. 50 shows the combustion efficiency in the engine plane in the Low-iVT mode and FIG. 52 shows the 2nd mode. FIG. 51 shows motor loss in the engine plane in the Low-iVT mode and FIG. 53 shows the 2nd mode.

  In the Low-iVT mode, when the output shaft rotational speed No is fixed, since it has a degree of freedom of other rotational speeds, even if the fuel = l− point on the engine plane shown in FIG. It has an operating point near the alpha ray. Also, with respect to the motor loss shown in FIG. 51, since the rotational speeds of the first and second motor generators MG1, MG2 have a degree of freedom, the motor loss is relatively small.

  On the other hand, in the 2nd mode, when the output shaft rotational speed No is fixed, the gear ratio is fixed, so that the other rotational speed (engine rotational speed) is fixed. At this time, the fuel point on the engine plane shown in FIG. 52 has an operating point at a position away from the α line. Further, regarding the motor loss shown in FIG. 53, the rotational speed of the second motor generator MG2 is fixed, but the motor loss becomes large.

From the above, when comparing engine power Pe (Low-iVT) and Pe (2nd),
Pe (Low-iVT) >> Pe (2nd)
Here, if the required power is P,
P = Pe (Low-iVT) + P1 (Low-iVT) + P2 (Low-iVT)
P = Pe (2nd) + P1 (2nd) + P2 (2nd)
It becomes. Therefore,
Pe (Low-iVT) + P1 (Low-iVT) + P2 (Low-iVT) = Pe (2nd) + P1 (2nd) + P2 (2nd)
Since the second motor generator MG2 is stopped in 2nd mode, P2 (2nd) = 0
Pe (Low-iVT) -Pe (2nd) = P1 (2nd)-{P1 (Low-iVT) + P2 (Low-iVT)}> 0
From the above relationship,
P1 (2nd)> P1 (Low-iVT) + P2 (Low-iVT)
It becomes.

When fuel = l−, the required driving force cannot be ensured only by the engine, so the shortage needs to be compensated by the first and second motor generators MG1 and MG2. However, the power P1 (2nd) of the first motor generator MG1 in the 2nd mode is larger than the sum of the two motor generators MG1 and MG2 in the Low-iVT mode. That is, it means that the power consumption is larger in the 2nd mode than in the Low-iVT mode. That is, as shown in FIG. 45, at the point where fuel = l−
E (2nd) <E (Low-iVT)
The relationship is obtained.

Here, there are cases where the power obtained in the 2nd mode and the Low-iVT mode is exactly the same. At this time,
P1 (2nd) = P1 (Low-iVT) + P2 (Low-iVT)
The relationship is obtained. Next, as the power relationship,
E (2nd) = P1 (2nd) -Loss (2nd)
E (Low-iVT) = P1 (Low-iVT) + P2 (Low-iVT) -Loss (Low-iVT)
The relationship is obtained. At this time, the difference in power has the following relationship.
E (2nd) -E (Low-iVT) = Loss (2nd) -Loss (Low-iVT)
At this time, in the 2nd mode, only the first motor generator MG1 is used.
Loss (2nd) <Loss (Low-iVT)
From this relationship,
E (2nd)> E (Low-iVT)
It becomes. That is, when the power obtained in both the 2nd mode and the Low-iVT mode is the same at a certain operating point, it can be seen that the power obtained in the 2nd mode is greater than the power obtained in the Low-iVT mode.

  When the fuel consumption increases and the engine power Pe increases, it is assumed that the vehicle speed VSP and the required driving force F are constant, so that the supply of the engine power Pe becomes excessive. At this time, excessive supply of engine power Pe is converted into electric power by causing the motor generator to act as a generator. That is, in both the 2nd mode and the Low-iVT mode, the electric power E becomes + (battery charging direction).

As shown in FIG. 50, when the fuel consumption fuel increases in the Low-iVT mode, the engine power Pe increases, but the engine operating point is located in the vicinity of the α line. Moreover, even if the engine speed increases, the engine torque becomes constant. Therefore, from the relational expression (3) in the Low-iVT mode, the torques T ₁ and T ₂ of the motor generator do not change. Rotational speed N ₁ of motor generator by an increase in the engine speed Ne, as N ₂ is changed, the rotational speed of the first motor generator MG1 increases, the rotational speed of the second motor-generator MG2 is decreased. For this reason, the total motor loss is substantially constant.

When the fuel consumption increases in the 2nd mode, the engine speed becomes constant when the vehicle speed is constant. The rotational speed of the first motor generator MG1 from equation (5) is constant, the torque T ₁ of the first motor generator MG1 is reduced. First motor generator MG1 acts as a generator, and motor loss also increases.

Furthermore, when the fuel consumption increases, the operating point in the Low-iVT mode approaches the α-ray, but the operating point in the 2nd mode moves away from the α-ray. That is,
Pe (Low-iVT)> Pe (2nd)
Therefore,
P1 (Low-iVT) + P2 (Low-iVT) <P1 (2nd)
It becomes. This relationship indicates that the power consumption of the motor in the Low-iVT mode is smaller than that in the 2nd mode (only the first motor generator MG1 operates). That is, when the motor generator acts as a generator, the battery charging power obtained from the motor in the Low-iVT mode is larger than the battery charging power obtained from the motor in the 2nd mode. Therefore,
E (Low-iVT)> E (2nd)
It can be seen that this result agrees with the result shown in FIG.

  As described above, at the operating point 2ND in Z5, it is understood that the low-iVT mode is the optimum mode when the SOC is low, the second mode when the SOC is medium, and the low-iVT mode when the SOC is high.

[Mode transition at Z8 and Z9]
In Z8 and Z9, transition between High-iVT mode and High mode is performed. This [High-iVT mode, High mode] combination is very similar to the [Low-iVT mode, 2nd mode] combination. That is, the characteristics of the High-iVT mode and the Low-iVT mode are similar, and the characteristics of the High mode and the 2nd mode are similar. However, the relational expressions of the rotational speeds of the motor generators MG1 and MG2 are different. For example, the relational expression of the rotational speed N2 of the second motor generator MG2 is
For Low-iVT mode
N ₂ (Low-iVT) =-(1 + β) No / δ + βNe / δ
In High-iVT mode
N ₂ (High-iVT) = (1 + β) No-βNe
It becomes. That is, N ₂ (Low-iVT) = δN ₂ (High-iVT) (where δ <1). This is because the High-iVT mode can be used in a wider vehicle speed range than the Low-iVT mode.

(About operating points at Z9)
The relationship between the High-iVT mode and the High mode in Z9 is similar to the relationship between the Low-iVT mode and the 2nd mode in Z6 described above. FIG. 56 shows the power functions of the High mode and the High-iVT mode at the operating point (VSP = G (> E), F = H (<F)). The relationship between these two power functions is the same as the relationship between the power functions of the Low-iVT mode and the 2nd mode shown in FIG. 37 described in Z6. Therefore, the logic described in Z6 can be applied as it is.

(About operating points in Z8)
The relationship between the High-iVT mode and the High mode in Z8 is similar to the relationship between the Low-iVT mode and the 2nd mode in Z5 described above. FIG. 57 shows the power functions of the High-iVT mode and the High mode at the operating point (VSP = I (<G), F = J (≈H)). The relationship between the two power functions is the same as the relationship between the power functions of the Low-iVT mode and the 2nd mode shown in FIG. 45 described in Z5. Therefore, the logic described in Z5 can be applied as it is.

[About mode transition in Z2 and Z3]
In Z2 and Z3, transition between Low-iVT mode and Low mode is performed. This combination of [Low-iVT mode, Low mode] is very similar to the combination of [Low-iVT mode, 2nd mode]. That is, both the low mode and the second mode are similar in characteristics because the gear ratio is fixed. However, the gear ratio is different. If the gear ratio in Low mode is K (Low) and the gear ratio in 2nd mode is K (2nd),
K (Low) = α (1 + β) / {αβ-δ (1 + α + β)}
K (2nd) = (1 + β) / β
It becomes. Therefore,
K (Low) / K (2nd) = αβ / {αβ-δ (1 + α + β)}> 1
And K (Low)> K (2nd). That is, at the same vehicle speed, it can be seen that the engine speed in the Low mode is larger than the engine speed in the 2nd mode.

(EV mode configuration)
Next, the EV mode will be described. FIG. 58 is a diagram summarizing an area where the mode change is large and an area where the mode change is small as shown in FIGS. 26 to 28 when focusing on the EV mode. In the EV mode, the vehicle speed VSP-required driving force F map is divided into seven parts of Za to Zg. The characteristics of EV mode depend on SOC. When the SOC is high, the EV mode area is wide, and when the SOC is low, the EV mode area is narrow.
Za: High vehicle speed, low driving force range
Zb: Medium to high vehicle speed, low driving force range
Zc: Low vehicle speed, low driving force range
Zd: Extremely low vehicle speed, low driving force range
Ze: Medium vehicle speed, low driving force range
Zf: Low vehicle speed, low driving force range
Zg: Extremely low vehicle speed, medium to high driving force range

Here, Table 2 shows the set modes in each zone corresponding to the three SOCs of low SOC, medium SOC, and high SOC. ○ represents the selected mode, and x represents that the mode is not selected. Actually, each mode changes continuously according to the SOC.
(Table 2)

  In EV mode, five modes are basically used to cover all vehicle speed ranges. When the vehicle speed VSP increases from 0 to VSPmax, the EV-Low mode, EV-Low-iVT mode, EV-2nd mode, EV-High-iVT mode, and EV-High mode are used.

Here, of the above five modes, three modes are important in order to cover all vehicle speed ranges. By using these three modes, the optimum mode map can be greatly simplified only by a relatively small deterioration in fuel consumption.
1) Use EV-Low mode at low vehicle speeds.
2) Use EV-Low-iVT mode from low to medium speeds.
3) Use EV-High-iVT mode from medium to high vehicle speeds.

  About each mode of EV mode, the content demonstrated in HEV mode is simplified and it can apply almost as it is. That is, since the engine is not used, the fuel consumption is 0, and when the output shaft rotational speed No is determined, the degree of freedom of rotation is lost, so the operating point is determined as one point.

  For example, consider driving points with high vehicle speed and low driving force. At this operating point, five modes of EV-Low-iVT mode, EV-High-iVT mode, EV-High mode, High-iVT mode, and High mode can be selected. FIG. 59 shows the power functions of these five modes. All EV modes exist where the fuel consumption is fuel = 0. FIG. 60 is an enlarged view of the fuel = 0 portion.

  FIG. 61 is a diagram showing the relationship between fuel consumption and drive efficiency based on the power function shown in FIG. FIG. 62 shows the relationship between the driving efficiency and the optimum mode. Note that the logic described in the above-described optimal mode map construction logic is applied to the logic for deriving this relationship.

  As is apparent from FIG. 62, the High-iVT mode is selected when the SOC is low, and the EV-High-iVT mode is selected when the SOC is medium to high. That is, when the electric power stored in the battery is low, it is necessary to charge the battery. At this time, the High-iVT mode using the engine is selected. On the other hand, when the electric power stored in the battery is secured to the extent that the vehicle can run without using the engine, the EV-High-iVT mode with the smallest power consumption is selected among the EV modes.

[Optimum mode selection algorithm]
Next, an algorithm for selecting an optimum mode using a mode map set based on the above-described optimum mode map construction logic will be described.

(Main algorithm)
FIG. 63 is a flowchart showing the main algorithm.
In step C1, the EV algorithm is executed.
In Step C2, it is determined whether Mode = 0 indicating that there is no selectable mode in the EV algorithm is selected. If Mode = 0, the process proceeds to Step C3. Otherwise, the control flow ends. Repeat step C1.
In step C3, the HEV algorithm is executed.

(EV algorithm)
FIG. 64 is a flowchart showing the EV algorithm.
In step b1, the vehicle speed VSP, the required driving force F, and SOC are determined, and the driving point P (VSP, F, SOC) is determined.
In step b2, it is determined whether or not the driving point P belongs to Za on the map defined by the vehicle speed excluding the SOC and the required driving force. If it belongs, the process proceeds to step b5, otherwise the process proceeds to step b3.
In step b3, it is determined whether or not the operating point P belongs to Zb as in step b2. If it belongs, the process proceeds to step b4, otherwise the process proceeds to step b6.
In step b4, it is determined whether or not the threshold value is lower than a threshold value low indicating that the SOC is low. When the threshold value is large, the process proceeds to step b5, and otherwise the process proceeds to step b18.
In step b6, it is determined whether or not the operating point P belongs to Ze. If it belongs, the process proceeds to step b7. Otherwise, the process proceeds to step b8.
In step b7, it is determined whether or not the SOC is larger than a threshold medium indicating a medium level. If so, the process proceeds to step b5, and otherwise, the process proceeds to step b18.

In step b8, it is determined whether or not the operating point P belongs to Zc. If it belongs, the process proceeds to step b9. Otherwise, the process proceeds to step b11.
In step b9, it is determined whether or not the SOC is larger than the threshold value low. If so, the process proceeds to step b10, and otherwise, the process proceeds to step b18.
At step b10, select the EV-Low-iVT mode as an optimal mode, reads the rotational speed N ₁ of the first motor generator MG1 in the EV-Low-iVT mode. The other variables N ₂ , T ₁ , T ₂ are calculated based on the read rotation speed N ₁ .
In step b11, it is determined whether or not the operating point P belongs to Zf. If it belongs, the process proceeds to step b12. Otherwise, the process proceeds to step b13.
In step b12, it is determined whether or not the SOC is larger than the threshold medium. If so, the process proceeds to step b10, and otherwise, the process proceeds to step b18.

In step b13, it is determined whether or not the operating point P belongs to Zd. If it belongs, the process proceeds to step b14. Otherwise, the process proceeds to step b16.
In step b14, it is determined whether or not the SOC is larger than the threshold value low. If so, the process proceeds to step b15, and otherwise, the process proceeds to step b18.
In step b15, the EV-Low mode is selected as the optimum mode, and the variables N ₁ , N ₂ , T ₁ , T ₂ in the EV-Low mode are calculated.
In step b16, it is determined whether or not the operating point P belongs to Zg. If it belongs, the process proceeds to step b17. Otherwise, the process proceeds to step b18.
In step b17, it is determined whether or not the SOC is larger than the threshold medium. If so, the process proceeds to step b15, and otherwise, the process proceeds to step b18.
In step b18, the mode is set to zero.

(HEV algorithm)
FIG. 65 is a flowchart showing the HEV algorithm.
In step a1, the vehicle speed VSP, the required driving force F, and SOC are determined, and the driving point P (VSP, F, SOC) is determined.
In step a2, it is determined whether or not the driving point P belongs to Z1 of the map defined by the vehicle speed excluding the SOC and the required driving force. If it belongs, the process proceeds to step a5, otherwise the process proceeds to step a3.
In step a3, it is determined whether or not the operating point P belongs to Z2 in the same manner as in step a2. If it belongs, the process proceeds to step a4. Otherwise, the process proceeds to step a6.
In step a4, it is determined whether or not the SOC is low. When SOC = low, the process proceeds to step a9, and otherwise, the process proceeds to step a5.
In step a6, it is determined whether or not the operating point P belongs to Z3. If it belongs, the process proceeds to step a7. Otherwise, the process proceeds to step a8.
In step a7, it is determined whether or not the SOC is low. If SOC = low, the process proceeds to step a5. Otherwise, the process proceeds to step a9.

In step a8, it is determined whether or not the operating point P belongs to Z4. If it belongs, the process proceeds to step a9. Otherwise, the process proceeds to step a10.
In step a9, the Low-iVT mode is selected as the optimum mode, and the engine speed Ne and the engine torque Te are read from the mode map. Based on this value, other variables N ₁ , N ₂ , T ₁ , T ₂ are calculated.
In step a10, it is determined whether or not the operating point P belongs to Z5. If it belongs, the process proceeds to step a11. Otherwise, the process proceeds to step a12.
In step a11, it is determined whether or not the SOC is medium. If SOC = medium, the process proceeds to step a14, and otherwise, the process proceeds to step a9.
In step a12, it is determined whether or not the operating point P belongs to Z6. If it belongs, the process proceeds to step a13. Otherwise, the process proceeds to step a15.
In step a13, it is determined whether or not the SOC is low. If SOC = low, the process proceeds to step a14. Otherwise, the process proceeds to step a9.
In step a14, the 2nd mode is selected as the optimum mode, and the engine torque Te is read from the mode map. Based on this value, other variables Ne, N ₁ , N ₂ , T ₁ and T ₂ are calculated.

In step a15, it is determined whether or not the operating point P belongs to Z7. If it belongs, the process proceeds to step a18. Otherwise, the process proceeds to step a16.
In step a16, it is determined whether or not the operating point P belongs to Z8. If it belongs, the process proceeds to step a17, otherwise the process proceeds to step a19.
In step a17, it is determined whether or not the SOC is medium. If SOC = medium, the process proceeds to step a21. Otherwise, the process proceeds to step a18.
In step a18, the High-iVT mode is selected as the optimum mode, and the engine speed Ne and the engine torque Te are read from the mode map. Based on this value, other variables N ₁ , N ₂ , T ₁ , T ₂ are calculated.
In step a19, it is determined whether or not the operating point P belongs to Z9. If it belongs, the process proceeds to step a20. Otherwise, the process proceeds to step a18.
In step a20, it is determined whether or not the SOC is low. If SOC = low, the process proceeds to step a21. Otherwise, the process proceeds to step a18.
In step a21, the High mode is selected as the optimum mode, and the engine torque Te is read from the mode map. Based on this value, other variables N ₁ , N ₂ , T ₁ , T ₂ are calculated.

  As described above, in the FR type E-iVT system of the first embodiment, the relationship between the power balance and the driving efficiency is derived from the relationship between the fuel consumption and the power balance, and the relationship between the fuel consumption and the driving efficiency. By determining the control mode according to the SOC from the relationship between the efficiency and the SOC, it is possible to select a control mode that can achieve the operating point while suppressing the fuel consumption.

  In the HEV mode, the two-dimensional map represented by the vehicle speed VSP and the required driving force F was divided into Z1 to Z10. Next, at the point (Z2, Z3, Z5, Z6, Z8, Z9) that needs to change the mode according to the SOC state, the control mode is selected according to the SOC state (HEV algorithm), An optimal control mode can be selected.

  In the EV mode, the two-dimensional map represented by the vehicle speed VSP and the required driving force F was divided into Za to Zg. Next, at the point (Zb, Ze, Zc, Zf, Zd, Zg) where the mode needs to be changed according to the SOC state, the control mode is selected according to the SOC state (EV algorithm). An optimal control mode can be selected.

  In addition, as a result of analyzing the operating point at which the control mode transitions according to the SOC using the engine plane, even if the fuel consumption is the same, the mode transition is based on the relationship between engine combustion efficiency and motor loss. Proved that the optimal control mode was selected.

1 is an overall view showing a mechanical configuration of a hybrid system in Embodiment 1. FIG. 1 is a block diagram illustrating a control configuration of a hybrid system in Embodiment 1. FIG. It is a figure showing the control mode of the hybrid system in Example 1. FIG. It is a figure showing the fastening state of the fastening element in each control mode of the hybrid system in Example 1. FIG. It is a hybrid system in Example 1, Comprising: It is a figure showing the rigid body lever according to the fastening state of a high clutch. It is a figure showing the rigid body lever in the High-iVT mode in Example 1. FIG. It is a high-iVT mode in Example 1, Comprising: It is a mode map showing a selectable area | region. 6 is a diagram illustrating a rigid lever in a high mode in Embodiment 1. FIG. 5 is a mode map representing a selectable region in the high mode according to the first exemplary embodiment. It is a figure showing the rigid lever in the Low-iVT mode in Example 1. FIG. It is a Low-iVT mode in Example 1, Comprising: It is a mode map showing a selectable area | region. FIG. 3 is a diagram illustrating a rigid lever in the low mode in the first embodiment. 5 is a mode map representing a selectable region in the low mode in the first embodiment. 6 is a diagram illustrating a rigid lever in the 2nd mode in Embodiment 1. FIG. 2 is a mode map representing a selectable region in the 2nd mode in the first embodiment. It is a figure showing the rigid lever in EV-High-iVT mode in Example 1. FIG. It is EV-High-iVT mode in Example 1, Comprising: It is a mode map showing a selectable area | region. It is a figure showing the rigid body lever in EV-High mode in Example 1. FIG. 5 is a mode map representing a selectable region in the EV-High mode in the first embodiment. It is a figure showing the rigid lever in EV-Low-iVT mode in Example 1. FIG. It is EV-Low-iVT mode in Example 1, Comprising: It is a mode map showing a selectable area | region. It is a figure showing the rigid lever in EV-Low mode in Example 1. FIG. 5 is a mode map representing a selectable region in the EV-Low mode in the first embodiment. It is a figure showing the rigid body lever in EV-2nd mode in Example 1. FIG. It is a EV-2nd mode in Example 1, Comprising: It is a mode map showing a selectable area | region. It is a mode map in Example 1 in SOC = Low. 3 is a mode map in SOC = medium of the first embodiment. It is a mode map in Example 1 in SOC = High. It is a figure showing the electric power function in the operating point (A, B) of Example 1. FIG. It is a figure showing the relationship between the fuel consumption in the operating point (A, B) of Example 1, and electric power. It is a figure showing the power differential function in the operating point (A, B) of Example 1. FIG. It is a figure showing the relationship between the fuel consumption in the operating point (A, B) of Example 1, and drive efficiency. It is a figure showing the relationship between the driving efficiency in the operating point (A, B) of Example 1, and fuel consumption. It is a figure showing the relationship between the driving efficiency in the operating point (A, B) of Example 1, and the optimal mode. It is the figure which simplified the mode map of the HEV mode of Example 1. FIG. It is a figure showing the position of the operating point (C, D) in the HEV mode map of Example 1. It is a figure showing the relationship between the fuel consumption in the operating point (C, D) of Example 1, and drive efficiency. It is a figure showing the relationship between the drive efficiency in the operating point (C, D) of Example 1, and fuel consumption. It is a figure showing the relationship between the drive efficiency in the operating point (C, D) of Example 1, and the optimal mode. FIG. 5 is an engine plan view showing combustion efficiency when the 2nd mode is selected at the operating point (C, D) of the first embodiment. FIG. 5 is an engine plan view showing motor loss when the 2nd mode is selected at the operating point (C, D) of the first embodiment. FIG. 6 is an engine plan view showing combustion efficiency when the Low-iVT mode is selected at the operating point (C, D) of the first embodiment. FIG. 3 is an engine plan view showing motor loss when the Low-iVT mode is selected at the operating point (C, D) of the first embodiment. It is a figure showing the position of the operating point (E, F) in the HEV mode map of Example 1. It is a figure showing the relationship between the fuel consumption in the operating point (E, F) of Example 1, and electric power. It is a figure showing the relationship between the drive efficiency in the operating point (E, F) of Example 1, and fuel consumption. It is a figure showing the relationship between the drive efficiency in the operating point (E, F) of Example 1, and the optimal mode. FIG. 5 is an engine plan view showing combustion efficiency when the low mode is selected at the operating point (C, D) of the first embodiment. FIG. 5 is an engine plan view showing motor loss when the Low mode is selected at the operating point (C, D) of the first embodiment. FIG. 6 is an engine plan view showing combustion efficiency when the Low-iVT mode is selected at the operating point (C, D) of the first embodiment. FIG. 3 is an engine plan view showing motor loss when the Low-iVT mode is selected at the operating point (C, D) of the first embodiment. FIG. 5 is an engine plan view showing combustion efficiency when the 2nd mode is selected at the operating point (C, D) of the first embodiment. FIG. 5 is an engine plan view showing motor loss when the 2nd mode is selected at the operating point (C, D) of the first embodiment. FIG. 6 is an engine plan view showing combustion efficiency when the High-iVT mode is selected at the operating point (C, D) of the first embodiment. FIG. 5 is an engine plan view showing motor loss when the High-iVT mode is selected at the operating point (C, D) of the first embodiment. It is a figure showing the relationship between the fuel consumption in the operating point (G, H) of Example 1, and electric power. It is a figure showing the relationship between the fuel consumption in the operating point (I, J) of Example 1, and electric power. It is the figure which simplified the mode map of EV mode of Example 1. FIG. It is a figure showing the relationship between the fuel consumption in the driving | running point (high vehicle speed, low driving force) of Example 1, and electric power. FIG. 59 is an enlarged view of the vicinity of fuel consumption = 0 in FIG. 58. It is a figure showing the relationship between the driving efficiency in the operating point (high vehicle speed, low driving force) of Example 1, and fuel consumption. It is a figure showing the relationship between the driving efficiency in the driving | running point (high vehicle speed, low driving force) of Example 1, and optimal mode. 3 is a flowchart illustrating a main algorithm in selecting an optimum mode according to the first embodiment. 3 is a flowchart illustrating an EV algorithm in selecting an optimum mode according to the first embodiment. 3 is a flowchart showing an HEV algorithm in selecting an optimum mode according to the first embodiment.

Explanation of symbols

1 Transmission case 3 Compound current 2-layer motor
MG1 1st motor generator
MG2 Second motor generator 4 First planetary gear 5 Second planetary gear 6 Third planetary gear
EC engine clutch
LB Low brake
HC high clutch
HLB High / Low Brake 11 Motor Controller 12 Engine Controller 13 Inverter 14 Battery 15 Engine

Claims (6)

It is mounted on a hybrid vehicle that has multiple combinations of engine and motor generator output states (control modes) that can achieve one output state to the output shaft, and the vehicle speed, the driver's required driving force (driving force), the battery In the method of creating a mode map that sets the control mode according to the operating point determined by the state of charge (SOC),
A control mode selection step for selecting a control mode achievable at the driving point determined by the vehicle speed and driving force regardless of the SOC;
A power balance calculation step for calculating a power balance for fuel consumption in each control mode selected in the control mode selection step;
A power function calculation step in which the maximum value of each power balance calculated in the power balance calculation step is a power function with respect to fuel consumption;
A driving efficiency function calculating step of calculating a driving efficiency function for fuel consumption from the power function;
From the power function and the drive efficiency function, a control mode function capable of obtaining a maximum power with respect to the drive efficiency is calculated, and a control mode function corresponding to the SOC is calculated based on the relationship between the drive efficiency and the SOC. A control mode function calculation step;
Modoma'-flops creation method comprising. A hybrid vehicle mode map created by the mode map creating method according to claim 1 . The mode map creation method according to claim 1,
The hybrid vehicle
A first planetary gear having a first sun gear, a first carrier, a first ring gear;
A second planetary gear having a second sun gear, a second carrier, a second ring gear;
A third planetary gear having a third sun gear, a third carrier, a third ring gear;
A first rotating member connecting the second carrier and the third ring gear;
A second rotating member connecting the first ring gear and the third sun gear;
A third rotating member connecting the first sun gear and the second sun gear;
A first motor generator coupled to the second ring gear;
A second motor generator coupled to the third rotating member;
A first clutch that connects and disconnects the third rotating member and the first carrier;
A second clutch that connects and disconnects the first rotating member and the engine;
A first brake for connecting and disconnecting the first carrier and the fixing member;
A second brake for connecting and disconnecting the first motor generator and the fixing member;
The output shaft coupled to the third carrier;
Have
A mode map creation method, characterized in that the vehicle is a hybrid vehicle capable of achieving various output states (control modes) on an output shaft by a combination of engagement states of the first and second clutches and the first and second brakes.

The hybrid vehicle mode map created by the mode map creation method according to claim 3 is set, and the first clutch, the second clutch, and the first brake are engaged, and the second brake is released. The mode region for the control mode (2nd mode) is a hybrid vehicle mode map characterized in that the higher the SOC, the lower the vehicle speed and the lower the driving force side. 4. A mode map for a hybrid vehicle created by the mode map creating method according to claim 3 , wherein the first clutch, the second clutch, and the second brake are engaged, and the first brake is released. The mode area for the control mode (High mode) is a hybrid vehicle mode map characterized in that the higher the SOC, the lower the vehicle speed side. In the hybrid vehicle mode map according to claim 4 and / or claim 5 ,
A hybrid vehicle mode map using a control mode other than the 2nd mode and the High mode when the SOC is equal to or higher than a predetermined value representing a high state.

Images