JP2005163718A - Controller for hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve energy efficiency when it is required to drive an engine for small demand load when a hybrid vehicle stops in the hybrid vehicle. <P>SOLUTION: This controller for the hybrid vehicle is provided with an operation mode switching means 51 for switching the engine to highly efficient low output/highly efficient operation in a low output zone and normal operation, a generator 13 driven by the engine 3, a driving motor 9 for rotating and driving a driving shaft on one side of the vehicle, a clutch 5 provided in a transmission path of output of the engine 3, a battery 10 charged by the generator 13 and supplying electric power to the driving motor 9 and auxiliary machinery, a driving control means 50 for connecting the clutch 5 under the opertion condition that it is required to transmit engine output to a driving wheel and releasing it in a case other than it, and a cylinder number control means 51 for halting operation of a cylinder in a part of the engine and operating remaining cylinders by low output/highly efficient operation when demand load of the engine is a first predetermined value equivalent to slight load or less when releasing the clutch 5 so that engine output becomes output corresponding to the demand load. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an improvement of a control device for a hybrid vehicle.

  A hybrid vehicle that performs so-called idle stop that stops the operation of the engine, such as when the vehicle temporarily stops, is known from Patent Document 1.

  When it is necessary to supply power to the auxiliary machine during the idle stop, power is supplied from the battery. However, if the battery capacity falls below the specified value at this time, even if the power consumption required by the auxiliary equipment is small, the engine is started, the generator is driven in a low load state, and the battery is being charged. , Supplying power to auxiliary equipment.

Note that Patent Document 2 discloses that in a gasoline engine, during low-load operation, the operation mode is switched from a normal Otto cycle to a mirror cycle to improve thermal efficiency.
Japanese Patent Laid-Open No. 11-332011 JP-A-9-166030

  However, in the case of the hybrid vehicle, since the engine is driven with an output corresponding to a small auxiliary electric load, the fuel efficiency of the engine is not good, and even if the surplus power is stored, the entire system as a hybrid vehicle The energy efficiency of this will decrease.

  The present invention has been proposed to solve such problems, and in a hybrid vehicle, it is intended to improve energy efficiency when it is necessary to drive an engine against a small required load when the vehicle is stopped. Objective.

  A control apparatus for a hybrid vehicle according to the present invention includes an engine having a plurality of cylinders, and an operation mode switching means capable of switching an operation mode of the engine to a low output / high efficiency operation with high efficiency in a low output range and a normal operation. A generator driven by the engine, a drive motor that rotationally drives one drive shaft of the vehicle, and a path that transmits the output of the engine to the other drive shaft of the vehicle or the drive motor. And a power storage device that is charged by the generator and supplies electric power to the drive motor and vehicle auxiliary equipment. Then, the clutch is connected under an operating condition in which the engine output needs to be transmitted to the drive wheels, and the clutch is disengaged in other cases, and the required load of the engine when the clutch is disengaged corresponds to a light load. If it is less than the value, the number of cylinders is controlled so that the operation of some cylinders of the engine is stopped and the remaining cylinders are operated at a low output and high efficiency operation so that the engine output becomes an output corresponding to the required load. Do the driving.

  Therefore, in the present invention, when the vehicle is stopped with the clutch released, for example, when it is necessary to drive the engine to supply power to an auxiliary machine, the operation is performed with only some of the cylinders. And in a cylinder that operates at this time, unlike normal operation, switching to operation with low output but high efficiency enables high efficiency operation with extremely low load without imposing a burden on the power storage device, The energy efficiency of the entire system can be increased.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  1 and 2 show a hybrid vehicle drive system to which the present invention is applied. FIG. 1 shows a front-wheel drive type, and FIG. 2 shows a front-wheel drive type.

  In FIG. 1, 1 is a front wheel of the vehicle, and 2 is a rear wheel. Reference numeral 3 denotes an engine that drives the vehicle as a driving source of the vehicle or drives a generator 13 to be described later for power generation. 4 is a stepped or continuously variable transmission, and a clutch 5 for selectively interrupting transmission of power is interposed between the engine 3 and the transmission 4. The output side of the transmission 4 is connected to an axle on the front wheel 1 side via a differential gear 7. Therefore, by connecting the clutch 5, the output of the engine 1 is transmitted to the front wheels 1 via the transmission 4, and the front wheels 1 are driven.

  The output of the drive motor 9 is transmitted to the axle on the rear wheel 2 side via the differential gear 8. As will be described later, the drive motor 9 receives power supplied from the battery 10 and drives the rear wheel 2.

  The output of the engine 3 is also transmitted to the auxiliary machine 12 and the generator 13 via the electromagnetic clutch 11. When the electromagnetic clutch 11 is off, power transmission from the engine 3 is cut off.

  In contrast, in FIG. 2, a drive motor 9 is connected in series to the transmission 4, and the axle of the front wheel 1 is connected to the output side of the drive motor 9 via the differential gear 7, and the outputs of the engine 3 and the drive motor 9 are connected. Are transmitted to the front wheel 1 together.

  However, the outputs of the engine 3 and the drive motor 9 are not transmitted to the rear wheels 2, and in this case, the vehicle is a front wheel drive type.

  The present invention can be applied to any of these types of hybrid drive systems shown in FIGS.

  FIG. 3 shows the configuration of the engine 3. As an example, an in-line four-cylinder engine of # 1 cylinder to # 4 cylinder is shown. However, the present invention is not limited to a four-cylinder engine, and can be applied to other multi-cylinder engines, for example, various types of engines including two-cylinder, six-cylinder, and eight-cylinder.

  The engine 3 is an engine capable of switching the operation mode between normal operation and low-power / high-efficiency operation. Specifically, the premixed compression self-ignition (hereinafter also referred to as HCCI), premixed spark, and the like. It is an engine capable of switching the combustion state between ignition (hereinafter also referred to as SI).

FIG. 9 shows the thermal efficiency-power ratio characteristic of the engine 3 applied to the present invention. HCCI combustion is performed in the region of the output ratio of about 10 to 25% in the figure, and SI combustion is performed in other parts. That is, the convex portion in the curve corresponds to HCCI combustion, and when only SI combustion is performed without performing HCCI combustion, a smooth curve having no convex portion is obtained.
Here, since HCCI combustion is a well-known technique, a detailed description thereof will be omitted. However, in HCCI combustion, self-ignition is performed using the in-cylinder pressure of the engine, so that spark ignition combustion that starts combustion from one point is performed. In comparison, since combustion is started at a plurality of locations, it is not necessary to propagate the combustion, combustion at a lean air-fuel ratio is possible, and thermal efficiency is dramatically improved. However, in order to perform HCCI combustion, it is necessary to adjust the in-cylinder temperature, the in-cylinder pressure, the air-fuel ratio, and the like to the optimum conditions for self-ignition. Although the HCCI fuel region can be moved and expanded depending on the engine design, the HCCI combustion region is generally very narrow. In the engine 3 applied to the present invention, the region where HCCI combustion is possible is set to a range of 10 to 25% as described above, but this is set by avoiding the vicinity of idling that cannot be used for running. This is the result of making combustion possible to use as much as possible. In addition, switching from SI combustion to HCCI combustion requires that the in-cylinder temperature, in-cylinder pressure, air-fuel ratio, and the like be changed instantaneously, which may deteriorate drivability. Therefore, in the present invention, as will be described later, HCCI combustion is performed only when the clutch is released, such as when the engine 3 is idle-stopped when the vehicle is temporarily stopped, or when the vehicle is running with only the motor. By doing so, the influence on drivability is avoided.

  The intake manifold 30 is provided with a fuel injection valve 32 corresponding to each cylinder in each branch, and injects fuel supplied to each cylinder into the intake air. A three-way catalyst 33 for purifying exhaust gas is attached to the exhaust manifold 31, an air-fuel ratio sensor 34 for detecting the exhaust air-fuel ratio is upstream of the three-way catalyst 33, and oxygen in the exhaust gas is downstream. Each of the oxygen sensors 35 for detecting the concentration is attached. Based on these sensor outputs, feedback control is performed so that the amount of fuel injected from the fuel injection valve 32 matches the target value.

  Reference numeral 36 denotes a temperature sensor for detecting the temperature of the three-way catalyst 33. As will be described later, when the catalyst temperature is low, the execution of the HCCI combustion is stopped, and the exhaust gas temperature is increased by SI combustion to activate the catalyst. To maintain.

  FIG. 4 shows a control system of the hybrid vehicle as a block diagram (however, corresponding to the configuration of FIG. 1), and an engine controller (also referred to as an ECU) 51 is provided to control the engine 3. Various signals representative of the operating state of the engine 3, an air amount sensor signal, a rotation speed sensor signal, a knock sensor signal, a water temperature sensor signal, an oil temperature sensor signal, and the like are input to the ECU 51, and will be described later based on these signals. The operation of the engine 3 is controlled.

  The generator 13 that is driven by the power from the engine 3 to generate power is controlled in power generation torque by vector control from the generator controller 52.

  In the transmission 4, the operating hydraulic pressure is controlled by the transmission controller 53, and the gear position is switched according to this, and a transmission completion signal, a rotation speed, a control hydraulic pressure, and other signals are transmitted from the transmission 4. As the transmission 4, an automatic transmission, an automatic mechanical transmission, a continuous transmission, or the like can be used.

  The clutch 5 can be a wet clutch, a dry clutch, an electromagnetic clutch, or the like, and is set to a capacity that can sufficiently transmit the output torque of the engine 3. The operation of the clutch 5 is, for example, from the transmission controller 53. Control by signal.

  As the drive motor 9 for driving the rear wheel 2 (or the front wheel 1), an embedded permanent magnet synchronous motor (IPM), a switch reluctance motor (SRM), or the like is used as a highly efficient motor. In addition to generating driving force for the vehicle, regenerative braking is performed as a generator during deceleration, braking, etc., and the inertia energy of the vehicle is recovered to generate power. In order to control the drive motor 9, a motor controller 54 is provided, and the drive motor 9 is vector-controlled during driving or braking.

  The battery 10 supplies electric power to the drive motor 9 to generate running torque, and is charged by the generated power of the generator 13 and the drive motor (as a generator) 9. The battery controller 55 controls the output of the battery 10. A voltage signal and a current signal are sent from the battery 10 to the battery controller 55, and the battery output is adjusted based on these signals. However, it is desirable that the power consumed by the drive motor 9 is as much as possible covered by the power generated by the generator 13, and the generator controller 52 controls the power generation amount of the generator 13 according to the required load of the drive motor 9, At this time, surplus power is charged in the battery 10, and the shortage of power is supplied (discharged) from the battery 10.

  As the battery 10, a nickel metal hydride battery, a lithium ion battery, a capacitor, or the like is used. The battery controller 55 integrates the electric power calculated from the voltage and current of the battery 10, divides the integrated electric power value by the battery capacity, calculates the battery charge state (referred to as SOC), and will be described later based on this SOC. The amount of power generated by the generator 13 is controlled by a signal from the hybrid controller 50.

  Further, an auxiliary machine controller 56 is provided, and controls driving of auxiliary machines such as the air conditioner 25 and the power steering 26 in addition to the auxiliary machine 12 driven directly by the engine 3 described above.

  In addition, a hydraulic controller 57 is provided to control the braking hydraulic pressure supplied to the braking devices 21 and 22 of the front wheel 1 and the rear wheel 2 during braking, and the hydraulic controller 57 is also controlled by a control signal from the hybrid controller 50. Operation is controlled.

  Then, the hybrid controller 50 comprehensively performs the operations of the engine controller 51, the generator controller 52, the transmission controller 53, the motor controller 54, the battery controller 55, the auxiliary machine controller 56, and the hydraulic controller 57 according to the operating state. Control appropriately in an integrated manner.

  Basically, the hybrid controller 50 drives the vehicle by driving only the drive motor 9 in an area where the driving load and the vehicle speed of the vehicle are low, for example. Connected, the output of the engine 3 is transmitted to the wheel side via the transmission 4, and the driving force of the engine 3 is added to the drive motor 9 to drive the vehicle, or the vehicle is driven only by the engine 3 and driven. When the motor 9 travels, the generator 3 is driven by the engine 3 to generate electric power. At this time, when the generator 13 generates electric power consumed by the drive motor 9 and the battery 10 is insufficiently charged, The generator 13 is driven in order to appropriately charge the battery, and in this case, control is performed so that the engine 3 is operated in a state where fuel consumption is as good as possible.

  Of these, in the present invention, for example, when the vehicle is temporarily stopped, for example, when the required load of the engine 3 is small, power is consumed to drive the auxiliary machine, or the SOC of the battery 10 is predetermined. When it becomes necessary to operate the engine 3 at a very low load, such as when the value becomes lower than the value, the operation mode is changed from normal spark ignition (SI) combustion to premixed compression ignition for some cylinders of the engine 3. (HCCI) By switching to combustion and stopping the operation of the remaining cylinders, control is performed to minimize deterioration of fuel consumption while ensuring the required amount of engine load during HCCI combustion. There is. Here, simply considering the theoretical fuel consumption, it is possible to charge the power storage device with HCCI combustion in all cylinders, but the HCCI combustion region is set to a region that can be used for traveling. The output will be excessive with respect to the required power of the auxiliary equipment. Therefore, when considering the charge / discharge loss of the power storage device and the power storage capacity of the power storage device, it is desirable to output only the required power of the auxiliary machine with high efficiency. Therefore, in the present invention, some cylinders are deactivated so that the HCCI combustion can be used even in a lower load region for driving the auxiliary machine.

  Therefore, the engine controller 51 receives detection signals such as a brake sensor 41 that detects the operation of the brake pedal, a vehicle speed sensor 42 that detects the vehicle speed of the vehicle, and an accelerator opening sensor 43 that detects the operation of the accelerator pedal. Then, when the engine controller 51 determines the stop state of the vehicle based on these, the clutch 5 is released to perform the idle stop control, and further, the battery charge state and the auxiliary devices sent via the hybrid controller 50 are transmitted. Based on a signal such as the driving state, the operation mode switching of the engine 3 and the cylinder deactivation control are executed.

  Here, engine operation mode switching and cylinder deactivation control will be described according to the flowcharts shown in FIGS. Note that the following control flow is all calculated every certain time (for example, 10 msec). The predetermined value in the control flow has a hysteresis.

  First, FIG. 5 shows a main flow of engine cylinder deactivation control, which will be described.

  In step S1-1, the connected state of the clutch 5 is read. If the clutch 5 is not in the connected state in step S1-2, the process proceeds to step S1-3 and the subsequent steps. If the clutch 5 is in the connected state, the process proceeds to step S1-9. Then, the load following mode, which is a normal operation, is executed. In addition, although this load follow-up mode is demonstrated later, it is a mode which transfers when the output from the drive motor 9 is requested | required with the engine 3 independently, and the electric power generation amount according to the motor load to the generator 13 The engine 3 is controlled by ordinary spark ignition (SI) combustion. Therefore, it is possible to avoid deterioration of operability due to switching between HCCI combustion and SI combustion.

  When the clutch 5 is not connected, the required load of the engine 3 is calculated and read in step S1-3. In this case, the calculated load value is calculated based on the auxiliary machine load and each output of the drive motor 9.

  The clutch 5 is released, for example, when the engine 3 is idle-stopped when the vehicle is temporarily stopped, or when the output of the engine 3 is not required for traveling of the vehicle. A determination is made based on the operating conditions, and the clutch 5 is controlled.

  In step S1-4, the calculated load value of the engine 3 is compared with the predetermined value Lux. If the calculated load value is smaller than Lux, the process proceeds to step S1-5 to read the battery SOC. Shifts to step S1-9 to control the engine 3 in the load following mode as described above.

  Here, Laux is a load value equivalent to the auxiliary machine load, and by determining whether the engine load request is a load smaller than this Laux, it is less than the minimum output when HCCI combustion is performed on all the cylinders of the engine. We are monitoring whether it is okay. That is, HCCI combustion is performed when the load request can be met by the generated output in HCCI combustion, and when the load request is larger than this, a higher output can be generated by SI combustion.

  In step S1-6, the battery state of charge SOC is compared with the prescribed value Schg. If it is smaller than Schg, the routine proceeds to step S1-7, where HCCI combustion is performed in all cylinders of the engine. Drive 3 Note that all cylinder HCCI combustion is performed because engine friction loss is taken into consideration, so that the battery can be charged without excess or deficiency. Thereafter, the process returns to the start and the above operation is repeated.

  In HCCI combustion, as shown in FIG. 9, in a region where the engine output ratio is small, the thermal efficiency is very high, and therefore the engine 3 can be operated with good fuel efficiency even if the output itself is small.

  In this case, the battery charging mode is continued until the load calculation value becomes greater than or equal to Lux in step S1-4 or the battery SOC becomes greater than or equal to the specified value Schg.

  On the other hand, when the battery SOC is larger than the specified value Schg in step S1-6, the process proceeds to step S1-11 and the load calculation value is compared with a predetermined value Laux-min.

  Here, when the load request is smaller than the predetermined value Laux-min, the routine proceeds to step S1-13, the operation of all the engine cylinders is stopped, and the idle stop state is set. The predetermined value Laux-min corresponds to the engine output when the load request is only a relatively light electrical load (auxiliary load) such as a vehicle lamp, for example, and only one cylinder is subjected to HCCI combustion. In this case, since the battery 10 is also in a predetermined charging state at this time, even if the engine 3 is idle-stopped, the load request of the auxiliary machine can be satisfied by the power supply from the battery 10.

  When considering the hybrid drive system as a whole, it is preferable to avoid unnecessary charging of the battery 10 and to run the engine only at maximum efficiency. However, when the load demand is small and the engine is set to the minimum output in the low output / high efficiency operation and there is surplus power, and the battery SOC is sufficient, the engine 3 is completely stopped and the idle stop is stopped. Do it.

  In this case, after step S1-13, the process returns to the start. Here, in the resting state of all the cylinders of the engine, the load demand exceeds Laux (step S1-4), the SOC decreases below the specified value Schg (step S1-6), and the auxiliary machine load increases (step S1-). Continue unless changes such as 11) occur.

  If the load calculation value is equal to or greater than Lux-min in step S1-11, the process proceeds to step S1-12 to execute an auxiliary machine drive mode described later. In this auxiliary machine drive mode, the engine is not all cylinders deactivated, but it is an extremely low load operation region in which output until all cylinders HCCI combustion is not required, only some cylinders perform HCCI combustion, and other cylinders deactivate. To control.

  Therefore, when the load request is equal to or less than the load value Laux (minimum output due to all cylinders HCCI combustion) and the load value Laux-min, the accessory drive mode is executed when the battery SOC is equal to or greater than the specified value Schg. become.

  Here, the control of the accessory drive mode will be described with reference to the flowchart of FIG.

  First, in step S2-1, a variable i relating to the number of engine cylinders is set to zero. The variable i corresponds to the number of cylinders to be operated. When the maximum number of cylinders is used, i = 4 (in the case of a four-cylinder engine).

  In step S2-2, it is determined whether the variable i matches the maximum number of cylinders. If they match, all four cylinders are already in operation, so the process proceeds to step S2-6 to operate in the load following mode and return to the start of FIG. On the other hand, if they do not match, the process proceeds to step S2-3 to calculate an estimated engine output value when some cylinders are deactivated. The estimated engine value is calculated by the following equation (1).

Estimated engine output = (HCCI region maximum output + HCCI region minimum output) × (1/2) × (number of cylinders i) × friction coefficient (1)
Since the number of cylinders is always zero at the first time of the control loop, the actual calculation starts from the second week loop.

  The friction coefficient is mapped from the relationship between the number of cylinders and the friction loss.

  Proceeding to step S2-4, the number of cylinders i at which the estimated engine output value obtained by the equation (1) is equal to or greater than the auxiliary load Laux is obtained.

  This is to obtain the number of cylinders capable of HCCI combustion, to reduce the friction loss by reducing the number of idle cylinders as much as possible, and to minimize the amount of charge stored in the battery 10 and to convert the burden on the battery 10 and conversion. This is to minimize the loss.

  If the condition of step S2-4 is not satisfied, the process proceeds to step S2-5, 1 is added to the number i of cylinders for HCCI combustion, the process returns to step S2-2 again, and the above operation is repeated.

  When the engine output satisfies this condition in step S2-4, the process proceeds to step S2-8, and the number i of cylinders at that time is adopted as the number of cylinders for HCCI combustion. In step S2-9, the number of stopped cylinders is set to the number of stopped cylinders obtained by subtracting the number of HCCI combustion cylinders i obtained in step S2-8 from the maximum number of cylinders.

  Next, the process proceeds to step S2-10, and cylinder deactivation control, that is, control for stopping the operation of the cylinder by stopping the supply of fuel to the specific cylinder is performed. Thereafter, the process returns to the start of FIG.

  Next, cylinder deactivation control will be described with reference to the flowchart shown in FIG.

  In step S3-1, the operations from step S3-1 to step S3-5 are repeated until the number of cylinders to be deactivated obtained in step S2-9 described above becomes the number of deactivated cylinders = k.

  In step S3-2, the crank angle is detected. The crank angle is obtained from the output of an engine speed sensor (crank angle sensor), for example. In step S3-3, a cylinder in the exhaust stroke is detected from the obtained crank angle. In step S3-4, in order to stop the fuel supply to the detected cylinder in the exhaust stroke, the operation of the fuel injection valve 32 of the cylinder in the exhaust stroke is prohibited, that is, the fuel injection is stopped.

  In step S3-5, the number k of cylinders deactivated is incremented by 1, and k = k + 1.

  When the target number of cylinders to be deactivated is deactivated in step S3-1, the process returns to the start of FIG.

  Finally, the load following mode will be described with reference to the flowchart of FIG.

  In this flow, the engine combustion mode is switched in accordance with the required load of the engine. In step S4-1, the accelerator pedal opening APO is read. In step S4-2, the output required for the engine 3 is calculated.

  In the load follow mode at the upper stage of step S4-2, the engine output corresponding to the accelerator opening is read with reference to, for example, a map defined from the relationship with the accelerator opening. In the lower battery charging mode, the engine output is obtained by adding the output required according to the accelerator opening and the output acceptable by the battery. In this case as well, it can be defined in advance in a map or the like from the relationship with the amount of battery charge that can be received by the battery.

  Next, in step S4-3, the catalyst temperature of the three-way catalyst 33 is compared with a predetermined value Tcat. If the catalyst temperature is higher than the predetermined value, it is assumed that HCCI combustion with low engine output is possible, and step S4- Go to 4.

  In step S4-4, it is determined whether or not the requested engine output is within the output range of HCCI combustion. That is, it is determined whether the output is between the maximum output Lhccih and the minimum output Lhccil in HCCI combustion. If the output is not within this range, the process proceeds to step S4-5, and the engine 3 is set to SI combustion for all cylinders. To control. Then, after all cylinders have shifted to SI combustion, the clutch 5 is brought into an engaged (engaged) state in step S4-6, and the process returns to the start of FIG.

  On the other hand, if it is determined in step S4-4 that the requested engine output is within the output range of HCCI combustion, the process proceeds to step S4-8, where all the cylinders of the engine 3 are HCCI-combusted and burned. Return to start.

  In step S4-3, if the catalyst temperature is equal to or lower than the predetermined value Tcat, the HCCI combustion is not performed in order to maintain the activity of the three-way catalyst 33, and the process proceeds to step S4-5 to perform SI combustion. Increase catalyst temperature.

  Next, the overall operation will be described.

  In an operating region where the required load of the engine 3 is small, for example, when the vehicle is temporarily stopped, the operation mode of the engine 3 is changed from normal SI combustion to HCCI in a state where the clutch 5 is released and the engine 3 is disconnected from the drive system. Switching to combustion is performed, and fuel supply to some cylinders is stopped according to the required load.

  Although HCCI combustion has a low output, it has excellent thermal efficiency, and therefore the fuel consumption of the engine 3 is very good. In addition, since the operation of some cylinders is suspended according to the required load at that time, the number of deactivated cylinders increases as the required load decreases.

  Further, in a smaller region where the engine required load is only an electric load such as a vehicle lighting, the engine 3 is completely stopped when the state of charge of the battery 10 is equal to or higher than a specified value, Power is supplied.

  When the required load becomes large, such as when the driving force of the engine 3 is required depending on the driving conditions of the vehicle, the operation mode is switched from HCCI combustion to SI combustion, and therefore an output corresponding to the load request can be generated.

  As described above, according to the present embodiment, when the required load of the engine 3 is a light load corresponding to an auxiliary machine load or the like, such as during idling stop with the clutch 5 released, some cylinders of the engine 3 By switching the remaining cylinders to low power / high efficiency operation, the battery 10 is not burdened, that is, without increasing the size of the battery 10, efficient operation at an extremely low load can be achieved. This can improve the fuel efficiency of the entire system.

  By making HCCI combustion, that is, premixed compression self-ignition combustion, low-power and high-efficiency operation, noise and vibration can be reduced, and even if the engine is operated during the so-called idle stop, the driver feels uncomfortable. Less is.

  In addition, when the engine demand load is smaller, the number of cylinders to be deactivated is increased according to the demand load, so that fuel efficiency can be reliably improved even in a low load area where deterioration of fuel efficiency is unavoidable. .

  In addition, when the battery 10 is in a predetermined charged state, when the engine required load is further reduced, power is supplied from the battery 10 to an auxiliary machine or the like to completely stop the operation of all the engine cylinders. The fuel economy can be further improved without forcing you to do so.

  Further, when the battery 10 is charged, if the engine demand load is small due to other auxiliary machines or the like, the battery can be charged efficiently by performing HCCI combustion for all cylinders.

  Further, during idle stop, when the accelerator pedal is depressed, there is a start request, and the engine required load increases, the engine 5 shifts to SI combustion before the clutch 5 is connected. The torque pulsation at the time of return from the engine and the torque pulsation accompanying the switching from the HCCI combustion to the SI combustion are not transmitted to the drive shaft, and the drivability at the time of starting from the vehicle stopped state is not impaired.

  On the other hand, when it is determined that the temperature of the three-way catalyst 33 installed in the exhaust system may be lower than the activation temperature, the operation by HCCI combustion is prohibited and the exhaust gas temperature is raised by returning to SI combustion. The catalytic function is maintained by the activation of the three-way catalyst 33.

  In the above description, when the engine is operated at an extremely low load, since HCCI combustion has a relatively low output and a low rotation speed, it is exemplified as a preferred embodiment with less uncomfortable feeling while the vehicle is stopped. The maximum efficiency in SI combustion may be used, or the engine that can use both the Atkinson cycle and the Otto cycle uses the Atkinson cycle with high thermal efficiency (although the output is relatively reduced). You may make it do.

  The present invention can be applied to a control device for a hybrid vehicle.

It is a block diagram which shows an example of the drive system in embodiment of this invention. It is a block diagram which similarly shows the other example of a drive system. It is a block diagram of an engine similarly. It is also a block diagram of the control system. It is a flowchart which shows control operation. It is a flowchart which shows control operation. It is a flowchart which shows control operation. It is a flowchart which shows control operation. It is explanatory drawing which shows the thermal efficiency of HCCI combustion.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Front wheel 2 Rear wheel 3 Engine 4 Transmission 5 Clutch 9 Drive motor 10 Battery 13 Generator 35 Three-way catalyst 50 Hybrid controller 51 Engine controller

Claims (11)

An engine having a plurality of cylinders;
An operation mode switching means capable of switching the operation mode of the engine between a low output and high efficiency operation with high efficiency in a low output range, and normal operation;
A generator driven by the engine;
A drive motor that rotationally drives one drive shaft of the vehicle;
A clutch interposed in a path for transmitting the output of the engine to the other drive shaft of the vehicle or the drive motor;
A power storage device that is charged by the generator and supplies electric power to the drive motor and auxiliary equipment of the vehicle;
Requested load detection means for detecting a load required for the engine in accordance with a running condition of the vehicle and a storage condition of the power storage device;
Drive control means for connecting the clutch under operating conditions where the engine output needs to be transmitted to the drive wheels, and releasing the clutch otherwise;
If the requested load of the engine is equal to or less than a first predetermined value corresponding to a light load when the clutch is released, the operation of some cylinders of the engine is performed so that the engine output becomes an output corresponding to the requested load. A control apparatus for a hybrid vehicle, comprising: a cylinder number control means for stopping and operating the remaining cylinders with low output and high efficiency operation.   The hybrid vehicle control device according to claim 1, wherein the drive control means releases a clutch when the vehicle stops.   The control apparatus for a hybrid vehicle according to claim 1 or 2, wherein the first predetermined value is a value corresponding to a minimum engine output when all the cylinders are operated at a low output and a high efficiency.   The control apparatus for a hybrid vehicle according to any one of claims 1 to 3, wherein the cylinder number control means reduces the number of cylinders to be stopped as the required load increases.   5. The cylinder number control means according to claim 4, wherein the number of cylinders to be deactivated is switched to normal operation when the number of cylinders to be deactivated becomes zero and the required load cannot be satisfied even when combustion in all cylinders is performed at low output and high efficiency. Control device for hybrid vehicle.   When the state of charge of the power storage device is equal to or greater than a specified value, and the engine required load is equal to or smaller than a second predetermined value that is smaller than the first predetermined value, the operation of all the cylinders of the engine is performed. The control apparatus of the hybrid vehicle as described in any one of Claims 1-4 stopped.   The control apparatus for a hybrid vehicle according to claim 6, wherein the second predetermined value is a value corresponding to a minimum engine output when at least one cylinder is operated at a low output and a high efficiency.   The cylinder number control means performs low output and high efficiency operation in all cylinders when the engine required load is equal to or less than the first predetermined value and the power storage amount of the power storage device is equal to or less than a specified value. Item 8. The hybrid vehicle control device according to any one of Items 1 to 7.   The low-power / high-efficiency operation is an operation by a combustion method by premixed compression self-ignition, and the normal operation is an operation by combustion by a premixed spark ignition type. Hybrid vehicle control device.   The hybrid according to claim 9, wherein the cylinder number control means prohibits the operation by the premixed compression self-ignition when it is determined that the temperature of the catalyst installed in the exhaust system may be lower than the activation temperature. Vehicle control device.   11. The hybrid vehicle control device according to claim 1, wherein when the clutch is connected, the drive control unit executes clutch connection after the operation mode switching unit switches to normal operation. 11. .

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