JP2006283634A - Engine control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an engine control device capable of opening and closing an intake control valve in proper timing. <P>SOLUTION: This engine control device has the intake control valve 23 arranged in an intake passage 11 on the upstream side of an intake valve 16, capable of closing the inside of the intake passage and openable-closable synchronously with opening-closing of the intake valve, a means 100 for opening the intake control valve in the middle of an intake stroke and closing the valve thereafter, a means 100 for determining a target value of the air volume flowing in a cylinder 12 after opening the intake control valve on the basis of an engine operation state, a pressure detecting means 55 for detecting pressure on the downstream of the intake control valve, a means 100 for estimating downstream side pressure on and after its detection on the basis of the downstream side pressure detected before opening the intake control valve, and a means 100 for determining a target value of the valve opening timing of the intake control valve on the basis of the estimated downstream side pressure and the target value of the air volume. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an engine control device, and more particularly to an engine control device capable of increasing the amount of air flowing into a cylinder by an intake control valve provided in an intake passage.

  An intake control valve that can close the intake passage and can be opened and closed in synchronization with the opening and closing of the intake valve is provided in the intake passage on the upstream side of the intake valve, and the intake control valve is opened instantly during the intake stroke. It is known that a larger amount of intake air is charged into a cylinder by utilizing the inertia supercharging effect or the pressure pulsation of the intake air (see, for example, Patent Document 1). Since the intake control valve can be opened and closed within one intake stroke, such supercharging can be started at the same time that the accelerator pedal is depressed, and is more responsive than turbocharging that waits for the start of the turbine. It is suitable for eliminating the acceleration delay. Further, since the intake air amount can be increased as compared with the case of natural intake, the torque generated by the engine can be increased.

JP 2000-248946 A

  By the way, in the engine control, a target air amount that is a target value of the air amount flowing into the cylinder is determined based on parameters representing the engine operation state such as the engine rotation speed and the accelerator opening, and the determined target air In some cases, the air amount is controlled so that the actual air amount matches the amount, and the fuel injection amount, fuel injection timing, ignition timing, and the like are set based on the target air amount. Generally, the actual air amount is made to coincide with the target air amount by controlling the opening of the intake throttle valve.

  On the other hand, when the intake control valve as described above is employed, the air amount is controlled by controlling the opening / closing timing of the intake control valve. Therefore, in order to obtain a desired air amount, it is necessary to open and close the intake control valve at an appropriate timing.

  Therefore, the present invention has been made in view of such circumstances, and an object thereof is to provide an engine control device capable of opening and closing an intake control valve at an appropriate timing.

  In order to achieve the above object, an engine control apparatus according to an aspect of the present invention is provided in an intake passage upstream of an intake valve, can close the intake passage, and is synchronized with opening and closing of the intake valve. An intake control valve that can be opened and closed, an intake control valve control means that opens the intake control valve during the intake stroke, and then closes the intake control valve; Target air amount determining means for determining a target value of the post-valve air amount flowing into the engine, pressure detecting means for detecting the pressure downstream of the intake control valve, and the pressure detection before opening the intake control valve Pressure estimation means for estimating downstream pressure after the detection based on the downstream pressure detected by the means, the downstream pressure estimated by the pressure estimation means, and the amount of air after opening. And opening the intake control valve based on the target value. Characterized in that a target opening timing determining means for determining a target value of the period.

  As a result of diligent research, the present inventors have determined that the intake control valve opening timing, the intake control valve opening period, the pressure on the downstream side of the intake control valve at the intake control valve opening timing, and the intake control valve It has been found that there is a close relationship between the amount of air flowing into the cylinder when the valve is opened (ie, the amount of air after valve opening). In general, when trying to increase the amount of inflow air, the pressure on the downstream side of the intake control valve is lowered (the differential pressure on the upstream and downstream sides of the intake control valve increases and the flow velocity at the time of valve opening increases), and therefore the valve opening timing It is effective to delay the valve (for the same reason) or to take an appropriate valve opening period (close the valve immediately before the air flows backward). This embodiment of the present invention has been made based on the knowledge of the present inventors. Such a relationship between the four parties can be replaced with a three-way relationship excluding the valve opening period by, for example, taking the maximum value of the air amount in each valve opening period. Thus, the target value of the valve opening timing can be determined based on the downstream pressure of the intake control valve and the target value of the air amount after the valve opening.

  Preferably, the pressure estimation means is based on at least one downstream pressure detected by the pressure detection means before the intake control valve is opened, and is downstream of the intake control valve after the final detection. It is characterized by estimating pressure.

  Preferably, the apparatus further comprises downstream pressure determining means for determining the downstream pressure at the target value of the valve opening timing based on the target value of the air amount and the target value of the valve opening timing. To do.

  Preferably, the target value for the valve opening period of the intake control valve is determined based on the target value for the valve opening timing, the downstream pressure at the target value for the valve opening timing, and the target value for the air amount. It further comprises target valve opening period determining means.

  Preferably, the target valve opening timing determining means and the target valve opening period determining means are based on a map in which a relationship between the post-valve air amount, the downstream pressure, the valve opening timing, and the valve opening period is determined in advance. And determining a target value of the valve opening timing and the valve opening period, respectively.

  Preferably, based on the valve opening detecting means for detecting the actual opening of the intake control valve, the time when the actual valve opening is detected by the valve opening detecting means, and the target value of the valve opening period, And a target valve closing timing determining means for determining a target value of the valve closing timing of the intake control valve.

  There is a time lag between the target valve opening timing and target valve closing timing and the actual valve opening timing and valve closing timing, and this time lag varies due to various factors. This variation causes variations in the intake air amount. According to such a configuration, since the target valve closing timing is calculated from the actual valve opening timing, the variation in the time lag from the target valve opening timing to the actual valve opening timing can be ignored, and the cause of the variation can be reduced to reduce the air The amount variation can be suppressed.

  Preferably, the intake control valve control means detects an actual valve closing when the intake control valve is closed at a target value of the valve closing timing determined by the target valve closing timing determination means. An actual opening period for determining an actual valve opening period of the intake control valve based on a detection means, a timing when the actual valve closing is detected by the valve closing detection means, and a timing when the actual valve opening is detected; The pressure detection at the valve period determining means, the actual valve opening period determined by the actual valve opening period determining means, the time when the actual valve opening is detected, and the time when the actual valve opening is detected An actual air amount estimating means for estimating an actual air amount based on the downstream pressure detected by the means is further provided.

  Preferably, the apparatus further comprises control amount determining means for determining a control amount based on the actual air amount estimated by the actual air amount estimating means.

  This control amount is, for example, at least one of a fuel injection amount, a fuel injection timing, and an ignition timing.

  An engine control apparatus according to another embodiment of the present invention is provided in an intake passage upstream of an intake valve, and is capable of closing the intake passage and opening and closing in synchronization with opening and closing of the intake valve. A control valve, an intake control valve control means for opening the intake control valve during the intake stroke, and then closing the intake valve; and an opening that flows into the cylinder after the intake control valve is opened based on the engine operating state. Target air amount determining means for determining a target value of the post-valve air amount, pressure detecting means for detecting the pressure downstream of the intake control valve, and detected by the pressure detecting means before the intake control valve is opened. Pressure estimation means for estimating the downstream pressure after the detection based on the downstream pressure, the downstream pressure estimated by the pressure estimation means, and a target value of the post-valve air amount, Based on the target value of the opening timing of the intake control valve Target valve opening timing determining means to determine; target value of the valve opening timing determined by the target valve opening timing determining means; the downstream pressure at the target value of the valve opening timing; and the air amount after valve opening And a target valve opening period determining means for determining a target value for the valve opening period of the intake control valve based on the target value of the intake control valve, and the intake control valve control means for opening the intake control valve at the target value of the valve opening timing. Based on the valve opening detecting means for detecting the actual opening of the intake control valve when the valve is opened, the time when the actual valve opening is detected by the valve opening detecting means, and the target value of the valve opening period And target valve closing timing determining means for determining a target value of the valve closing timing of the intake control valve.

  Preferably, the target air amount determination means determines a target value of the air amount based on an engine operating state, and an opening that flows into the cylinder from the target value of the air amount before the intake control valve is opened. The target value of the post-valve air amount is determined by subtracting the estimated value of the pre-valve air amount.

  Preferably, the target air amount determining means estimates the air amount before opening based on at least two downstream pressures detected by the pressure detecting means before opening the intake control valve. Features.

  Preferably, at least one of the at least two downstream pressures is a downstream pressure detected by the pressure detecting means before the intake valve is opened.

  According to the present invention, an excellent effect that the intake control valve can be opened and closed at an appropriate timing is exhibited.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.
FIG. 1 schematically shows a configuration of an engine control apparatus according to the present embodiment. In the present embodiment, the engine 1 is a vehicular multi-cylinder gasoline engine (only one cylinder is shown in the figure), and fuel made of gasoline is directly injected from the injector 10 into the combustion chamber 13 in the cylinder 12 and formed thereby. The air-fuel mixture is ignited by the spark plug 14 and exhaust gas is discharged through the exhaust passage 17.

  Thus, the engine is a so-called direct injection type, and can perform the following stratified combustion. That is, the fuel is injected from the injector 10 into the concave portion 40 provided on the top surface portion of the piston 24 while the piston 24 is raised, and the flow of the tumble fuel spray that rolls up along the inner surface of the concave portion 40. In the process of generating the fuel, air and fuel are mixed, and a relatively rich air-fuel mixture layer is formed in the vicinity of the spark plug 14, and a relatively lean air-fuel mixture layer is formed around the rich air-fuel mixture layer. Is done. Thus, the air-fuel mixture is stratified and stratified combustion is realized. According to the stratified combustion, while making the air-fuel ratio of the entire combustion chamber much leaner than the stoichiometric air-fuel ratio, reliable ignition combustion can be ensured and fuel efficiency can be greatly improved. The engine can also perform combustion other than lean combustion, such as stoichiometric combustion in which the air-fuel ratio of the entire combustion chamber is substantially the stoichiometric air-fuel ratio.

  As is known, the intake passage 11 is defined by an intake pipe 47, an intake manifold 43, and an intake port 15 connected in order from the upstream side. The intake manifold 43 has a surge tank 48 as a confluence portion common to each cylinder and a branch pipe 49 for each cylinder. The outlet of the intake port 15 is opened and closed by the intake valve 16. As is known, the exhaust passage 17 is defined by an exhaust port 19, an exhaust manifold 50, a catalyst 18, and an exhaust pipe 51 connected in order from the upstream side. The inlet of the exhaust port 19 is opened and closed by the exhaust valve 20. In the present embodiment, the intake valve 16 and the exhaust valve 20 are mechanically opened and closed at a constant cycle by a camshaft (not shown) that is rotationally driven by the crankshaft 26 at a cycle that is (1/2) times that of the crankshaft 26. However, the valve opening timing and the valve opening period may be controlled according to the engine operating state by a variable valve timing mechanism, an actuator, or the like. In this embodiment, the overlap is set between the valve opening periods of the intake valve 16 and the exhaust valve 20, but this may not be necessary. The catalyst 18 is provided in the middle of the exhaust pipe to remove harmful substances such as CO, HC, NOx in the exhaust gas.

  The intake passage 11 is provided with an air flow meter 21, an intake throttle valve 22, and an intake control valve 23 in order from the upstream side. The air flow meter 21 outputs a signal corresponding to the air flow rate passing through the air flow meter 21 to an electronic control unit (hereinafter referred to as ECU) 100 as a control means. The ECU 100 calculates the amount of air as an estimated value that actually flows into the cylinder based on the detected value of the air flow meter 21. Note that the inflow air amount may be calculated based on the intake pressure detected by the intake pressure sensor 41. The intake throttle valve 22 can be controlled. In this embodiment, the intake throttle valve 22 is electrically operated, and its opening degree is controlled by the ECU 100. The intake control valve 23 will be described in detail later. As described above, the intake control valve 23 is provided on the upstream side of the intake valve 16, and the intake throttle valve 22 is provided on the upstream side of the intake control valve 23. An injector 10 is provided on the downstream side of the intake control valve 23.

  A piston 24 is accommodated in the cylinder 12 so as to reciprocate. The piston 24 is connected to the crankshaft 26 via a connecting rod 25.

  The electrical configuration of the engine control apparatus will be described. In addition to the injector 10, spark plug 14, air flow meter 21, intake throttle valve 22, intake control valve 23, the ECU 100 includes a crank angle sensor 28, an oxygen concentration sensor 29, an accelerator opening sensor 30, a brake switch 31, an intake valve. An atmospheric pressure sensor 41, an intake air temperature sensor 42, and a pressure sensor 55 are connected.

  The injector 10 is opened and closed based on an on / off signal output from the ECU 100, thereby executing and stopping fuel injection. The spark plug 14 emits a spark based on an ignition signal output from the ECU 100. The intake throttle valve 22 is in the form of a butterfly valve, and detects the valve element 37 disposed in the intake passage 11, an electric actuator 38 such as a rotary solenoid that drives the valve element 37, and the opening degree of the valve element 37. Sensor 39. The accelerator opening sensor 30 outputs to the ECU 100 a signal corresponding to the operation amount (depression amount) of the accelerator pedal by the driver.

  The crank angle sensor 28 outputs a pulse signal to the ECU 100 at predetermined angular intervals of the crankshaft 26. Based on this pulse signal, ECU 100 detects the crank angle and calculates the engine rotation speed. The oxygen concentration sensor 29 outputs a signal corresponding to the oxygen concentration in the exhaust gas to the ECU 100. The brake switch 31 outputs to the ECU 100 an on / off signal corresponding to the operation of the brake pedal 44 by the driver. It is on when the brake is activated.

  The intake pressure sensor 41 is provided in the intake passage 11 at a position downstream of the intake throttle valve 22 and upstream of the intake control valve 23 (hereinafter referred to as an “intake manifold passage 11a”). Is referred to as “in-manifold pressure”). The intake air temperature sensor 42 outputs a signal corresponding to the intake air temperature to the ECU 100. The pressure sensor 55 is provided in the intake passage 11 (hereinafter referred to as “port passage 11b”) at a position downstream of the intake control valve 23 and upstream of the intake valve 16, and the pressure at the position (hereinafter referred to as “port passage 11b”). A signal corresponding to “port pressure” is output to the ECU 100. A pressure sensor 55 having a high response is used. In the present embodiment, one intake pressure sensor 41 and one intake temperature sensor 42 are provided in each surge tank 48, and a pressure sensor 55 is provided for each cylinder, more specifically, for each branch pipe 49 of each cylinder.

  The intake control valve 23 is provided for each branch pipe 49 of each cylinder at a position upstream of the pressure sensor 55. The intake control valve 23 includes a valve body 33 disposed in the intake passage 11 (more specifically, the branch pipe 49), and an electric actuator 34 such as a rotary solenoid that drives the valve body 33. Further, the intake control valve 23 includes an opening degree sensor 54 that detects the opening degree of the valve element 33. The opening sensor 54 is preferably a non-contact type. The intake control valve 23 can close the inside of the intake passage 11. Unlike the intake throttle valve 22 in particular, the intake control valve 23 has a structure in which the intake passage 11 is hermetically closed when the valve is fully closed, and passage of intake air is blocked. On the other hand, the intake throttle valve 22 allows the intake air to pass only by restricting the intake passage 11 to the maximum when fully closed. Further, the electric actuator 34 of the intake control valve 23 can be operated at a much higher speed than the electric actuator 38 of the intake throttle valve 22 and has high responsiveness. Then, it can be opened and closed in the order of about 10 ° CA at an engine speed of 2000 rpm. Thereby, the intake control valve 23 can be opened and closed in synchronization with the opening and closing of the intake valve 16. In the present embodiment, the intake control valve 23 is in the form of a butterfly valve, but may be in another form such as a shutter valve.

  The opening degree of the intake control valve 23 is controlled from fully open to fully closed in accordance with an opening signal output from the ECU 100 to the electric actuator 34. The intake control valve 23 is provided for each cylinder. When each cylinder has a plurality of intake passages 11 (branch pipes 49), the intake control valve 23 is provided for each intake passage 11. The plurality of intake control valves 23 provided in this way can be individually controlled for each cylinder and for each intake passage 11.

  In the present embodiment, the intake control valve 23 is controlled in units of individual cylinders, and the opening degree is controlled only when the cylinders are fully opened or fully closed. In the present embodiment, when the intake control valve 23 is “open” or “closed”, it means “fully open” or “fully closed” of the intake control valve 23. Further, “full open” and “fully closed” do not necessarily mean mechanical full open and full close, but mean the degree of restriction to the passing air. For example, in the case of “full open”, mechanical full open Even if not, if there is no decrease in the flow rate of the passing air, it is in a fully open state. In the present embodiment, when the intake control valve 23 is “actuated”, it means that the intake control valve 23 is opened and closed during one cylinder cycle. When the intake control valve 23 is “non-actuated”, it is This means that the control valve 23 is held fully open.

  Next, setting of the valve opening timing and the valve opening period of the intake control valve 23 which is characteristic in the present embodiment will be described. Each map described below is created in advance through experiments and analysis and stored in the ECU 100.

  First, an outline of changes in pressure and air flow rate in the intake stroke when the intake control valve 23 is operated to perform the above-described inertia supercharging will be described with reference to FIG. In the figure, the opening degree of the intake control valve 23 when the crank angle advances, the port pressure on the downstream side of the intake control valve, the average value of the intake manifold pressure on the upstream side of the intake control valve (average intake manifold pressure), The transition of the flow rate (g / s) of the inflowing air is shown. CA_Po, CA_Pc, and CA_P_w represent the opening timing, closing timing, and opening period of the intake control valve 23, respectively. These opening timing and closing timing are respectively determined by the ECU 100 to the intake control valve 23. Is expressed as timing (target value). These have the relationship CA_Pc = CA_Po + CA_Pw.

  As shown in the figure, before the intake control valve 23 is opened, the port pressure gradually decreases as the piston 24 descends. When the intake control valve 23 is instantaneously opened at the valve opening timing CA_Po, air flows into the cylinder at once due to the differential pressure between the upstream side and the downstream side of the intake control valve formed just before that, and the inertia Supercharging is executed (see the part (Ga2)). At this time, the port pressure is higher than the average intake manifold pressure. When the intake control valve 23 and the intake valve 16 are closed in this state, the high pressure is held in the port passage 11b. When the intake valve 16 is opened in the next intake stroke, the air in the port passage 11b flows into the cylinder due to the high pressure and the negative pressure due to the lowering of the piston 24 (see the part (Ga1)). . When there is an overlap as in the present embodiment, this inflowing air scavenges exhaust gas (residual gas) remaining in the cylinder into the exhaust passage 17 and also partially blows out into the exhaust passage 17. Such an effect does not occur when there is no overlap.

  Among these, the intake air amount based on the main air inflow performed after the intake control valve opening in the latter half of the intake stroke is Ga2, and the intake air amount based on the air inflow performed before the intake control valve opening in the initial intake stroke is Ga1. It is. Hereinafter, these Ga2 and Ga1 are referred to as “the air amount after opening” and “the air amount before opening”, respectively. Late air inflow is due to inertial supercharging for increasing air volume, which is the original purpose. In addition, the air inflow in the previous period is intended to scavenge the residual gas in the cylinder to the exhaust system using the port pressure maintained from the previous intake stroke, and also increase the amount of air into the cylinder. . Since this initial inflow reaches about 20% of the total, it is also important to accurately estimate this amount.

  Next, the main routine for engine control in this embodiment will be described with reference to FIG. This main routine is executed by the ECU 100 for each cylinder and for each predetermined crank angle.

  First, in step S101, a target air amount Ga_trg, which is a target value of the air amount to be supplied to a certain cylinder, is calculated. Here, first, the engine rotational speed Ne and the accelerator opening degree Ac calculated and detected based on the output signals of the crank angle sensor 28 and the accelerator opening degree sensor 30 are acquired. Based on the accelerator opening degree Ac, a torque required for the engine, that is, a target torque Tt is determined. Naturally, the target torque Tt increases as the accelerator opening degree Ac increases. Next, based on the engine speed Ne and the target torque Tt, the target air amount Ga_trg is calculated using the target air amount map shown in FIG. Note that the target air amount Ga_trg, the pre-valve air amount Ga1, the post-valve air amount Ga2, and the like are the air amount (g / cylinder) that is taken into one engine cylinder in one intake stroke.

  Next, in step S102, it is determined whether or not the intake control valve 23 is in the operating range based on the target air amount Ga_trg and the engine rotational speed Ne that are parameters representing the engine operating state. This determination is made using an operating range map as shown in FIG. In this map, the entire area is divided into an operating area A and a non-operating area B. The operating area A exists on the low rotation side and the medium and high load side of the engine. When the engine operating state is in the operating range A, the intake control valve 23 is operated to increase the air amount. When the engine operating state is in the non-operating range B, the intake control valve 23 is deactivated. The boundary line between the operating area A and the non-operating area B is an area where the maximum air amount can be obtained when the intake control valve is not operating.

  When the values of the target air amount Ga_trg and the engine rotational speed Ne are in the operating range A, the process proceeds to step S103 and the operating flag is turned on. On the other hand, when it is not in the operation area A (that is, when it is in the non-operation area B), the process proceeds to step S104 and the operation flag is turned off. Thus, the presence or absence of the intake control valve operation request is determined based on the engine operating state.

  Next, it progresses to step S105 and it is determined whether an operation flag is ON. When it is off, the routine proceeds to step S119, where the intake control valve 23 is opened, the air amount Ga flowing into the cylinder is calculated based on the detected value of the air flow meter 21 at step S120, and then the routine proceeds to step S118. On the other hand, when it is on, the routine proceeds to step S106, where the pre-valve air amount Ga1 is estimated. The estimation of the pre-valve air amount Ga1 will be described later. Since this main routine is sequentially executed for each cylinder, at the start and end of the operation of the intake control valve 23, the air amount estimation based on the operation state of some cylinders (steps S106 to S117) and the rest The air amount is estimated based on the assumption that the cylinders in the non-operating state (step S120).

  After step S106, the process proceeds to step S107, and the target value of the air amount after opening (target air amount after opening) Ga2_trg is calculated by the formula: Ga2_trg = Ga_trg−Ga1.

  Next, the process proceeds to step S108, and by executing the control 1 described later, the target value (target valve opening timing) CA_Po of the valve opening timing of the intake control valve 23 and the target value (target valve opening period) CA_Pw of the valve opening period. Are calculated respectively.

  Next, in step S109, it is determined whether or not the actual crank angle detected by the crank angle sensor 28 is the target valve opening timing CA_Po.

  When the crank angle is the target valve opening timing CA_Po, the intake control valve 23 is opened in step S110. That is, a valve opening signal is output from the ECU 100 to the intake control valve 23. In step S111, the actual valve opening timing (actual valve opening timing) CA_Popen of the intake control valve 23 is detected and temporarily stored in the memory of the ECU 100. At the same time, the port pressure at the actual valve opening timing CA_Popen is detected by the pressure sensor 55, and is temporarily stored in the memory of the ECU 100 as P4. Thus, the process proceeds to step S112. On the other hand, if it is determined in step S109 that the crank angle is not the target valve opening timing CA_Po, steps S110 and S111 are skipped and the process proceeds to step S112.

  In step S112, a target value (target valve closing timing) CA_Pc of the valve closing timing of the intake control valve 23 is calculated by executing control 2 described later.

  In the next step S113, it is determined whether or not the actual crank angle detected by the crank angle sensor 28 is the target valve closing timing CA_Pc.

  When the crank angle is the target valve closing timing CA_Pc, the intake control valve 23 is closed in step S114. That is, a valve closing signal is output from the ECU 100 to the intake control valve 23. In step S115, the actual valve closing timing (actual valve closing timing) CA_Pclose of the intake control valve 23 is detected and temporarily stored in the memory of the ECU 100. Thus, the process proceeds to step S116. On the other hand, if it is determined in step S113 that the crank angle is not the target valve closing timing CA_Pc, steps S114 and S115 are skipped and the process proceeds to step S116.

  In step S116, the actual valve opening period CA_Pwidth is calculated by the formula: CA_Pwidth = CA_Pclose−CA_Popen, and after the valve opening based on the actual valve opening timing CA_Popen, the actual valve opening period CA_Pwidth, and the port pressure P4 at the actual valve opening timing CA_Popen. An air amount Ga2 is calculated. This will be described later.

  If the pre-valve air amount Ga1 and the post-valve air amount Ga2 are thus obtained, the process proceeds to step S117, where the actual and estimated air amount Ga is calculated by the formula: Ga = Ga1 + Ga2.

  Next, in step S118, the ignition timing Tigb is determined based on the air amount Ga with reference to the ignition timing map of FIG. This routine is completed as described above. Although only the case of the ignition timing has been described here as an example of the control amount, other control amounts such as the fuel injection amount and the fuel injection timing can be determined by the same method. The ECU 100 controls the spark plug 14 and the injector 10 of each cylinder based on these control amounts.

Details of the main routine will be described below.
First, the estimation of the pre-valve air amount Ga1 in step S106 will be described. The pre-valve air amount Ga1 can be estimated from a change in port pressure at timings before and after the intake valve is opened. Here, for simplicity, it is assumed that there is no overlap, and the amount of air flowing into the cylinder from the port passage 11b before opening the intake control valve is equal to the amount of air decreased from the port passage 11b. Since the volume of the port passage 11b is determined geometrically and is a known constant value, the volume of the port passage 11b is opened from the change in the air density in the port passage 11b from just before the intake valve 16 is opened to just before the intake control valve 23 is opened. The pre-valve air amount Ga1 can be estimated.

A decrease in port pressure when air flows into the cylinder from the port passage 11b can be regarded as an adiabatic change, and the change in density depends on the pressure P10 before the intake valve is opened, and after the intake valve is opened and the intake control valve is opened. The pressure P11 before the valve (see FIG. 7) is detected by the pressure sensor 55, and is obtained by the following equation.
ρ11 / ρ10 = (P10 / P11) ^ (− 1 / k) (1)

  Here, ρ10 and ρ11 are air densities when P10 and P11 are detected, respectively. These are called the density before opening the intake valve and the density before opening the intake control valve. k is a predetermined constant. The symbol “^” means power and the right side: (P10 / P11) ^ (− 1 / k) means (P10 / P11) to the power of (−1 / k) (the same applies hereinafter).

Therefore, the pre-valve air amount Ga1 flowing into the cylinder is calculated by the following equation.
Ga1 = V × (ρ10−ρ11) = V × ρ10 × (1- (P10 / P11) ^ (− 1 / k))
... (2)

Here, V is the volume of the port passage 11b.
The density ρ10 before opening the intake valve can be calculated from the intake air temperature and the intake manifold pressure. In the present embodiment, values detected by the intake air temperature sensor 42 and the intake pressure sensor 41 are used as the intake air temperature and the intake manifold pressure, respectively.

Therefore, the air amount Ga1 before opening can be calculated from the intake air temperature, the intake pressure, the pressure P10 before opening the intake valve and the pressure P11 before opening the intake control valve according to the equation (2). In the present embodiment, the ECU 100 performs such calculation to calculate the pre-valve air amount Ga1.
In the present embodiment, since there is an overlap, correction is performed in consideration of blow-through of the intake air during the overlap to the exhaust system. That is, the blow-through amount Ga_ex is calculated based on the pre-valve air amount Ga1 and using the blow-through amount map of FIG. The quantity Ga1 (= Ga1-Ga_ex) is calculated. In the map, Ga1max is the maximum value of the pre-valve air amount based on the cylinder volume at the time of overlap (this can be regarded as the intake top dead center). When there is no overlap, no intake air blow-in occurs, and thus such correction is omitted.

  Next, the control 1 for calculating the target valve opening timing CA_Po and the target valve opening period CA_Pw will be described with reference to FIG. In addition, since each timing etc. relevant to this control 1 are shown in FIG. 10, please refer suitably.

First, in step S201, it is determined whether or not the actual crank angle detected by the crank angle sensor 28 is the first pressure detection timing CA_1. The first pressure detection timing CA_1 is set to be a timing after the intake valve is opened and after the exhaust valve is closed, and is 40 ° ATDC, for example.
When the crank angle is the first pressure detection time CA_1, the port pressure at the time CA_1 is detected by the pressure sensor 55 in step S202, and is temporarily stored in the memory of the ECU 100 as P1. Thus, the process proceeds to step S203. On the other hand, if it is determined in step S201 that the crank angle is not the first pressure detection time CA_1, step S202 is skipped and the process proceeds to step S203.

  In step S203, the second pressure detection timing CA_2 is calculated based on the engine rotational speed Ne with reference to the second pressure detection timing map of FIG.

  Next, in step S204, it is determined whether or not the actual crank angle detected by the crank angle sensor 28 is the second pressure detection timing CA_2.

  When the crank angle is the second pressure detection time CA_2, the port pressure at the time CA_2 is detected by the pressure sensor 55 in step S205, and is temporarily stored in the memory of the ECU 100 as P2. Thus, the process proceeds to step S206. On the other hand, if it is determined in step S204 that the crank angle is not the second pressure detection timing CA_2, step S205 is skipped and the process proceeds to step S206.

  In step S206, the port pressure P3 after the final second pressure detection timing CA_2 is estimated based on the port pressures P1 and P2. This point will be described in detail later.

  Next, in step S207, the target valve opening timing CA_Po and the target valve opening period CA_Pw are calculated based on the target post-opening air amount Ga2_trg obtained in step S107 of FIG. 3 and the port pressure P3. This routine is completed.

  Generally, in this control 1, the port pressure at two points before the intake control valve is opened is detected, the port pressure P3 after the final detection is estimated, and the estimated port pressure P3 and the target post-opening air amount. Based on Ga2_trg, a process of calculating the target valve opening timing CA_Po and the target valve opening period CA_Pw is executed.

  Since the cylinder volume change after the exhaust valve is closed can be regarded as an adiabatic change, the port pressure after that can be estimated by detecting these two port pressures. Here, with respect to step S201, the first pressure detection timing CA_1 is set after the intake valve is opened because time is required until the pressure in the port passage 11b becomes substantially equal to the in-cylinder pressure. The reason that the timing CA_1 is after the exhaust valve is closed is that if the port passage 11b or the cylinder 12 communicates with the exhaust passage 17, the port pressure changes due to the influence of the exhaust pressure.

  Regarding step S203, in the map of FIG. 11, the second pressure detection time CA_2 is advanced as the engine speed Ne increases. This is because the opening timing of the intake control valve is advanced as the engine speed Ne increases.

Regarding step S206, the port pressure P3 is estimated by the following method.
First, k is calculated from the equation of adiabatic change: P2 / P1 = (V1 / V2) ^ k. Here, V1 is the sum of the port passage 11b and the cylinder internal volume at the first pressure detection timing CA_1, and V2 is the sum of the port passage 11b and the cylinder internal volume at the second pressure detection timing CA_2. Since the cylinder internal volume is a function of the crank angle, each cylinder internal volume can be calculated by knowing the respective times CA_1 and CA_2.

Next, P3 is calculated from P3 = P2 (V2 / V3) ^ k. V3 is the sum of the port passage 11b and the cylinder internal volume at the time when P3 is desired to be calculated.
Thereby, the port pressure P3 at each crank angle after the second pressure detection timing CA_2 can be estimated. If k is a constant obtained in advance by experiment or the like, only one of the port pressures P1 and P2 can be detected to estimate the port pressure P3. For example, the port pressure P3 can be estimated from P3 = P1 (V1 / V3) ^ k based only on the port pressure P1.

  Next, calculation of the target valve opening timing CA_Po and the target valve opening period CA_Pw regarding step S207 will be described.

  Here, the post-valve air amount map shown in FIG. 12 is used. This post-valve air amount map is a three-dimensional map created so that the target post-valve air amount Ga2_trg can be calculated from the three parameters of the port pressure P3, the target valve opening timing CA_Po, and the target valve opening period CA_Pw. . For example, when a map in a certain valve opening period CA_Pw_n is extracted, the map is as shown in FIG. TDC is an intake top dead center, and BDC is an intake bottom dead center. As will be described later, this map is also used to calculate the post-valve air amount Ga2 from the port pressure P4, the valve opening timing CA_Popen, and the valve opening period CA_Pwidth as actual values. As can be seen, in general, the air amount increases as the valve opening timing is delayed, and the air amount decreases as the valve opening timing delays from a certain region. This is because the period from the opening of the intake control valve 23 to the closing of the intake valve 16 is shortened. 12 and 13 are those when the engine speed is a certain value.

  As a result of diligent research, the present inventors have flown into the cylinder when the intake control valve 23 is opened and the three parameters as described above (that is, the port pressure at the time of valve opening, the valve opening timing and the valve opening period). It was found that the amount of air to be related to each other. In particular, the air flow rate after the intake control valve 23 is opened largely depends on the opening timing of the intake control valve 23 and the port pressure at that time. The post-valve air amount map is created through repeated processes such as experiments and analysis based on such knowledge. In general, when trying to increase the amount of intake air, the port pressure P2 at the time of valve opening is lowered (the differential pressure on the upstream and downstream sides of the intake control valve increases and the flow velocity at the time of valve opening increases), or the valve opening timing is delayed. (For the same reason and when the cylinder volume is large, the air can be pushed in), it is effective to increase the valve opening period (to increase the air inflow time). However, as can be seen from the air volume peak in the map, the valve opening timing includes the port pressure at the time of valve opening, the cylinder volume, the valve opening period after valve opening (or the intake valve closing timing), etc. There is an optimal timing in relation.

  If this map is used, the post-valve air amount can be estimated from the three parameters. However, in the case of the present embodiment, the valve opening timing and the valve opening period are calculated using the map when the valve opening port pressure and the post-valve air amount are known.

  Here, in the post-valve air amount map of FIG. 12, the post-valve air amount map is as shown in FIG. 14 by taking the maximum value of the target post-open air amount Ga2_trg in each target valve opening period CA_Pw. An operation or process for dropping into a two-dimensional map (referred to as a maximum air amount map after valve opening) is performed. To explain this more easily, first, it is assumed that the three-dimensional map of FIG. 12 is composed of a plurality of two-dimensional maps for each target valve opening period CA_Pw, and each of these sheets is set as the target valve opening period CA_Pw. In the axial direction (arrow direction). Roughly speaking, it is an image in which a plane defined by both the target valve opening timing CA_Po and the port pressure P3 is skewed countlessly from the direction of the arrow. Then, when the points at which the target post-opening air amount Ga2_trg becomes maximum for each target valve opening timing CA_Po and each port pressure P3 are extracted and plotted from a plurality of maps, a two-dimensional map as shown in FIG. 14 is obtained. It is done. In the present embodiment, such an operation or process is performed by an internal process of the ECU 100. However, a two-dimensional map may be created in advance and stored in the ECU 100. In this two-dimensional map, the inside of the equal air amount curve 4 (thick line) whose apex overlaps with the intake manifold pressure is a region where the air amount can be increased as compared with the case where there is no intake control valve 23, and the left side of the curve 4 (the valve opening timing is The earlier side) is a region where only an air amount equivalent to that without the intake control valve 23 can be obtained, and the right side of the curve 4 (the side with the later valve opening timing) has a smaller air amount than without the intake control valve 23. This is an area that can only be obtained.

  The port pressure P3 as the estimated value obtained in step S206 of FIG. 9 is superimposed on the two-dimensional map thus created as shown in FIG. In the figure, the port pressure before the second pressure detection time CA_2 is also shown for convenience. Then, the intersection of the curve of the port pressure P3 that changes in the decreasing direction as the crank angle progresses and the equal air amount curve (thick line) having the target post-valve air amount Ga2_trg = S in the map is obtained. The crank angle corresponding to the earliest point is determined as the target valve opening timing CA_Po = X to be obtained. Then, the port pressure P3 corresponding to the one point is determined as the port pressure P3 = Y to be obtained.

  If the only target valve opening timing CA_Po = X and the port pressure P3 = Y are determined in this way, then one of the maps from which these are obtained is extracted. That is, the three-dimensional map of FIG. 12 is considered to have a plurality of maps for each target valve opening period CA_Pw, but the target valve opening timing CA_Po = X, the port pressure P3 = Y, and the air amount after the target valve opening. There should be one map corresponding to Ga2_trg = S. Therefore, this one sheet is extracted from the three-dimensional map of FIG. 12, and the target valve opening timing CA_Po = X, port pressure P3 = Y, target post-valve air amount Ga2_trg = S is applied to one sheet and the target to be obtained. The valve opening period CA_Pw = Z is determined. The processing as described above is performed by the ECU 100, and the target valve opening timing CA_Po and the target valve opening period CA_Pw in step S207 of FIG. 9 are calculated.

  Here, the valve opening timing X and the valve opening period Z will be described with reference to FIGS. 16 and 17. FIG. 16 is a graph showing how much air is obtained when the valve opening timing is changed. Here, it is assumed that the valve opening period is optimal. When the valve opening timing is X, the actual air amount is equal to the target air amount. If the valve opening timing is made earlier than this, the actual air amount becomes smaller than the target air amount, and in many areas, becomes equal to the air amount when the intake control valve is not operated. This is because when the valve opening timing is too early, the cylinder volume at the time of valve opening is small, and the differential pressure on the upstream and downstream sides of the intake control valve is also small. This region corresponds to the left region of curve 4 in FIG. When the valve opening timing is made later than X, the actual air amount gradually increases but then decreases, and eventually becomes smaller than the target air amount. Such a crest portion is a portion where the supercharging effect by the intake control valve 23 can be obtained, that is, a portion corresponding to a region inside the curve 4 in FIG. 14, and the actual air amount is when the intake control valve is not operated. The region below the air amount corresponds to the region on the right side of the curve 4 in FIG. The reason why the actual air amount is lower than the air amount when the intake control valve is not operating is that the period from the opening of the intake control valve 23 to the closing of the intake valve 16 is shortened, and sufficient air inflow time cannot be secured. It is.

  FIG. 17 shows how the valve opening period changes when the valve opening timing is changed. Here, the relationship when the maximum amount of air can be obtained is shown. As shown by the broken line, when the intake control valve is closed simultaneously with the intake valve closing, the relationship of the valve opening period to the valve opening timing is inversely proportional, and the valve opening period is zero when the intake valve is closed. On the other hand, in the case of this embodiment shown by the solid line, when the valve opening timing is X or later, the valve opening period Z is shorter than the broken line, and the intake control valve is closed earlier than the intake valve. This is for the purpose of confining the air once flowing into the cylinder and becoming supercharged in the cylinder to prevent backflow and pressure loss.

  FIG. 18 is a view similar to FIG. 15 and shows the relationship between the valve opening timing, the port pressure, and the air amount. When trying to obtain the target air amount S, the valve opening timing may be any timing between the timings A and B of the two intersections of the target air amount S and the port pressure P3. However, in this embodiment, the earliest time A = X is adopted. The reason for this is that opening the intake control valve as soon as possible reduces the pumping loss and lowers the temperature rise in the cylinder. This is because it becomes smaller.

  Here, the third reason will be described. FIG. 19 shows the relationship between the valve closing timing and the air amount, and the three peaks in the figure are curves when the valve closing timing is changed when the valve opening timings are A, B, and C, respectively. In the case of the earliest valve opening timing A and the latest valve opening timing B, the target air amount S is obtained at the peak of the mountain, and even if the valve closing timing is shifted, the change in the air amount is small. On the other hand, in the case of the intermediate valve opening timing C, the valve closing timings at which the target air amount S is obtained are Cc1 and Cc2, and both are located in the middle of the mountain slope, so the air when the valve closing timing is shifted The change in quantity will be large. This is the reason why the intermediate valve opening timing C is not adopted and the valve opening timing A located at the end is adopted.

  Next, detection of the actual valve opening timing CA_Popen and the actual valve closing timing CA_Pclose in steps S111 and S115 will be described.

  FIG. 20 shows a change in the opening degree of the intake control valve 23 when the intake control valve 23 is opened and closed. When the actual crank angle reaches the target valve opening timing CA_Po, at the same time, a valve opening signal is sent from the ECU 100 to the intake control valve 23, whereby the electric actuator 34 of the intake control valve 23 is actuated to the valve opening side. The control valve 23 is fully opened (opening degree 100%). Thereafter, when the actual crank angle reaches the target valve closing timing CA_Pc, at the same time, a valve closing signal is sent from the ECU 100 to the intake control valve 23, whereby the electric actuator 34 of the intake control valve 23 is operated to the valve closing side. The intake control valve 23 is fully closed (opening degree 0%).

  During this opening / closing operation, there is a time lag between when the valve opening signal or the valve closing signal is sent and when the intake control valve 23 actually starts to move. In view of this time lag, the timing at which the intake control valve opening is actually detected by the opening sensor 54 of the intake control valve 23 is detected as the actual valve opening timing CA_Popen and the actual valve closing timing CA_Pclose, respectively. ing. The crank angle sensor 28 is used for this detection.

  Specifically, when the detected value of the opening sensor 54 of the intake control valve 23 exceeds a predetermined value V1 that is slightly open from the value corresponding to the opening of 0%, that is, when the intake control valve 23 starts to open. The ECU 100 determines that the intake control valve 23 is actually opened, and stores the crank angle at this time as the actual valve opening timing CA_Popen. Further, when the detected value of the opening sensor 54 of the intake control valve 23 falls below a predetermined value V2 that is slightly close to the value corresponding to the opening 100%, that is, when the intake control valve 23 starts to close, the ECU 100 The actual closing of the intake control valve 23 is determined, and the crank angle at this time is stored as the actual closing timing CA_Pclose. Thus, the actual opening and closing of the intake control valve 23 is detected by the ECU 100 and the opening degree sensor 54.

Here, the actual opening and closing of the intake control valve 23 are detected when the intake control valve 23 starts to open and close. However, the opening of the intake control valve 23 is arbitrary after the intake control valve 23 starts to open. With regard to the closing of the valve, it is possible to detect the actual opening and closing of the intake control valve 23 at any timing from when the intake control valve 23 starts to close to when it closes. For example, an intermediate opening such as 30%, 50% or 70% (for example, V1 ′, V2 ′ in the figure)
) May detect the actual opening and closing of the valve. By the way, due to the characteristics of the opening sensor 54, it may be difficult to detect the opening or closing of the intake control valve 23. In this case, the intermediate openings V1 ′ and V2 at which the operating speed of the intake control valve 23 is high. It is good to detect with '.

Further, in consideration of the operation time Δt required for actual opening and closing of the intake control valve 23, a timing obtained by subtracting the operation time Δt from the target valve opening timing CA_Po and the target valve closing timing CA_Pc is set as a new target valve opening timing. The intake control valve 23 may be controlled as CA_Po ′ and target valve closing timing CA_Pc ′.
Next, the control 2 in step S112 of FIG. 3, that is, calculation of the target valve closing timing CA_Pc will be described.

Here, the ECU 100 performs a calculation based on the following formula to calculate the target valve closing timing CA_Pc.
CA_Pc = CA_Popen + CA_Pw (3)

That is, the target valve closing timing CA_Pc is calculated by adding the target valve opening period CA_Pw to the actual valve opening timing CA_Popen instead of the target valve opening timing CA_Po. This is based on the following reason.
In the system using the intake control valve 23, the air amount is controlled according to the opening / closing timing of the intake control valve 23. Therefore, it is important to accurately control the opening / closing timing. Here, as a way of thinking, there is also a method of calculating the target valve closing timing CA_Pc by adding the target valve opening period CA_Pw to the target valve opening timing CA_Po. However, there is a time lag as described above before the intake control valve 23 starts moving by sending the valve opening and closing signals to the target valve opening timing CA_Po and the target valve closing timing CA_Pc, respectively. If the bearing of the intake control valve deteriorates, it will be prolonged. Thus, even if the valve opening and closing signals are sent at the correct timing, the actual valve opening and closing timing varies, and this variation results in variations in the intake air amount.

  Here, if the target valve closing timing CA_Pc is calculated from the target valve opening timing CA_Po instead of the actual valve opening timing CA_Popen, the variation in the time lag from the target valve opening timing CA_Po to the actual valve opening timing and the target valve closing timing Due to the time lag variation from the time CA_Pc to the actual valve closing time, the variation becomes double.

  On the other hand, if the target valve closing timing CA_Pc is calculated from the actual valve opening timing CA_Popen, the variation in the time lag from the target valve opening timing CA_Po to the actual valve opening timing will be ignored, and from the target valve closing timing CA_Pc Only the time lag until the actual valve closing timing causes variation. That is, as compared with the former case, there is an advantage that variation factors can be reduced and variation in air amount can be suppressed.

Here, FIG. 21 and FIG. 22 show test results comparing the case where the valve opening period is changed with the valve opening period constant and the case where the valve opening period is changed while the valve opening period is constant, respectively. .
First, as shown in FIG. 21, when the valve opening time is changed with the valve opening period kept constant, the valve opening time deviation of 43CA (crank angle) is allowed in order to keep the air amount deviation below 3%. Is done. On the other hand, as shown in FIG. 22, when the valve opening period is changed with the valve opening timing constant, in order to keep the deviation of the air amount to 3% or less, the valve opening of 9 CA (crank angle) is used. Only a time lag is allowed. From this result, it is understood that the deviation of the valve opening period causes an air amount deviation of about 5 times the deviation of the opening / closing timing of the intake control valve. Therefore, rather than controlling the valve opening / closing timing independently, shifting the valve closing timing in accordance with the deviation of the valve opening timing is more important in suppressing variation in the air amount. As described above, according to the present embodiment, the target valve closing timing CA_Pc can be shifted according to the amount of deviation from the target valve closing timing CA_Pc to the actual valve opening timing CA_Popen. Is possible.

  For example, in the conventional air amount control using a variable valve timing mechanism that mechanically changes the opening timing of the intake valve, the air is relatively slower than in the case of inertia supercharging with high-speed air as in this embodiment. To flow. For this reason, the intake air amount is determined by the in-cylinder pressure and the cylinder volume when the intake valve is closed, and even if the valve opening timing is deviated, the intake air amount is not significantly affected.

Here, in the present embodiment, the following method can be employed to further increase the accuracy. That is, as the actual valve opening timing of the intake control valve 23 is delayed from the target valve opening timing, the intake air amount increases in the same valve opening period, so the valve closing timing is advanced by that amount and the valve opening period is shortened. That is, a new target valve closing timing CA_Pc ′ is calculated by the following equation.
CA_Pc ′ = CA_Popen + CA_Pw−α × (CA_Popen−CA_Po) (4)
Here, α is a constant obtained by experiments or the like.

  Next, calculation of the post-valve air amount Ga2 in step S116 of FIG. 3 will be described. At this stage, the actual valve opening timing CA_Popen, the actual valve opening period CA_Pwidth, and the port pressure P4 at the actual valve opening timing CA_Popen as actual values have already been obtained. Therefore, based on these three values, the post-valve air amount Ga2 as an actual value and an estimated value is calculated using the post-valve air amount map of FIG. As a result, the post-valve air amount Ga2 closer to the true value than the target post-valve air amount Ga2_trg can be obtained, and the total air amount Ga is obtained using this value (step S117) to control the engine. Can be used for

  In this embodiment, the port pressure is maintained and the initial air inflow of the intake stroke is performed. However, the initial air inflow is set to a substantially constant value without maintaining the high port pressure of the previous intake stroke. You can also In this case, the post-valve opening air amount that is the late inflow air amount is obtained by setting the pre-valve air amount Ga1 that is the initial inflow air amount to a constant value or by simplifying the process of calculating the pre-valve air amount Ga1. The quantity target value Ga2_trg may be determined.

  The present invention can be applied to any type of engine other than a gasoline engine. In the case of a gasoline engine, not only the direct injection type or the in-cylinder injection type as described above, but also an intake passage injection type engine or a so-called dual injection type engine capable of performing both the intake passage injection and the in-cylinder injection. it can. Moreover, it is applicable also to the engine using alternative fuels, such as a diesel engine and alcohol, liquefied natural gas. The present invention can also be applied to a supercharged engine. Particularly, in this case, since the intake manifold pressure is higher than that of natural intake air, the differential pressure on the upstream and downstream sides of the intake control valve can be increased, and the inertia supercharging effect is further promoted. Can do. The map as shown in the above embodiment can be replaced with an arithmetic expression.

  In the above embodiment, the intake control valve control means, the target air amount determination means, the pressure estimation means, the target valve opening timing determination means, the downstream pressure determination means, the target valve opening period determination means, and the target valve closing timing determination according to the present invention. Means, an actual valve opening period determining means, an actual air amount estimating means, and a control amount determining means are constituted by the ECU 100, the pressure detecting means is constituted by the pressure sensor 55, and the valve opening detecting means and the valve closing detecting means are opened by the ECU 100. The degree sensor 54 is used.

  Embodiments of the present invention are not limited to the above-described embodiments, and all modifications, applications, and equivalents included in the spirit of the present invention defined by the claims are included in the present invention. Therefore, the present invention should not be construed as being limited, but can be applied to any other technique within the scope of the idea of the present invention.

1 is a system diagram schematically showing a configuration of an engine control device according to an embodiment of the present invention. It is a time chart which shows the mode of the change of the pressure at the time of an intake control valve action | operation, and an air flow rate. It is a flowchart of the main routine of the engine control which concerns on this embodiment. It is a target air amount map. It is a working area map of an intake control valve. It is an ignition timing map. It is an auxiliary | assistant time chart regarding estimation of the air quantity before valve opening. It is a blow-through amount map. 3 is a flowchart of a control 1 routine. 4 is an auxiliary time chart regarding control 1; It is a 2nd pressure detection time map. It is an air amount map after valve opening. It is an air amount map after valve opening in a certain valve opening period. It is a maximum air amount map after valve opening. It is a figure for demonstrating the determination method of the target valve opening time and the port pressure in this target valve opening time. It is a graph which shows the relationship between valve opening time and air quantity. It is a graph which shows the relationship between a valve opening time and a valve opening period. It is a figure for demonstrating the setting method of valve opening time. It is a figure for demonstrating the setting method of valve opening time. It is a graph which shows the opening degree change of the intake control valve at the time of the opening / closing operation | movement of an intake control valve. It is a graph which shows the influence on the air quantity with respect to the gap of valve opening timing. It is a graph which shows the influence on the air quantity with respect to the shift | offset | difference of a valve opening period.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 10 Injector 11 Intake passage 11a Intake manifold passage 11b Port passage 12 Cylinder 13 Combustion chamber 14 Spark plug 15 Intake port 16 Intake valve 17 Exhaust passage 18 Catalyst 19 Exhaust port 20 Exhaust valve 22 Intake throttle valve 23 Intake control valve 33 Valve body 34 Actuator 41 Intake pressure sensor 42 Intake temperature sensor 54 Opening sensor 55 Pressure sensor 100 Electronic control unit (ECU)
CA_Po Target opening timing of intake control valve
CA_Pc Target valve closing timing for intake control valve
CA_Pw Target opening period of intake control valve
CA_Popen Actual opening timing of intake control valve
CA_Pclose Actual valve closing timing of intake control valve
CA_Pwidth Intake control valve actual opening period
Ga_trg Target air amount Ga Air amount Ga1 Air amount before valve opening
Ga2_trg Target value of air amount after valve opening Ga2 Air amount after valve opening P3 Port pressure P4 at target valve opening timing of intake control valve Port pressure at actual valve opening timing of intake control valve

Claims (12)

An intake control valve provided in an intake passage on the upstream side of the intake valve, capable of closing the intake passage and opening and closing in synchronization with opening and closing of the intake valve;
An intake control valve control means for opening the intake control valve during the intake stroke and then closing the intake control valve;
Target air amount determining means for determining a target value of the post-valve air amount flowing into the cylinder after the intake control valve is opened based on the engine operating state;
Pressure detecting means for detecting the pressure on the downstream side of the intake control valve;
Based on the downstream pressure detected by the pressure detection means before the intake control valve is opened, pressure estimation means for estimating the downstream pressure after the detection;
Target valve opening timing determining means for determining a target value of the valve opening timing of the intake control valve based on the downstream pressure estimated by the pressure estimating means and the target value of the post-valve air amount. An engine control device characterized by that.   The pressure estimation means estimates a downstream pressure of the intake control valve after the final detection based on at least one downstream pressure detected by the pressure detection means before the intake control valve is opened. The engine control apparatus according to claim 1, wherein:   The apparatus further comprises downstream pressure determining means for determining the downstream pressure at the target value of the valve opening timing based on the target value of the post-valve air amount and the target value of the valve opening timing. The engine control device according to claim 1 or 2.   Based on the target value of the valve opening timing, the downstream pressure at the target value of the valve opening timing, and the target value of the air amount after the valve opening, a target value of the valve opening period of the intake control valve is determined. 4. The engine control apparatus according to claim 1, further comprising a target valve opening period determining means.   The target valve opening timing determining means and the target valve opening period determining means are each based on a map in which a relationship between the post-valve air amount, the downstream pressure, the valve opening timing, and the valve opening period is determined in advance. The engine control device according to claim 4, wherein a target value of the valve opening timing and the valve opening period is determined. A valve opening detecting means for detecting an actual valve opening of the intake control valve;
Target valve closing timing determining means for determining a target value of the valve closing timing of the intake control valve based on the timing when the actual valve opening is detected by the valve opening detecting means and the target value of the valve opening period; The engine control device according to claim 4 or 5, further comprising: A valve closing detection unit for detecting an actual valve closing when the intake control valve control unit closes the intake control valve at a target value of the valve closing timing determined by the target valve closing timing determination unit; ,
An actual valve opening period determining means for determining an actual valve opening period of the intake control valve based on the time when the actual valve closing is detected by the valve closing detecting means and the time when the actual valve opening is detected. When,
The actual valve opening period determined by the actual valve opening period determining means, the time when the actual valve opening is detected, and the pressure detecting means detected at the time when the actual valve opening is detected The engine control device according to claim 6, further comprising an actual air amount estimating means for estimating an actual air amount based on the downstream pressure.   8. The engine control apparatus according to claim 7, further comprising control amount determining means for determining a control amount based on the actual air amount estimated by the actual air amount estimating means. An intake control valve provided in an intake passage on the upstream side of the intake valve, capable of closing the intake passage and opening and closing in synchronization with opening and closing of the intake valve;
An intake control valve control means for opening the intake control valve during the intake stroke and then closing the intake control valve;
Target air amount determining means for determining a target value of the post-valve air amount flowing into the cylinder after the intake control valve is opened based on the engine operating state;
Pressure detecting means for detecting the pressure on the downstream side of the intake control valve;
Pressure estimation means for estimating the downstream pressure after the detection based on the downstream pressure detected by the pressure detection means before opening the intake control valve;
Target valve opening timing determining means for determining a target value of the valve opening timing of the intake control valve based on the downstream pressure estimated by the pressure estimating means and the target value of the post-valve air amount;
The intake control based on the target value of the valve opening timing determined by the target valve opening timing determining means, the downstream pressure at the target value of the valve opening timing, and the target value of the air amount after opening. Target valve opening period determining means for determining a target value of the valve opening period;
A valve opening detecting means for detecting an actual valve opening of the intake control valve when the intake control valve is opened by the intake control valve control means at a target value of the valve opening timing;
Target valve closing timing determining means for determining a target value of the valve closing timing of the intake control valve based on the timing when the actual valve opening is detected by the valve opening detecting means and the target value of the valve opening period; An engine control device comprising the engine control device.   The target air amount determination means determines a target value of the air amount based on the engine operating state, and the pre-valve air that flows into the cylinder from the target value of the air amount before the intake control valve is opened. The engine control device according to claim 1, wherein a target value of the post-valve air amount is determined by subtracting an estimated value of the amount.   The target air amount determining means estimates the air amount before opening based on at least two downstream pressures detected by the pressure detecting means before opening the intake control valve. The engine control device according to claim 10. 12. The downstream pressure detected by the pressure detecting means before the intake valve is opened is at least one of the at least two downstream pressures. Engine control device.

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