JP2019163735A - Internal combustion engine control device - Google Patents

Abstract

To improve knock resistance in an operation of an internal combustion engine which uses a scavenging mode and a low-pressure EGR mode in combination.SOLUTION: An internal combustion engine comprises an intake valve, an exhaust valve and an EGR valve for making exhaust gas recirculate via the intake valve. An internal combustion engine control device comprises: a valve drive unit for driving the intake valve, the exhaust valve and the EGR valve; and an overlap control part for controlling the valve drive unit so as to change a period of performing an overlap operation for simultaneously opening the intake valve and the exhaust valve after valve-opening of the EGR valve for shifting an operation mode to a second operation mode according to a delay of an EGR gas, when the operation mode is shifted from a first operation mode for simultaneously opening the intake valve and the exhaust valve to the second operation mode for making the exhaust gas recirculate via the intake valve.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an internal combustion engine control apparatus.

  Regulations on automobile fuel consumption and harmful exhaust components are being strengthened, and will continue to become stricter in the future. In particular, regarding fuel consumption, since the carbon dioxide emitted has a great influence on global warming, further reduction in fuel consumption is required. For example, when the internal combustion engine is running at a low speed and a high load, the overlap amount that the intake valve and the exhaust valve are opened simultaneously is increased so that the pressure difference between the intake side and the exhaust side of the internal combustion engine causes so-called scavenging. There is known a control device capable of executing a scavenging operation for promoting a scavenging effect (cylinder scavenging). On the other hand, there is also known a control device capable of executing an EGR (Exhaust Gas Recirculation) mode in which an EGR valve is opened to recirculate exhaust gas to the intake port side. A control device using both modes in one engine is also known from Patent Document 1, for example.

Japanese Patent No. 5998901

  An object of the present invention is to provide a control device for an internal combustion engine that can improve knock resistance in an operation in an internal combustion engine that uses both a scavenging mode and a low pressure EGR mode.

  The present invention is an internal combustion engine controller for controlling an internal combustion engine. The internal combustion engine includes an intake valve, an exhaust valve, and an EGR valve for recirculating exhaust gas through the intake valve. The internal combustion engine control device includes: a valve driving device that drives the intake valve, the exhaust valve, and the EGR valve; and a first operation mode that opens the intake valve and the exhaust valve at the same time; In the case of shifting to the second operation mode in which recirculation is performed via the engine, after the EGR valve is opened for shifting to the second operation mode, the intake valve and the exhaust valve are simultaneously opened. And an overlap control unit that controls the valve driving device so as to change a period during which the lap operation is performed according to the delay of the EGR gas.

  ADVANTAGE OF THE INVENTION According to this invention, the control apparatus of the internal combustion engine which can improve knock resistance in the operation | movement in the internal combustion engine which used scavenging mode and low pressure EGR mode together can be provided.

It is the schematic which shows the basic composition of the internal combustion engine provided with the fuel-injection control apparatus which concerns on 1st Embodiment. It is a functional block diagram which shows the structure of ECU200 of 1st Embodiment. It is a graph explaining the concept of the control apparatus of the internal combustion engine of 1st Embodiment. It is a timing chart which shows operation of a comparative example. It is a timing chart which shows operation | movement of 1st Embodiment. It is a timing chart which shows operation | movement of 1st Embodiment. It is the schematic which shows operation | movement of 1st Embodiment. It is a timing chart which shows operation | movement of 2nd Embodiment. It is a schematic diagram explaining the outline | summary of 3rd Embodiment. It is a block diagram explaining the structure of the control apparatus of 3rd Embodiment. It is a graph explaining the effect of 3rd Embodiment. It is a graph explaining the effect of 3rd Embodiment. It is a graph explaining the effect of 3rd Embodiment.

  Hereinafter, the present embodiment will be described with reference to the accompanying drawings. In the accompanying drawings, functionally identical elements may be denoted by the same numbers. Note that the attached drawings show an embodiment and an implementation example according to the principle of the present disclosure, but these are for the purpose of understanding the present disclosure, and are never used to interpret the present disclosure in a limited manner. It is not a thing. The descriptions in this specification are merely exemplary, and are not intended to limit the scope of the claims or the application in any way whatsoever.

  This embodiment has been described in sufficient detail for those skilled in the art to practice the present disclosure, but other implementations and configurations are possible and depart from the scope and spirit of the technical idea of the present disclosure. It is necessary to understand that the configuration and structure can be changed and various elements can be replaced. Therefore, the following description should not be interpreted as being limited to this.

[First Embodiment]
FIG. 1 shows a basic configuration of an internal combustion engine provided with a fuel injection control device according to a first embodiment of the present invention.
In FIG. 1, an internal combustion engine 100 as a control target is controlled by an ECU 200 as a fuel injection control device and an accelerator opening sensor 300 that detects an accelerator opening.

  The internal combustion engine 100 includes a piston 101, an intake valve 102, and an exhaust valve 103 in a cylinder. As an example, the internal combustion engine 100 may be an internal combustion engine having a plurality of, for example, four cylinders (cylinders), but FIG. 1 representatively shows only one of the plurality of cylinders. Show.

  The cylinder head is provided with an ignition plug 105 and an ignition coil 106. Further, the cylinder head is provided with a fuel injection valve 107 that directly injects fuel into the combustion chamber in the cylinder. Although not shown, the water jacket of the cylinder may be provided with a coolant temperature sensor.

  An intake pipe 110 for introducing air sucked into the internal combustion engine 100 is provided upstream of the intake valve 102, and exhaust gas discharged from the cylinder is discharged downstream of the exhaust valve 103. An exhaust pipe 111 is provided.

  The intake pipe 110 is provided with an intercooler 112 for cooling the intake air, a throttle valve 113 for adjusting the intake air amount according to the accelerator opening, and a surge tank 114 for adjusting the flow of the intake air.

  The exhaust pipe 111 communicates with an exhaust passage 121, and a three-way catalyst 123, an air-fuel ratio sensor 124, and a turbine 125b are provided in the exhaust passage 121. The three-way catalyst 123 is for purifying the exhaust gas, and the air-fuel ratio sensor 124 is a sensor for detecting the air-fuel ratio of the exhaust gas. Further, the turbine 125b generates a driving force for driving the compressor 125a using the energy of the exhaust gas.

  The exhaust passage 121 is branched to an EGR pipe 126 on the downstream side of the three-way catalyst 123. The EGR pipe 126 is a pipe for recirculating (recirculating) exhaust gas to the intake side as EGR gas. The EGR pipe 126 includes an EGR cooler 127 that cools the EGR, an EGR valve 128 that adjusts the amount of EGR gas, and a pressure sensor 133 that measures the pressure before and after the EGR valve 128. Further, a three-way catalyst 129 different from the three-way catalyst 123 is provided further downstream of the exhaust passage 121.

  The intake pipe 110 communicates with the intake passage 130 on the compressor 125a side. The intake passage 130 is provided with a mass flow meter 131 for measuring the air flow rate and a pressure adjusting valve 132 for adjusting the intake pressure. The aforementioned EGR pipe 126 is connected to the intake passage 130. Further, the intake pipe 110 is provided with an oxygen concentration sensor 134 for detecting the oxygen concentration of the mixed gas on the intake side (the gas obtained by mixing the intake air supplied from the intake passage 130 and the EGR gas).

  ECU 200 calculates a required torque based on detection signals from accelerator opening sensor 300 and various sensor signals. The ECU 200 determines the opening degree of the pressure adjustment valve 132, the opening degree of the throttle valve 113, the injection pulse period of the fuel injection valve 107, the ignition timing of the ignition plug 105, based on the operating state of the internal combustion engine 100 obtained from the outputs of various sensors. The main operating amounts of the internal combustion engine 100 such as the opening / closing timing of the intake valve 102 and the exhaust valve 103 and the opening degree of the EGR valve 128 are calculated.

  The mixed gas passes through the intercooler 112, the intake pipe 110, and the surge tank 114, and then flows into the combustion chamber R1 through the intake valve 102. This mixed gas together with the fuel injected from the fuel injection valve 107 forms an air-fuel mixture in the combustion chamber R1. The air-fuel mixture is ignited and burned by a spark generated from the spark plug 105 at a predetermined ignition timing. The piston 101 is pushed down by the combustion pressure resulting from the combustion of the air-fuel mixture and becomes the driving force of the internal combustion engine 100.

  The exhaust gas after combustion is sent to the three-way catalyst 123 through the exhaust valve 103, the exhaust pipe 111, and the turbine 125b. After the NOx, CO, and HC components are purified in the three-way catalyst 123, the exhaust gas passes through the exhaust passage 121. It is purified again by the three-way catalyst 129 and discharged outside.

  A part of the exhaust gas is introduced into the intake passage 130 as EGR gas through the EGR pipe 126, the EGR cooler 127, and the EGR valve 128, and the intake air and the EGR gas are merged in this introduction region. The mixed gas composed of intake air and EGR gas passes through the intake pipe 110 and the like and reaches the combustion chamber R1.

FIG. 2 is a functional block diagram showing the configuration of the ECU 200 according to the first embodiment.
The ECU 200 generally includes an input circuit 201, a CPU 202, a RAM 203, a ROM 204, an input / output port 205, an EGR delay estimation unit 206, an overlap command signal generation unit 207, and various drive circuits 208 to 213.

  The input circuit 201 is an interface circuit that receives detection signals from various sensors. The CPU 202 is an arithmetic control circuit that controls the entire ECU 200. A RAM 203 is a storage unit for temporarily storing various types of input / output data. The ROM 204 stores a control program describing the contents of arithmetic processing. The input / output port 205 causes the detection signal input from the input circuit 201 to be input to the CPU 202 via the RAM 203 (after being temporarily stored), and signals transferred from the CPU 202, RAM 203, and ROM 204 to be supplied to various drive circuits 208 to 213. It has the function to output toward Of the detection signals sent to the input circuit 201, the detection signal inputted as an analog signal is inputted after being converted into a digital signal by an A / D converter (not shown) provided in the input circuit 201.

  For example, the drive circuits 208 to 213 include a pressure adjustment valve drive circuit 208, a throttle valve drive circuit 209, a variable valve mechanism (VTC) drive circuit 210, a fuel injection valve drive circuit 211, an ignition signal output circuit 212, and an EGR valve drive. A circuit 213 is provided. The pressure adjustment valve drive circuit 208 is an actuator that drives the pressure adjustment valve 132. The throttle valve drive circuit 209 is an actuator that drives the throttle valve 113. The VTC drive circuit 210 is an actuator (valve drive circuit) that drives the intake valve 102 and the exhaust valve 103. The fuel injection valve drive circuit 211 is an actuator that drives the fuel injection valve 107. The ignition signal output circuit 212 outputs an ignition signal for igniting the ignition plug 105. The EGR valve drive circuit 213 is an actuator (valve drive circuit) that drives the EGR valve 128.

With reference to FIG. 3, the concept of the control apparatus for the internal combustion engine of the first embodiment will be described.
The internal combustion engine 100 according to the first embodiment is controlled by the ECU 200 so as to execute the scavenging mode (first operation mode) in a high load region near WOT (Wide-Open Throttle) and at a low rotational speed. Be controlled. In the scavenging mode, air is supplied from the intake pipe 110 to the exhaust pipe 111 by providing an overlap period in which the intake valve 102 and the exhaust valve 103 are simultaneously opened in one cycle (intake, compression, combustion, exhaust). This is an operation mode in which residual gas remaining in the combustion chamber is blown out. When the residual gas in the combustion chamber R1 is swept out to the outside, the temperature in the combustion chamber R1 is lowered, and knock resistance is improved.

  On the other hand, in the internal combustion engine 100 according to the first embodiment, when the operation is continued in a high load region near the WOT and the rotation speed is increased, and a rotation speed (high rotation speed) greater than a predetermined value is obtained. The ECU 200 performs control so as to execute the low pressure EGR mode (second operation mode) instead of the scavenging mode (first operation mode). In the low pressure EGR mode, the exhaust gas is recirculated from the EGR pipe 126 and the like to the intake pipe 110 side, whereby the temperature in the combustion chamber R1 can be lowered, and knock resistance is improved.

  As described above, in the internal combustion engine 100 according to the first embodiment, in the high load region near the WOT, the scavenging mode is executed in the low rotational speed region, and the low pressure EGR mode is executed in the high rotational speed region. Is done. When the ECU 200 detects that the predetermined threshold rotation speed has been reached in the high load range based on the outputs of the various sensors, the ECU 200 sends a command signal for switching from the scavenging mode to the low pressure EGR mode to the input / output port 205. Output. In the control device of the first embodiment, a known mirror cycle or an operation by high pressure EGR can be executed in the low load region.

  However, when switching between the scavenging mode and the low-pressure EGR mode in a high load region with a predetermined rotational speed as a boundary, there is a problem that the occurrence probability of knock increases. This problem will be described with reference to a comparative example in FIG.

  In this comparative example, the transition from the scavenging mode to the low pressure EGR mode is instructed by the ECU 200 at time t1, the opening of the EGR valve 128 is started from time t1, and the overlap in the scavenging mode ends at time t1. The overlap width Wol indicating the size of the overlap in which the intake valve 102 and the exhaust valve 103 are simultaneously opened in one cycle is also zero after time t1.

  However, in the operation of this comparative example, there is a risk that the occurrence probability of knocking will increase. In general, in low pressure EGR, the distance (pipe length) from the EGR valve 128 to the combustion chamber R1 tends to be long. Therefore, in the operation of this comparative example, the arrival of EGR gas after time t1 and the intake air The increase in the EGR rate, which is the ratio of EGR gas, is delayed. A sufficient amount of EGR gas reaches the combustion chamber R1 near, for example, time t2. In this case, in the period (transition period) between times t1 and t2, the EGR gas is insufficient, so the ratio of the residual gas in the combustion chamber R1 (residual gas ratio Rrg) increases, and the cylinder in the combustion chamber R1 further increases. The internal temperature Ts also increases. As a result, the occurrence probability of knocking increases in the combustion chamber R1.

  Therefore, in the first embodiment, the EGR delay estimation unit 206 estimates the degree of delay of the EGR gas, and according to the estimation result, the overlap period in the scavenging mode is only the time according to the estimation result. Execute the control to extend. The operation of the first embodiment will be described below with reference to FIG.

  In the first embodiment, for example, at time t1, the EGR valve opening signal Segr instructing the transition from the scavenging mode to the low pressure EGR mode rises, and the opening of the EGR valve 128 is started from time t1. However, it is estimated that the EGR gas does not sufficiently reach the combustion chamber R1 immediately after the time t1, and then reaches a sufficient amount in the vicinity of the time t2 after a predetermined time has elapsed. The degree of delay of the EGR gas (delay time Td = t2−t1) is estimated by the EGR delay estimation unit 206. For example, the EGR delay estimation unit 206 can measure the differential pressure before and after the EGR valve 128 by the pressure sensor 133 and can also measure the opening degree of the EGR valve 128 to estimate the delay in arrival of the EGR gas. .

  As another example, the EGR delay estimation unit 206 measures the oxygen concentration of the mixed gas in the intake pipe 110 by the oxygen concentration sensor 134 and thereby measures the EGR rate, thereby delaying the arrival of the EGR gas. Can be estimated. Further, by measuring the outputs of the pressure sensor 133 and the oxygen concentration sensor 134 together, it is possible to determine the degree of delay in arrival of the EGR gas.

  Further, as described in Japanese Patent Application No. 2017-125947 filed earlier by the present applicant, the reference space of the intake passage is divided into a plurality of unit spaces along a streamline through which a mixed gas of intake air and EGR gas flows. And a physical model based on the advection equation for estimating the EGR rate of the mixed gas corresponding to each unit space is constructed, and by the physical model, the EGR rate of the unit space connected to this from the head unit space Can be estimated in order, and the delay of the EGR gas flowing into the combustion chamber R1 can be estimated.

  When the delay time Td is estimated by the EGR delay estimation unit 206, the overlap command signal generation unit 207 performs an overlap in which the intake valve 102 and the exhaust valve 103 are simultaneously opened by the time corresponding to the delay time Td. Extend the period to do it. Specifically, the overlap width Wol indicating the size of the overlap in which the intake valve 102 and the exhaust valve 103 are simultaneously opened in one cycle does not become zero immediately after time t1, but EGR. The timing at which the overlap width Wol becomes zero is delayed by the time corresponding to the delay time Td estimated by the delay estimation unit 206. The determination of the degree of timing delay is performed by the overlap command signal output from the above-described overlap command signal generation unit 207 according to the delay time Td. That is, the overlap command signal generation unit 207 opens the EGR valve 128 at the time t1 for shifting to the low pressure EGR mode, and then performs an overlap period during which the intake valve 102 and the exhaust valve 103 are simultaneously opened. It functions as an overlap control unit that changes according to the estimation result in the delay estimation unit 206.

  In this way, the period during which the overlap is performed is extended according to the delay time Td, so that the intake valve 102 and the exhaust valve 103 are also after the time t1 when the EGR valve 128 is opened and the low pressure EGR mode is started. Are simultaneously opened for a predetermined time, thereby sweeping out the high-temperature gas in the combustion chamber R1 and decreasing the residual gas ratio Rrg. Therefore, the temperature of the combustion chamber R1 (in-cylinder temperature Ts) is also reduced, and the probability of knocking can be reduced. After the overlap is continued for a predetermined period in this way, at time t2 when it is estimated that the EGR gas is sufficiently supplied, the overlap operation is terminated (the overlap width Wol is set to zero), and the normal low pressure EGR is performed. Enter mode.

  In the first embodiment, according to the estimation result of EGR gas delay, in addition to extending the overlap operation by the overlap command signal Sol, as shown in FIG. Control by the ECU 200 is performed so that the timing for increasing the advance amount is also delayed in accordance with the delay time Td. Specifically, an overlap command signal Sol is generated in accordance with the delay time Td estimated by the EGR delay estimation unit 206, and the ignition signal output circuit 212 follows the ignition plug 105 as shown in the timing chart of FIG. The advance control signal Sig that indicates the advance amount of ignition is changed. For example, when the arrival of the EGR gas is delayed to around time t2, the timing at which the advance angle control signal Sig rises is also delayed in accordance with this, and the ignition timing of the spark plug 105 is delayed. By delaying the ignition timing, it is possible to further reduce the probability of occurrence of knocking during the transition period from the scavenging mode to the low pressure EGR mode.

  FIG. 6 is a schematic diagram illustrating overlap width control performed after time t1. FIG. 6 is an example of the overlap command signal Sol generated by the overlap command signal generation unit 207, and FIG. 7 conceptually illustrates a change in the overlap width Wo. As shown in FIG. 6, the overlap command signal Sol generated by the overlap command signal generator 207 has a pulse width Tol corresponding to the estimated delay time Td.

  In the example of FIG. 6, the overlap command signal Sol has the pulse width Tol according to the delay time Td as described above, but the voltage value is the time when the scavenging mode is shifted to the low pressure EGR mode. After t1, it decreases stepwise (for example, decreases to V1, V2, V3). Then, the control program of the ECU 200 determines the voltage value of the overlap command signal Sol and sets the overlap width Wol according to the voltage value. In accordance with the overlap width Wol, the intake valve 102 and the exhaust valve 103 are driven by the VTC drive circuit 210, and the overlap operation is executed.

  For example, as shown in FIG. 7, in a cycle (combustion, exhaust, intake, compression) executed in a period in which the voltage value of the overlap command signal Sol is V1, the overlap width Wol is set to W1.

When the voltage value is V2, the overlap width Wol is set to W2 (<W1).
When the voltage value is V3, the overlap width Wol is set to W3 (<W2).

  When the voltage value of the overlap command signal Sol becomes 0, the overlap width Wol is set to zero, and thereafter the normal low pressure EGR mode is executed.

  That is, the overlap command signal generation unit 207 has a shorter overlap width Wol in the second cycle after the first cycle in the plurality of cycles than in the first cycle in the plurality of cycles. The overlap command signal Sol is generated so that

  The overlap width W1 immediately after time t1 when the mode is shifted to the low-pressure EGR mode can be set to a value that is substantially the same as, or at least not significantly different from, the overlap width in the scavenging mode, for example. At the stage where the EGR gas is not sufficiently sent into the combustion chamber R1 as in the vicinity of the time t1, the residual gas in the combustion chamber R1 is reduced by taking in a lot of intake air by increasing the overlap width Wol, The in-cylinder temperature Ts can be lowered, thereby reducing the occurrence probability of knocking.

  Thereafter, as described above, the overlap width Wol is gradually shortened every time the voltage value of the overlap command signal Sol decreases with time. Then, the overlap width Wol is gradually decreased until the time t2 when a sufficient amount of EGR gas is expected to reach the combustion chamber R1, and finally the overlap width Wol is set to zero or a value close to zero. Thereafter, the normal low pressure EGR mode is executed. Note that the number of voltage value stages in the overlap command signal Sol and the time length of each stage can be arbitrarily set within a range in which knocking can be effectively suppressed. In the example of FIG. 6, the overlap width decreases stepwise, but it is not necessary to be limited to this. For example, the overlap width may decrease continuously.

  As described above, in the first embodiment, when operating in a high load range near WOT (Wide-Open Throttle), the scavenging mode is executed in a low rotational speed state, and a predetermined value or more is reached. In the high rotational speed state, the operation is continued by switching from the scavenging mode to the low pressure EGR mode. At the time of this switching, the transition to the low pressure EGR mode also continues (extends) the overlap operation for simultaneously opening the intake valve 102 and the exhaust valve 103 for a period corresponding to the delay of the EGR gas. According to this operation, even if the arrival of the EGR gas is delayed, the residual gas in the cylinder can be swept out and the in-cylinder temperature Ts can be lowered, so that the occurrence probability of knocking can be reduced.

[Second Embodiment]
Next, an internal combustion engine control apparatus according to a second embodiment of the present invention will be described with reference to FIG. Since the external configuration of the internal combustion engine and the internal combustion engine control device of the second embodiment may be the same as that of the first embodiment (FIGS. 1 to 2), detailed description thereof will be omitted. However, in this embodiment, the operation when shifting from the scavenging mode to the low pressure EGR is different from that of the first embodiment. This will be described with reference to FIG.

  As shown in FIG. 8, in the second embodiment, as in the first embodiment, when the delay time Td is estimated by the EGR delay estimation unit 206, the overlap command signal generation unit 207 Control is performed to extend the overlap period during which the intake valve 102 and the exhaust valve 103 are opened simultaneously by the time corresponding to the time Td. However, the advance angle control signal Sig is raised at time t1 in order to increase the advance amount of the spark plug 105 substantially at the same time as time t1 when the EGR valve 128 opens. By continuing the overlap operation after time t1, an increase in the residual gas rate Rrg and an increase in the in-cylinder temperature Ts are avoided, so that even if the advance amount of the spark plug 105 increases after the time t1, knocking May be sufficiently prevented. In this case, the operation of the second embodiment described above can be adopted. According to the second embodiment, in addition to obtaining the same effect as that of the first embodiment, it is possible to improve the fuel efficiency as compared with the first embodiment.

[Third Embodiment]
Next, an internal combustion engine control apparatus according to a third embodiment of the present invention will be described with reference to FIGS. The external configuration of the internal combustion engine and the internal combustion engine control apparatus of the third embodiment may be the same as that of the above-described embodiment (FIGS. 1 to 2), and thus a detailed description thereof is omitted. In addition, when switching from the scavenging mode to the low pressure EGR mode, the overlap operation for simultaneously opening the intake valve 102 and the exhaust valve 103 is performed only during the period corresponding to the delay of the EGR gas even after switching to the low pressure EGR mode. The point that it is continuously executed is the same as in the above-described embodiment. However, in the third embodiment, the method for measuring the flow rate of the mixed gas flowing into the internal combustion engine 100, and the fuel injection control and the ignition control based on the measurement result are different from the above-described embodiments. Specifically, the trap air amount Ftr injected (trapped) into the cylinder is estimated in consideration of the blow-through amount Fth (including the blow-back amount returning to the suction side) that does not stop in the cylinder and blows through as it is, The point which performs fuel-injection control, ignition control, etc. based on this differs from 1st Embodiment.

  A method of estimating the trap air amount Ftr will be described with reference to FIG. When switching from the scavenging mode to the low pressure EGR mode, when the overlap operation for simultaneously opening the intake valve 102 and the exhaust valve 103 is performed for a predetermined time after switching to the low pressure EGR mode, the overlap operation causes the cylinder to It is important to estimate the amount of air injected into the. In this case, for example, it may not be sufficient to measure the intake flow rate measured by the mass flow meter 131 installed in the intake passage 130, for example. For example, the amount of air blown through Fth that does not substantially pass through the cylinder and blows out toward the exhaust pipe 111 (in contrast, the amount of air blown back into the intake pipe 110 (including the amount of blowback Fbr)) cannot be ignored. In consideration of these, it is necessary to accurately estimate the amount of air injected into the cylinder (trap air amount Ftr).

  Next, the configuration of the ECU 200 for fuel injection control and ignition control will be described with reference to FIG. The control device according to the third embodiment includes, for example, a divider 301, an intake efficiency calculation unit 302, a VTC phase influence calculation unit 303, a multiplier 304, a subtractor 305, a divider, as a part of a functional block of the ECU 200. An arithmetic unit 306, arithmetic units 307 to 309, and a multiplier 310 are provided.

  The divider 301 calculates the ratio between the intake pressure Pmani and the atmospheric pressure Patm. Note that the data regarding the intake pressure Pmani and the atmospheric pressure atm can be acquired based on the intake pipe 110 and a pressure sensor (not shown) provided outside the internal combustion engine.

  The intake efficiency calculation unit 302 calculates the intake efficiency of the internal combustion engine 100 based on the engine speed and the output signal of the divider 301. Further, the VTC phase influence calculation unit 303 drives the drive signal of the VTC drive circuit 210 based on the engine speed, the output signal of the divider 301, and the operation phases (valve operation phases) of the intake valve 102 and the exhaust valve 103. The degree of influence on the intake efficiency is calculated.

  Multiplier 304 multiplies the output signal of intake efficiency calculation unit 302 and the output signal of VTC phase influence calculation unit 303. The output signal (multiplication signal) TP is output to the injection valve drive circuit 211 as fuel injection control information.

  The subtractor 305 subtracts the output signal of the multiplier 310 described later from the output signal of the multiplier 304. The output signal LDATA is output to the ignition signal output circuit 212 as combustion control and ignition control information.

The divider 306, the calculation units 307 to 309, and the multiplier 310 are portions that are responsible for calculating the above-described blow-through amount Fth. The divider 306 calculates a ratio between the exhaust pressure Pexh and the intake pressure Pmani. Further, the calculation unit 307 calculates a pressure dependency term P × Ψ (Pmani, Pexh) based on the ratio of the obtained exhaust pressure Pexh and intake pressure Pmani. The computing unit 308 computes the VVT-dependent term A _{O / L} based on the overlap width Wol and the center phase (center phase) of the overlap portion.

  In addition, the calculation unit 309 calculates √ (1 / RTmani) according to the intake air temperature Tmani.

  The multiplier 310 multiplies the output signals of the calculators 307 to 309 and calculates a blow-through amount Fth equal to the left side of the following expression.

  The subtractor 305 outputs an output signal LDATA obtained by subtracting the blow-through amount Fth calculated by the multiplier 310 from the output signal of the multiplier 304. This data LDATA includes only a factor corresponding to the trap air amount Ftr by subtracting a factor corresponding to the blow-through amount Fth.

  FIG. 11 is a graph with the pressure dependence term P × Ψ as the horizontal axis and the blow-through amount Fth as the vertical axis. The curve C1 shows the case where the overlap width Wol is large, and the curve C2 shows the overlap. The case where the width Wol is small is shown. As is apparent from FIG. 11, when the overlap width Wol is large, the pressure dependence term P × Ψ also increases, and the slope of the curve also increases. Therefore, when the overlap width Wol is changed, the blow-through amount Fth also changes greatly.

  For this reason, as shown in FIG. 10, the probability of knocking can be further reduced by estimating the blow-through amount Fth according to the overlap width Wol and using this in combustion control and ignition control.

The effect of the third embodiment will be described with reference to FIGS.
FIG. 12 is a graph of the trap air amount Ftr estimated without considering the blow-through amount Fth and the actual measurement of the trap air amount Ftr when the overlap period is extended when shifting from the scavenging mode to the low pressure EGR. It is a graph which shows the graph of a value, and the error between both. There is an error of about 20% between the estimated value and the actually measured value.

  FIG. 13 is a graph showing a trap air amount Ftr estimated in consideration of the blow-through amount Fth, a measured value graph of the trap air amount Ftr, and an error between the two in the same case. There is almost no error between the estimated value and the actually measured value.

  According to the third embodiment, the same effect as the first embodiment can be obtained, and the trap air amount Ftr can be accurately grasped and reflected in the combustion control and the ignition control. Therefore, fuel efficiency can be improved as compared with the first embodiment.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 100 ... Internal combustion engine, 101 ... Piston, 102 ... Intake valve, 103 ... Exhaust valve, 105 ... Spark plug, 106 ... Ignition coil, 107 ... Fuel injection valve, 110 ... Intake pipe, 111 ... Exhaust pipe, 112 ... Intercooler, DESCRIPTION OF SYMBOLS 113 ... Throttle valve, 114 ... Surge tank, 121 ... Exhaust passage, 121 ... Exhaust passage, 123, 129 ... Three-way catalyst, 124 ... Air-fuel ratio sensor, 125a ... Compressor, 125b ... Turbine, 126 ... EGR piping, 127 ... EGR Cooler, 128 ... EGR valve, 130 ... Intake passage, 131 ... Mass flow meter, 132 ... Pressure adjustment valve, 133 ... Pressure sensor, 134 ... Oxygen concentration sensor, 201 ... Input circuit, 205 ... I / O port, 206 ... EGR delay Estimating unit, 207... Overlap command signal generating unit, 208. Circuit, 209 ... throttle valve driving circuit, 210 ... variable valve timing (VTC) driving circuit, 211 ... fuel injector driving circuit, 212 ... ignition signal output circuit, 213 ... valve drive circuit, 300 ... accelerator opening sensor.

Claims (5)

An internal combustion engine controller that controls an internal combustion engine that includes an intake valve, an exhaust valve, and an EGR valve for recirculating exhaust gas through the intake valve,
A valve driving device for driving the intake valve, the exhaust valve, and the EGR valve;
When shifting from the first operation mode in which the intake valve and the exhaust valve are simultaneously opened to the second operation mode in which the exhaust gas is recirculated through the intake valve, the transition to the second operation mode is performed. Therefore, after the EGR valve is opened, the valve driving device is controlled so as to change the period for performing the overlap operation for simultaneously opening the intake valve and the exhaust valve in accordance with the delay of the EGR gas. An internal combustion engine control device comprising an overlap control unit. An EGR delay estimator for estimating the delay of the EGR gas;
The internal combustion engine control device according to claim 1, wherein the overlap control unit changes a period during which the overlap operation is executed according to an estimation result of the EGR delay estimation unit.   The overlap controller may overlap the overlap operation in the overlap operation in the second cycle after the first cycle in the plurality of cycles than in the first cycle in the plurality of cycles. The internal combustion engine control device according to claim 2, wherein the valve drive device is controlled so as to be shorter.   The timing at which the advance amount of the ignition plug of the internal combustion engine is increased after the EGR valve is opened for the transition to the second operation mode is changed according to an estimation result of the EGR delay estimation unit. The internal combustion engine control device according to 2 or 3. A flow rate sensor for measuring a flow rate of intake air taken into the internal combustion engine;
A trap air amount calculation unit that measures the amount of trap air trapped in the internal combustion engine by the overlap operation;
5. The internal combustion engine control device according to claim 1, wherein the trap air amount calculation unit estimates a blow-through amount that is blown through without being trapped by the internal combustion engine according to information related to the overlap operation.

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