JP6982449B2 - Engine control unit - Google Patents

Description

The present invention relates to an engine control device having a control valve (TGV or the like) that changes the gas flow in the cylinder and controlling an engine that performs EGR.

Tumble flow (longitudinal vortex) in the cylinder and in the combustion chamber by blocking a part of the flow path cross-sectional area of the intake port that introduces combustion air (fresh air) into the cylinder in an engine mounted on an automobile or the like. It is known to provide a control valve (tumble generation valve / TGV) for enhancing the gas flow such as the above and improving the combustion speed.
Further, in order to improve the thermal efficiency and the exhaust gas properties when the engine is partially loaded, it is known to perform exhaust gas recirculation (EGR) in which a part of the exhaust gas is mixed with fresh air and present in the combustion chamber.
The EGR includes an external EGR that conveys exhaust gas from the exhaust device to the intake device using an EGR flow path provided outside the engine, and exhaust gas exhaust (scavenging) by changing the valve timing with a variable valve timing mechanism. There is an internal EGR that suppresses exhaust gas and causes exhaust gas to stay in the cylinder.

As a conventional technique relating to a gas flow control valve or EGR as described above, for example, Patent Document 1 includes a vortex flow generation mechanism (TGV) for generating a tumble, and a variable valve timing mechanism is used to control retarding and advancing. A control device for an internal combustion engine that controls combustion speed and suppresses torque fluctuations is described.
Patent Document 2 describes a control device for an internal combustion engine that drives both an external EGR and an internal EGR and controls a tumble flow by a TGV to ensure a good combustion speed and a combustion state.
Patent Document 3 describes that an external EGR and an internal EGR are used in combination in an in-cylinder injection type internal combustion engine provided with a TGV and a variable valve timing mechanism.

Japanese Unexamined Patent Publication No. 2004-144101 Japanese Unexamined Patent Publication No. 2009-97411 Japanese Unexamined Patent Publication No. 2007-40310

In an engine that controls the gas flow in the cylinder by the TGV, there is a delay (accumulation delay) in the change in the EGR rate in the cylinder with respect to the change in the combustion speed due to the change in the flow during the TGV operation. In some cases, the combustion speed could not be obtained and the torque fluctuated abruptly, causing a shock or the like.
For example, when the TGV is changed from the closed state to the open state and the target EGR rate in the cylinder decreases, the external EGR is temporarily introduced more than the target due to the accumulation pressure delay, the combustion becomes slow, and the combustion speed decreases. However, it may cause a decrease in torque.
On the other hand, when the TGV is changed from the open state to the closed state and the target EGR rate in the cylinder increases, the external EGR becomes smaller than the target due to the accumulation pressure delay, so that the knocking resistance deteriorates due to the decrease in the EGR rate in the cylinder. , There is concern about the occurrence of knocking. When knocking occurs, it becomes necessary to retard the ignition timing in order to suppress it, which also causes a decrease in torque.
In view of the above-mentioned problems, an object of the present invention is to provide an engine control device that appropriately controls the combustion speed in a transient state of a control valve that changes the gas flow in the cylinder.

The present invention solves the above-mentioned problems by the following solution means.
The invention according to claim 1 comprises a gas flow control valve control unit that controls a gas flow control valve that changes the gas flow in the cylinder by opening and closing a part of the flow path cross section of the intake flow path, and a gas flow control valve control unit in the cylinder. An engine control device for controlling an engine including an EGR amount control unit that adjusts the amount of exhaust gas recirculated or retained in the cylinder so that the EGR rate becomes a predetermined target EGR rate, wherein the EGR amount control unit is When the transition from the closed state to the open state of the gas flow control valve is predicted , the EGR rate in the cylinder becomes the target EGR rate immediately after the gas flow control valve is opened . The EGR rate suppression control for suppressing the amount is executed, and the gas flow control valve control unit changes the gas flow control valve from the closed state to the open state after a predetermined delay time has elapsed after the EGR rate suppression control is started. It is an engine control device characterized by transition.
According to this, after the EGR rate suppression control is performed, the gas flow control valve is opened after a predetermined delay time elapses, so that even if there is an EGR accumulator delay, the inside of the cylinder is operated during the operation of the gas flow control valve. It is possible to keep the actual EGR rate close to the target EGR rate, suppress the torque decrease caused by the temporary excessive EGR rate and slow combustion, and cause a shock to the vehicle body. Can be prevented.

According to the second aspect of the present invention, the load state detecting unit that detects the change rate of the load of the engine and the transition from the closed state to the open state of the gas flow control valve when the change rate is equal to or higher than a predetermined threshold value. The gas flow control valve control unit has an ignition timing control unit that advances the ignition timing of the engine when predicted, and the gas flow control valve control unit has the delay time when the ignition timing is advanced. The engine control device according to claim 1, wherein the gas flow control valve is changed from the closed state to the open state before the lapse of time.
According to this, when the load change is abrupt, the ignition timing of the engine is advanced to improve the combustion speed without waiting for the lapse of the delay time after the EGR rate suppression control is started, so that the combustion speed can be improved at an early stage. The gas flow control valve can be changed to the open state, and the time response delay of the output torque of the engine can be improved.

In the invention according to claim 3, in the EGR amount control unit, when the transition from the open state to the closed state of the gas flow control valve is predicted , the EGR rate in the cylinder causes the gas flow valve to be in the closed state. The EGR rate increase control for increasing the amount of the exhaust gas is executed so as to reach the target EGR rate immediately after the above, and the gas flow control valve control unit has a predetermined delay time after the EGR rate increase control is started. The engine control device according to claim 1 or 2, wherein the gas flow control valve is changed from an open state to a closed state after the lapse of time.
The invention according to claim 4 comprises a gas flow control valve control unit that controls a gas flow control valve that changes the gas flow in the cylinder by opening and closing a part of the flow path cross section of the intake flow path, and a gas flow control valve control unit in the cylinder. An engine control device for controlling an engine including an EGR amount control unit that adjusts the amount of exhaust gas recirculated or retained in the cylinder so that the EGR rate becomes a predetermined target EGR rate, wherein the EGR amount control unit is When the transition from the open state to the closed state of the gas flow control valve is predicted , the EGR rate in the cylinder becomes the target EGR rate immediately after the gas flow control valve is closed . The EGR rate increase control for increasing the amount is executed, and the gas flow control valve control unit opens the gas flow control valve from the open state to the closed state after a predetermined delay time has elapsed after the EGR rate increase control is started. It is an engine control device characterized by transition.
According to each of these inventions, after the EGR rate increase control is performed, the gas flow control valve is closed after a predetermined delay time elapses, so that the gas flow control valve operates even if there is an EGR accumulator delay. Sometimes it becomes possible to keep the actual EGR rate in the cylinder close to the target EGR rate, temporarily causing the EGR rate to become too low and knocking to occur, or to delay the ignition timing as a response to knocking. It is possible to suppress the resulting decrease in torque and prevent the vehicle body from being shocked.

The invention according to claim 5 has a load state detection unit that detects the change rate of the load of the engine, and a transition from the open state to the closed state of the gas flow control valve when the change rate is equal to or higher than a predetermined threshold value. The gas flow control valve control unit has an ignition timing control unit that retards the ignition timing of the engine when predicted, and the gas flow control valve control unit has the delay time when the ignition timing is retarded. The engine control device according to claim 3 or 4, wherein the gas flow control valve is changed from the open state to the closed state before the lapse of time.
According to this, when the load change is abrupt, the ignition timing of the engine is retarded without waiting for the lapse of the delay time after the EGR rate increase control is started to prevent knocking, thereby preventing the gas at an early stage. The flow control valve can be moved to the closed state, and the time response delay of the output torque of the engine can be improved.

As described above, according to the present invention, it is possible to provide an engine control device that appropriately controls the combustion speed in a transient state of a control valve that changes the gas flow in the cylinder.

It is a figure which shows typically the structure of the engine which has the embodiment of the engine control device to which this invention is applied. It is a flowchart which shows the operation at the time of transition from the closed state to the open state of the TGV in the engine control device of an embodiment. It is a flowchart which shows the operation at the time of transition from the open state to the closed state of the TGV in the engine control device of an embodiment.

Hereinafter, embodiments of an engine control device to which the present invention is applied will be described.
The engine control device of the embodiment is provided in a direct-injection turbocharged gasoline engine mounted as a driving power source in an automobile such as a passenger car.
FIG. 1 is a diagram schematically showing a configuration of an engine having an engine control device according to an embodiment.
As shown in FIG. 1, the engine 1 includes a main body 10, an intake device 20, an exhaust device 30, a turbocharger 40, a fuel supply device 50, an exhaust fuel processing device 60, an EGR device 70, an engine control unit (ECU) 100, and the like. It is configured to have.

The main body 10 is a main engine portion of the engine 1, and is, for example, a horizontally opposed 4-cylinder 4-stroke DOHC gasoline direct injection engine.
The main body 10 includes a crankshaft 11, a cylinder block 12, a cylinder head 13, an intake valve drive system 14, an exhaust valve drive system 15, a spark plug 16, and the like.

The crankshaft 11 is an output shaft of the engine 1, and pistons of each cylinder (not shown) are connected via a connecting rod (connecting rod).
The cylinder block 12 is a block-shaped member having cylinders for each cylinder, and is divided into left and right parts with a crankshaft 11 interposed therebetween.
The right half of the cylinder block 12 (the left and right here refer to the left and right of the vehicle body in the vehicle-mounted state in a vertical position) is provided with the first and third cylinders in order from the front side of the vehicle, and the left half. The second and fourth cylinders are provided in the section.

A crankcase portion for accommodating the crankshaft 11 is provided at the joint portion of each of the left and right half portions of the cylinder block 12.
The crankshaft 11 is rotatably supported by a main bearing provided in the cylinder block 12.
The cylinder block 12 is provided with a crank angle sensor (not shown) that detects the angular position of the crankshaft 11.

Cylinder heads 13 are provided at both left and right ends of the cylinder block 12, respectively.
The cylinder head 13 includes a combustion chamber, an intake port, an exhaust port, an intake valve, an exhaust valve, and the like.
The combustion chamber is a recess provided facing the crown surface of the piston (not shown), and constitutes a part of a space where the air-fuel mixture compressed by the piston burns.
The intake port is a flow path for introducing combustion air (fresh air) into the combustion chamber.
The exhaust port is a flow path for discharging burned gas (exhaust gas) from the combustion chamber.
The intake valve and the exhaust valve open and close the intake port and the exhaust port at predetermined valve timings, respectively.

The intake valve drive system 14 and the exhaust valve drive system 15 are, for example, a cam sprocket driven from a crank sprocket provided at the end of the crankshaft 11 via a timing chain (not shown), and a camshaft driven by the cam sprocket. Etc., respectively.
Further, the intake valve drive system 14 and the exhaust valve drive system 15 are provided with a valve timing variable mechanism for relative rotation of the cam sprocket and the camshaft around the rotation center axis by a hydraulic actuator.

The spark plug 16 generates an electric spark in the combustion chamber at a predetermined ignition timing according to the ignition signal transmitted by the ECU 100, and ignites the air-fuel mixture.

The intake device 20 sucks in outside air and introduces it into the intake port of the cylinder head 13 as combustion air.
The intake device 20 includes an intake duct 21, an air cleaner 22, an air flow meter 23, an air bypass valve 24, an intercooler 25, a throttle 26, an intake manifold 27, a tumble generator valve 28, and the like.

The intake duct 21 is a pipeline through which combustion air sucked from the outside is conveyed.
A compressor 41 of the turbocharger 40 is provided in the middle portion of the intake duct 21 as described later.

The air cleaner 22 is provided near the inlet of the intake duct 21 and includes an air cleaner element for filtering foreign substances such as dust, an air cleaner case for accommodating the air cleaner element, and the like.
The air flow meter 23 is a sensor provided at the outlet of the air cleaner 22 and measuring the flow rate of the passing air.
The output of the air flow meter 23 is transmitted to the ECU 100 and used for controlling the fuel injection amount and the like, estimating the load state, and the like.

The air bypass valve 24 opens and closes a bypass flow path that bypasses a part of the air flowing in the intake duct 21 between the upstream side and the downstream side of the compressor 41.
The opening degree (the amount of air to be bypassed) of the air bypass valve 24 can be changed according to a command from the ECU 100. The air bypass valve 24 may be, for example, a valve that switches its opening degree between fully closed and fully open, or a valve that can be controlled to an arbitrary opening degree between fully closed and fully open.
At the time of supercharging, by opening the air bypass valve 24, a part of the supercharged fresh air in the intake duct 21 on the downstream side of the compressor 41 is returned to the upstream side of the compressor 41.
This makes it possible to reduce the differential pressure between the upstream side and the downstream side of the compressor 41.
The air bypass valve 24 is opened, for example, to protect the blade of the turbine 42 during deceleration, suppress the flow rate of purge gas when the purge valve 66 is open and stuck, and is normally closed.

The intercooler 25 cools the air compressed in the compressor 41 by, for example, heat exchange with a running wind (air flow generated for the vehicle body due to the running of the vehicle).
The throttle 26 includes a throttle valve that adjusts the intake air amount for adjusting the output of the engine 1.
The throttle valve is an electric butterfly valve that is driven to open and close by an electric actuator so as to have a predetermined opening degree in response to a command from the ECU 100.
The throttle 26 is arranged adjacent to the outlet of the intercooler 25.
A pressure sensor 26a for detecting the intake pipe pressure is provided on the inlet side (upstream side) of the throttle 26.
The output of the pressure sensor 26a is transmitted to the ECU 100.

The intake manifold 27 is a branch pipe that distributes the air discharged from the throttle 26 to the intake port of each cylinder.
The intake manifold 27 is provided with a pressure sensor 27a that detects the intake pipe pressure on the downstream side of the throttle 26.
The output of the pressure sensor 27a is transmitted to the ECU 100.

The tumble generator valve (TGV) 28 is provided in the flow path of the intake manifold 27, and controls the state of the tumble flow formed in the cylinder by switching the state of the air flow path from the intake manifold 27 to the intake port. It is a gas flow control valve.

The flow path in the intake manifold 27 is divided into two sections by a partition wall (not shown) in a part of the downstream side (intake port side).
The TGV 28 changes between a closed state in which the flow path on one side of the partition wall is substantially closed and an open state in which the flow path is opened.
The TGV 28 has a function of promoting the tumble flow in the cylinder with respect to the open state when the TGV 28 is in the closed state.
In the TGV28, for example, in a region where the engine 1 has a relatively low rotation speed and a low load, the tumble flow in the cylinder is strengthened by being closed, the combustion speed is improved, the equivalence is improved, and the thermal efficiency and torque are improved. To improve.
On the other hand, in the region where the engine 1 has a relatively high rotation speed and a high load, the gas flow in the cylinder is originally active, and the TGV 28 is opened in order to prioritize the filling efficiency.
The TGV 28 is switched according to a command from the ECU 100.
The control of the TGV 28 by the ECU 100 will be described in detail later.

The exhaust device 30 discharges burnt gas (exhaust gas) from the exhaust port of the cylinder head 13.
The exhaust device 30 includes an exhaust manifold 31, an exhaust pipe 32, a front catalyst 33, a rear catalyst 34, a silencer 35, and the like.

The exhaust manifold 31 is an exhaust gas flow path (pipeline) that collects exhaust gas emitted from the exhaust port of each cylinder and introduces it into the turbine 42 of the turbocharger 40.

The exhaust pipe 32 is an exhaust gas flow path (pipeline) that discharges the exhaust gas emitted from the turbine 42 of the turbocharger 40 to the outside.
A front catalyst 33 and a rear catalyst 34 are sequentially provided in the middle of the exhaust manifold 31 from the turbine 42 side.

The front catalyst 33 and the rear catalyst 34 are three-way catalysts in which a noble metal such as platinum, rhodium, or palladium is supported on a carrier such as alumina, and HC, CO, and NOx are reduced.
The front A / F sensor 33a and the rear A / F sensor 33b for detecting the air-fuel ratio (A / F) based on the properties of the exhaust gas are provided at the inlet and outlet of the front catalyst 33, respectively.
The outputs of the front A / F sensor 33a and the rear A / F sensor 33b are transmitted to the ECU 100 and used for air-fuel ratio feedback control of the fuel injection amount, deterioration diagnosis of the front catalyst 33, and the like.

The silencer 35 is arranged adjacent to the outlet portion of the exhaust pipe 32, and reduces the acoustic energy of the exhaust gas to suppress the exhaust noise.
The exhaust pipe 32 is branched into, for example, two in the vicinity of the outlet portion, and the silencer 35 is provided in a portion downstream of the branch portion.

The turbocharger 40 is an exhaust turbine supercharger that compresses fresh air by using the energy of exhaust gas.
The turbocharger 40 includes a compressor 41, a turbine 42, a bearing housing 43, a wastegate valve 44, and the like.

The compressor 41 is a centrifugal compressor that compresses combustion air.
The turbine 42 drives the compressor 41 by using the energy of the exhaust gas.
The bearing housing 43 is provided between the compressor 41 and the turbine 42.
The bearing housing 43 includes a bearing, a lubricating device, and the like that connect between the housings of the compressor 41 and the turbine 42 and rotatably support the shaft connecting the compressor wheel and the turbine wheel.

The wastegate valve 44 opens and closes a wastegate flow path that bypasses a part of the exhaust gas from the inlet side to the outlet side of the turbine 42.
The wastegate valve 44 has an electric actuator for driving opening / closing and an opening sensor (not shown) for detecting an opening position, and the opening is controlled by the ECU 100.

The fuel supply device 50 supplies fuel to each cylinder of the engine 1.
The fuel supply device 50 includes a fuel tank 51, a feed pump 52, a feed line 53, a high pressure pump 54, a high pressure fuel line 55, an injector 56, and the like.

The fuel tank 51 is a container in which gasoline as fuel is stored.
The feed pump 52 discharges the fuel in the fuel tank 51 and conveys it to the high-pressure pump 54.
The feed line 53 is a fuel flow path for transporting the fuel discharged by the feed pump 52 to the high pressure pump 54.

The high-pressure pump 54 is attached to the cylinder head 13 and driven via a camshaft to increase the fuel pressure.
The high-pressure pump 54 includes a plunger that reciprocates in the cylinder to pressurize the fuel in conjunction with the rotation of the camshaft, and an electromagnetic metering valve, and controls the duty ratio of the electromagnetic metering valve by the ECU 100 to control the high-pressure fuel. The fuel pressure in the line 55 can be adjusted.
The high-pressure fuel line 55 is a fuel flow path for transporting the fuel after boosting by the high-pressure pump 54 to the injectors 56 provided in each cylinder.
The injector 56 is an injection valve that injects fuel supplied from the high-pressure fuel line 55 into the combustion chamber of each cylinder in response to an injection signal from the ECU 100.

The evaporative fuel processing device 60 temporarily stores the fuel evaporative gas (evapo) generated by evaporating the fuel (gasoline) in the fuel tank 51 in the canister 61, and at the same time, the intake duct 21 is used as a purge gas when the engine 1 is operated. It is introduced inside (canister purge) and burned in the combustion chamber.
The evaporative fuel processing device 60 includes a canister 61, an evaporator check module 62, a purge line 63, 64, 65, a purge valve 66, a pressure sensor 67, an ejector 68, and the like.

The canister 61 is a charcoal canister configured by accommodating activated carbon capable of adsorbing fuel evaporative gas in a case.
In the canister 61, fuel evaporative gas is introduced from the fuel tank 51 via the pipe 61a.
A fuel cut valve 61b for preventing the inflow of liquid phase fuel is provided at the end of the pipe 61a on the fuel tank 50 side.

The evaporator check module (ELCM) 62 is provided adjacent to the canister 61 and automatically detects a leak of fuel evaporative gas from the evaporative fuel processing device 60.

The purge lines 63, 64, and 65 are pipelines for introducing the fuel evaporative gas stored in the canister 61 into the intake duct 21 of the intake device 20 as the purge gas during the operation of the engine 1.
The upstream end of the purge line 63 is connected to the canister 61, and the downstream end of the purge line 63 is connected to the inlet side of the purge valve 66.
The upstream end of the purge line 64 is connected to the exit side of the purge valve 66, and the downstream end is connected to the intake manifold 27.
A check valve 64a is provided in the middle of the purge line 64.
The check valve 64a is a check valve that prevents backflow of purge gas from the intake manifold 27 side to the purge valve 66 side.

The purge line 65 introduces a part of the purge gas flowing out from the purge valve 66 to the purge line 64 into the ejector 68.
The purge line 65 branches from the region between the purge valve 66 and the check valve 64a in the purge line 64, and the downstream end is connected to the region downstream of the nozzle 68b in the ejector 68.
A check valve 65a is provided in the middle of the purge line 65.
The check valve 65a is a check valve that prevents backflow of purge gas from the ejector 68 side to the purge valve 66 side.

The purge valve 66 is a solenoid valve capable of switching between an open state in which purge gas can pass from the purge line 63 to the purge lines 64 and 65 and a closed state in which the purge line 63 and the purge line 64 are cut off.
The purge valve 66 is opened and closed in response to an open command and a close command from the ECU 100.

The pressure sensor 67 is provided in the middle of the purge line 63 and detects the pressure of the purge gas in the purge line 63.
The output of the pressure sensor 67 is transmitted to the ECU 100.

The ejector 68 is a negative pressure generator that sucks purge gas by utilizing the differential pressure between the upstream side and the downstream side of the compressor 41 of the turbocharger 40 and introduces it into the intake duct 21.
The ejector 68 is formed in the shape of a tubular container, and is configured to have an introduction pipe line 68a, a nozzle 68b, a discharge port 68c, and the like.
The introduction pipe 68a is a pipe for introducing air extracted from the region downstream of the compressor 41 of the intake duct 21 to the upstream end of the ejector 68.
The nozzle 68b is introduced from the introduction pipe line 68a, narrows the air flow flowing in the ejector 68 to increase the flow velocity, and generates a negative pressure by the Venturi effect.

The downstream end of the purge line 65 is connected to a region downstream of the nozzle 68b in the ejector 68 so that the purge gas is sucked into the ejector 68 by the negative pressure generated by the nozzle 68b and merges with the air flow. It has become.
The discharge port 68c is provided at the downstream end of the ejector 68, and is a communication point for introducing the merged air and purge gas from the inside of the ejector 68 into the region upstream of the compressor 41 in the intake duct 21.

The EGR device 70 extracts a part of the exhaust gas from the exhaust manifold 31 as EGR gas and performs exhaust gas recirculation (EGR) to be introduced into the intake manifold 27.
The EGR device 70 includes an EGR flow path 71, an EGR cooler 72, an EGR valve 73, and the like.

The EGR flow path 71 is a pipeline for introducing exhaust gas (EGR gas) from the exhaust manifold 31 to the intake manifold 27.
The EGR cooler 72 is provided in the middle of the EGR flow path 71, and cools the EGR gas flowing through the EGR flow path 71 by heat exchange with the cooling water of the engine 1 to enable cooled EGR.

The EGR valve 73 is a metering valve provided on the downstream side of the EGR cooler 72 in the EGR flow path 71 and regulates the flow rate of the EGR gas passing through the EGR flow path 71.
The EGR valve 73 has a valve body driven by an electric actuator such as a solenoid.
The opening degree of the EGR valve 73 is controlled by the ECU 100 in the steady state using an opening degree map set based on a predetermined target EGR rate (EGR gas flow rate / intake flow rate).
The opening degree map is configured so that the target opening degree of the EGR valve 73 is read out from the rotation speed (rotational speed) of the crankshaft 10 of the engine 1 and the load factor with respect to the total load.
The opening map is set so that the combustion speed (or mean effective pressure in the cylinder) and knocking resistance performance in each operating region of the engine 1 are appropriate.
In the steady operation, the EGR valve 73 controls the valve opening rate at the time of opening / closing and opening according to the opening degree instruction value given from the ECU 100.

The engine control unit (ECU) 100 is an engine control device that comprehensively controls the engine 1 and its accessories.
In FIG. 1, only the connection with the TGV 28 and the EGR valve 73 is shown by the broken line, but the ECU 100 is actually connected to each sensor, device, etc. directly or via an in-vehicle LAN or the like so as to be able to communicate with each other. ing.
The ECU 100 includes, for example, information processing means such as a CPU, storage means such as RAM and ROM, an input / output interface, and a bus connecting these.
The output of each sensor provided in the engine 1 is transmitted to the ECU 100, and a control signal can be output to a control target such as an actuator, valves, spark plugs, injectors, etc. provided in the engine 1. It has become.

The ECU 100 calculates the driver required torque based on the operation amount (depression amount) of the accelerator pedal (not shown), and opens the throttle 26 so that the torque (actual torque) actually generated by the engine 1 approaches the driver required torque. The output (torque) of the engine 1 is adjusted by controlling the degree, valve timing, boost pressure, ignition timing, fuel injection amount, injection timing, and the like.

Further, the ECU 100 functions as an EGR amount control unit that controls the EGR rate in the cylinder so that the combustion speed in the engine 1 approaches a predetermined target combustion speed in cooperation with the EGR valve 73.
The target combustion speed is set for each operating region such as engine speed (crankshaft rotation speed) and load. The target EGR rate is set according to the target combustion rate, and the above-mentioned opening map is set so that the actual EGR rate during steady operation substantially matches the target EGR rate.
Further, the ECU 100 also functions as a gas flow control valve control unit that closes the TGV 28 when the engine speed and the load are within a predetermined range, and opens the TGV 28 in other cases.

Hereinafter, the operation of the TGV 28 in the engine control device of the embodiment when the TGV 28 is opened and closed will be described.
When the TGV 28 is operated, it may be a problem that the gas flow in the cylinder changes abruptly, the combustion speed changes, and the torque suddenly changes, especially at the initial stage of the operation.
For example, when the TGV28 changes from the closed state to the open state, the tumble flow in the cylinder tends to weaken and the combustion speed tends to decrease. Therefore, in order to maintain the combustion speed and suppress torque fluctuation, EGR is used. It needs to be suppressed.
However, since there is a pressure accumulation delay until the EGR rate in the cylinder changes after changing the opening degree of the EGR valve 73, when the TGV28 and the EGR valve 73 are operated at the same time, the EGR temporarily changes. There is a concern that the combustion speed will decrease due to excessive gas recirculation.
Therefore, in the embodiment, the control described below is performed.
FIG. 2 is a flowchart showing the operation of the TGV in the engine control device of the embodiment when the TGV is in the closed state to the open state.
The process shown in FIG. 2 is started on the premise that the TGV 28 is in the closed state.
Hereinafter, each step will be described step by step.

<Step S01: Engine speed / load acquisition>
The ECU 100 acquires information on the engine rotation speed (rotational speed of the crankshaft) from the crank angle sensor, and also loads the engine from the accelerator pedal sensor, the air flow meter 23, etc. (% when the torque at full open is 100%). Get information about.
Then, the process proceeds to step S02.

<Step S02: TGV closed → open prediction establishment judgment>
Whether or not the TGV 28 changes from the closed state to the open state within a predetermined period (for example, within several hundred msec) in the future based on the change from the current value and the immediately preceding value of the engine speed and the load acquired in step S01. To determine.
For example, on a map in which the open / closed state of the TGV 28 is set from the engine speed and load, a predetermined switching preparation area is provided in the boundary area between the open area and the closed area, and the current operating state is in the switching preparation area. The configuration may be such that the transition is predicted in some cases.
If the transition to the open state of TGV28 is predicted, the process proceeds to step S03, and in other cases, the process returns to step S01, and the subsequent processing is repeated.

<Step S03: EGR valve opening reduction>
The ECU 100 lowers the target opening degree of the EGR valve 73 and reduces the opening degree of the EGR valve 73 by a predetermined amount.
The opening degree of the EGR valve 73 is set, for example, so that the EGR rate in the cylinder substantially matches the target EGR rate immediately after opening the TGV 28.
After that, the process proceeds to step S04.

<Step S04: Judgment of load change speed>
The ECU 100 determines whether or not the change speed (change per unit time) of the load of the engine 1 is equal to or higher than a predetermined value.
For example, if the change speed of the driver required torque is equal to or higher than a preset predetermined threshold value, the process proceeds to step S08, and if it is less than the threshold value, the process proceeds to step S05.

<Step S05: TGV delay time calculation>
The ECU 100 calculates the delay time (TGV delay time) from driving the EGR valve 73 in step S03 to starting driving the TGV 28.
The TGV delay time is the desired target EGR rate in the engine 1 after the operation of the EGR valve 73 in consideration of the accumulator delay from the change in the opening degree of the EGR valve 73 to the change in the actual EGR rate in the cylinder. That is, it is set as a delay time until the target combustion rate is obtained.
For the TGV delay time, for example, considering the internal volume of the intake manifold 27 and the internal volume of the cylinder, how the EGR rate after operating the EGR valve 73 changes due to the accumulator delay is a primary delay factor. It can be obtained as a transient response.
Further, the actual combustion speed in the engine 1 is estimated from, for example, the mean effective pressure detected by the in-cylinder pressure sensor, the angular velocity of the crankshaft 11 in the combustion stroke, the angular acceleration, and the like, and the estimated combustion speed is the desired target combustion. The time that substantially matches the velocity may be the end of the TGV delay time.
Further, when the control of the present invention is simply applied, the TGV delay time may be set in advance as the map value read from the engine rotation speed-load.
Then, the process proceeds to step S06.

<Step S06: Judgment of passage of TGV delay time>
The ECU 100 determines whether the elapsed time after driving the EGR valve 73 to a predetermined opening in step S03 has elapsed the TGV delay time set in step S05 (whether it is equal to or longer than the TGV delay time).
If the elapsed time has elapsed the TGV delay time, the process proceeds to step S07, and if not, step S06 is repeated.

<Step S07: Transition from TGV closed state to open state>
The ECU 100 shifts the TGV 28 from the closed state to the open state.
After that, a series of processes is terminated.

<Step S08: Ignition timing advance angle>
The ECU 100 temporarily advances the ignition timing of the spark plug 16 within a range in which knocking does not matter, in order to improve the combustion speed.
Here, the time for advancing the ignition timing can be substantially the same as the above-mentioned TGV delay time.
This prevents the amount of external EGR from temporarily increasing after the TGV 28 is opened, and the actual EGR rate becomes higher than the target EGR rate, resulting in slow combustion.
Then, the process proceeds to step S07.

FIG. 3 is a flowchart showing the operation of the TGV in the engine control device of the embodiment when the TGV is in the open state to the closed state.
The process shown in FIG. 3 is started on the premise that the TGV is in the open state.
Hereinafter, each step will be described step by step.

<Step S11: Engine speed / load acquisition>
Similar to step S01, the ECU 100 acquires information on the engine speed and the load.
Then, the process proceeds to step S12.

<Step S12: TGV open → closed prediction establishment judgment>
Whether or not the TGV 28 changes from the open state to the closed state within a predetermined period (for example, within several hundred msec) in the future based on the change from the current value and the immediately preceding value of the engine speed and the load acquired in step S11. To determine.
If the transition of the TGV 28 to the closed state is predicted, the process proceeds to step S13, and in other cases, the process returns to step S11, and the subsequent processes are repeated.

<Step S13: Increase in EGR valve opening>
The ECU 100 improves the target opening degree of the EGR valve 73 and increases the opening degree of the EGR valve 73 by a predetermined amount.
The opening degree of the EGR valve 73 is set, for example, so that the EGR rate in the cylinder substantially matches the target EGR rate immediately after closing the TGV 28.
After that, the process proceeds to step S14.

<Step S14: Judgment of load change speed>
The ECU 100 determines whether or not the change speed (change per unit time) of the load of the engine 1 is equal to or higher than a predetermined value.
For example, if the change speed of the driver required torque is equal to or higher than a preset predetermined threshold value, the process proceeds to step S18, and if it is less than the threshold value, the process proceeds to step S15.

<Step S15: TGV delay time calculation>
The ECU 100 calculates the delay time (TGV delay time) from driving the EGR valve 73 in step S13 to starting driving the TGV 28 in substantially the same manner as in step S05 described above.
Then, the process proceeds to step S16.

<Step S16: TGV delay time elapsed determination>
The ECU 100 determines whether the elapsed time after driving the EGR valve 73 to a predetermined opening in step S13 has elapsed the TGV delay time set in step S15 (whether it is equal to or longer than the TGV delay time).
If the elapsed time has elapsed the TGV delay time, the process proceeds to step S17, and if not, step S16 is repeated.

<Step S17: Transition from TGV closed state to open state>
The ECU 100 changes the TGV 28 from the open state to the closed state.
After that, a series of processes is terminated.

<Step S18: Ignition timing retard>
The ECU 100 temporarily retards the ignition timing of the spark plug 16 to suppress knocking.
Here, the time for retarding the ignition timing can be substantially the same as the above-mentioned TGV delay time.
As a result, after the TGV 28 is closed, the amount of external EGR temporarily decreases, and the actual EGR rate becomes lower than the target EGR rate to prevent knocking from occurring.
After that, the process proceeds to step S17.

According to the embodiment described above, the effects described below can be obtained.
(1) By opening the TGV 28 after the elapse of a predetermined TGV delay time after reducing the opening degree of the EGR valve 73 in order to suppress the EGR rate, even if there is a delay in the accumulation of EGR, the TGV 28 is in operation. It is possible to keep the actual EGR rate in the cylinder close to the target EGR rate, suppress the torque drop caused by the temporary excessive EGR rate and slow combustion, and cause a shock to the vehicle body. Can be prevented from doing so.
(2) When the load change when opening the TGV28 is sudden, after the opening operation of the EGR valve 73 is started, the ignition timing of the engine is advanced without waiting for the lapse of the delay time to improve the combustion speed. By doing so, the TGV 28 can be moved to the open state at an early stage, and the time response delay of the output torque of the engine can be improved.
(3) By closing the TGV28 after the predetermined TGV delay time has elapsed after increasing the opening degree of the EGR valve 73 in order to increase the EGR rate, even if there is an EGR accumulation delay, the TGV28 is operating. It is possible to keep the actual EGR rate in the cylinder close to the target EGR rate, which is caused by the fact that the EGR rate temporarily becomes too low and knocking occurs, or the ignition timing is retarded as a response to knocking. It is possible to suppress the decrease in torque and prevent the vehicle body from being shocked.
(4) When the load change when closing the TGV28 is sudden, the opening operation of the EGR valve 73 is started, and the ignition timing of the engine is retarded without waiting for the lapse of the post-delay time to prevent knocking. As a result, the TGV 28 can be moved to the closed state at an early stage, and the time response delay of the output torque of the engine can be improved.

(Modification example)
The present invention is not limited to the embodiments described above, and various modifications and changes can be made, and these are also within the technical scope of the present invention.
(1) The configuration of the engine control device and the engine can be appropriately changed without being limited to the above-described embodiment.
For example, the cylinder layout of the engine, the number of cylinders, the combustion injection method, the valve drive method, the presence / absence and type of the supercharger, and the like are not limited to the configuration of the embodiment and can be appropriately changed.
(2) Although the embodiment relates to a premixed spark ignition type gasoline engine, the present invention can also be applied to a compression ignition type diesel engine. In this case, by advancing and retarding the fuel injection timing, the ignition timing (ignition timing) can be advanced and retarded, and substantially the same effect as the ignition timing control in a spark ignition type engine can be obtained. can.
(3) In the embodiment, the EGR rate is controlled by an external EGR using an EGR device having a flow path outside the engine, but by changing the valve timing by using a variable valve timing mechanism. The EGR rate may be controlled by adjusting the amount of internal EGR using the exhaust gas remaining in the cylinder.
(4) In the embodiment, the gas flow control valve is a tumble generator valve (TGV) having a function of strengthening the tumble flow in the cylinder. , Tumble, and swirl other than those that enhance gas flow (gas turbulence) can also be used.

1 Engine 10 Main body 11 Crank shaft 12 Cylinder block 13 Cylinder head 14 Intake valve drive system 15 Exhaust valve drive system 16 Ignition plug 20 Intake device 21 Intake duct 22 Air cleaner 23 Air flow meter 24 Air bypass valve 25 Intercooler 26 Throttle 26a Pressure sensor 27 Intake Manifold 27a Pressure Sensor 28 Tumble Generator Valve 30 Exhaust Device 31 Exhaust Manifold 32 Exhaust Pipe 33 Front Catalyst 33a Front A / F Sensor 33b Rear A / F Sensor 34 Rear Catalyst 35 Silencer 40 Turbo Charger 41 Compressor 42 Turbine 43 Bearing Housing 44 Wastegate valve 50 Fuel supply device 51 Fuel tank 52 Feed pump 53 Feed line 54 High pressure pump 55 High pressure fuel line 56 Injector 60 Evaporative fuel processing device 61 Canister 61a Piping 61b Fuel cut valve 62 Eva polyk check module (ELCM)
63 Purge line 64 Purge line 64a Check valve 65 Purge line 66 Purge valve 67 Pressure sensor 68 Ejector 68a Introductory line 68b Nozzle 68c Discharge port 70 EGR device 71 EGR flow path 72 EGR cooler 73 EGR valve 100 Engine control unit (ECU)

Claims (5)

A gas flow control valve control unit that controls a gas flow control valve that changes the gas flow in the cylinder by opening and closing a part of the cross section of the intake flow path.
An engine control device for controlling an engine including an EGR amount control unit that adjusts the amount of exhaust gas recirculated or retained in the cylinder so that the EGR rate in the cylinder becomes a predetermined target EGR rate.
In the EGR amount control unit, when the transition from the closed state to the open state of the gas flow control valve is predicted , the EGR rate in the cylinder is the target EGR rate immediately after the gas flow valve is opened. The EGR rate suppression control that suppresses the amount of the exhaust gas is executed so as to be
The gas flow control valve control unit is an engine control device characterized in that the gas flow control valve is changed from a closed state to an open state after a predetermined delay time has elapsed after the EGR rate suppression control is started. A load state detection unit that detects the rate of change in the load of the engine,
It has an ignition timing control unit that advances the ignition timing of the engine when the change rate is equal to or higher than a predetermined threshold value and the transition from the closed state to the open state of the gas flow control valve is predicted.
The claim is characterized in that, when the ignition timing is advanced, the gas flow control valve control unit shifts the gas flow control valve from the closed state to the open state before the lapse of the delay time. Item 1. The engine control device according to item 1. In the EGR amount control unit, when the transition from the open state to the closed state of the gas flow control valve is predicted , the EGR rate in the cylinder is the target EGR rate immediately after the gas flow valve is closed. The EGR rate increase control that increases the amount of the exhaust gas is executed so as to be
Claim 1 or claim, wherein the gas flow control valve control unit shifts the gas flow control valve from an open state to a closed state after a predetermined delay time elapses after the EGR rate increase control is started. Item 2. The engine control device according to item 2. A gas flow control valve control unit that controls a gas flow control valve that changes the gas flow in the cylinder by opening and closing a part of the cross section of the intake flow path.
An engine control device for controlling an engine including an EGR amount control unit that adjusts the amount of exhaust gas recirculated or retained in the cylinder so that the EGR rate in the cylinder becomes a predetermined target EGR rate.
In the EGR amount control unit, when the transition from the open state to the closed state of the gas flow control valve is predicted , the EGR rate in the cylinder is the target EGR rate immediately after the gas flow valve is closed. The EGR rate increase control that increases the amount of the exhaust gas is executed so as to be
The gas flow control valve control unit is an engine control device characterized in that the gas flow control valve is changed from an open state to a closed state after a predetermined delay time has elapsed after the EGR rate increase control is started. A load state detection unit that detects the rate of change in the load of the engine,
It has an ignition timing control unit that retards the ignition timing of the engine when the change rate is equal to or higher than a predetermined threshold value and the transition from the open state to the closed state of the gas flow control valve is predicted.
The claim is characterized in that, when the ignition timing retard is performed, the gas flow control valve control unit shifts the gas flow control valve from an open state to a closed state before the lapse of the delay time. The engine control device according to claim 3 or 4.

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