JP2020147150A - Vehicle control device - Google Patents

Abstract

To curb degradation of exhaust emissions when an internal combustion engine is started up in cold time through cranking of a starter.SOLUTION: When starting up an internal combustion engine 1 in cold time through cranking of a starter 21, a control device 200 of a vehicle 100 is adapted to: inject fuel through a fuel injection valve 42 so as to prevent an amount of the fuel injected through the fuel injection valve 42 from becoming less than a lower limit; combust the fuel injected through the fuel injection valve 42 by igniting the same with an ignition timing delayed for a certain period for warming up a catalyst device 63 installed on in exhaust passage of the internal combustion engine 1; and, after an engine rotation speed becomes higher than a target idling rotation speed, perform regenerative drive of a rotating electrical machine 22 so that the engine rotation speed converges to the target idling rotation speed.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle control device.

Patent Document 1 intentionally rotates the engine in order to quickly stabilize the rotation speed of the internal combustion engine (hereinafter referred to as "engine rotation speed") at the target rotation speed when an acceleration request is made during coasting. When the speed is overshooted with respect to the target rotation speed and the engine rotation speed overshoots with respect to the target rotation speed, the rotary electric machine (motor generator) is regeneratively driven so as to reach the target rotation speed. The vehicle control device is disclosed.

Japanese Unexamined Patent Publication No. 2016-141379

However, in Patent Document 1, the overshoot that occurs when the internal combustion engine is started by cranking with a starter, that is, the increase in the engine rotation speed is regeneratively driven to suppress the rotation electric machine in the cold state. That is not disclosed.

Here, it is conceivable to start the internal combustion engine by cranking by a rotary electric machine, but it is necessary to start the internal combustion engine because the output power of the battery is limited from the viewpoint of suppressing the deterioration of the battery when it is cold. It may not be possible to supply power to the rotary electric machine. Therefore, when it is cold, it is conceivable to start the internal combustion engine by cranking with a starter.

However, when the internal combustion engine is started by cranking with a starter when it is cold and the engine rotation speed rises, if the fuel injection amount is reduced in order to suppress the blow-up, the catalyst device warms up when it is cold. Since the ignition timing is also retarded to accelerate the machine, combustion tends to be unstable. Therefore, the amount of unburned HC discharged may increase and the exhaust emission may deteriorate.

The present invention has been made by paying attention to such a problem, and when the internal combustion engine is started by cranking by a starter when it is cold, the exhaust emission is deteriorated when the catalyst device is warmed up. The purpose is to suppress the rise of the engine rotation speed while suppressing it.

In order to solve the above problems, a vehicle according to an embodiment of the present invention includes an internal combustion engine that generates power by burning fuel injected from a fuel injection valve by spark ignition with a spark plug, and cranking of the internal combustion engine. It is provided with a starter for performing the above and a rotary electric machine which is regenerated and driven by the power of an internal combustion engine. Then, when the vehicle control device for controlling this vehicle starts the internal combustion engine by cranking with a starter when it is cold, the fuel injected from the fuel injection valve is not less than a predetermined lower limit value. While injecting fuel from the injection valve, the ignition timing is delayed at a predetermined timing to warm up the catalyst device provided in the exhaust passage of the internal combustion engine, and the fuel injected from the fuel injection valve is ignited and burned. When the engine rotation speed becomes higher than a predetermined target idle rotation speed, the rotary electric machine is regeneratively driven to converge the engine rotation speed to the target idle rotation speed.

According to this aspect of the present invention, when the internal combustion engine is started by cranking with a starter when it is cold, combustion does not become unstable even if the ignition timing is delayed due to warming up of the catalyst device. The combustion injection amount from the fuel injection valve is controlled so that it does not fall below the lower limit, and when the engine speed becomes higher than the target idle speed, the rotary electric machine is regenerated to set the engine speed as the target idle speed. Is converged to. Therefore, when the internal combustion engine is started by cranking by the starter when it is cold, it is possible to suppress the deterioration of the exhaust emission when the warm-up of the catalyst device overlaps, and also to suppress the rise of the engine rotation speed. ..

It is a schematic block diagram which showed a part of the vehicle by one Embodiment of this invention, and the electronic control unit for controlling a vehicle. FIG. 2 is a schematic cross-sectional view of an internal combustion engine according to an embodiment of the present invention. FIG. 3 is a flowchart illustrating start control of an internal combustion engine according to an embodiment of the present invention. FIG. 4 is a flowchart illustrating the details of the first start processing according to the embodiment of the present invention. FIG. 5 is a flowchart illustrating the regenerative control of the rotary electric machine according to the embodiment of the present invention, which is carried out together with the first starting process. FIG. 6 is a time chart illustrating the first starting process and the operation of the regenerative control of the rotary electric machine performed in combination with the first starting process.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, similar components are given the same reference number.

FIG. 1 is a schematic configuration diagram showing a part of a vehicle 100 according to an embodiment of the present invention and an electronic control unit 200 for controlling the vehicle 100.

As shown in FIG. 1, the vehicle 100 includes an internal combustion engine 1 and a starting device 2 for starting the internal combustion engine 1.

The internal combustion engine 1 rotates the crankshaft 11 by burning fuel inside the internal combustion engine 1 to generate power for driving the vehicle 100. The output of the internal combustion engine 1 is finally transmitted to the wheel drive shaft (not shown) via a power transmission device (not shown) or the like. A flywheel 12 that rotates integrally with the crankshaft 11 is attached to one end of the crankshaft 11 (on the right side in the drawing). A ring gear 12a that meshes with a pinion gear 21b attached to an output shaft 21a of a starter 21, which will be described later, is attached to the outer periphery of the flywheel 12. A first pulley 13 that rotates integrally with the crankshaft 11 is attached to the other end of the crankshaft 11. Hereinafter, the detailed configuration of the internal combustion engine 1 will be described with reference to FIG.

FIG. 2 is a schematic cross-sectional view of the internal combustion engine 1.

As shown in FIG. 2, the internal combustion engine 1 includes an engine main body 30, an intake device 50, and an exhaust device 60.

The engine body 30 includes a cylinder block 31 and a cylinder head 32 fixed to the upper surface of the cylinder block 31.

A plurality of cylinders 33 are formed in the cylinder block 31. Inside the cylinder 33, a piston 34 that reciprocates inside the cylinder 33 in response to combustion pressure is housed. The piston 34 is connected to the crankshaft 11 (see FIG. 1) via a connecting rod (not shown), and the crankshaft 11 converts the reciprocating motion of the piston 34 into a rotary motion. The space defined by the inner wall surface of the cylinder head 32, the inner wall surface of the cylinder 33, and the crown surface of the piston 34 is the combustion chamber 35.

The cylinder head 32 includes an intake port 36 that opens to one side surface of the cylinder head 32 and opens to the combustion chamber 35, and an exhaust port 37 that opens to the other side surface of the cylinder head 32 and opens to the combustion chamber 35. Is formed.

Further, the cylinder head 32 includes an intake valve 38 for opening and closing the openings of the combustion chamber 35 and the intake port 36, an exhaust valve 39 for opening and closing the openings of the combustion chamber 35 and the exhaust port 37, and an intake valve 38. An intake camshaft 40 for opening and closing the exhaust valve 39 and an exhaust camshaft 41 for opening and closing the exhaust valve 39 are attached. At one end of the intake camshaft 40, a hydraulic variable valve mechanism (not shown) that can set the opening / closing timing of the intake valve 38 at an arbitrary timing is provided.

Further, the cylinder head 32 is ignited by a fuel injection valve 42 for injecting fuel into the combustion chamber 35 and an ignition for igniting a mixture of fuel and air injected from the fuel injection valve 42 in the combustion chamber 35. The plug 43 and the plug 43 are attached so as to face the combustion chamber 35, respectively. The fuel injection valve 42 may be installed so as to inject fuel into the intake port 36.

The intake device 50 is a device for guiding air into the cylinder 33 via the intake port 36, and includes an air cleaner 51, an intake pipe 52, an intake manifold 53, an air flow meter 214, and an electronically controlled throttle valve. 54 and.

The air cleaner 51 removes foreign matter such as sand contained in the air.

One end of the intake pipe 52 is connected to the air cleaner 51, and the other end is connected to the surge tank 53a of the intake manifold 53. The air (intake) that has flowed into the intake pipe 52 via the air cleaner 51 is guided by the intake pipe 52 to the surge tank 53a of the intake manifold 53.

The intake manifold 53 includes a surge tank 53a and a plurality of intake branch pipes 53b that branch from the surge tank 53a and are connected to the openings of the intake ports 36 formed on the side surface of the cylinder head. The air guided to the surge tank 53a is evenly distributed in each cylinder 33 via the intake branch pipe 53b. In this way, the intake pipe 52, the intake manifold 53, and the intake port 36 form an intake passage for guiding air into each cylinder 33.

The air flow meter 214 is provided in the intake pipe 52. The air flow meter 214 detects the flow rate of air flowing through the intake pipe 52 and being sucked into the combustion chamber 35 of each cylinder 33 (hereinafter referred to as “intake air amount”).

The throttle valve 54 is provided in the intake pipe 52 on the downstream side of the air flow meter 214. The throttle valve 54 is driven by the throttle actuator 55 to continuously or stepwise change the passage cross section of the intake pipe 52. The intake air amount is adjusted by adjusting the opening degree of the throttle valve 54 (hereinafter referred to as "throttle opening degree") by the throttle actuator 55. The throttle opening degree is detected by the throttle sensor 215.

The exhaust device 60 is a device for purifying the combustion gas (hereinafter referred to as "exhaust") generated in the combustion chamber 35 and discharging it to the outside air, and is an exhaust manifold 61, an exhaust pipe 62, and a catalyst device 63. And.

The exhaust manifold 61 includes a plurality of exhaust branch pipes connected to the openings of the exhaust ports 37 formed on the side surface of the cylinder head, and a collecting pipe in which the exhaust branch pipes 31a are assembled into one.

One end of the exhaust pipe 62 is connected to the collecting pipe of the exhaust manifold 61, and the other end is open to the outside air. The exhaust gas discharged from each cylinder 33 to the exhaust manifold 61 via the exhaust port 37 flows through the exhaust pipe 62 and is discharged to the outside air. In this way, the exhaust port 37, the exhaust manifold 61, and the exhaust pipe 62 form an exhaust passage through which the exhaust discharged from each cylinder 33 flows.

The catalyst device 63 is a device for purifying the exhaust gas and then discharging it to the outside air, and is a carrier on which various catalysts for purifying harmful substances (for example, an oxidation catalyst, a three-way catalyst, etc.) are supported.

In the present embodiment, the spark-ignition type internal combustion engine as described above has been illustrated as an example of the internal combustion engine 1, but the spark-ignition type internal combustion engine is not particularly limited to the above configuration, for example. , Cylinder arrangement, fuel injection mode, intake / exhaust system configuration, valve operating mechanism configuration, presence / absence of supercharger, supercharging mode, etc. may be different from the above configurations.

Returning to FIG. 1, the starting device 2 includes a starter 21, a rotary electric machine 22, a first battery 23, a second battery 24, a DC / DC converter 25, and an inverter 26.

The starter 21 is, for example, a DC series-wound motor. As described above, the pinion gear 21b is attached to the output shaft 21a of the starter 21. The starter 21 is electrically connected to the first battery 23 and is power-driven by receiving power supplied from the first battery 23. By driving the starter 21 by power running to rotate the output shaft 21a, the flywheel 12 to which the ring gear 12a that meshes with the pinion gear 21b is attached, and eventually the crankshaft 11 can be rotated. Therefore, the internal combustion engine 1 can be cranked by power-driving the starter 21 when the internal combustion engine 1 is started.

The rotary electric machine 22 is, for example, a three-phase AC synchronous type motor generator. A second pulley 14 that rotates integrally with the output shaft 22a of the rotary electric machine 22 is attached to the output shaft 22a of the rotary electric machine 22. The second pulley 14 is connected to the first pulley 13 via the belt 15. Further, the rotary electric machine 22 is electrically connected to the second battery 24 via the inverter 26, and is also electrically connected to the first battery 23 via the inverter 26 and the DC / DC converter 25.

The rotary electric machine 22 has a function as an electric motor, and is power-driven by receiving electric power from the second battery 24. By driving the rotary electric machine 22 by power running to rotate the second pulley 14 together with the output shaft 22a, the first pulley 13 and eventually the crankshaft 11 can be rotated via the belt 15. Therefore, even if the rotary electric machine 22 is driven by power when the internal combustion engine 1 is started, the internal combustion engine 1 can be cranked. Further, while the internal combustion engine 1 is in operation, the rotary electric machine 22 is driven by power to drive the so-called internal combustion engine 1, and the vehicle 100 is driven by using both the output torque of the internal combustion engine 1 and the output torque of the rotary electric machine 22. It can also be driven.

Further, the rotary electric machine 22 also has a function as a generator, and by rotating the crankshaft 11 to rotate the first pulley 13, the second pulley 14 and eventually the rotary electric machine 22 are connected via the belt 15. The output shaft 22a can be rotated. Therefore, when the crankshaft 11 is rotating, such as when the fuel is burned inside the internal combustion engine 1 or when the vehicle 100 is running inertially, the rotary electric machine 22 is regeneratively driven to generate electricity. The generated power can be charged to the first battery 23 and the second battery 24.

The first battery 23 is a rechargeable secondary battery such as a nickel-cadmium storage battery, a nickel-hydrogen storage battery, or a lithium-ion battery. The first battery 23 is electrically connected to the starter 21 so that the charging power charged in the first battery 23 can be supplied to the starter 21 to power drive the starter 21. Further, the first battery 23 electrically supplies the rotary electric machine 22 via the DC / DC converter 25 and the inverter 26 so that the generated power generated by the rotary electric machine 22 can be charged to the first battery 23. Be connected. A first SOC sensor 201 for detecting the charge amount SOC1 of the first battery 23 is attached to the first battery 23.

The second battery 24 is a battery having a higher voltage than the first battery 23, and is a rechargeable secondary battery such as a nickel-cadmium storage battery, a nickel-hydrogen storage battery, or a lithium ion battery. The second battery 24 supplies the charging power charged in the second battery 24 to the rotary electric machine 22 so that the rotary electric machine 22 can be driven by force, and the generated power generated by the rotary electric machine 22 is used. 2 The battery 24 is electrically connected to the rotary electric machine 22 via the inverter 26 so that the battery 24 can be charged. A second SOC sensor 202 for detecting the charge amount SOC2 of the second battery 24 is attached to the second battery 24.

The DC / DC converter 25 boosts the voltage between the terminals of the primary side terminal based on the control signal from the electronic control unit 200 and outputs the voltage from the secondary side terminal, and conversely, based on the control signal from the electronic control unit 200. It is provided with an electric circuit capable of stepping down the voltage between terminals of the secondary side terminal and outputting it from the primary side terminal. The primary terminal of the DC / DC converter 25 is connected to the output terminal of the first battery 23, and the secondary terminal is connected to the DC terminal of the inverter 26.

The inverter 26 converts the direct current input from the direct current terminal based on the control signal from the electronic control unit 200 into an alternating current (three-phase alternating current in this embodiment) and outputs it from the alternating current terminal, and vice versa. Each includes an electric circuit capable of converting an alternating current input from the alternating current side terminal into a direct current based on a control signal from the electronic control unit 200 and outputting the alternating current from the direct current side terminal. The DC side terminal of the inverter 26 is connected to the output terminal of the second battery 24 and the secondary side terminal of the DC / DC converter 25, and the AC side terminal of the inverter 26 is connected to the input / output terminal of the rotary electric machine 22.

The electronic control unit 200 is composed of a digital computer and includes a ROM (read-only memory), a RAM (random access memory), a CPU (microprocessor), an input port and an output port connected to each other by a bidirectional bus.

In addition to the above-mentioned first SOC sensor 201, second SOC sensor 202, air flow meter 214, and throttle sensor 215, the electronic control unit 200 includes an accelerator pedal (not shown) corresponding to the load (engine load) of the engine body 30. The output pulse is generated every time the crankshaft 11 (not shown) of the engine body 30 rotates by, for example, 15 ° as a signal for calculating the engine rotation speed NE and the load sensor 211 that generates an output voltage proportional to the amount of depression. Output signals from various sensors such as the crank angle sensor 212 for generating the above and the water temperature sensor 213 for detecting the temperature of the cooling water for cooling the engine body 30 corresponding to the temperature (engine temperature) of the engine body 30 are input.

Then, the electronic control unit 200 controls the internal combustion engine 1 and the starting device 2 based on the input output signals of various sensors and the like. Hereinafter, the control of the internal combustion engine 1 performed by the electronic control unit 200, particularly the start control of the internal combustion engine 1 will be described.

When the internal combustion engine 1 is started by cranking by the starter 21, the engine rotation speed NE cannot be increased to a predetermined target idle rotation speed by the output torque of the starter 21, so that the combustion of each cylinder 33 while driving the starter 21. It is necessary to burn the fuel in the chamber 35 to increase the engine speed NE. At this time, in order to ensure good startability even when there are variations in fuel properties and individual differences in the internal combustion engine 1, the engine rotation speed NE is temporarily increased to a rotation speed higher than the target idle rotation speed. After that, it is necessary to reduce the engine rotation speed NE toward the target idle rotation speed so that the engine rotation speed NE converges to the target idle rotation speed.

Therefore, when the internal combustion engine 1 is started by cranking by the starter 21, a phenomenon that the engine rotation speed NE becomes higher than the target idle rotation speed at the time of starting the internal combustion engine 1, that is, the engine rotation speed NE rises up.

On the other hand, when the internal combustion engine 1 is started by cranking by the rotary electric machine 22, the engine rotation speed NE can be increased to the target idle rotation speed by the output torque of the rotary electric machine 22. Therefore, after increasing the engine rotation speed NE to the target idle rotation speed by the output torque of the rotary electric machine 22, fuel is burned in the combustion chamber 35 of each cylinder 33 so that the engine rotation speed NE becomes the target idle rotation speed. By doing so, the internal combustion engine 1 can be started without temporarily increasing the engine rotation speed NE to a rotation speed higher than the target idle rotation speed.

Therefore, when the internal combustion engine 1 is started by cranking by the rotary electric machine 22, the engine rotation speed NE hardly rises when the internal combustion engine 1 is started.

Here, the electric power consumed by the rotary electric machine 22 when the internal combustion engine 1 is started by cranking by the rotary electric machine 22 is larger than the electric power consumed by the starter 21 when the internal combustion engine 1 is started by cranking by the starter 21. There are also many. Therefore, when the internal combustion engine 1 is started in the cold state where the cooling water temperature is equal to or lower than the predetermined water temperature, the output power of the second battery 24 is limited from the viewpoint of suppressing deterioration of the second battery 24. The electric power required to increase the engine rotation speed NE to the target idle rotation speed cannot be supplied to the electric machine 22.

Therefore, when it is cold, it is necessary to start the internal combustion engine 1 by cranking with the starter 21. However, as described above, when the internal combustion engine 1 is started by cranking by the starter 21, the engine rotation speed NE is set to the target idle rotation speed NEth3 (for a predetermined cold time) in order to ensure good startability. For example, it is necessary to once increase the rotation speed to a speed higher than 1000 [rpm]), then reduce the engine rotation speed NE toward the target idle rotation speed NEth3, and converge the engine rotation speed NE to the target idle rotation speed NEth3. is there.

At this time, once the engine rotation speed NE reaches the target idle rotation speed NEth3, the required torque for the internal combustion engine 1 is reduced to reduce the engine rotation speed NE toward the target idle rotation speed NEth3. Problems arise.

That is, once the engine rotation speed NE reaches the target idle rotation speed NEth3, if the required torque for the internal combustion engine 1 is reduced to reduce the engine rotation speed NE toward the target idle rotation speed NEth3, the target fuel injection is performed. The amount will decrease, and the amount of fuel injected from each fuel injection valve 42 will decrease. In addition, in the cold state, once the engine rotation speed NE reaches the target idle rotation speed NEth3, the ignition timing is warmed from the ignition timing for starting in order to complete the warm-up of the catalyst device 63 at an early stage. The ignition timing for accelerating the machine will be delayed step by step. Therefore, there arises a problem that combustion becomes unstable, the amount of unburned HC emitted becomes relatively large, and exhaust emissions deteriorate.

Therefore, in the present embodiment, when the internal combustion engine 1 is started by cranking by the starter 21 in the cold state, the engine is suppressed so that the fuel injection amount becomes a certain amount or less in order to suppress the deterioration of the exhaust emission. When the rotation speed NE becomes higher than the target idle rotation speed NEth3, the engine rotation speed NE is converged to the target idle rotation speed NEth3 by regeneratively driving the rotary electric machine 22.

FIG. 3 is a flowchart illustrating the start control of the internal combustion engine 1 according to the present embodiment. The electronic control unit 200 executes this routine when there is a start request or a restart request for the internal combustion engine 1 during one trip from the start to the end of the running of the vehicle 100.

In step S1, the electronic control unit 200 determines whether or not it is cold. In the present embodiment, the electronic control unit 200 reads the cooling water temperature Tw detected by the water temperature sensor 213, and if the cooling water temperature Tw is less than the predetermined water temperature Tw_l, determines that it is cold and proceeds to the process of step S2. .. On the other hand, if the cooling water temperature Tw is equal to or higher than the predetermined water temperature Tw_l, the electronic control unit 200 determines that it is warm and proceeds to the process of step S3.

In step S2, the electronic control unit 200 carries out the first starting process of starting the internal combustion engine 1 by cranking by the starter 21. Details of the first starting process will be described later with reference to FIG.

In step S3, the electronic control unit 200 performs a second start process of starting the internal combustion engine 1 by cranking by the rotary electric machine 22. In the second starting process, as described above, the power of the second battery 24 is supplied to the rotary electric machine 22, and the engine rotation speed NE is set by the output torque of the rotary electric machine 22 to the target idle rotation speed NEth2 (for a predetermined warm time). For example, after increasing to 800 [rpm]), fuel is injected from each fuel injection valve 42 to burn the fuel so that the engine rotation speed NE becomes the target idle rotation speed NEth2 for warm time, and the internal combustion engine This is the process of starting 1.

FIG. 4 is a flowchart illustrating the details of the first start processing.

In step S21, the electronic control unit 200 supplies the power of the first battery 23 to the starter 21 and performs cranking by the starter 21.

In step S22, the electronic control unit 200 reads the engine rotation speed NE calculated based on the output signal of the crank angle sensor 212, and the engine rotation speed NE is equal to or higher than the predetermined injection start rotation speed NEth1 (for example, 150 [rpm]). Judge whether or not it became. If the engine rotation speed NE is equal to or higher than the injection start rotation speed NEth 1, the electronic control unit 200 proceeds to the process of step S23. On the other hand, if the engine rotation speed NE is less than the injection start rotation speed NEth1, the electronic control unit 200 performs the process of step S22 again after a certain interval (for example, 10 [ms]).

In step S23, the electronic control unit 200 sets the target fuel injection amount tQ, the target fuel injection timing tA, and the target ignition timing tIT to the predetermined starting fuel injection amount Qs, fuel injection timing As, and ignition timing ITs, respectively. Set.

In step S24, the electronic control unit 200 starts fuel injection from the fuel injection valve 42 at the target fuel injection timing tA, injects fuel for the target fuel injection amount tQ, and uses the spark plug 43 at the target ignition timing tIT. Spark ignition is performed to operate the internal combustion engine 1.

In step S25, the electronic control unit 200 reads the engine rotation speed NE calculated based on the output signal of the crank angle sensor 212, and the engine rotation speed NE becomes equal to or higher than the target idle rotation speed NEth3 for a predetermined cold state. Determine if it is. If the engine rotation speed NE is equal to or higher than the idle rotation speed NEth3, the electronic control unit 200 proceeds to the process of step S26. On the other hand, if the engine rotation speed NE is less than the idle rotation speed NEth3, the electronic control unit 200 performs the process of step S23 again after a certain interval (for example, 10 [ms]).

In step S26, the electronic control unit 200 reads the engine rotation speed NE calculated based on the output signal of the crank angle sensor 212 and the engine load detected by the load sensor 211, and detects the engine operating state.

In step S27, the electronic control unit 200 determines the target fuel injection amount tQ and the target fuel injection timing tA, respectively, based on the engine operating state with reference to the warm-up promotion map created in advance by experiments or the like. The fuel injection amount Qh for promoting warm-up and the fuel injection timing Ah are set. At this time, when the engine rotation speed NE is higher than the target idle rotation speed NEth3, the engine rotation speed NE is lowered toward the target idle rotation speed NEth3, so that the target fuel injection amount tQ is the engine rotation. Compared with the speed NE being controlled (maintained) at the target idle rotation speed NEth3, the value is smaller.

Further, in step S27, the electronic control unit 200 sets the target ignition timing tIT to a predetermined ignition timing ITh for promoting warm-up, which is retarded by a predetermined amount from the ignition timing ITs for starting.

In step S28, the electronic control unit 200 determines whether or not the target fuel injection amount tQ set in step S27 is equal to or greater than a predetermined lower limit value Qlim. The lower limit value, Qlim, is that when the engine speed NE is higher than the target idle speed NEth3, the combustion becomes unstable due to the decrease in the fuel injection amount with the retardation of the ignition timing. It is a value set to suppress the fuel amount, and is, for example, the amount of fuel required to maintain the engine rotation speed NE at the target idle rotation speed NEth3. If the target fuel injection amount tQ set in step S27 is equal to or greater than the lower limit value Qlim, the electronic control unit 200 proceeds to the process of step S30. On the other hand, if the target fuel injection amount tQ set in step S27 is less than the lower limit value Qlim, the electronic control unit 200 proceeds to the process of step S29.

In step S29, the electronic control unit 200 corrects the target fuel injection amount tQ set in step S27 to the lower limit value Qlim. As a result, when the engine speed NE is higher than the target idle speed NEth3, the combustion becomes unstable due to the decrease in the fuel injection amount along with the retardation of the ignition timing. It can be suppressed. At this time, the target fuel injection timing tA may also be corrected in response to the correction of the target fuel injection amount tQ.

In step S30, the electronic control unit 200 starts fuel injection from the fuel injection valve 42 at the target fuel injection timing tA, injects fuel for the target fuel injection amount tQ, and uses the spark plug 43 at the target ignition timing tIT. Spark ignition is performed to operate the internal combustion engine 1.

In step S31, the electronic control unit 200 determines whether or not it is time to end the first start process. When the first start process should be completed, for example, when the cooling water temperature Tw becomes equal to or higher than the water temperature at which it can be determined that the warm-up of the catalyst device 63 is completed, or when the shift lever is in the P range (parking range) to the D range (parking range). For example, when switching to the drive range). The electronic control unit 200 ends the first start process if it should end the first start process. On the other hand, the electronic control unit 200 performs the process of step S26 again after a certain interval (for example, 10 [ms]) unless it is time to end the first start process.

FIG. 5 is a flowchart illustrating the regenerative control of the rotary electric machine 22 which is performed together with the first starting process.

In step S41, the electronic control unit 200 reads the engine rotation speed NE calculated based on the output signal of the crank angle sensor, and determines whether or not the engine rotation speed NE is higher than the target idle rotation speed NEth3. If the engine rotation speed NE is higher than the target idle rotation speed NEth3, the electronic control unit 200 proceeds to the process of step S42. On the other hand, if the engine rotation speed NE is less than the target idle rotation speed NEth3, the electronic control unit 200 ends this process.

In step S42, the electronic control unit 200 calculates the differential rotation speed ΔNE obtained by subtracting the idle rotation speed NEth3 from the engine rotation speed NE.

In step S43, the electronic control unit 200 refers to a table created in advance by an experiment or the like, and calculates a target regenerative torque when the rotary electric machine 22 functions as a generator based on the differential rotation speed ΔNE. The target regeneration torque is a negative torque required to reduce the engine speed NE, which is higher than the target idle rotation speed NEth3, to the target idle rotation speed NE. Basically, the larger the differential rotation speed ΔNE, the higher the target regeneration torque. It is squeezed (the amount of regeneration is increased).

In step S44, the electronic control unit 200 regeneratively drives the rotary electric machine 22 so that the regenerative torque becomes the target regenerative torque, and quickly converges the engine rotation speed NE to the target idle rotation idle rotation speed NEth3. As a result, when the engine rotation speed NE is higher than the target idle rotation speed NEth3, it is possible to suppress the blow-up of the engine rotation speed NE without reducing the fuel injection amount.

FIG. 6 is a time chart illustrating the operation of the regenerative control of the rotary electric machine 22 performed in combination with the first start process and the first start process. In FIG. 6, the solid line shows the control operation according to the present embodiment. On the other hand, the broken line indicates the conventional control operation, that is, after the engine rotation speed NE reaches the target idle rotation speed NEth3 once, the required torque (fuel injection amount) for the internal combustion engine 1 is reduced to set the engine rotation speed NE at the target idle rotation. The operation when the speed is lowered toward the speed NEth3 is shown.

As shown in FIG. 6, when the internal combustion engine 1 is started by cranking by the starter 21 in the cold state, the control according to the present embodiment controls the fuel injection amount so as not to be less than the lower limit value Qlim, and the differential rotation speed. The rotary electric machine 22 is regeneratively driven with a target regenerative torque corresponding to ΔNE.

Therefore, in the cold state, it is possible to suppress the instability of combustion due to the decrease in the fuel injection amount along with the retardation of the ignition timing, so that the deterioration of the exhaust emission can be suppressed. Further, when the internal combustion engine 1 is started by cranking by the starter 21, it is possible to suppress the increase in the engine rotation speed.

According to the present embodiment described above, in the vehicle 100, the internal combustion engine 1 for generating power by burning the fuel injected from the fuel injection valve 42 by spark-ignition with the spark plug 43, and the internal combustion engine 1 A starter 21 for performing ranking and a rotary electric machine 22 regenerated and driven by the power of the internal combustion engine 1 are provided. Then, the electronic control unit 200 (control device) of the vehicle 100 for controlling the vehicle 100 is the fuel injected from the fuel injection valve 42 when the internal combustion engine 1 is started by cranking by the starter 21 when it is cold. Fuel is injected from the fuel injection valve 42 so that the fuel does not fall below the predetermined lower limit value Qlim, and the ignition timing is retarded at a predetermined timing in order to warm up the catalyst device 63 provided in the exhaust passage of the internal combustion engine 1. When the fuel injected from the fuel injection valve 42 is ignited and burned, and the engine rotation speed NE becomes higher than the predetermined target idle rotation speed NEth3, the rotary electric machine 22 is regenerated to drive the engine rotation speed NE. Is configured to converge to the target idle rotation speed NEth3.

As a result, it is possible to suppress the instability of the fuel due to the decrease in the fuel injection amount along with the retardation of the ignition timing in the cold state, so that the deterioration of the exhaust emission can be suppressed. Further, the increase in the engine rotation speed when the internal combustion engine 1 is started by cranking by the starter 21 can be suppressed by regeneratively driving the rotary electric machine 22.

Although the embodiments of the present invention have been described above, the above embodiments are only a part of the application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiments. Absent.

1 Internal combustion engine 21 Starter 22 Rotating electric machine 42 Fuel injection valve 43 Spark plug 63 Catalyst device 100 Vehicle 200 Electronic control unit (control device)

Claims (1)

An internal combustion engine that generates power by burning the fuel injected from the fuel injection valve by spark-ignition with a spark plug.
A starter for cranking the internal combustion engine and
A regenerative electric machine that is regeneratively driven by the power of the internal combustion engine,
A vehicle control device for controlling a vehicle equipped with
When the internal combustion engine is started by cranking by the starter when it is cold, the fuel is injected from the fuel injection valve so that the fuel injected from the fuel injection valve does not fall below a predetermined lower limit value, and the internal combustion engine is injected. In order to warm up the catalytic device provided in the exhaust passage of the engine, the ignition timing is retarded at a predetermined timing to ignite and burn the fuel injected from the fuel injection valve, and the engine rotation speed is a predetermined target. When it becomes higher than the idle rotation speed, the rotary electric machine is regeneratively driven to converge the engine rotation speed to the target idle rotation speed.
Vehicle control device.

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