JP4126948B2 - Stop control device for internal combustion engine for vehicle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device that performs control to stop an internal combustion engine such as a diesel engine mounted on a vehicle under a predetermined condition by so-called eco-run control.
[0002]
[Prior art]
Control of starting and stopping of the internal combustion engine mounted on the vehicle is basically executed by the driver turning on / off an ignition switch or a main switch. On the other hand, recently, in order to reduce exhaust gas and improve fuel efficiency, in the situation where the driving force of the engine is not particularly required, the fuel supply to the engine is stopped or the engine is actively activated. The control to stop is started.
[0003]
The latter control that automatically stops the engine is a so-called eco-run control, and when a predetermined engine stop condition is met, such as when the brake is operated with the accelerator pedal off with the accelerator pedal released. The engine is stalled by stopping the fuel supply. When the fuel supply to the engine is stopped and the engine is automatically stopped, the engine has inertial force, so that the engine rotates inertia a predetermined number of times or a predetermined angle after the fuel is stopped.
[0004]
In that case, even if the supply of fuel is stopped, the air is sucked and the sucked air is compressed, so that torque fluctuation occurs due to compression and expansion of the intake air. Particularly in a diesel engine, since the compression ratio is high, the output torque of the engine changes greatly due to compression of intake air and subsequent expansion, which may cause vibrations and cause the passenger to feel uncomfortable.
[0005]
In order to solve such an inconvenience, in the invention described in Japanese Patent Application Laid-Open No. 2000-240483, when the internal combustion engine is stopped when a stop condition other than the stop operation of the driver is satisfied, the intake air is throttled. In this case, the fuel supply is stopped. Therefore, in the invention described in the above publication, when the internal combustion engine stop condition is satisfied, first, the throttle control of the intake air is executed, and after the elapse of a predetermined time, the intake air is completely throttled or up to a predetermined amount. In the throttled state, control for stopping fuel supply such as fuel injection is executed, and further, the internal combustion engine is substantially stopped after predetermined rotation by inertial force.
[0006]
[Problems to be solved by the invention]
In the invention described in the above publication, as described above, it takes time to throttle the intake air and stop the supply of fuel after the stop condition is established until the internal combustion engine is substantially stopped. There is a delay in the so-called automatic stop control of the engine. Therefore, for example, when the stop condition is not satisfied immediately after the above-described stop condition is satisfied, in other words, when the restart condition is satisfied immediately after the stop condition is satisfied, the stop control has already been started. Since the internal combustion engine cannot be immediately returned to the self-sustaining rotation state, the internal combustion engine is restarted after being cranked (motored) by the starter after the rotation of the internal combustion engine is stopped. In this case, since it takes a long time until the rotation of the internal combustion engine stops as described above, it takes a long time to start the restart control, and there may be a noticeable delay in the restart.
[0007]
The present invention has been made paying attention to the above technical problem, and an object thereof is to provide a stop control device capable of quickly stopping an internal combustion engine without causing a sense of incongruity. is there.
[0008]
[Means for Solving the Problem and Action]
In order to achieve the above object, the present invention provides fuel supply without restricting the intake air if the vehicle is running when the condition for stopping the internal combustion engine without depending on the stop operation of the passenger is satisfied. It is configured to stop and continue until the internal combustion engine stops. Vehicle Specifically, with the invention of claim 1, and means for stopping the internal combustion engine when predetermined stop conditions not according to the stop operation by the rider is satisfied, and means for throttling the intake air of an internal combustion engine in the stop control apparatus for use an internal combustion engine, a vehicle speed determination means for determining that the vehicle when said stop condition is satisfied is running, the stop condition is satisfied, whether one said without have the vehicle travels A first stop control means for stopping the internal combustion engine by stopping the supply of fuel to the internal combustion engine after the intake air is throttled when the vehicle speed determination means determines that the vehicle is stopped; and the stop condition There satisfied, and the vehicle is stopped immediately injected fuel without waiting to be squeezed previous SL inspiration if it is determined by the vehicle speed determining means for running, the injection of the fuel Throttle the inspiration after stopping That it comprises a second stop control means for stopping the internal combustion engine by that the stop control system according to claim.
[0009]
Therefore, according to the first aspect of the present invention, when the condition for stopping the internal combustion engine is established without depending on the operation of the occupant while the vehicle is traveling, the fuel injection is immediately stopped without restricting the intake air. As a result, the rotational speed of the internal combustion engine immediately decreases toward the stop, and finally the rotation of the internal combustion engine stops. In that case, the torque change due to the compression and expansion of the intake air during inertial rotation of the internal combustion engine may occur due to the fact that the intake air is not throttled, but since the vehicle is running, the torque change is caused by the vibration of the vehicle body. to appear as been suppressed, Ru is avoided that the passenger experience discomfort. In addition, even if inertial rotation of the internal combustion engine in which the fuel supply is stopped occurs, the intake air is throttled, so that the compression or expansion of the intake air or the vibration associated therewith does not occur, so even if the vehicle is almost stopped, there is a sense of incongruity. It does not occur. Further, when the fuel is stopped in a state where the vehicle is stopped, the fuel injection is stopped after the intake air is throttled.
[0010]
Further, the invention of claim 2, in the invention of claim 1, the means for squeezing the front Symbol intake comprises an intake throttle valve, the second stop control means, the intake throttle valve after stopping the injection of the fuel The stop control device includes a means for fully closing and opening the intake throttle valve from the fully closed position immediately before the rotational speed of the internal combustion engine becomes zero .
[0011]
Therefore, in the second aspect of the invention, the intake air is resumed immediately before the internal combustion engine that has stopped fuel injection is stopped, and the internal combustion engine is inhaled when the internal combustion engine stops.
[0012]
Further, the invention of claim 3, in the invention of claim 1 or 2, until the decrease in the return rotational speed rotational speed is predetermined for an internal combustion engine during deceleration, the fuel injection to the internal combustion engine means for executing a fuel cut control for stopping, when the internal combustion engine stop condition during deceleration running the fuel cut control is satisfied, after the rotational speed of the internal combustion engine decreases to the recovery rotational speed also stop control apparatus characterized by further example Bei a fuel stop means to continue the injection stop of the fuel.
[0013]
Thus, in the invention of claim 3, it is possible to obtain the same operation and effect as the invention of claim 1 or 2, in addition to this, the injection of fuel is stopped to the internal combustion engine by an in deceleration In this case, if the condition for stopping the internal combustion engine is established without depending on the passenger's operation, the fuel injection stop control due to the deceleration is canceled even if the rotational speed of the internal combustion engine decreases. It continues without being. In other words, when the conditions for stopping fuel injection and the conditions for stopping the internal combustion engine are satisfied by decelerating, the fuel injection stop for stopping the internal combustion engine is not performed in order. Since the control is executed, the number of revolutions of the internal combustion engine smoothly decreases without causing a situation such as the stop and injection of the fuel to be repeated. As a result, the time until the internal combustion engine is stopped can be shortened. Furthermore, since the process is executed while the vehicle is running, it is possible to avoid experiencing the vibration of the vehicle body or causing a sense of incongruity even if the intake air is not throttled. In other words, since it is not particularly necessary to throttle the intake air, the stop control of the internal combustion engine can be speeded up also in this respect.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described based on specific examples. First, an internal combustion engine that is an object of the present invention will be described. The internal combustion engine according to the present invention is an internal combustion engine that can be automatically stopped and automatically restarted by supplying and stopping fuel or air, or by turning ignition on and off. Examples are engines such as diesel engines, gasoline engines, and engines using gas as fuel. FIG. 3 shows a diesel engine as an example of the internal combustion engine (engine) 1. The example shown here is a so-called direct injection engine that directly injects fuel into the cylinders 2, 3, 4, and 5. And an exhaust gas recirculation mechanism (EGR) for exhaust gas purification.
[0017]
That is, each of the cylinders 2, 3, 4, and 5 is provided with injectors 6, 7, 8, and 9 for injecting fuel at a high pressure, and these injectors 6, 7, 8, and 9 provide high-pressure fuel. Is connected to a common rail 10 which is supplied under pressure. Each cylinder 2, 3, 4, 5 is provided with a glow 11, 12, 13, 14 respectively.
[0018]
An intake manifold 15 that distributes and supplies intake air to the cylinders 2, 3, 4, and 5 is connected to a compressor 17 in the exhaust supercharger 16. An intake air passage from the compressor 17 to the intake manifold 15 has an intercooler 18 that cools intake air that has been pressurized and rises in temperature, and an intake throttle valve (diesel throttle: D slot) 19 that controls the intake air amount. It is intervened. The intake throttle valve 19 is configured to be electrically controlled by an actuator (not shown) such as a motor.
[0019]
On the other hand, an exhaust manifold 20 connected to the exhaust port of each cylinder 2, 3, 4, 5 is connected to an exhaust turbine 21 in the supercharger 16. Further, the exhaust turbine 21 is communicated with a catalytic converter 22 provided with an exhaust purification catalyst.
[0020]
An exhaust gas recirculation pipe 23 is provided for guiding a part of the combustion exhaust gas generated in each cylinder 2, 3, 4, 5 to the intake manifold 15, and the exhaust gas recirculation pipe 23 has an EGR for cooling the exhaust gas. A cooler 24 and an EGR valve 25 that controls the flow rate of the exhaust gas are interposed in the order listed here from the exhaust manifold 20 side.
[0021]
Further, like the normal engine, it is necessary to forcibly rotate the engine 1 to the complete explosion speed by an external force at the time of starting, and a starter 26 is attached as a rotation drive mechanism for that purpose. The starter 26 can adopt an appropriate configuration. For example, the starter 26 advances a pinion gear (not shown) by an activation signal and meshes (i.e., engages) with a ring gear (not shown) in the engine 1. A configuration in which the engine 1 is rotated in this state can be employed.
[0022]
The engine 1 is automatically stopped when a predetermined condition such as a brake operation is performed with the accelerator opening being fully closed, and a stop condition such that the brake operation is subsequently released is satisfied. It is configured so that so-called eco-run control can be automatically restarted by disappearing. An engine electronic control unit (E-ECU) 27 and an eco-run electronic control unit (ECO-ECU) 28 for the control are provided.
[0023]
These electronic control units 27 and 28 are configured mainly with a microcomputer, and the engine electronic control unit 27 performs an operation based on the input data to control the operating state of the engine 1. It is configured. Specifically, when there is a start request, the starter 26 is driven to mesh the gear with the gear on the engine 1 side, the engine 1 is cranked, and the fuel injection amount based on the acceleration / deceleration request And the opening degree of the intake throttle valve 19 and the EGR valve 25 as needed, and further, the supercharging pressure by the supercharger 16 is controlled based on the acceleration / deceleration request. ing.
[0024]
The eco-run electronic control device 28 performs calculation based on the input data, determines whether the stop condition or the start condition of the engine 1 is satisfied, and determines whether the engine electronic control device 27 is in accordance with the determination result. 1 stop request and start request are output. The stop condition is, for example, that it is determined that the accelerator pedal is not depressed and that the brake is being operated. The start condition is that any of the contents of the stop condition is not satisfied, for example, the brake operation is released. When there is a stop request or a start request, the engine electronic control unit 27 executes stop or start control of the engine 1 according to the request, and when there is no such request, the engine electronic control device 27 sets the accelerator opening. It is configured to control the output (more specifically, the fuel injection amount) of the engine 1 according to the representative drive request amount.
[0025]
In order to perform these controls, an accelerator opening sensor 29, a crank angle sensor 30, and a crank angle reference position sensor 31 are connected to the electronic control unit 27. Although not specifically shown, any appropriate signal such as a vehicle speed signal is input to one of the electronic control devices 27 and 28.
[0026]
The control device according to the present invention including the electronic control devices 27 and 28 described above executes stop control of the engine 1 under so-called eco-run control, more specifically, fuel supply stop control as follows. FIG. 1 is a flowchart showing an example of the control. In this control, first, a stop command (eco-run ON) of the engine 1 based on the establishment of a condition for stopping the engine 1 is read (step S1). This stop command is output, for example, when the accelerator pedal is returned and the brake is operated while the vehicle is traveling.
[0027]
Next , it is determined whether or not the vehicle is stopped (step S2 ).
[0028]
If the determination in step S2 is affirmative, that is, if the automatic stop condition of the engine 1 by the eco-run control is satisfied while the vehicle is stopped, first, the intake throttle valve (D slot) 19 is fully closed. Control is performed (step S3). Thereafter, fuel injection is stopped (step S4).
[0029]
The control in step S3 and step S4 is a normal control when the engine 1 is automatically stopped by the eco-run control. After the fuel supply (specifically, injection) is stopped, the engine 1 is inertially rotated. However, since the intake air is suppressed, the compression or expansion of the intake air and the accompanying torque change do not occur, so the engine 1 stops smoothly without causing vibration.
[0030]
On the other hand, if a negative determination is made in step S2 because the vehicle has not stopped, the fuel supply (specifically, injection) is immediately stopped (step S5). That is, the fuel supply is stopped without executing the throttle control of the intake throttle valve 19. Therefore, when the engine 1 rotates with inertia force in conjunction with the stop of fuel injection, intake corresponding to the opening of the intake throttle valve 19 at that time occurs. For this reason, when the engine 1 rotates with inertial force, intake air compression and expansion may occur, and the engine torque may fluctuate. At this time, the vehicle is running, so the fluctuation of the engine torque is caused by the vehicle running. And is suppressed from appearing as vibration of the vehicle body.
[0031]
That is, when the vehicle is running, if the stop condition of the engine 1 by the eco-run control is satisfied, the fuel supply is immediately stopped without restricting the intake air. Therefore, the time until the engine 1 substantially stops is reduced. Shorter. Therefore, when the restart condition of the engine 1 is satisfied immediately after the stop condition is satisfied, the start timing of the restart control of the engine 1 is advanced, and a delay in restart is prevented or avoided.
[0032]
FIG. 2 schematically shows a time chart when the above control is performed. When the stop condition of the engine 1 based on the eco-run control is satisfied at a predetermined time t0 during deceleration, the fuel supply to the engine 1 is immediately stopped as described above. As a result, as indicated by the broken line in FIG. 2, the engine speed decreases at a gradient greater than the previous gradient. At that time, the intake throttle valve 19 is maintained at a predetermined opening, and the intake throttle control (diesel throttle) for automatically stopping the engine 1 at a predetermined time t1 after the fuel supply stop control is started. Control to reduce the opening (D throttle opening) is started.
[0033]
Therefore, the intake air is compressed and expanded from the time t0 when the fuel supply stop control is started to the time t1 when the intake air is throttled. However, since the vehicle is running, the torque fluctuation due to the compression and expansion of the intake air does not appear as the vibration of the vehicle body or does not become a vibration that can be felt.
[0034]
The intake throttle valve 19 is fully closed at time t2 just before the rotation of the engine 1 stops, and the rotation of the engine 1 stops at time t3 immediately after that. In addition, while the vehicle speed gradually decreases, the intake throttle valve 19 is kept fully closed, and at the time t3 when the engine speed becomes zero, the intake throttle valve 19 is controlled to be fully opened, and thereafter at a predetermined time t4. The intake throttle valve 19 is fully opened. This is a control for the subsequent restart of the engine 1. In the meantime, the vehicle speed continues to decrease, and at time t5, the vehicle speed becomes zero and the vehicle stops.
[0035]
On the other hand, when the above control according to the present invention is not used, that is, in the control of the comparative example in which the fuel supply is stopped after the intake air is throttled, the fuel to the engine 1 is supplied at the time t2 when the intake throttle valve 19 is fully closed. Supply is stopped. For this reason, the engine speed starts to decrease greatly from time t2, so that the rotation of the engine 1 stops at time t6 which is later than the time t3. That is, as compared with the case of the control according to the present invention, there is a time delay from the time t3 to the time t6. Therefore, for example, when the condition for restarting the engine 1 is established almost simultaneously with the time point t3, according to the present invention, since the engine 1 is stopped, the restart control can be executed immediately. On the other hand, in the control not according to the present invention, the restart control of the engine 1 is executed after waiting until the time t6 when the rotation of the engine 1 stops.
[0036]
Further, in the case of control not according to the present invention, the intake throttle valve 19 is controlled to be fully opened at time t6 when the rotation of the engine 1 is stopped, and the intake throttle valve 19 is fully opened at time t8 thereafter. Therefore, since the timing at which the intake throttle valve 19 is fully opened is delayed in preparation for the restart of the engine 1, the restart of the engine 1 is also delayed in this respect.
[0037]
By the way, in order to reduce exhaust gas and improve fuel consumption, so-called deceleration fuel cut (deceleration F / C) control that stops fuel supply during deceleration may be executed. This is because if the engine 1 is forcibly rotated by the inertial force of the vehicle at the time of deceleration and the fuel supply is resumed, the fuel supply is stopped to the lowest speed (return speed) at which the engine 1 can return to the independent rotation. It is control to do.
[0038]
When the control by the control device of the present invention is superposed on the deceleration fuel cut control, the return control by the deceleration fuel cut control is prohibited, and the fuel supply is stopped until the rotation of the engine 1 stops. This state is also described in FIG. 2, and the fuel supply is stopped even after time t9 when the engine speed has decreased to the return speed. Therefore, the engine 1 can be smoothly stopped.
[0039]
On the other hand, when the stop control of the engine 1 and the deceleration fuel cut control by the eco-run control during traveling are performed independently, the engine speed reaches the return speed before the intake throttle valve 19 is fully closed. Then, the fuel supply is resumed at that time, and then the fuel supply is stopped again when the intake throttle valve 19 is fully closed. That is, the fuel supply and stop are repeated, and the fuel efficiency improvement effect may be impaired, or the engine torque output and stop may be repeated to cause a sense of incongruity.
[0040]
Here, briefly explaining the relationship between the present invention and the above embodiment, the functional means of Step S2 shown in FIG. 1 corresponds to the vehicle speed determining means of the present invention, functional hand stage and subsequent step S5 the intake throttle valve closing means corresponds to the second stop control means and fuel stop means for the present invention. Also, functional means in step S 3 and S4 correspond to the first stop control means of the present invention.
[0041]
The present invention is not limited to the above specific example, and can also be applied to a control device for an engine that does not execute so-called deceleration fuel cut control. Further, as described above, the control device according to the present invention changes the control mode of the intake air for stopping the engine depending on whether the vehicle is stopped or running. It can be said that the control device is provided with means for changing the control content of the intake air in accordance with the vehicle speed at this time. Furthermore, the throttle of the intake air according to the present invention includes control for reducing the amount of exhaust gas recirculated.
[0042]
【The invention's effect】
As described above, according to the first aspect of the present invention, when the condition for stopping the internal combustion engine is satisfied without depending on the operation of the occupant when the vehicle is traveling, the intake air is not immediately throttled. Since the fuel supply is stopped, the internal combustion engine can be stopped quickly, and a delay in the stop control can be avoided or suppressed. In addition, the internal combustion engine may inertially rotate after the fuel supply is stopped, and torque changes due to intake air compression and expansion may occur. However, since the vehicle is running, the torque change appears as vibration of the vehicle body. without, Ru can be avoided to give an uncomfortable feeling to the passenger. In addition, even if inertial rotation of the internal combustion engine in which the fuel supply is stopped occurs, the intake air is throttled, so that the compression or expansion of the intake air or the vibration associated therewith does not occur. It does not occur. Further, when the fuel is stopped in a state where the vehicle is stopped, the fuel injection is stopped after the intake air is throttled.
[0043]
According to the invention of claim 2 , the intake air is resumed immediately before the internal combustion engine that stops the fuel injection is stopped, and the internal combustion engine is inhaled when the internal combustion engine stops.
[0044]
Furthermore, according to the invention of claim 3, it is possible to obtain the same effect as the invention of claim 1 or 2, in addition, the condition for stopping the fuel supply by a in deceleration rider If the conditions for stopping the internal combustion engine are satisfied without being dependent on the operation, the fuel supply stop control for stopping the internal combustion engine is executed without sequentially executing these controls. The time until the internal combustion engine is stopped can be shortened by smoothly reducing the rotational speed. In addition, since the process is executed while the vehicle is running, it is possible to avoid experiencing the vibration of the vehicle body or causing a sense of incongruity without reducing the intake air. In other words, since it is not particularly necessary to throttle the intake air, the stop control of the internal combustion engine can be speeded up also in this respect.
[Brief description of the drawings]
FIG. 1 is a flowchart for explaining an example of control executed by a control device of the present invention.
FIG. 2 is a time chart showing changes in engine speed when the control of FIG. 1 is executed together with an example when the control is not executed.
FIG. 3 is a block diagram schematically showing a control system of the internal combustion engine targeted by the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine, 27 ... Electronic control apparatus for engines, 28 ... Electronic control apparatus for eco-runs.

Claims (3)

And means for stopping the internal combustion engine when predetermined stop conditions not according to the stop operation by the rider is established, the stop control device for an internal combustion engine for a vehicle having a means for throttling the intake air of an internal combustion engine,
Vehicle speed determining means for determining whether or not the vehicle is running when the stop condition is satisfied;
The stop condition is satisfied, whether One said if it is determined by the vehicle speed determining means that the vehicle is stopped without been traveling by stopping the supply of fuel to the internal combustion engine after squeezing the intake First stop control means for stopping the internal combustion engine,
The stop condition is satisfied, and when said vehicle is traveling is determined by the vehicle speed determining means stops immediately injected fuel without waiting to be squeezed previous SL intake, the fuel And a second stop control means for stopping the internal combustion engine by restricting the intake air after stopping the injection of the vehicle. Means for squeezing the front Symbol intake comprises an intake throttle valve,
The second stop control means includes means for fully closing the intake throttle valve after stopping the fuel injection and opening the intake throttle valve from fully closed immediately before the rotation speed of the internal combustion engine becomes zero. stop control device for a vehicular internal combustion engine according to claim 1, characterized in that. Until the rotational speed of the internal combustion engine is reduced to restoration speed a predetermined at the time of deceleration, and means for executing a fuel cut control for stopping the fuel injection to the internal combustion engine,
When the internal combustion engine stop condition during deceleration running the fuel cut control is satisfied, the fuel stop means to continue the injection stop of the fuel even after the rotational speed of the internal combustion engine decreases to the recovery rotational speed When
More stop control apparatus of the vehicle dual internal combustion engine according to claim 1 or 2 shall be the feature that the e Bei.

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