JP2002295288A - Engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device, capable of securing the output adapting to a load, when an engine which is stopped is started. SOLUTION: This engine control device, which performs the control for starting the stopped engine, is provided with load predicting means (steps S1, S2 and S3) for predicting the load required, when starting the stopped engine, and an output control means (step S5 or S7) for controlling the output at that time, based on the result predicted by the load predicting means (steps S1, S2 and S3).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control device for starting a stopped engine.

[0002]

2. Description of the Related Art The output when an engine mounted on a vehicle is operated is basically controlled based on the operation state of an accelerator pedal indicating the intention of an occupant of the vehicle, that is, the so-called accelerator opening. . However, since the environment surrounding the vehicle changes every moment, if the engine output is controlled only by the operation state of the accelerator pedal,
The driving performance of the vehicle and the driving environment of the vehicle do not match, and there is a possibility that the driving performance is reduced or the drivability is reduced. Therefore, a control device has been proposed which detects the environment around the vehicle using various sensors in addition to the operation state of the accelerator pedal, and controls the engine output based on the detection result. 11-294
232 publication.

The engine idle speed control device described in Japanese Patent Application Laid-Open No. 11-294232 is intended for a vehicle in which a transmission with a torque converter is connected to the output side of the engine. When the stop state of the vehicle is detected, the inclination angle of the road surface is detected, and the idle speed of the engine is controlled based on the inclination angle of the road surface. By performing such control, it is possible to secure a sufficient creep force even when the vehicle is stopped on an uphill road or the like and the brake pedal is immediately released after the engine is controlled to the idle speed. Yes, the vehicle will not retreat.

[0004]

However, Japanese Patent Application Laid-Open No. H11-294232 only discloses that the load is detected when the engine is in an idling state. Is not described at all. Therefore, it has not been possible to suppress a problem that occurs when the stopped engine is started, for example, a decrease in the starting performance due to an insufficient output of the engine and a decrease in the drivability.

The present invention has been made in view of the above circumstances, and provides an engine control device that can secure an output corresponding to a load at the time of starting the engine when the stopped engine is started. It is intended to be.

[0006]

In order to achieve the above object, an invention according to a first aspect of the present invention is directed to an engine control apparatus for performing control for starting a stopped engine. Load estimating means for assuming start-up and estimating the engine load; and output control means for controlling engine output based on the prediction result of the load estimating means when starting a stopped engine. Are provided.

According to the first aspect of the invention, when the stopped engine is started, the engine output is controlled according to the required load. Therefore, at the time of starting the engine, excessive or insufficient engine output with respect to the state of the vehicle is suppressed.

A second aspect of the present invention is directed to an engine control device for performing control for starting a stopped diesel engine, in which a stopped diesel engine is started, and the load of the diesel engine is reduced. The load predicting means for predicting, and when starting the stopped diesel engine, controlling the amount of air supplied to the combustion chamber of the diesel engine based on the prediction result of the load predicting means, thereby controlling the diesel engine. Output control means for controlling the output when the engine is started.

According to the second aspect of the present invention, when the stopped diesel engine is started, the output of the diesel engine is controlled according to the required load.
Therefore, when starting the diesel engine, excess or deficiency of the engine output with respect to the state of the vehicle is suppressed.
In the case of a diesel engine, the ratio of the amount of fuel supplied to the combustion chamber to the amount of air supplied to the combustion chamber,
That is, although there is a possibility that a local shortage of air amount occurs and black smoke is generated based on the air-fuel ratio, according to the invention of claim 2, both the fuel supply amount and the air supply amount are controlled according to the load. By doing so, the generation of black smoke is suppressed.

According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the load predicting means has a function of predicting a load of the diesel engine when the vehicle is located on an uphill road. It is characterized by having.

According to the third aspect of the invention, in addition to the same effect as the first or second aspect of the invention, when the vehicle travels on an uphill road, the engine output is controlled according to the load based on the road gradient. Is done.

According to a fourth aspect of the present invention, in addition to any one of the first to third aspects, the output control means controls an opening of a throttle valve provided in an intake pipe communicating with the combustion chamber. Thus, a function of controlling the amount of air is provided.

According to the fourth aspect of the present invention, in addition to the same effect as in any one of the first to third aspects of the present invention, the amount of air supplied to the combustion chamber is controlled by controlling the opening of the throttle valve. Is adjusted, and the engine output at the time of starting the engine is controlled.

According to a fifth aspect of the present invention, in addition to any one of the first to third aspects, the output control means controls a capacity of a supercharger for compressing air in an intake pipe communicating with the combustion chamber. Thus, a function of controlling the amount of air is provided.

According to the fifth aspect of the invention, in addition to the same effect as in any one of the first to third aspects of the present invention, the amount of air supplied to the combustion chamber is controlled by controlling the capacity of the supercharger. Is adjusted, and the engine output at the time of starting the engine is controlled.

According to a sixth aspect of the present invention, in addition to the configuration of any one of the first to fifth aspects, the output control means further includes an exhaust gas recirculation system that returns a part of the exhaust gas discharged from the combustion chamber to an intake system. The present invention is further characterized by further having a function of controlling the amount of exhaust gas returned from the circulation device.

The exhaust gas recirculation device, which is an accessory device of the engine, returns a part of the exhaust gas discharged from the combustion chamber to the intake system to lower the combustion temperature of the combustion chamber. Low and black smoke is likely to be generated. Therefore, in addition to controlling the engine output according to the load, if the amount of exhaust gas returned to the combustion chamber side is reduced according to the load, the generation of black smoke is suppressed. You.

According to a seventh aspect of the present invention, in addition to the configuration of any one of the first to sixth aspects, the output control means is configured to control a state in which the start of the engine is completed based on a result of prediction by the load predicting means. It has a function of controlling the engine output.

According to the seventh aspect of the present invention, in addition to the effects similar to those of any one of the first to sixth aspects of the present invention, the engine can be started in a state where the start of the engine is completed based on a load predicted in advance. Output is controlled. Therefore, in the state where the start of the engine is completed, the excess or deficiency of the engine output with respect to the state of the vehicle is suppressed.

[0020]

Next, the basic principle of the present invention will be described with reference to FIG. In FIG. 7, an engine 100, which is a driving force source mounted on a vehicle Ve, is a power unit that outputs power by burning fuel.
As 00, an internal combustion engine, for example, a diesel engine, a gasoline engine, an LPG engine, a methanol engine, a hydrogen engine, or the like can be used. As the engine 100, a known engine having a combustion chamber for burning fuel, an intake system for supplying air to the combustion chamber, and an exhaust system for exhausting gas remaining in the combustion chamber to the outside of the combustion chamber can be used. .

Further, factors that affect the output of the engine 100 include thermal efficiency, charging efficiency, rotational speed, mechanical efficiency, and the like. In the present invention, the output control device 101 relating to thermal efficiency, charging efficiency, and rotational speed. The engine output is controlled by the function. The output control device 101 includes, for example, an air amount control device that controls the amount of air supplied to the combustion chamber, a fuel supply amount control device that controls the amount of fuel supplied to the combustion chamber, and ignition of an air-fuel mixture existing in the combustion chamber. Ignition timing control device, an exhaust gas recirculation device for suppressing the generation of harmful components in exhaust gas generated by fuel combustion by returning a part of the exhaust gas to the air system, and the like. .

The air amount control device includes an electronic throttle valve provided in an intake pipe and a supercharger for compressing air in the intake pipe. Examples of the supercharger include a turbocharger driven by the exhaust energy of the exhaust gas of the engine 100 and a supercharger driven by an electric motor which is a power source other than the engine 100.

An electronic control unit 102 for controlling the output control unit 101 is provided, and a signal from the start request detection sensor 103 and a signal from the load detection sensor 104 are input to the electronic control unit 101. The start request detection sensor 103 is for detecting the operation by the occupant of the vehicle, that is, the presence or absence of a request to start the engine 100. This start request detection sensor 103 is, for example,
It is composed of an ignition switch, an accelerator opening sensor, a brake switch, and the like. Load detection sensor 10
Reference numeral 4 is for detecting a load corresponding to a state of the vehicle Ve, for example, a road gradient, a vehicle weight, and the like. As the load detection sensor 104, for example, an inclination angle sensor for detecting the inclination angle or the inclination of the road on which the vehicle Ve is located, and information on whether or not the road on which the vehicle Ve is located is an uphill road, And a vehicle weight detection sensor and the like.

In the vehicle Ve shown in FIG.
Assuming that the stopped engine 100 is started,
A load when starting the engine 100 is detected by a signal from the load detection sensor 104. For example, while the vehicle is stopped, it is possible to determine whether or not the vehicle is stopped on an uphill road based on a signal from the inclination angle sensor. Also, while the vehicle is traveling, it is possible to determine whether or not the vehicle is traveling on an uphill road based on the signal of the acceleration sensor.

Then, based on the signal of the load sensor 104, a target output of the engine 100 is calculated corresponding to the load when the engine 100 is started. further,
When the start request detection sensor 103 detects that there is a start request, the output control device 101 is controlled so that a target output is obtained. That is, while the engine 100 is cranked by the starter motor,
Control of the intake air amount, control of the ignition timing, control of the fuel injection amount, control of the exhaust gas return amount, and the like are performed.

In the second aspect of the present invention, "the state in which the start of the engine is completed" means that the cranking by the starter motor has been completed and the engine speed has reached a speed at which the engine can rotate independently, for example, It means an idling state. The present invention can be applied to both a vehicle having only an engine as a driving force source and a vehicle having an electric motor and an engine as a driving force source.

[0027]

Next, an embodiment which embodies the basic principle shown in FIG. 7 will be described. FIG. 2 is a conceptual diagram showing the configuration of the diesel engine 1 and the transmission 17 mounted on the vehicle. The diesel engine 1 has an engine body 1A and an accessory device 1B. First, the engine body 1A
Are formed facing a top surface of the piston (not shown), a piston (not shown) disposed reciprocally in a plurality of cylinders of the cylinder block, a cylinder head (not shown), and a plurality of cylinders of the cylinder block. It has a combustion chamber 2 and the like.

Next, the auxiliary device 1B will be described. A fuel injection device 3 for injecting light oil as fuel into each combustion chamber 2 is provided. Further, an intake valve and an exhaust valve which face each combustion chamber 2 and are opened and closed by rotation of a crankshaft (not shown) are provided. Further, an intake manifold 4 communicating with each combustion chamber 2 is provided, and an intake pipe 5 is connected to the intake manifold 4. An electronic throttle valve 6 is provided in the intake pipe 5 to control the amount of intake air supplied to each combustion chamber 2 via the intake pipe 5. The electronic throttle valve 6 is driven by an actuator such as an electric motor.
The degree of opening can be controlled.

On the other hand, an exhaust manifold 7 is connected to each of the combustion chambers 2, and an exhaust pipe 8 is connected to the exhaust manifold 7. An exhaust purification catalyst 9 for reducing harmful components in the exhaust gas is provided in the exhaust pipe 8 in the exhaust gas exhaust path.

A turbocharger 10 is provided for the intake pipe 5 and the exhaust pipe 8. The turbocharger 10 corresponds to a position upstream of the electronic throttle valve 6 in the air intake direction of the intake pipe 5 and a position upstream of the exhaust purification catalyst 9 in the exhaust gas exhaust direction of the exhaust pipe 8. Are located. The turbocharger 10 includes a compressor 11 provided inside the intake pipe 5, a turbine 12 provided inside the exhaust pipe 8, and a shaft (FIG. 1) connecting the compressor 11 and the turbine 12 so as to be integrally rotatable. (Not shown).

The turbocharger 10 rotates the turbine 12 by the exhaust energy of the exhaust gas flowing through the exhaust pipe 8 and transmits the power of the turbine 12 to the compressor 11 via a shaft, thereby forming the intake pipe 5. The internal air is compressed and supplied to the combustion chamber 2 side. That is, the turbocharger 10
It has a function of controlling the amount of intake air to the combustion chamber 2. In this embodiment, the turbocharger 1
As 0, a variable displacement turbocharger capable of controlling the discharge amount corresponding to the rotation speed of the compressor 11 is used.

Further, in the air suction direction of the intake pipe 5,
An intercooler 13 is provided between the turbocharger 10 and the electronic throttle valve 6. The intercooler 13 is for cooling air that has been compressed by the turbocharger 10 and has increased in temperature.
Further, as an accessory device 1B of the diesel engine 1,
Exhaust Gas Recirculation (EGR)
) Is provided. The exhaust gas recirculation device 14 returns a part of the gas discharged from the combustion chamber 2 to the exhaust manifold 4 to the intake system,
This is for lowering the combustion temperature of the combustion chamber 2 to suppress the generation of nitrogen oxides and the generation of PM (particulates; exhaust particulates) due to an increase in the amount of intake air. The exhaust gas recirculation device 14 includes a pipe 15 connecting the exhaust manifold 7 and the intake manifold 4, and a pipe 15
And an EGR valve 16 for controlling the flow rate of gas returned from the exhaust manifold 7 to the intake manifold 4.

FIG. 3 is a block diagram showing a control system of the vehicle, in which an electronic control unit 18 is provided. The electronic control unit 18 is a central processing unit (CPU or MPU)
And a microcomputer mainly including a storage device (RAM and ROM) and an input / output interface.

The electronic control unit 18 includes a signal of an ignition switch 19 for detecting an operation state of an ignition key (not shown), a signal of a main switch 20 for eco-run, a signal of a vehicle speed sensor 21, and an accelerator pedal (not shown). Signal of an accelerator opening sensor 22 for detecting an operation state of the brake pedal, a signal of a brake switch 23 for detecting an operation state of a brake pedal (not shown), an engine speed sensor 2
4, a signal from a cooling water temperature sensor 25, a signal from a throttle position sensor 26 for detecting the opening of the electronic throttle valve 6, a signal from a turbo displacement sensor 27 for detecting the discharge amount of the turbocharger 10, and the opening of the EGR valve 16. From the EGR valve opening sensor 28, a signal from the air conditioner switch 29, a signal from the crank angle sensor 30,
A signal from a shift position sensor 31 for detecting an operation position of a shift device for controlling the transmission 17, and an ascending road detection sensor 3 for detecting an inclination angle of a road on which the vehicle is located.
2, a signal from the vehicle weight detection sensor 34, and the like.

The shift position sensor 31
For example, P (parking) position, R (reverse)
Position, N (Neutral) Position, D (Drive) Position, 3 Position, 2 Position, L
(Low) position and the like can be detected.

The electronic control unit 18 stores the diesel engine 1 based on the inclination angle of the road and the vehicle weight.
And load control data for predicting a load required at the time of starting the engine, and data for controlling the output of the diesel engine 1 based on the load predictive data.

On the other hand, from the electronic control unit 18,
Control signal for starter motor 33, fuel injection device 3
, A signal for controlling the opening of the electronic throttle valve 6, a signal for controlling the opening of the EGR valve 16, a signal for controlling the capacity of the turbocharger 10, and the like.

Here, the structure of the present invention and FIGS.
The diesel engine 1 corresponds to the engine of the present invention, and the turbocharger 1
0 corresponds to the supercharger of the present invention, the electronic throttle valve 6 corresponds to the throttle valve of the present invention, and the intake manifold 4 corresponds to the intake system of the present invention.

Next, control of the system shown in FIGS. 2 and 3 will be described. First, in a state where the eco-run main switch 19 is turned off, the start, operation, and stop of the diesel engine 1 are basically controlled based on the operation of an ignition key. The ignition switch 19 can detect lock, accessory, on, and start positions.
When “lock” or “accessory” is selected by 9, the starter motor 33 is not driven and the fuel injection by the fuel injection device 3 is not performed.
That is, the diesel engine 1 is stopped.

Then, when the ignition switch 19 detects "ON" and then detects "START", the starter motor 33 is driven and the diesel engine 1 rotates initially. Also, electronic throttle valve 6
Is controlled, and the intake valve is opened with the rotation of the crankshaft, air is sucked into the combustion chamber 2, the intake valve is closed, and the piston operates toward the top dead center. At the same time, the air in the combustion chamber 2 is compressed, and is brought into a high pressure and high temperature state. And the fuel injection device 3
Fuel is injected by the combustion chamber, and the fuel is injected into the combustion chamber 2
It mixes with the air inside and ignites itself and burns. The heat generated by the combustion causes the piston to move toward the bottom dead center.

Next, when the piston moves to the vicinity of the bottom dead center, the exhaust valve is opened. Thereafter, when the piston moves toward the top dead center, the gas remaining in the combustion chamber 2 is exhausted by the exhaust manifold 7. The exhaust gas is exhausted to the atmosphere via the exhaust pipe 8. As described above, when the known intake stroke, compression stroke, explosion process, and exhaust stroke are performed, and the engine speed increases to a predetermined speed, for example, a speed at which the engine can rotate independently, cranking by the starter motor 33 ends. I do.

Here, a method of controlling the output of the diesel engine 1 will be briefly described. First, the accelerator opening sensor 22
The output of the diesel engine 1 can be controlled by controlling the opening of the electronic throttle valve 6 on the basis of the above signal and other conditions to control the amount of air taken in from the intake pipe 5.

Further, the turbine 12 of the turbocharger 10 is rotated by the exhaust energy of the exhaust gas in the exhaust pipe 8 and the compressor 11 is integrated with the turbine 12.
To compress the air in the intake pipe 5,
The amount of air supply to the combustion chamber 2 can be increased.
As described above, the output of the diesel engine 1 can be controlled by the function of the turbocharger 10.

On the other hand, a part of the exhaust gas discharged from the combustion chamber 2 to the exhaust manifold 7 can be controlled by the exhaust gas recirculation device 14 to return to the intake manifold 4 side. That is, by mixing the exhaust gas containing carbon dioxide gas into the air sucked into the combustion chamber 2, the temperature rise when the mixed gas is burned in the combustion chamber 2 is suppressed, and the generation of nitrogen oxides is suppressed. You.

When the operating force is released after the ignition key is operated to the start position, the ignition key returns to the on position. Further, when the ignition key is returned from the ON position to the accessory position while the diesel engine 1 is operating, the fuel injection control is stopped, the electronic throttle valve 6 is fully closed, and the diesel engine 1 is stopped.

By the way, the eco-run main switch 20
Is turned on, the ignition switch 19
The start, operation, and stop of the diesel engine 1 can be controlled based on stop conditions other than the detection signal.
Such control is called an “eco-run system”. First,
When the stop condition is satisfied during the operation of the diesel engine 1, the diesel engine 1 can be stopped by controlling the electronic throttle valve 6 and the fuel injection device 3. If the stop condition is not satisfied after the diesel engine 1 is stopped in this way, the diesel engine 1 is started in the same manner as described above.

Whether or not the above stop condition is satisfied is determined by
For example, the determination can be made based on a signal from the accelerator opening sensor 21, a signal from the brake switch 23, a signal from the shift position sensor 31, and the like. If all of the following items are detected: the accelerator pedal is not depressed, the brake pedal is depressed, and the D position is selected, the stop condition is satisfied. Is determined. On the other hand, when at least one item is resolved, it is determined that "the stop condition is not satisfied". It should be noted that the item "vehicle speed is zero" may be added to the item for determining whether or not the stop condition is satisfied.

By the way, during operation of the diesel engine 1, by controlling the amount of air supplied to the combustion chamber 2, it is possible to perform control to lower the combustion temperature and reduce the generation of nitrogen oxides. When the required output is low, control of returning a part of the exhaust gas to the intake manifold 4 side can be performed by the function of the exhaust gas recirculation device 14. However, when the vehicle stops on an uphill road and the stop condition is satisfied and the diesel engine 1 is stopped, and then the stop condition is not satisfied and the diesel engine 1 is started, as described above, “the air amount is reduced. When the "control to suppress" and the "control to recirculate exhaust gas" are performed, the following problem may occur.

That is, when the vehicle is stopped on an uphill road,
When it is predicted that a high load is required when the vehicle starts, in order to increase the fuel injection amount and the amount of air supplied to the combustion chamber 2 via the intake pipe 5,
It is necessary to perform control to increase the opening of the electronic throttle valve 6 and control to decrease the opening of the EGR valve 16 in order to reduce the amount of exhaust gas returned to the intake system by the exhaust gas recirculation device 14. However, devices such as the electronic throttle valve 6 and the EGR valve 16 have a slow operation of an actuator such as a motor for controlling the opening thereof, and the state of the electronic throttle valve 6 and the EGR valve 16 corresponds to a low load. It took a long time to shift from the state to a state corresponding to a high load, and there was a possibility that black smoke (smoke) was generated.

Then, the vehicle stops on the uphill road to stop the diesel engine 1, and thereafter the diesel engine 1
An example of control for suppressing the generation of black smoke when starting is started will be described with reference to the flowchart of FIG.

First, when the eco-run main switch 20 is turned on and it is determined that "stop conditions including the vehicle speed being zero have been satisfied", fuel injection is stopped, and the electronic throttle valve 6 is turned off. The engine is fully closed, and the diesel engine 1 is stopped (step S1). Following this step S1, assuming that a request to start the diesel engine 1 has occurred, it is predicted based on the state of the vehicle whether the load to be carried by the diesel engine 1 will be a high load equal to or greater than a predetermined value. Is performed (step S2).

For example, when it is detected based on the signal of the uphill road detection sensor 32 that "the road where the vehicle is stopped is a flat road", a negative determination is made in step S2. The normal idling control is selected (step S3), and this control routine ends. This “normal idling control” refers to the cooling water temperature sensor 25.
Based on the signal of the air conditioner switch 29, etc.
This means that the fuel injection device 3 and the electronic throttle valve 6 are controlled to control the engine speed to a predetermined idle speed. Further, by controlling the opening degree of the EGR valve 16, the amount of exhaust gas returned to the combustion chamber 2 side by the exhaust gas recirculation device 14 is adjusted to a low-temperature combustion state, so that generation of nitrogen oxides can be suppressed. .

Normal idling control is performed, for example, as shown in FIG.
Is executed based on the map shown in FIG. In FIG. 4, the vertical axis indicates the load, the fuel injection amount and the intake air amount (in other words, the required air amount) corresponding to the load, and the horizontal axis indicates the engine speed. In step S3, the fuel injection amount, the intake air amount, and the engine speed can be controlled corresponding to the area A1 in FIG.

On the other hand, at the time of determination in step S2,
For example, when it is detected that “the road on which the vehicle is stopped is an uphill road”, the determination in step S2 is affirmative. The driving force required when the vehicle starts on an uphill road, that is, the diesel engine 1
, In other words, the target engine output is predicted (step S4). This load can be predicted based on the inclination angle of the uphill road where the vehicle is stopped and the vehicle weight. Next, the load predicted in step S4,
Then, based on the map shown in FIG. 4, the fuel injection amount and the required air amount corresponding to the predicted load are calculated (step S5).

When the judgment is affirmative in step S2, the load is larger than when the judgment is negative in step S2. Therefore, in step S5, the fuel injection amount and the required air amount are calculated based on FIG. 4 in association with the region B1 having a larger load than the region A1. Area A
1 and the area B1, the engine speeds are almost the same, but the required air amount in the area B1 is
The difference is that the air amount is larger than the required air amount in the area A1. The required air amount is set to an amount of air that does not generate black smoke during combustion based on the correspondence relationship with the fuel injection amount.

After step S5, when it is determined that "the stop condition is not satisfied" and a request to start the diesel engine 1 is generated (step S6), the starter motor 33 is driven to rotate the diesel engine 1 initially. At the same time, the opening degree of the electronic throttle valve 6 or the capacity of the turbocharger 10 is controlled so that the required air amount calculated in step S5 is sucked.
The fuel injection control device 3 is controlled so that the required fuel injection amount calculated in step S5 is injected into the combustion chamber 2 (step S7), and the control routine ends.

In step S7, EG
The opening of the R valve 16 is also controlled. Specifically, the opening degree of the EGR valve 16 in the case of step S3 is
The opening of the EGR valve 16 in the case of step S7 is set smaller. By such control, the amount of exhaust gas returned to the combustion chamber 2 is smaller in step S7 than in step S3. By performing the above control, a decrease in the combustion temperature is suppressed, the combustion state is stabilized, and the engine output can be increased.

FIG. 5 is a graph showing changes in the amount of intake air with time after the start of the diesel engine 1 is started. In the diagram of FIG. 5, the vertical axis represents the intake air amount, and the horizontal axis represents time. That is, at the time t1, the cranking of the diesel engine 1 by the starter motor 33 is started, and regarding the change of the intake air amount thereafter, the intake air amount of the embodiment shown by the broken line is:
It increases so as to approach the required air amount ATG calculated in step S5. Thereafter, the rotation speed of the diesel engine 1 reaches a rotation speed at which the vehicle can rotate independently, the start of the diesel engine 1 is completed at time t2, and at the time t3 when the accelerator pedal is depressed and the vehicle starts, at the time t3 of the embodiment. The intake air amount has reached the required air amount ATG.

If the accelerator pedal is depressed at the time of step S6, at least one of the electronic throttle valve 6, the turbocharger 10, and the exhaust gas recirculation device 14 is controlled based on the load prediction at step S4. In this case, it is needless to say that the control is performed in consideration of the accelerator opening.

As described above, when the request for starting the diesel engine 1 is generated when the vehicle is stopped on the uphill and the diesel engine 1 is stopped, the step By performing the control from S2 to S7, the difference between the actual intake air amount of the diesel engine 1 and the required air amount corresponding to the load in the state where the start of the diesel engine 1 is completed is reduced as much as possible. ing.

In other words, when a vehicle having only the diesel engine 1 as a driving force source starts on an uphill road, the driving force required to stop the vehicle on the uphill road is determined by the output of the diesel engine 1. Thus, it is possible to suppress a decrease in startability and a decrease in drivability of the vehicle. Further, in this embodiment, when calculating the required air amount in step S5, the required air amount capable of suppressing the generation of black smoke is set and the exhaust gas return amount is reduced. Generation of black smoke at the time of starting can be suppressed.

On the other hand, FIG. 5 shows a comparative example in which the intake air amount is reduced in order to reduce the generation of nitrogen oxides when the engine is stopped on an uphill road and then the engine is started. It is shown. In this comparative example, the intake air amount is reduced after time t1 in order to reduce the generation of nitrogen oxides. Thereafter, due to the operation of the device for controlling the intake air amount, the intake air amount increases from time t2, and at time t3, the intake air amount matches the required air amount. That is, in the comparative example,
In a state where the engine has been started, the engine output becomes insufficient with respect to the driving force required to stop the vehicle on the uphill road. Further, when the engine has been started, only the fuel injection amount increases in response to the load on the uphill road, and the intake air amount with respect to the fuel injection amount becomes insufficient. As a result, black smoke may be generated.

Here, the correspondence between the functional means shown in FIG. 1 and the configuration of the present invention will be described. Steps S1, S2 and S4 correspond to the load estimating means of the present invention, and step S5 Step S7 corresponds to the output control means of the present invention.

FIG. 6 is a flowchart showing another control example applied to the diesel engine 1. Here, when the step numbers shown in the flowchart of FIG. 6 and the step numbers shown in the flowchart of FIG. 1 are the same,
The same control as the control of the steps in the flowchart of FIG.
This means that it is performed in the steps of the flowchart of FIG.

In the flowchart of FIG. 6, following the step S6, the "low-temperature combustion control" in which the combustion state in the combustion chamber 2 is a low-temperature combustion, in other words, a large amount of EGR combustion is not performed (step S8). The control routine ends. The low-temperature combustion control is performed by suppressing the amount of air taken into the combustion chamber via the intake pipe 5 and increasing the amount of exhaust gas returned from the exhaust manifold 7 to the intake manifold 4 to a predetermined amount or more. This means that the combustion temperature in the combustion chamber 2 is reduced to suppress the generation of nitrogen oxides. When this low-temperature combustion control is performed, the ignitability in the combustion chamber 2 decreases, and the output of the diesel engine 1 decreases. For this reason,
When there is no need to increase the engine output to a predetermined value or more, low-temperature combustion control is performed.

However, if the determination in step S2 is affirmative, even if the vehicle is stopped,
Since it is predicted that the load to be borne by the diesel engine 1 will be high, when starting the diesel engine 1 in step S8, the low-temperature combustion control is not performed. In step S8, the opening degree of the electronic throttle valve 6 or the turbocharger 1 is set so that the required air amount calculated in step S5 in FIG.
Of course, the fuel injection device 3 is controlled so that the required fuel injection amount calculated in step S5 is injected into the combustion chamber 2 while controlling the capacity of 0.

In the control example of the flowchart of FIG. 6, the same effect as in the control example of FIG. 1 can be obtained.
Here, the correspondence between the functional means shown in FIG. 6 and the configuration of the present invention will be described. Steps S1, S2,
Step S4 corresponds to the load prediction means of the present invention, and steps S5, S6, and S8 correspond to the output control means of the present invention.

In the control examples shown in FIGS. 1 and 6, in step S2, "uphill road" is used to determine "whether or not the road requires a high load when starting the diesel engine 1." Is determined, in step S2, "whether the road is an uphill road and its inclination angle is equal to or greater than a predetermined angle" is determined in step S2, and based on the determination result, Step S3 or Step S
A control routine that proceeds to step 4 may be employed.

In the above description, while the vehicle is stopped,
Although the case where the control example of FIG. 1 or FIG. 6 is performed is described, the control example of FIG. 1 or FIG. 6 is used while the vehicle is traveling, that is, when the accelerator pedal is fully closed and the vehicle coasts. You can do that too. That is, in step S1, all of the fact that the accelerator pedal is not depressed, the brake pedal is depressed, and the D position is selected are detected, and the diesel engine 1 is stopped. In step S4, a load when a request to start the diesel engine 1 is generated during coasting of the vehicle is predicted. In addition, when performing the control example of FIG. 1 or FIG. 6 while the vehicle is coasting, the control contents of the other steps are the same as the case of performing the control example of FIG. 1 or FIG. 6 while the vehicle is stopped. .

In the control examples shown in FIGS. 1 and 6, the load for operating the stopped diesel engine 1 is predicted before the request to start the diesel engine 1 is generated. At the same time as or immediately after the request to start the diesel engine 1 is performed, the load of the diesel engine 1 is determined,
A control routine for controlling the output of the diesel engine 1 based on the determination result is also included in the basic principle described with reference to FIG.

[0071]

As described above, according to the first aspect of the present invention,
When starting a stopped engine, the engine output is controlled according to the load required for the engine. Therefore, at the time of starting the engine, it is possible to suppress the excess and deficiency of the driving force of the vehicle, and it is possible to suppress the deterioration of the traveling performance and the drivability of the vehicle.

According to the second aspect of the invention, when the stopped diesel engine is started, the output of the diesel engine is controlled in accordance with the load required for the diesel engine. Therefore, at the time of starting the diesel engine, excess or deficiency of the driving force of the vehicle is suppressed, and deterioration of the running performance and drivability of the vehicle can be suppressed. Also, in the case of a diesel engine, depending on the air-fuel ratio, there is a possibility that local air shortage occurs and black smoke is generated, but if both the fuel supply amount and the air supply amount are controlled according to the load, The generation of black smoke is suppressed.

According to the third aspect of the invention, the same effects as those of the first or second aspect of the invention can be obtained. In addition, when the vehicle travels on an uphill road, the engine output is controlled according to the road gradient. . Therefore, even when the vehicle is located on an uphill road, the driving force required for the vehicle is ensured.

According to the fourth aspect of the present invention, in addition to obtaining the same effects as those of the first to third aspects, the air supplied to the combustion chamber is controlled by controlling the opening of the throttle valve. The amount is adjusted to control the engine output when starting the diesel engine.

According to the fifth aspect of the invention, in addition to obtaining the same effects as in any one of the first to third aspects, the amount of air supplied to the combustion chamber by the function of the supercharger is supplied to the combustion chamber. Is adjusted, and the engine output at the time of starting the diesel engine is controlled.

By the way, the exhaust gas recirculation device returns a part of the exhaust gas discharged from the combustion chamber to the intake system to lower the combustion temperature, so that the ignitability is reduced and black smoke is generated. It's easy to do. On the other hand, according to the invention of claim 6, if the exhaust gas return amount is reduced in order to increase the engine output according to the load, the decrease in the combustion temperature is suppressed, the combustion is stabilized, and the black smoke is reduced. Can be suppressed.

According to the seventh aspect of the present invention, in addition to obtaining the same effects as those of any one of the first to sixth aspects, the engine in a state in which the start of the engine is completed based on the load predicted in advance. Output can be controlled. Therefore,
When the start of the engine is completed, excess or deficiency of the driving force of the vehicle is suppressed, and it is possible to suppress a decrease in running performance and a decrease in drivability.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an embodiment of an engine control device according to the present invention.

FIG. 2 is a conceptual diagram showing a configuration of a power train of a vehicle to which the present invention is applied.

FIG. 3 is a block diagram showing a control system of the vehicle shown in FIG.

FIG. 4 is a map used in the control example of FIG. 1;

FIG. 5 is a diagram comparing the intake air amount of the control example of FIG. 1 with the intake air amount of a comparative example.

FIG. 6 is a flowchart showing another embodiment of the engine control device according to the present invention.

FIG. 7 is a conceptual diagram showing a basic principle of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Diesel engine, 4 ... Intake manifold, 6 ... Electronic throttle valve, 10 ... Turbocharger, 14 ... Exhaust gas recirculation device, 18 ... Electronic control device, 100 ... Engine, Pa ... Passenger, Ve ...
vehicle.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 21/08 311 F02D 23/00 F 3G301 23/00 J 23/02 E 23/02 41/04 360G 41 / 04 360 43/00 301K 43/00 301 301R 301N 301W F02M 25/07 570E F02M 25/07 570 570J 570P F02B 37/12 301N F term (reference) 3G005 EA15 FA04 FA35 GA01 GB24 GD07 GE08 HA04 HA12 HA18 JA39 JA39 JA39 JB02 JB09 JB11 JB17 JB22 JB27 3G062 AA01 AA05 BA02 BA04 CA01 CA03 CA06 GA01 GA04 GA05 GA06 GA15 GA16 GA21 GA25 GA27 GA28 GA29 GA31 3G065 AA00 AA01 AA03 CA00 CA12 DA04 EA01 GA00 GA11 GA29 GA31 GA07 AGABA AKA KA04 FA00 FA04 FA05 FA06 FA10 FA36 3G092 AA02 AA17 AA18 AB05 AB07 AB09 BA02 DB02 DB03 DC03 DC09 FA18 FA31 GA01 HF12Z HF19Z HF23Z HF26Z HF30Z HG03Z 3G301 HA01 HA02 HA11 HA13 HA21 HA22 HA23 JA00 JA24 KA01 KA28 LA00 LA03 PF02Z PF03Z PF05Z PF08Z PF16Z PG00Z

Claims (7)

[Claims] 1. An engine control device for performing control for starting a stopped engine, wherein a load estimating means for assuming a case where the stopped engine is started and estimating the engine load; And an output control means for controlling an engine output based on a result of the prediction by the load predicting means when the engine is started. 2. An engine control device for performing control for starting a stopped diesel engine, wherein a load predicting means for assuming a case where the stopped diesel engine is started, and for predicting a load of the diesel engine. When starting the stopped diesel engine, by controlling the amount of air supplied to the combustion chamber of the diesel engine based on the prediction result of the load prediction means, the output when the diesel engine is started And an output control means for controlling the control of the engine. 3. The load predicting means has a function of predicting a load on the diesel engine when the vehicle is located on an uphill road.
Or the control device for an engine according to 2. 4. The output control means has a function of controlling the amount of air by controlling an opening degree of a throttle valve provided in an intake pipe communicating with the combustion chamber. The engine control device according to any one of claims 1 to 3. 5. The output control means has a function of controlling the amount of air by controlling a capacity of a supercharger for compressing air in an intake pipe communicating with the combustion chamber. The engine control device according to any one of claims 1 to 3. 6. An exhaust gas recirculation device for returning a part of exhaust gas discharged from the combustion chamber to an intake system, wherein the output control means further has a function of controlling an exhaust gas return amount. The engine control device according to any one of claims 1 to 5, wherein 7. The apparatus according to claim 1, wherein said output control means has a function of controlling an engine output in a state where said engine has been started based on a prediction result of said load prediction means. 7. The control device for an engine according to any one of 6.