JP2003020981A - Control device at the time of starting internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the performance of a diesel engine in the starting and in controlling the exhaust emission at the time of starting. SOLUTION: When a request for starting the engine is transmitted to the diesel engine 1, an intake throttle valve 7 is closed and an EGR valve 5 is fully opened. At the same time, motoring of the diesel engine 1 is started by a motor generator 51. When the motoring rotation speed reaches a prescribed value, the fuel feeding is started by a fuel injection device 10. Then, the motor driving current is detected by a current sensor 47, and the combustion condition is judged as the self-sustaining degree. The intake throttle valve 7 starts to open after the ignition, while the EGR valve is fully opened till the opening of the intake throttle valve 7 reaches a prescribed value. After that, the opening of the intake throttle valve 7 becomes larger and that of the EGR valve 5 becomes smaller as the self-sustaining degree is higher until the complete explosion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a start-up control device for an internal combustion engine (particularly a diesel engine) which suppresses the emission of unburned components while improving the ignitability at start-up, and particularly applied to a hybrid vehicle. The present invention relates to a startup control device for an internal combustion engine.

[0002]

2. Description of the Related Art In recent years, hybrid vehicles having a combination of a motor and an engine have been developed from the viewpoint of improving fuel efficiency and reducing CO ₂ emissions. The hybrid vehicles are mainly series hybrid systems and parallel hybrid systems. There is. The series hybrid system is configured to include, for example, a generator, an engine that drives the generator, a battery that charges electric power generated by the generator, and a motor that receives a power supply from the battery and generates a vehicle drive output. It is operated at the highest efficiency point for power generation.

The parallel hybrid system is configured to include, for example, an engine, a battery, and a motor / generator that charges the battery with the electric power generated as a motor when receiving power from the battery and as a generator when driven by the engine. In order to improve the operating efficiency of the engine, the driving force required for vehicle traveling is selectively obtained from the engine or the motor according to the traveling state.

In the above hybrid vehicle, the engine is driven as needed, and the generator drives the engine. Therefore, it is necessary to purify the exhaust gas when the engine is running, but even in a hybrid vehicle, when the engine is sufficiently warmed up and running stably, the exhaust gas is the same as a normal engine. Unburnt components (HC, CO, PM) and N
Ox can be sufficiently purified.

Here, as typical post-treatment systems for exhaust gas purification, oxidation catalysts, three-way catalysts and NOx trap catalysts, or electric heating catalysts thereof (hereinafter referred to as E
HC)) and are used alone or in combination depending on the exhaust characteristics of the engine and the usage conditions. Normal,
When the engine is started, the motoring is performed at a low rotation speed, so the air charging efficiency is low, the amount of air introduced into the engine combustion chamber is insufficient, the temperature of the engine itself is low, or the engine combustion chamber is low. Since the temperature of the air introduced into the compressor is low, the compression end temperature may also be low.

In such a case, ignition and combustion of the fuel in the combustion chamber are likely to be unstable, and as a result, the exhaust gas contains a large amount of unburned components. In addition, the temperature of the post-treatment system such as the catalyst is low at the time of starting, and the activity of the catalyst or the like is often not sufficiently obtained. Therefore, when the engine is started, the exhaust gas is not completely purified and is easily released into the atmosphere. In particular, in a hybrid vehicle in which a starting operation (starting or stopping) is performed more frequently than an ordinary engine, improvement in ignition performance and exhaust gas purification performance at the time of starting is strongly required.

By the way, when a diesel engine excellent in thermal efficiency (fuel consumption) is applied to a hybrid vehicle, improvement of ignitability and exhaust gas purification performance is strongly demanded. This is because the diesel engine is a compression ignition system, so when the engine is cold, it is necessary to provide starting assistance such as preheating the combustion chamber with a glow plug.
This is because the combustion stability is inferior to the case where a normal gasoline engine is applied.

[0008]

Here, as a means for improving the exhaust gas purification performance at the time of starting the hybrid vehicle, there is, for example, the one described in JP-A-8-61193. In this hybrid vehicle, deterioration of exhaust emission is prevented by starting fuel supply when EHC is activated and the motoring rotation speed reaches a predetermined value at the time of starting.

Further, for improving the ignitability at the time of starting the diesel engine, for example, Japanese Patent Laid-Open No.
There is one described in Japanese Patent No. 274087. In this engine, pilot injection that injects a small amount of fuel prior to main injection is performed, and the EGR passage is always opened to recirculate exhaust gas during the period from the start of motoring to the complete explosion to raise the temperature in the combustion chamber. However, in a hybrid vehicle that uses a diesel engine, as in the former case, simply increasing the motoring rotation speed at start-up to increase the air charging efficiency does not increase the engine temperature. Is insufficient to raise the compression end temperature to a temperature at which compression ignition of fuel is possible in low cooling.

Further, since the diesel engine does not throttle the amount of air introduced at the time of starting, there is a large amount of low-temperature exhaust gas at the time of starting. If the exhaust gas is at a high temperature, the exhaust gas can activate the exhaust gas purification device, but in the case of a diesel engine, since the exhaust gas is at a low temperature and a large amount, it is disadvantageous to the activation of the exhaust gas purification device. Will work. For this reason, in order to activate EHC during motoring with a low exhaust temperature in a diesel engine,
It requires much more electricity than a normal gasoline engine.

Therefore, in a diesel engine,
Increasing the motoring rotation speed at the time of starting is accompanied by an increase in low-temperature exhaust gas, and a larger (unrealistic) power supply is required to activate EHC during motoring. Therefore, in the hybrid vehicle to which the diesel engine is applied, it is necessary to improve the exhaust gas purification performance by simultaneously activating the EHC and increasing the motoring rotation speed as in the former case.
Very difficult.

Further, like the latter, when the EGR passage is constantly opened to circulate the gas during the period from the start of motoring to the complete explosion, a part of the fuel burns and the temperature of the gas rises to the engine combustion chamber. At first glance, it seems that it is effective in raising the temperature of the combustion chamber and promoting the ignition of the fuel because it is recirculated. However, actually, particularly in the initial stage of ignition when the engine is cold, the temperature of the working gas in the combustion chamber may decrease due to the latent heat of vaporization of the fuel supplied into the combustion chamber. In other words, the effect of increasing the temperature due to the reflux gas cannot be expected from the time the fuel is supplied until the combustion is started, or more specifically, the fuel is burned to some extent.

Further, since the ratio of the inert gas in the reflux gas increases after the combustion is started after ignition,
Combustion may be hindered and a large amount of unburned components may be discharged. As described above, the conventional ones cannot sufficiently secure the ignitability and the exhaust gas purification performance of the internal combustion engine, particularly at the time of starting the diesel engine applied to the hybrid vehicle.

The present invention has been made in view of the above problems, and it is possible to improve ignition performance at the time of starting and to sufficiently suppress discharge of unburned components at the time of starting control of an internal combustion engine. The purpose is to provide a device.

[0015]

Therefore, in the invention according to claim 1, the combustion state of the engine from the start of the fuel supply at the engine start to the complete explosion to the self-sustaining operation is defined as the self-sustaining degree of the engine. Independent operation degree determining means for determining, and intake control means for controlling intake conditions introduced into the combustion chamber of the engine according to the independent operation degree determined by the independent operation degree determining means,
It is characterized by including.

The invention according to claim 2 is an exhaust gas purification device arranged in an exhaust passage of an engine, and an EGR passage branched from an exhaust passage downstream of the exhaust purification device and communicating with an intake passage.
An EGR valve that opens and closes the EGR passage and an intake throttle valve that adjusts the amount of fresh air introduced into the engine are provided, and the intake control means reduces the amount of recirculated gas as the degree of self-sustaining operation increases. It is characterized in that the opening degrees of the EGR valve and the intake throttle valve are controlled so as to increase the amount of fresh air.

According to a third aspect of the present invention, an exhaust gas purification device arranged in an exhaust passage of an engine, an EGR passage branched from an exhaust passage downstream of the exhaust purification device and communicating with an intake passage,
An EGR valve that opens and closes the EGR passage, an intake throttle valve that adjusts the amount of fresh air introduced into the engine, and an engine temperature detection unit that detects the temperature of the engine are provided, and the intake control unit controls the fuel supply. In the period until the start, the opening degree of the EGR valve and the intake throttle valve is controlled so that the amount of fresh air is reduced and the amount of recirculated gas is increased as the detected engine temperature is lower. .

According to a fourth aspect of the invention, the EGR valve is maintained until the opening of the intake throttle valve becomes equal to or larger than a predetermined opening during the period from the start of the engine to the self-sustained operation. Is to be fully opened. The invention according to claim 5 is provided with an activating means for activating the exhaust gas purification device and an exhaust gas purification device temperature detecting means for detecting a temperature of the exhaust gas purification device, and the detected temperature of the exhaust gas purification device is predetermined. The activation means is activated when the temperature is lower than the temperature.

The invention according to claim 6 is characterized in that the exhaust gas purification device is an electrically heated catalyst, which is heated by activation of electricity to be activated. The invention according to claim 7 is provided with a motor for motoring the engine at the time of starting, and a drive current detection means for detecting a drive current of the motor, wherein the independent drive degree determination means detects the motor drive current or fuel. It is characterized in that the self-sustained operation degree of the engine is determined based on the attenuation rate of the detected motor drive current with respect to the motor drive current immediately before the start of supply.

According to the eighth aspect of the present invention, the smaller the motor drive current detected by the self-sustained operation degree judging means is, or the larger the attenuation rate of the motor drive current detected with respect to the motor drive current immediately before the start of fuel supply is, the larger the engine is. The self-sustained operation of the engine is determined to be high, and when the detected motor drive current is less than or equal to a predetermined reference value or when the damping rate is greater than or equal to a predetermined reference damping rate Characterize.

According to a ninth aspect of the present invention, there is provided rotation speed detection means for detecting the rotation speed of the engine, and at least during the period from the start of fuel supply until the self-sustaining operation determination means determines the engine to perform self-sustaining operation. It is characterized in that the motor is controlled so that the motoring rotation speed of the engine becomes constant.

The invention according to claim 10 is characterized in that the transmission of the engine power to the vehicle drive wheels is prohibited during the period from the start of the fuel supply to the self-sustaining operation of the engine. The invention according to claim 11 is characterized in that the starting control device is applied to an internal combustion engine of a hybrid vehicle.

[0023]

According to the invention of claim 1, the combustion state of the engine from the start of fuel supply at the start to the complete explosion to the self-sustained operation is determined as the self-sustained operation degree, and the determined self-sustained operation degree. Since the intake condition introduced into the combustion chamber of the engine is controlled in accordance with the above, it is possible to execute control for optimum intake according to each combustion state.

As a result, it is possible to improve the ignitability when starting the engine, prevent misfire, and suppress the discharge of unburned components. According to the second aspect of the invention, in the period from the start of fuel supply at the engine start to the self-sustaining operation, the higher the self-sustaining operation degree, the more the amount of recirculation gas and the more the amount of fresh air. Since the opening degrees of the EGR valve and the intake throttle valve are controlled, when the self-sustaining degree of operation including before ignition is low, the working gas introduced into the combustion chamber is controlled to have a large amount of recirculation gas and little fresh air.

As a result, the amount of working gas introduced into the combustion chamber is secured while suppressing the release of unburned components to the atmosphere. As a result, the compression end temperature is increased to accelerate ignition, and the reflux gas whose temperature has risen is circulated to the exhaust gas purification device instead of flowing a large amount of low-temperature fresh air, so that activation of the exhaust gas purification device is also promoted. It Further, when the self-sustaining degree of operation increases after ignition, the amount of fresh air is increased and the amount of recirculated gas is reduced accordingly. As a result, it is possible to prevent the excessive inert gas from being recirculated and to ensure stable combustibility.

As a result, it is possible to secure the ignitability and the combustibility at the time of starting, and to effectively prevent the discharge of unburned components to the atmosphere. According to the invention of claim 3, the EGR valve and the intake air are reduced so that the amount of fresh air is decreased and the amount of recirculated gas is increased as the detected engine temperature is lower in the period until the start of fuel supply. Since the opening of the throttle valve is controlled, the amount of working gas introduced into the combustion chamber can be secured to raise the compression end temperature, and the heating effect of the recirculation gas can be effectively used for activating the exhaust gas purification device.

According to the invention of claim 4, the EGR valve is fully opened until the opening degree of the intake throttle valve becomes a predetermined opening degree or more during the period from the start of the engine to the self-sustained operation. Therefore, the negative pressure is not generated on the downstream side of the intake throttle valve, and the maximum amount of the working gas introduced into the combustion chamber is secured. As a result, the heating effect of the recirculation gas can be effectively utilized by activating the exhaust gas purification device.

Before starting the supply of fuel, the opening of the intake throttle valve is controlled to increase as the engine temperature rises to prevent the working gas from becoming overheated and to secure the amount of fresh air. After the start of fuel supply (after ignition), control is performed so that the opening degree of the intake throttle valve increases as the self-sustained operation degree increases, and stable combustibility is ensured. According to the invention of claim 5, the activation means is activated when the temperature of the exhaust gas purification device is equal to or lower than the predetermined temperature. Therefore, it is possible to raise the temperature of the exhaust gas purification device to activate it as it is. As a result, the activation means can be made compact due to the synergistic effect, and power consumption can be reduced. In addition, it becomes possible to activate the exhaust purification device early. Further, the ignitability can be further improved before ignition and the combustibility can be improved after ignition.

According to the sixth aspect of the present invention, since the exhaust gas purification device is an electrically heated catalyst, the activation means only needs to control the energization, and it is not necessary to separately provide a new device. . That is, it is possible to significantly reduce the power consumption for activating the exhaust emission control device. According to the invention of claim 7, the self-sustained operation degree of the engine (combustion state of the engine) can be easily determined by detecting the motor drive current for motoring the engine at the time of starting.

That is, since the drive current of the motor for motoring the engine also changes according to the change in the self-sustained operation degree of the engine (combustion state of the engine), the self-sustained operation degree of the engine is determined based on the detected motor drive current. it can. In addition, the damping ratio (driving current damping ratio) for the motor driving current immediately before the start of fuel supply is calculated from the detected motor driving current,
By determining the degree of self-sustaining operation of the engine based on the calculated drive current attenuation rate, the combustion state of the engine from the start of fuel supply to the complete explosion can be accurately detected.

According to the eighth aspect of the invention, the degree of self-sustained operation of the engine is determined based on the detected motor drive current or the calculated drive current attenuation rate. It is very easy to judge the degree.
Also, both may be used in combination, and according to this, it is possible to improve the accuracy of determining the self-sustained operation degree.

Further, when the detected motor drive current is less than or equal to a reference current value (which is preferably set on the basis of the engine temperature) preset as a value indicating complete explosion, or the calculated drive current attenuation rate. However, since the complete explosion of the engine is judged when it exceeds the reference attenuation rate (which is preferably set based on the temperature of the engine) preset as a value indicating the complete explosion, the complete explosion timing of the engine is accurately detected. it can.

Also in this case, if both are used in combination, the accuracy of detecting the complete explosion timing can be further improved. According to the ninth aspect of the invention, at least during the period from the start of fuel supply to the time when the self-sustained operation judging means judges the self-sustained operation of the engine, the motoring rotational speed of the engine is controlled to be constant. Therefore, the accuracy of determining the self-sustained operation degree can be further improved.

According to the tenth aspect of the present invention, the transmission of the engine power to the vehicle drive wheels is prohibited during the period from the start of the fuel supply to the self-sustaining operation of the engine. It is possible to reliably avoid the situation where power is generated.
According to the invention of claim 11, a diesel engine having excellent thermal efficiency can be applied to a hybrid vehicle that is frequently started.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system configuration diagram of a start-up control device for a hybrid vehicle according to a first embodiment of the present invention. Particularly, as a hybrid vehicle, an electric motor and an internal combustion engine are used independently or in combination for vehicle traveling. Parallel Hybrid Electric Vehicle (hereinafter, P-HEV)
That is) a diesel engine is applied.

In FIG. 1, P-HEV is an output of a diesel engine (hereinafter, simply engine) 1 and a battery 5
The vehicle is driven by two types of power sources, that is, the output of a vehicle drive motor / generator 53 (which functions as a vehicle drive motor and a generator) that receives power supply from 0. The output of the engine 1 is transmitted to a starting motor / generator 51 (which functions as an engine driving motor and generator at the time of starting) for power generation, and a power transmission mechanism (for example, a CVT with an electromagnetic clutch) for driving a vehicle. ) 52 via differential gear 54 to drive wheels 55a, 55b.

The output distribution of the engine 1 used for power generation and vehicle driving is controlled by the hybrid control unit 40. Further, the hybrid control unit 40 includes a battery 50.
Control the electric power supply to the starting motor generator 51 and the vehicle driving motor generator 53, and at the time of decelerating the vehicle driving motor generator 5
It also controls the recovery of regenerative power from the battery 3 to the battery 50.

Hybrid control unit 40
In order to monitor vehicle driving information (including stop),
A signal L from the accelerator sensor 41 (an output signal proportional to the amount of depression of the accelerator pedal), a signal STA from the start key 42 (a signal corresponding to the Acc position and the ON position, which does not have a Start position unlike a normal vehicle), shift The signal SFT from the lever position sensor 43, the signal BR from the brake actuation switch 44, the signal Vcar from the vehicle speed sensor 45, the signal Bcap from the battery remaining capacity sensor 46, the signal Cst from the current sensor 47 when the engine is driven, etc. are input. Then, the start of the engine 1 and its output distribution are determined based on the input signal, the necessity of output sharing for vehicle traveling is determined, and the start command and the output sharing command are sent to the engine control unit 30. Emit.

Then, the engine control unit 30 starts or stops the engine 1 and controls the output of the engine 1 in accordance with a command from the hybrid control unit 40. Further, in the engine control unit 30, a signal Tw from the water temperature sensor 31, a signal from the crank angle sensor 32 (engine rotation speed Ne and crank angle), a signal from the cylinder discrimination sensor 33 (cylinder discrimination signal) Cyl, common rail. The signal PCR from the pressure sensor 34 for detecting the pressure and the signal T1 from the exhaust temperature sensor 35 for detecting the exhaust temperature T1 are input to the outlet of the EHC 8.

An electrically heated catalyst (EHC) 8 is provided immediately below the exhaust manifold 3a on the upstream side of the exhaust passage 3 of the engine 1 to purify the exhaust of the engine 1. EHC
8 is an electric heating type having a honeycomb structure in which a ferritic stainless steel thin plate is wound around a center electrode.
Is a center electrode, and 8b is a ground electrode. As the catalyst, for example, an oxidation catalyst supported, a noble metal such as Pd or Pt supported on activated alumina, a zeolite having a noble metal (particularly Pt) ion-exchanged, or a combination of both materials can be used.

EG driven by a stepping motor
The R valve 5 is provided with an EGR passage 4 branched from an exhaust passage at an outlet of the EHC 8 (upstream of the turbine 3b of the supercharger).
A part of the exhaust gas is recirculated to the intake pipe 2d of the intake passage 2. The intake passage 2 is provided with an air cleaner 2a, a compressor 2b of a supercharger, an intercooler 2c, an intake throttle valve 7 which is driven to open and close by an actuator (for example, a stepping motor type) 6, and an intake pipe 2d from the upstream side.

The fuel supply system is a diesel fuel (light oil)
Tank 20, fuel supply passage 16 for supplying diesel fuel to the engine fuel injection apparatus 10, fuel return passage for returning return fuel (spill fuel) from the engine fuel injection apparatus 10 to the diesel fuel tank 20 It is composed of nineteen. The fuel injection device 10 is a well-known common rail fuel injection device, and includes the supply pump 1
1, a common rail (pressure storage chamber) 14, and a fuel injection valve 15 provided for each cylinder. The fuel pressurized by the supply pump 11 is temporarily stored in the common rail 14 via the fuel supply passage 12, and then the common rail 14 high-pressure fuels are distributed to the fuel injection valves 15 for the number of cylinders.

Further, in order to control the pressure of the common rail 14, a part of the fuel discharged from the supply pump 11 is returned to the fuel supply passage 16 through an overflow passage 17 in which a one-way valve 18 is provided. . Here, the pressure control valve 13 is provided in the overflow passage 17, and the pressure control valve 13 is controlled according to the duty signal from the engine control unit 30 to change the flow passage area of the overflow passage 17. Adjust the amount of fuel discharged to the common rail 14
Control the pressure of 4.

The fuel injection valve 15 is an electronic fuel injection valve that opens and closes a fuel supply passage to the engine combustion chamber in response to an ON-OFF signal from the engine control unit 30. Injection is performed, and the injection is stopped by the OFF signal. Note that the fuel injection amount increases as the ON signal of the fuel injection valve 15 increases, but also changes depending on the fuel pressure of the common rail 14.

Further, the engine 1 is provided with a glow plug 21 for assisting the engine start facing the combustion chamber of each cylinder, and preheats the combustion chamber when the engine is cold to assist engine start. The start-up control device having the above configuration is controlled by the hybrid control unit 40 and the engine control unit 30.

The control of the hybrid system performed by the hybrid control unit 40 and the engine control unit will be described below. 2 is a basic control routine of the hybrid system, FIG. 3 is a time chart of start-up control, and FIGS. 4 to 7 are engine control units when an output sharing command is issued from the hybrid control unit 40 to the engine 1. It is a subroutine relating to control at the time of starting the hybrid system performed by 30.

In the basic control routine of the hybrid system shown in FIG. 2, in step 100 (denoted as S100 in the figure; the same applies hereinafter), the accelerator sensor 4 is used as vehicle information.
1 signal L, start key 42 signal STA, shift lever position sensor 43 signal SFT, brake activation switch 44 signal BR, vehicle speed sensor 45 signal Vca
r, the signal Bcap of the battery remaining capacity sensor 46, and the signal Cst of the current sensor 47, and as the engine information, the water temperature Tw, the engine rotation speed Ne, and the cylinder discrimination signal Cy.
1, the common rail pressure RCR and the exhaust temperature T1 at the outlet of the EHC 8 are read, and the routine proceeds to step 200.

In step 200, the driving force necessary for vehicle traveling according to the accelerator pedal depression amount L of the driver, that is, the driving force required by the driver for vehicle traveling is calculated, and the step is calculated. Proceed to 300. The signal STA of the start key 42 in this case
Is basically the ON position, and the signal SFT of the shift lever position sensor 43 is the Drive position.

In step 300, the operation mode is determined according to the calculated driving force required for running the vehicle, the brake operating state BR, the vehicle speed Vcar, and the remaining battery charge Bcap. The operation modes are roughly divided into the patterns described below, and are defined based on the maximum output of the engine, the fuel consumption rate characteristics, the capacity of the battery, the maximum output of the motor, and the like.

In the following description, the starting motor / generator 51 and the vehicle driving motor / generator 53 will be simply referred to as the motors 51, 53 or the generators 51, 53 depending on the function at that time. [Motor running mode] Basically, the vehicle is run only by the output of the motor 53 when starting or in a low load region. Therefore, the remaining capacity Bcap of the battery 50 must always be kept at or above a predetermined value (a level at which the rated power of the battery can be stably supplied). Therefore, the battery 50
Is charged by power generation while the engine is running, as will be described later.

[Engine running mode] For example, the battery 5
In order to prevent over-discharging of the battery 50 when the remaining capacity Bcap of 0 is below a predetermined value, it is possible to obtain advantageous thermal efficiency by outputting the required driving force with the engine 1, or the remaining capacity Bcap of the battery 50 is In order to prevent the battery 50 from being overcharged when the value is equal to or more than the predetermined value, the vehicle travels only with the output of the engine 1.

[Engine Output Split Mode] When the remaining capacity Bcap of the battery 50 is less than or equal to a predetermined value, it is advantageous to split the output of the engine 1 into a vehicle drive and a power generation (charging) of the generator 51. When it is obtained, the output of the engine 1 is divided into that for running the vehicle and that for power generation (charging).

[Motor Assist Mode] When a large driving force is required in acceleration operation or the like, and most of the remaining capacity Bcap of the battery 50 is equal to or higher than a predetermined value and the rated power can be stably supplied, most of the The driving force is shared by the output of the engine 1, and the insufficient amount is assisted by the output of the motor 53.

[Engine power generation mode when vehicle is stopped] When the vehicle is stopped, the engine 1 is basically stopped. However, when the remaining capacity Bcap of the battery 50 becomes less than or equal to a predetermined value due to the motor running being continued for a long time, in order to prevent the battery 50 from being over-discharged, the engine 1 is operated to stop the generator 51 when the vehicle is stopped. Drive to generate electricity and charge. That is, the output of the engine 1 at this time is the drive wheels 5a and 5b.
Is used as power for power generation (charging).

[Deceleration Regeneration Mode] The engine 1 is basically stopped during deceleration. Then, the kinetic energy during deceleration is recovered as electric power by the generators 51 and 53, and the battery 50 is charged. In the above description, when the output of the engine 1 is not used as the driving force for running the vehicle,
That is, the power transmission mechanism 52 is disconnected from the engine 1 (for example, the CYT with an electromagnetic clutch) in the motor running mode, the engine stop mode engine generation mode, and the deceleration regeneration mode.

After determining one of the above operation modes,
Go to step 400. In step 400, based on the driving force required for vehicle traveling and the determined driving mode,
The shared output shared by the motor 53 and the engine 1 is calculated. In step 500, it is determined whether the output sharing of the engine 1 is necessary (that is, whether the engine 1 needs to be operated) based on the sharing output calculated in step 400.

When the output sharing of the engine 1 is not necessary, the routine proceeds to step 900, where the operation stop operation control of the engine 1 (hereinafter referred to as stop control) is performed. That is,
The hybrid control unit 40 issues a stop command to the engine control unit 30, and the engine control unit 30 follows the command
Stop control. As a result, the operations of the EGR valve 5 and the intake throttle valve 7 are stopped, and the fuel supply is stopped and maintained (the pressure control valve 13 of the supply pump 11 and the fuel injection valve 15 are OF
Then, the engine 1 is stopped or held stopped.

When it is necessary to share the output of the engine 1 (when the engine 1 needs to be operated), step 600
Proceed to. In step 600, it is determined whether the engine 1 has already been started. If the engine 1 has not been started yet, the routine proceeds to step 800, where the starting operation control of the engine 1 according to the present invention (hereinafter, referred to as starting control) is performed. The control operation at the time of starting performed here is also controlled by the hybrid control unit 40 and the engine control unit 30.

When the engine 1 has already been started (ie, the hybrid control unit 40 has already been started).
Is issuing an output command to the engine control unit 30 and the engine control unit 30 is controlling the output of the engine 1 according to the command),
Proceeding to step 700, the output control of the engine 1 for obtaining the output shared by the engine 1 calculated in step 400 is continued or started.

After the output control of the engine 1 in step 700, the start control of the engine 1 in step 800 or the stop control of the engine 1 in step 900 is performed,
Proceed to step 1100. In step 1100, the control unit for hybrid 40 uses step 300.
The power generation control of the generator 51 is performed based on the operation mode determined in.

In step 1200, the motor generator is controlled. That is, if the shared output of the motor is calculated in step 400, the output (motor driving force) for that is output to the motor 53 (functioning the motor generator 53 as a motor). Also,
If decelerating (motor / generator 51, 53
Function as generators) Generators 51, 5
By 3, the kinetic energy at the time of deceleration is recovered as electric power and the battery 50 is charged.

In step 1300, the gear ratio control and ON-OFF control of the power transmission mechanism 52 are performed based on the driving mode, the vehicle speed Vcar and the like. Next, the starting control performed at step 800 in the basic control routine (FIG. 2) of the hybrid system will be described. Figure 3
Is a time chart showing the start-up control,
It is roughly divided into the following three stages. First, these will be described.

[First Stage: Preheating / Motoring Control] At this stage, the motor 51 starts the motoring of the engine 1 and the engine rotation speed Ne becomes the target rotation speed N.
The fuel supply from the fuel injection valve 15 to the engine 1 is stopped until s (for example, idling speed) is reached. The engine rotation speed Ne is equal to the target rotation speed Ns.
When the fuel injection amount reaches, the fuel injection valve 15 is driven to inject and supply the fuel.

The glow plug 21 has a water temperature (water temperature sensor 3
ON so that the lower the signal Tw) of 1, the higher the degree of heating
-The energization is controlled by adjusting the OFF time. EGR valve 5
Is controlled so as to keep the intake throttle valve 7 fully open until the opening degree of the intake throttle valve 7 reaches a predetermined opening degree. Further, the EGR valve 5 and the intake throttle valve 7 reduce the amount of fresh air introduced into the combustion chamber of the engine 1 to increase the amount of recirculation gas as the water temperature Tw decreases, that is, the intake throttle valve 7 has It is controlled so that the opening degree is decreased and the opening degree of the EGR valve 5 is increased.

The EHC 8 is electrically heated on the basis of the exhaust temperature when the exhaust temperature (signal T1 of the exhaust temperature sensor 35) is below a predetermined temperature. [Second stage: complete explosion determination control] At this stage, the motor 51
Thus, the motoring rotation speed Ne of the engine 1 is maintained constant.

The fuel is supplied according to the demand of the engine 1 from the start of the supply. For example, the lower the water temperature is, the more the fuel is increased and the drive of the fuel injection valve 15 is controlled so as to advance the injection timing. The degree of self-sustaining operation (degree of complete explosion) is determined, and the opening of the intake throttle valve 7 is increased so that the amount of recirculation gas decreases and the amount of fresh air increases as the degree of self-sustaining operation increases.
The opening of the valve 5 is controlled to be small.

Here, the degree of self-sustaining operation (degree of complete explosion) indicates the degree to which the combustion state approaches the complete explosion when the complete explosion is set to the independent operation. For example, the current sensor 4
It is determined based on the signal Cst of 7. In the present embodiment, the larger the attenuation rate of the current drive current with respect to the motoring current (drive current) of the engine 1 immediately before the start of fuel supply, or the smaller the fluctuation rate of the current drive current, the higher the degree of self-sustaining operation. When the damping rate of the motoring current reaches a predetermined value or when the fluctuation rate becomes less than or equal to a predetermined value, it is determined that the complete explosion, that is, the self-sustained operation.

It is also effective to raise the compression pressure and raise the compression end temperature in order to improve the ignitability through the first step to the second step. Therefore, in order to reduce the amount of working gas (fresh air + recirculation gas) introduced into the combustion chamber of the engine 1 as much as possible, the opening of the EGR valve 5 is fully opened when the opening of the intake throttle valve 7 is equal to or less than a predetermined opening. After the opening of the intake throttle valve 7 reaches a predetermined opening, the intake throttle valve 7 is closed by closing the EGR valve 5 as the opening further increases.
Do not generate negative pressure downstream of the.

When the water temperature Tw is high, that is, when the compression end temperature is high and the ignitability is relatively good (that is, when the water temperature is high in the first stage), the operation introduced into the combustion chamber of the engine 1 is performed. Since the proportion of fresh air in the gas is increased to prevent the working gas from overheating, the air filling rate does not decrease, black smoke is generated after ignition, and the compression end temperature is too high, resulting in an extremely early stage. It is possible to prevent generation of abnormal combustion noise due to ignition.

After the first stage, the EHC 8 is electrically heated based on the exhaust temperature when the exhaust temperature (signal T1 of the exhaust temperature sensor 35) is below a predetermined temperature. [Third stage: control after complete explosion] After the complete explosion is determined, the motoring by the motor 51 is stopped. The engine 1 is operating independently, and fuel is supplied according to the output request until the engine is stopped. And the intake throttle valve 7 is also E
It is controlled to be ON (open) or OFF (closed) according to the GR request (held at a predetermined opening by the actuator 6). Since the intake throttle valve 7 in this case is controlled in accordance with the request of EGR, the starting operation stage (first, second
The opening degree does not have to be the same as the opening degree, and the EGR valve 5 is also controlled to be opened / closed in accordance with the EGR request.

Until the predetermined time after the complete explosion elapses, the EHC 8 and the flow plug 21 are continuously controlled (ON or ON-OFF control), and the engine self-sustaining operation is assisted to purify the exhaust gas by the EHC 8. Processing is accelerated. The subroutine of FIG. 4 is for controlling the start-up control, and this control routine includes preheating / motoring control, complete explosion determination control, and complete explosion control subroutines.

In FIG. 4, in step 801, it is determined whether or not the post-combustion control end flag is 1 (is standing). The post-combustion control end flag is set to 1 when the above-described third step (post-combustion control) is completed. If the post-combustion control end flag is 1, it means that the post-combustion control has been completed, that is, the starting operation has been completed.
Then, the engine started flag is set to 1. On the other hand, if the control completion flag after complete explosion is not 1, step 8
Go to 02.

In step 802, it is determined whether the complete explosion flag is 1. This complete explosion flag is set to 1 after the fuel supply to the engine 1 is started until the complete explosion occurs. If the complete explosion flag is 1, the above-described second step (complete explosion determination control) is completed. Indicates that. If the complete explosion flag is 1, the complete explosion determination control has been completed, so the routine proceeds to step 850, where post-complete explosion control (the above-described third stage) is performed. On the other hand, if the complete explosion flag is not 1, the process proceeds to step 803.

At step 803, the ignition start flag is 1
Or not. As for the ignition start flag, the above-described first stage (preheating / motoring control) ends, the motoring rotation speed Ne reaches the target rotation speed Ns, fuel is supplied to the combustion chamber of the engine 1, and ignition is started. Then it is set to 1. If the ignition start flag is 1, the routine proceeds to step 830, where complete explosion determination control (second step described above) is performed. On the other hand, if the ignition start flag is not 1, the routine proceeds to step 810, where preheating / motoring control (first step described above) is performed.

The subroutine of FIG. 5 is the first control of the start time.
This is a control routine for preheating / motoring, which is a stage, and is performed in step 810 of FIG. 5, in step 811, the energization time ratio (ON-OFF ratio) of the glow plug 21, the drive signal of the actuator 6 of the intake throttle valve 7 and the drive signal of the EGR valve 5 are set by data retrieval. Specifically, each table data set in advance according to the water temperature Tw is stored in the ROM, and this table data is searched and set.

In step 812, the glow plug 21, the intake throttle valve 7, and the EGR valve 5 are based on the retrieved data.
To drive. Note that the lower the glow plug 21 and the water temperature Tw, the higher the degree of superheat (that is, the higher the ON time ratio) is controlled. Intake throttle valve 7 and E
As shown in FIG. 8, the GR valve 5 reduces the amount of fresh air as the water temperature Tw is lower, but increases the flow rate of the reflux gas to introduce the working gas (fresh air) into the combustion chamber of the engine 1. Try not to reduce the amount of + reflux gas) as much as possible. That is, the lower the water temperature Tw, the lower the passage area opening ratio H of the intake throttle valve 7, and the opening degree thereof is controlled so that the passage area opening ratio of the EGR valve 5 becomes higher. Further, the EGR valve 5 is driven so as to be fully opened until the opening degree of the intake throttle valve 7 reaches a predetermined opening degree.

In step 813, the exhaust temperature T1 on the downstream side of the EHC8 is detected as a value representing the temperature of the EHC8,
The exhaust temperature T1 is a predetermined temperature Ts at which the catalyst is activated (for example,
250 ° C.) or higher. If the exhaust gas T1 is lower than the predetermined temperature, the routine proceeds to step 815, where E
Turn on HC8 (that is, heat the catalyst) and proceed to step 816.

If the exhaust gas T1 is above the predetermined temperature,
The routine proceeds to step 814, where the EHC8 is turned off (that is, the heating of the catalyst is completed), and the routine proceeds to step 816. In step 816, the motor 51 is driven to start motoring of the engine 1. In step 817, it is determined whether the engine rotation speed Ne is equal to or higher than a predetermined rotation speed Ns (for example, 600 rpm) (whether the predetermined rotation speed Ns is reached).

The engine rotation speed Ne is the predetermined rotation speed N.
If it has reached s, the routine proceeds to step 818, and if it has not reached the predetermined rotation speed Ns, this control is terminated (return). In step 818, the pressure control valve 13 is stored in the ROM in advance so that the common rail pressure is set according to the motoring rotation speed of the engine 1.
Drive control.

In step 819, the fuel injection valve 15 is driven in order to inject the fuel, which is stored in the ROM in advance and set according to the water temperature Tw, to the engine 1.
Then, the process proceeds to step 820, and the ignition start flag is set to 1. The subroutine shown in FIG. 6 is the second control at the time of starting.
FIG. 4 is a control routine related to the determination of complete explosion, which is a stage.
Step 830.

In FIG. 6, the common rail pressure control at the time of starting at step 831, the injection amount control at the time of starting at step 832, and the motoring rotation control at step 833 are performed from the preheating / motoring control of the first stage (FIG. 5). It will be continued. In step 834, the current sensor 47
Based on the signal Cst of the current, the current for the drive current Cst0 of the engine 1 immediately before starting the fuel supply by the motor 51 (the drive current when the motoring rotation speed Ne reaches a predetermined rotation speed Ns is stored in the RAM) The attenuation rate of the drive current Cst1 is calculated as the drive current attenuation rate by the following equation, and the process proceeds to step 835.

Drive current attenuation rate (%) = [(Cst0-C
st1) / Cst0] × 100 In step 835, the calculated drive current attenuation rate and water temperature T
The data after the start of ignition is searched according to w, the energization time ratio (ON-OFF) of the glow plug 21, the intake throttle valve 7
The drive signal of the actuator 6 and the drive signal of the EGR valve 5 are set. Specifically, the drive current attenuation rate and the water temperature Tw
The map data set according to the above is stored in the ROM in advance, and the map data is searched for.

In step 836, the glow plug 21 is energized based on the retrieved map data to drive the intake throttle valve 7 and the EGR valve 5. In addition, as shown in FIG. 9, in the stage from the start of fuel supply to the combustion chamber at the time of start up to the complete explosion (self-sustaining operation), the higher the self-sustaining operation degree (complete explosion degree), the more the drive current decay. The rate is high. Therefore, the higher the drive current attenuation rate, the more the amount of recirculation gas is reduced. However, the amount of fresh air is increased to introduce the amount of working gas (fresh air + recirculation gas) introduced into the combustion chamber of the engine 1 as much as possible. The opening degrees of the EGR valve and the intake throttle valve 7 are controlled so as not to decrease. In addition, the intake throttle valve 7
Until the opening degree reaches a predetermined opening degree, the EGR valve 5 is driven so as to keep the opening degree fully open.

In order to prevent damage to the glow plug 21 due to overheating, it is desirable to control the ON time ratio to decrease as the drive current attenuation ratio increases.
In step 837, the exhaust temperature T1 on the downstream side of the EHC8 is detected as a value representing the temperature of the EHC8, and it is determined whether or not the temperature is equal to or higher than a predetermined temperature Ts (for example, 250 ° C.) at which the catalyst is activated.

If the exhaust gas T1 is lower than the predetermined temperature,
Proceeding to step 839, the EHC 8 is turned on (that is, the catalyst is electrically heated), and the process proceeds to step 840. If the exhaust gas T1 is equal to or higher than the predetermined temperature, step 838
Then, the EHC 8 is turned off (that is, the energization heating of the catalyst is ended), and the routine proceeds to step 840.

Steps 837 to 859 are shown in FIG.
This is the same as steps 814 to 815 in. In step 840, it is determined whether or not the drive power supply attenuation rate has become equal to or higher than a predetermined value (whether or not the predetermined value has been reached). This predetermined value is previously obtained by an experiment or the like according to the water temperature Tw, and is stored as a reference attenuation rate indicating complete explosion.

If the drive power supply attenuation rate has reached the predetermined value (that is, if complete explosion), the routine proceeds to step 841 and the complete explosion flag is set to 1. If the drive power source attenuation rate has not reached the predetermined value (that is, if the complete explosion has not been reached), the routine proceeds to step 842, where the complete explosion flag is set to 0. In the above flow, the complete explosion is determined by the decay rate of the drive current, but the complete explosion may be determined by the detected drive current (motoring current value) Cst1 itself. In this case, complete explosion is determined when the drive current value (motoring current value) Cst1 becomes equal to or less than the reference drive current value preset according to the water temperature Tw. Further, the complete explosion may be determined using both the drive current attenuation rate and the drive current value. By doing so, the accuracy of the complete explosion determination can be further improved.

The subroutine of FIG. 7 is the third of the control at startup.
This is a control routine for the stage after the complete explosion, which is performed in step 850 of FIG. In FIG. 7, step 8
At 51, it is determined whether or not the post-complete explosion time setting flag is 1. This post-explosion time setting flag is the glow plug 2
1 and EHC8 are used to measure the controlled time after the complete explosion, and 1 indicates that the control after the complete explosion has started.

If the post-explosion time setting flag is not 1, the routine proceeds to step 854, where table data stored in advance in the ROM and set according to the water temperature Tw is searched to control the glow plug 21 and the EHC 8 after the complete explosion. Set the required time (control time after complete explosion). The control time after the complete explosion is set to be longer as the water temperature Tw is lower. However, it is desirable to set the control time within a short time (up to several seconds at the maximum) after the complete explosion is determined.

Then, the process proceeds to step 855 to set the post-complete explosion time setting flag to 1. Returning to step 851, if the post-explosion time setting flag is 1, step 852
Proceed to. In step 852, the glow plug 21 and E
It is determined whether or not the control time of the HC 8 has reached the set control time after complete explosion.

If the control time after the complete explosion has not been reached, the routine proceeds to step 856, where the intake throttle valve 7 is driven and the EGR valve 5 is driven.
Is turned off (valve closed), and in order to prevent overheating of the glow plug 21, the ON ratio is set to the minimum and the glow plug 21 is energized. Then, the process proceeds to step 857, and it is determined whether the exhaust temperature T1 is equal to or higher than a predetermined temperature Ts (for example, 250 ° C.) at which the catalyst is activated. If the exhaust gas T1 is lower than the predetermined temperature, the process proceeds to step 859. Then the EHC 8 is turned on (that is, the catalyst is electrically heated) and the process returns. If the exhaust gas T1 is equal to or higher than the predetermined temperature Ts, the routine proceeds to step 858, the EHC 8 is turned off (that is, the electricity heating of the catalyst is finished), and the routine returns.

Steps 857 to 859 are shown in FIG.
This is the same as steps 814 to 815 in. Returning to step 852, if the post-combustion control time has been reached, the routine proceeds to step 853, where the post-combustion control end flag is set to 1, and the glow plug 21 and EHC 8 are turned off, and control after the complete explosion is completed.

By performing the engine start-up control as described above, it is possible to secure good startability and exhaust gas purification performance at the start even when a diesel engine is applied to the hybrid vehicle. The above explanation is P
-When the diesel engine is applied to the HEV, the present invention is not limited to this, and the starting control device according to the present invention can be applied to a vehicle of a series hybrid system (S-HEV).

The structural difference between S-HEV and P-HEV will be briefly described with reference to FIG.
1 does not have the power transmission mechanism 52 shown in FIG. Therefore, the output of the engine is not directly transmitted to the drive wheels as the driving force, and the vehicle is basically driven only by the driving force of the motor 53, and the vehicle according to the accelerator pedal depression amount L of the driver. The driving force required to drive the vehicle is entirely covered by the motor output. That is, all the output of the engine is transmitted to the generator 51 for power generation, and the engine is basically operated at the load and the rotation speed at which maximum efficiency is obtained.

The starting control device according to the present invention can be applied to not only hybrid vehicles but also ordinary diesel engines.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of a parallel hybrid vehicle showing an embodiment of the present invention.

FIG. 2 is a flowchart showing a basic control routine of a hybrid system.

FIG. 3 is a time chart of a starting operation performed at the time of starting.

FIG. 4 is a flowchart showing a start-time control routine for controlling a start operation.

FIG. 5 is a flowchart showing a preheating / motoring control routine.

FIG. 6 is a flowchart showing a control routine for complete explosion determination.

FIG. 7 is a flowchart showing a control routine after complete explosion.

FIG. 8 is a diagram showing an example of opening ratios of an intake throttle valve and an EGR valve.

FIG. 9 is a diagram showing the relationship between the cooling water temperature, the motor drive current attenuation rate, and the combustion state of the engine.

[Explanation of symbols]

1 diesel engine 5 EGR valve 7 Intake throttle valve 8 Electric heating type catalyst (EHC) 10 Fuel injection device 30 Engine control unit 31 Water temperature sensor 40 Hybrid control unit 47 Current sensor 50 battery 51 Motor generator for starting 53 Vehicle drive motor generator

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 43/00 301 F02D 43/00 301N 301T 301W 45/00 314B 45/00 314 F02M 25/07 570E F02M 25 / 07 570 570J B60K 9/00 ZHVC F term (reference) 3G062 AA01 CA01 DA01 DA02 GA06 GA08 GA09 GA15 GA16 GA25 GA28 GA30 GA31 3G084 AA00 AA01 BA05 BA20 BA24 BA32 CA01 DA09 DA10 FA20 FA27 FA33 3G092 A02 A18 AB03 A02 AB03 A02 BB08 CA01 DB03 DC03 DC09 EA01 EA02 EA08 EA12 FA06 FA18 FA30 FA31 GA01 HA06X HC07Z HD01Z HD02X HD07X HE01Z HE08Z HF02Z HF05Z HF08Z HF12Z HF19Z HF21Z EA21 DB01 DA01 CA01 DA01 BA01 DA01 BA05 BA01 BA01 BA01 BA01 BA01 AB01 AB01 AB01 AB02 AB02 AB02 HA02 HA11 HA13 HA27 JA03 JA21 KA01 KA11 LA03 LB11 MA11 MA18 NE01 NE06 NE19 PA11Z PC10Z PD12Z PD15Z PE01Z PE08Z PF01Z PF03Z PF07Z PF12Z PF16Z PG02Z

Claims (11)

[Claims] 1. A self-sustaining operation degree determining means for determining a combustion state of the engine from the start of fuel supply at the engine start up to a complete explosion until self-sustaining operation, as an independent operation degree of the engine, and an independent operation degree determining means. An intake control means for controlling an intake condition to be introduced into a combustion chamber of an engine according to the self-sustained operation degree determined by 1. 2. An exhaust gas purification device arranged in an exhaust passage of an engine, an EGR passage branched from an exhaust passage on the downstream side of the exhaust purification device and communicating with an intake passage, and an EGR valve opening and closing the EGR passage, An intake throttle valve that adjusts the amount of fresh air to be introduced into the engine; and the intake control means decreases the amount of recirculated gas and increases the amount of fresh air as the self-sustaining degree of operation increases. E
2. The start-up control device for an internal combustion engine according to claim 1, wherein the opening degree of the GR valve and the intake throttle valve is controlled. 3. An exhaust gas purification device arranged in an exhaust passage of an engine, an EGR passage branched from an exhaust passage on the downstream side of the exhaust purification device and communicating with an intake passage, and an EGR valve opening and closing the EGR passage, An intake throttle valve for adjusting the amount of fresh air introduced into the engine, and an engine temperature detecting means for detecting the temperature of the engine are provided, and the intake control means is the engine detected during the period until the start of fuel supply. 2. The opening degree of the EGR valve and the intake throttle valve is controlled so that the amount of fresh air is decreased and the amount of recirculated gas is increased as the temperature of the air is lower.
Alternatively, the startup control device for the internal combustion engine according to claim 2. 4. The intake control means fully opens the EGR valve until the opening of the intake throttle valve becomes equal to or more than a predetermined opening during a period from the start of the engine to the self-sustaining operation. The start-up control device for an internal combustion engine according to claim 2 or 3, characterized in that: 5. An exhaust gas purification device temperature detecting means for detecting the temperature of the exhaust gas purification device, comprising an activation means for activating the exhaust gas purification device, wherein the detected temperature of the exhaust gas purification device is below a predetermined temperature. In case,
2. The activating means is activated.
5. The start-up control device for an internal combustion engine according to claim 4. 6. The start-up control device for an internal combustion engine according to claim 5, wherein the exhaust gas purification device is an electrically heated catalyst and is heated and activated by energization. 7. A motor for motoring the engine at the time of starting, and drive current detection means for detecting a drive current of the motor,
The self-sustained operation degree determination means determines the self-sustained operation degree of the engine based on the detected motor drive current or the damping rate of the detected motor drive current with respect to the motor drive current immediately before the start of fuel supply. The startup control device for an internal combustion engine according to any one of claims 1 to 6. 8. The self-sustained operation degree determining means has a higher self-sustained operation degree as the detected motor drive current is smaller or the attenuation rate of the detected motor drive current with respect to the motor drive current immediately before the start of fuel supply is larger. 8. The self-sustained operation of the engine is determined when the detected motor drive current is below a predetermined reference value or when the damping rate is above a predetermined reference damping rate. A start-up control device for an internal combustion engine as described above. 9. A motoring of the engine by the motor at least during a period from the start of fuel supply to the time when the self-sustaining operation judging means judges the self-sustaining operation of the engine. 9. The startup control device for an internal combustion engine according to claim 8, wherein the rotation speed is controlled so as to be constant. 10. The method according to claim 1, wherein transmission of the engine power to the vehicle drive wheels is prohibited during the period from the start of fuel supply to the self-sustaining operation of the engine. A control device for starting an internal combustion engine according to claim 1. 11. The startup control of an internal combustion engine according to claim 1, wherein the startup control device is applied to an internal combustion engine of a hybrid vehicle. apparatus.