JP3610792B2 - Vehicle engine start control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a start control device for an engine mounted on a vehicle, and more particularly to a start control device suitable for an engine of a hybrid vehicle.
[0002]
[Prior art]
A hybrid vehicle having both an engine (internal combustion engine) and a motor as a prime mover and running with one or both driving forces is known (for example, “Automotive Engineering” VOL.46 issued by Railway Japan Co., Ltd.). No. 7, June 1997, pages 39-52).
[0003]
[Problems to be solved by the invention]
By the way, a variable valve system that can control the opening and closing timing of the intake valve of the engine is provided, and the compression valve ratio is delayed by delaying the intake valve closing timing when the engine is started for the first time after the vehicle starts operating or when the vehicle is restarted. A hybrid vehicle has been proposed in which unpleasant vibrations at the time of engine start and restart are reduced by reducing the engine speed (Japanese Patent Application No. 10-248276).
[0004]
In this case, when standard gasoline is used as the reference fuel and fuel that is less volatile than this reference fuel (this fuel is hereinafter referred to as “heavy fuel”) is used in hybrid vehicles, the heavy fuel is inherently startable. However, in the hybrid vehicle as described above, since the actual compression ratio is lowered due to the retard of the intake valve closing timing when the engine is started, the startability tends to deteriorate. For this reason, even at room temperature, the restart period (the period from the start of restart until the engine completes explosion) is increased, affecting start acceleration performance, and starting failure is likely to occur at extremely low temperatures.
[0005]
In addition, a restart failure also occurs due to deterioration of the engine over time (hereinafter simply referred to as “deterioration of the engine”) due to carbon deposition in the combustion chamber or spark plug.
[0006]
Therefore, the present invention measures the period required for the restart at the restart after the engine warm-up is completed, determines the startability rank based on the measured value, and stores the determined startability rank. By using the stored startability rank to perform the restart control after determining the startability rank, even when heavy fuel is used or when the engine has deteriorated, the engine can be started. The purpose is to facilitate restart after sex rank determination.
[0007]
JP-A-8-4571 discloses a technique for increasing the warm-up fuel after starting when the engine speed drops below a predetermined value after starting the engine. However, this technique improves the engine state after the engine is started, and cannot improve the startability (restartability) of the engine itself.
[0008]
[Means for Solving the Problems]
As shown in FIG. 8, the first invention is a means 61 for measuring a period (time or the number of times the engine has been rotated) required for restart after engine warm-up is completed, and based on this measurement value. Means 62 for determining the startability rank indicating whether the startability is good, means 63 for storing the startability rank, and control at restart after the determination of the startability rank using the stored startability rank Means 64 for performingWhen the engine water temperature Tw is equal to or higher than the predetermined value and the engine is stopped when the vehicle is stopped and then restarted, the predetermined value is increased as the startability is worsened based on the stored startability rank. .
[0014]
First2In this invention, the timing for measuring the period required for restart in the first invention is the earliest restart time after completion of engine warm-up.
[0015]
First3In the invention of the first aspect, the warning device warns when the startability exceeds the limit as judged from the stored startability rank in the first invention.
[0016]
First4In the invention, the startability rank determined based on the measurement value in the first invention is two or more stages.
[0017]
First5In this invention, the startability rank determined based on the measured value in the first invention is held even after the ignition key switch is turned off.
[0018]
[Action / Effect]
According to the first invention, when the startability is poor based on the stored startability rank, the heavy fuel is used by performing the restart control so that the restart is facilitated. Even when the engine is deteriorated while using the reference fuel, it is possible to facilitate the restart from the restart after the startability rank determination.
[0019]
Also,Regardless of the volatility of the fuel or the deterioration of the engine, the restart period can be kept almost constant from the time of restart after the startability rank determination, which prevents heavy fuel use and engine deterioration. Even when it occurs, the start acceleration performance can be guaranteed from the restart after the startability rank determination.
[0024]
If the startability rank is determined only once, and it is determined that fueling is performed after the startability rank is determined, the startability rank may not correspond to the fuel after refueling.2In this invention, since the startability rank is determined at the earliest restart after the engine warm-up is completed, it is possible to cope with fuel exchange.
[0025]
First3According to the invention, it is possible to promote engine repair and refueling of the reference fuel.
[0026]
First4According to the invention, the configuration can be simplified by making the startability rank stepwise.
[0027]
First5According to the invention, the startability rank is maintained even after the ignition key switch is turned off, so that when different fuels are not refueled after the ignition key switch is turned off the last time, when using heavy fuel or engine Even in the case where the deterioration has occurred, the start can be easily performed from the first start after the start of the next vehicle operation.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, FIG. 1 shows a configuration example of a hybrid vehicle to which the present invention can be applied. This is a parallel hybrid vehicle that travels using the power of either one or both of an engine (internal combustion engine) and a motor (rotary electric machine that also serves as a generator) according to traveling conditions. In a hybrid vehicle, the vehicle is basically driven by a motor only in a relatively light operating range. When the load increases, the engine is started to ensure the required driving force, and the motor and engine are used together as necessary. The maximum driving force can be demonstrated.
[0029]
In FIG. 1, a thick solid line indicates a transmission path of mechanical force, and a thick broken line indicates a power line. A thin solid line indicates a control line, and a double line indicates a hydraulic system.
[0030]
The power train of the vehicle includes a motor 1, an engine 2, a clutch 3, a motor 4, a continuously variable transmission 5, a speed reducer 6, a differential device 7, and drive wheels 8. The output shaft of the motor 1, the output shaft of the engine 2, and the input shaft of the clutch 3 are connected to each other, and the output shaft of the clutch 3, the output shaft of the motor 4 and the input shaft of the continuously variable transmission 5 are connected to each other. ing.
[0031]
When the clutch 3 is engaged, the engine 2 and the motor 4 serve as a vehicle propulsion source, and when the clutch 3 is released, only the motor 4 serves as a vehicle propulsion source. The driving force of the engine 2 or the motor 4 is transmitted to the drive wheels 8 via the continuously variable transmission 5, the speed reducer 6, and the differential device 7. The continuously variable transmission 5 is supplied with pressure oil necessary for shifting from the hydraulic device 9. An oil pump (not shown) of the hydraulic device 9 is driven by a motor 10.
[0032]
The motor 1 is mainly used for engine start and power generation, and the motor 4 is mainly used for vehicle propulsion (power running) and braking. The motor 10 is for driving an oil pump of the hydraulic device 9. In addition, when the clutch 3 is engaged, the motor 1 can be used for vehicle propulsion and braking, and the motor 4 can be used for engine starting and power generation. The clutch 3 is a powder clutch and can adjust the transmission torque. The continuously variable transmission 5 is a continuously variable transmission such as a belt type or a toroidal type, and the gear ratio can be adjusted steplessly.
[0033]
The motors 1, 4 and 10 are driven by inverters 11, 12 and 13, respectively. In the case where a DC electric motor is used for the motors 1, 4 and 10, a DC / DC converter is used instead of the inverter. The inverters 11 to 13 are connected to the main battery 15 via a common DC link 14. The inverter 11 to 13 converts the DC charging power of the main battery 15 into AC power and supplies it to the motors 1, 4, 10. 4 to convert the AC generated power into DC power and charge the main battery 15. In addition, since the inverters 11 to 13 are connected to each other via the DC link 14, the power generated by the motor during the regenerative operation can be directly supplied to the motor during the power running operation without going through the main battery 15. it can. Various batteries such as a lithium ion battery, a nickel / hydrogen battery, a lead battery, and an electric double layer capacitor, a so-called power capacitor, are applied to the main battery 15.
[0034]
Reference numeral 16 denotes a controller (control device) which includes a microcomputer, its peripheral components, various actuators, and the like. The transmission torque of the clutch 3, the rotational speeds and output torques of the motors 1, 4, 10 and the gear ratio of the continuously variable transmission 5 The fuel injection amount / injection timing and ignition timing of the engine 2 are controlled.
[0035]
As shown in FIG. 2, the controller 16 includes an ignition key switch 20, a select lever switch 21, an accelerator pedal sensor 22, a brake switch 23, a vehicle speed sensor 24, a battery temperature sensor 25, a battery SOC detection device 26, and a crank angle sensor 27. A throttle opening sensor 28 is connected. The ignition key switch 20 is closed when the ignition key of the vehicle is set to the ON position or the START position (hereinafter, the switch closing is referred to as ON or ON, and the opening is referred to as OFF or OFF). The select lever switch 21 is one of P, N, R, and D switches according to the set position of a select lever (not shown) that switches to any of the ranges of parking P, neutral N, reverse R, and drive D. Turns on.
[0036]
The accelerator pedal sensor 22 detects the amount of depression of the accelerator pedal, and the brake switch 23 detects the depression state of the brake pedal (at this time, switch on). The vehicle speed sensor 24 detects the traveling speed of the vehicle, and the battery temperature sensor 25 detects the temperature of the main battery 15. Further, the battery SOC detection device 26 detects SOC (battery charge amount) which is a representative value of the actual capacity of the main battery 15, and the throttle opening sensor 28 detects the throttle valve opening of the engine 2. Further, the crank angle sensor 27 outputs a REF signal (crank angle reference position signal, each signal at 180 ° for a 4-cylinder engine and every 120 ° for a 6-cylinder engine) and a POS signal (a signal for each unit angle). To do. The time between the REF signals is measured by the controller 16, and the rotational speed of the engine 2 is detected from this time measurement value.
[0037]
The controller 16 is also connected with a fuel injection device 30, an ignition device 31, a variable valve operating device 32, and the like of the engine 2. The controller 16 controls the fuel injection device 30 to supply and stop the fuel to the engine 2 and adjust the fuel injection amount / injection timing, and drives the ignition device 31 to control the ignition timing of the engine 2. The controller 16 is supplied with power from a low-voltage auxiliary battery 33.
[0038]
Further, the controller 16 controls the variable valve device 32 to adjust the operating state of the intake / exhaust valve of the engine 2.
[0039]
Here, the variable valve operating device 32 will be described with reference to the mechanical configuration example of FIG. 3. This is because the operating angle (the valve opening period and the valve closing timing) of the intake cam (intake valve cam) 51 of the engine. The variable valve operating device is configured by the cam operating angle variable mechanism 50 that can be changed. The controller is similar to those disclosed in, for example, Japanese Patent Laid-Open Nos. 9-242520 and 9-268930. Based on the hydraulic pressure from the solenoid valve 41 controlled to 16, the actuator 52 that drives the eccentric shaft 53 about the axis and the intake cam 51 connected to the eccentric shaft 53 via the housing 54 rotate. The operating angle of the intake cam 51 is changed by swinging the eccentric shaft 53 about the axis relative to the intake cam 51 to maximize the opening timing and closing timing of the intake valve (not shown). And it is capable of stepwise or continuously changed between the minimum operation angle from rotation angle. The operating angle of the intake cam 51 is detected by a cam rotation angle sensor 29, and the controller 16 drives the solenoid valve 41 so that the intake valve operating timing according to the engine operating state is included, including at the time of starting, to operate the intake cam 51. Control the corners.
[0040]
Now, by using such a variable valve device, when the engine is started or restarted during vehicle operation, the intake valve closing timing is delayed to lower the compression ratio, thereby reducing unpleasant vibration at the time of engine start or restart. It is reduced.
[0041]
In this case, there is no problem when using the reference fuel. However, when heavy fuel is used, the heavy fuel is inherently poor in starting performance. As a result, the actual compression ratio is reduced, so that the startability tends to deteriorate. For this reason, even at room temperature, the restart period (the period from the start of restart until the engine completes explosion) increases, which affects start acceleration performance, and is likely to cause a restart failure in an extremely low temperature range.
[0042]
In addition, even when the reference fuel is used, there is no problem at first, but a restart failure occurs due to deterioration of the engine.
[0043]
Therefore, in the controller 16, at the restart after the engine warm-up is completed after the start of the vehicle operation, the number of REF signals input from the start of the restart to the complete explosion of the engine (the engine is within the period required for the restart). (Corresponding to the number of rotations) is measured, and based on this measurement value, it is determined which startability rank is in the stage divided into three, and the determined startability rank is stored in the RAM in the controller 16 In addition, the control at restart after the startability rank determination is performed using the stored startability rank.
[0044]
This control content executed by the controller 16 will be described according to a flowchart.
[0045]
First, FIG. 4 is for determining the startability rank and is executed at regular intervals.
[0046]
In step 1, the startability rank determined flag is checked. Since this flag is initially set to “0” at the start of operation of the vehicle, the process proceeds to steps 2, 3, 4, and 5 to check whether or not the engine is being restarted after warm-up is completed. If the engine is warming up after restarting, the number of REF signals input from the start of restart until the engine is completely exhausted is measured in steps 6, 7, 8, and 9.
[0047]
More specifically, the cooling water temperature Tw is read in step 2, and the cooling water temperature Tw is compared with a predetermined value Tw1 in step 3. The predetermined value Tw1 determines the warm-up completion temperature. When Tw ≦ Tw1, the engine is not in the warm-up completion state, and thus the current process is terminated.
[0048]
When Tw> Tw1 (warm-up completion state), the process proceeds to steps 4 and 5 to check the state of the current starter switch (abbreviated as “ST SW” in the figure) and the state of the previous starter switch.
[0049]
When the current starter switch state is ON and the previous starter switch state is OFF (that is, when the starter switch is switched from OFF to ON), it is determined that it is the restart start timing, and in step 6, the REF signal is After instructing the start of counting, the process proceeds to step 7. If the starter switch is continuously ON, step 6 is skipped and the process proceeds to step 7.
[0050]
In response to the instruction to start counting the REF signal, the counter increments the value by one each time the REF signal is input in another routine (not shown).
[0051]
In step 7, the engine speed Ne is read, and this is compared with a predetermined value Ne1 in step 8. Here, the predetermined value Ne1 determines the complete explosion speed. Therefore, when Ne ≦ Ne1, since the engine has not completely exploded, the current process is terminated.
[0052]
When Ne> Ne1 (the engine is completely detonated), the process proceeds from step 8 to step 9 to instruct to stop counting the REF signal. Since the REF signal count stop instruction stops the REF signal count in a routine (not shown), the counter value at that time is shifted to ns. As a result, the number of REF signals input from the start of restart until the engine completes explosion is entered in ns at the first restart after the completion of engine warm-up. The larger the value of ns, the longer the restart period is (that is, the restart is not easy).
[0053]
Next, in steps 10, 11, 12, 13, and 14, a value that becomes so large that restarting is not easy is set as the startability rank SR using this ns. In this case, for simplicity, the startability rank SR is set in three parts.
[0054]
Specifically, in steps 10 and 11, ns is compared with predetermined values ns1 and ns2 (where ns2> Ns1), and in steps 12, 13, and 14,
(1) When ns ≦ ns1, the starting rank SR = 1,
(2) When ns1 <ns ≦ ns2, the starting rank SR = 2
(3) When ns2 <ns, the starting rank SR = 3
The starting rank SR is set as follows.
[0055]
Here, factors affecting the ease of restart include fuel properties, particularly volatility. For example, when the reference fuel is used, ns ≦ ns1 (that is, startability rank SR = 1), but when heavy fuel is used, the period from the start of restart to the complete engine explosion is prolonged, and ns1 < Since ns ≦ ns2, the startability rank SR = 2.
[0056]
In order to make use of the startability rank SR set in this way for the fuel increase at the next restart during the same vehicle operation, the startability rank SR is stored in the RAM in step 15 and then the startability in step 16. The rank determined flag = 1.
[0057]
Due to the startability rank determined flag = 1, it is not possible to proceed to step 2 and thereafter from the next time. This is to avoid repeated determination of the startability rank. However, the present invention is not limited to this, and the startability rank may be determined periodically during the same vehicle operation.
[0058]
Next, FIG. 5 is for performing start control, and is executed at regular intervals independently of the flow of FIG.
[0059]
In step 21, the starter switch is viewed. When the starter switch is ON, the routine proceeds to step 22 where the startability rank determined flag is checked. When the startability rank determined flag = 0, it is the first engine start at the start of operation of the vehicle, and since the startability rank has not yet been determined, the process proceeds to step 23 and, similarly to the conventional device,
[0060]
[Expression 1]
Ti = Tst × Knst × Ktst × 2
However, Tst: Basic injection pulse width at start
Knst: rotational speed correction coefficient
Ktst: Time correction coefficient
The starting fuel injection pulse width Ti at the time of sequential injection is calculated by the following formula, and this is transferred to the output register in step 24.
[0061]
Here, Knst in Equation (1) is a value corresponding to the cranking rotation speed, and Ktst is a value corresponding to the cranking time, and Tst as the basic injection amount at the start (restarting) is determined by these increase correction coefficients. The fuel is increased.
[0062]
In sequential injection, fuel is injected once every two engine revolutions by opening the fuel injection valve for each cylinder during the Ti period. In addition, in the cylinder direct fuel injection spark ignition engine, the injection at the time of starting is limited to sequential injection, but in other engines, it is not limited to this, and all cylinders may be simultaneously injected. Further, the calculation formula of the fuel injection pulse width at the start is not limited to Formula 1.
[0063]
On the other hand, when the startability rank determined flag = 1, the routine proceeds from step 22 to steps 25 and 26, where the startability rank SR and the cooling water temperature Tw are read from the RAM, and FIG. By searching the map, the startability rank correction coefficient Ksr is obtained, and using this correction coefficient Ksr
[0064]
[Expression 2]
Ti = Tst × Knst × Ktst × (1 + Ksr) × 2
The starting fuel injection pulse width Ti at the time of sequential injection is calculated by the following equation, and this is transferred to the output register (steps 28 and 24).
[0065]
Here, Equation 2 is a new addition of the term (1 + Ksr). Knst × Ktst determines the amount of fuel increase at start-up with respect to the reference fuel. However, when heavy fuel is used or the engine is deteriorated, restarting is easier on the basis of this reference fuel. That is why the increase correction corresponding to is performed.
[0066]
As shown in FIG. 6, the startability rank correction coefficient Ksr is 0 when SR = 1 (in the case of reference fuel), whereas it is 0 when SR = 2 or 3 (in the case of heavy fuel). Is a value that becomes higher than 0 as the cooling water temperature Tw decreases in a low temperature region where the cooling water temperature Tw is equal to or lower than the predetermined value Tw2.
[0067]
Here, the operation of the present embodiment will be described with reference to FIG. 7. FIG. 7 shows a case where the engine is stopped and restarted after the engine warm-up is completed after the vehicle operation is started.
[0068]
When the starter switch is switched from OFF to ON at timing A in response to a request from the controller 16, a starting operation is performed (cranking is performed by the motor 1 and fuel injection to the engine 2 is performed). Since the restartability is good when the fuel is used, the engine speed Ne exceeds the predetermined value Ne1 as early as timing B, and the engine is completely exploded (restarted). The period until the complete explosion is short.
[0069]
That is, when the reference fuel is used, it is not necessary to increase the increased amount of fuel at the restart even after the startability rank determination. In the illustrated example, the number of REF signal inputs (ns) until the engine completes explosion is 3, so if the predetermined value ns1 = 4 is set, the startability rank SR = 1, and therefore the startability rank correction from FIG. The coefficient Ksr = 0, and the increased amount of fuel at the time of restart is the same as that of the conventional device.
[0070]
On the other hand, when heavy fuel is used and the coolant temperature at the time of restart is equal to or lower than the predetermined value Tw2, the timing of complete explosion of the engine is greatly delayed from B to C, and the engine completes explosion. Since the number (ns) of REF signals input until the time is 7, ns exceeds a predetermined value ns1, the startability rank SR = 2, and this is stored in the RAM. At the time of restart after the startability rank determination, if the coolant temperature is lower than the predetermined value Tw2, the startability rank correction coefficient Ksr becomes a value larger than 0, and the fuel injection amount at restart is more than that for the reference fuel. The amount of increase is corrected by (1 + Ksr). Even if the fuel is not volatile, the amount of fuel that contributes to combustion increases due to the increase correction corresponding to the ease of restarting. The restart period can be approximately the same as the time.
[0071]
Even when the reference fuel is used, if the engine is deteriorated, the restart will be in the same manner as when heavy fuel is used, but this time is the same as when heavy fuel is used. Since the increase correction corresponding to the ease of restart is performed, the restart period can be substantially the same as before the engine has deteriorated.
[0072]
As described above, in the present embodiment, at the restart after the engine warm-up is completed after the start of the vehicle operation, the number of rotations of the engine from the start of the restart until the complete explosion of the engine is measured. The startability rank in which the startability rank is divided into three is determined, the determined startability rank is stored in the RAM in the controller 16, and the startability rank is determined based on the stored startability rank. When the fuel is getting worse, it has been corrected to increase the amount of fuel increased at the time of restart, so even when heavy fuel is used, the restart period should be almost the same as when using the reference fuel. Even when the engine is deteriorated while using the reference fuel, the restart period can be almost the same as that before the engine is deteriorated.
[0073]
In addition, when the startability rank is determined only once, if it is determined that fueling is performed after the startability rank is determined, the startability rank may not correspond to the fuel after refueling. In the present embodiment, the startability rank is determined at the earliest restart after the engine warm-up is completed after the start of operation of the vehicle.
[0074]
In the embodiment, the control at the time of restart after determining the startability rank is described as correcting the increased fuel at the time of restart based on the startability rank, but the restart after determining the startability rank The time control is not limited to this, and may be as follows.
[0075]
<1> The controller 16 stops the engine when the temperature of the engine coolant is equal to or higher than a predetermined value when the vehicle is stopped even during operation of the vehicle, and restarts the engine in response to a subsequent start or power generation request.
[0076]
In this case, after the startability rank is determined, the predetermined value for determining whether or not to perform the restart is increased as the startability rank SR is increased, so that the volatility of the fuel and the deterioration of the engine are determined. Regardless of this, the restart period after the startability rank determination can be kept almost constant, which enables restart after the startability rank determination even when heavy fuel is used or the engine has deteriorated. Start acceleration performance can be guaranteed from time to time.
[0077]
<2> While the engine friction torque increases as the engine speed increases since the engine starts, the torque of the engine starting motor 1 is limited by the output performance of the battery 15, so It gets smaller with the rise. As a result, the rotational speed corresponding to the intersection of both torques becomes a stable cranking rotational speed.
[0078]
Thus, the torque of the engine starting motor 1 is configured to be variably controllable, and when restarting after the startability rank determination, the torque of the engine starter motor is increased and stabilized as the startability rank SR increases. By increasing the cranking speed, even when heavy fuel is used or the engine has deteriorated, the compression pressure increases from the restart after the startability rank determination, and the complete explosion is likely to occur. It becomes easy.
[0079]
<3> The controller 16 detects the SOC (battery charge amount) which is a representative value of the actual capacity of the main battery 15 by the detection device 26, and controls the motors 1 and 4 so as to match the target SOC. Yes.
[0080]
In this case, by increasing the target SOC as the startability rank SR increases, even when heavy fuel is used or when the engine has deteriorated, the engine is stable from the restart after the startability rank determination. The cranking speed can be increased, which facilitates complete explosion at low temperatures.
[0081]
<4> The controller 16 sets a target value for the intake valve closing timing at the time of restart. In this case, when the startability rank SR is increased, the target value is moved to the advance side, so that even when heavy fuel is used or the engine is deteriorated, the engine restarts after the startability rank determination. Therefore, the actual compression ratio is increased, and the compression pressure can be increased.
[0082]
<5> When the startability rank is the highest (when SR = 3 in the above embodiment), the warning device (warning light or warning buzzer) provided in the driver's cab causes engine deterioration or heavy fuel By warning the driver that there is a possibility that the engine is being used, it is possible to prompt engine repair or refueling of the reference fuel.
[0083]
In the embodiment, the present invention is applied to a hybrid vehicle. However, the present invention is not limited to this, and the present invention can be applied to all vehicles equipped with an engine. In particular, it is preferable to apply the present invention to a so-called idle stop vehicle in which the engine is automatically stopped when the vehicle stops due to a signal or the like, and is restarted when the vehicle starts.
[0084]
In the embodiment, the case where the value corresponding to the number of rotations of the engine from the start of the restart to the complete explosion of the engine is measured as the period required for the restart is not limited to this.
[0085]
In the embodiment, the case where there are three startability ranks has been described.
[0086]
In the embodiment, when the ignition key switch is turned OFF when the vehicle is stopped, the startability rank value stored in the RAM is lost. However, when the ignition key switch is turned OFF, the RAM value is transferred to the nonvolatile memory. By making a backup, etc., the startability rank value can be held even after the ignition key switch is turned off.
[0087]
At this time, the start-up control using the startability rank can be performed from the first start after the ignition key switch is turned on next time, and fuel of different types is supplied after the previous ignition key switch is turned off. Unless otherwise, even when heavy fuel is used or when the engine has deteriorated, it is possible to easily start from the first start after the start of the next vehicle operation.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a configuration example of a hybrid vehicle to which the present invention can be applied.
FIG. 2 is a block diagram of a controller.
FIG. 3 is a schematic configuration diagram of an embodiment of a variable valve operating apparatus.
FIG. 4 is a flowchart for explaining startability rank determination;
FIG. 5 is a flowchart for explaining start-up injection control;
FIG. 6 is a characteristic diagram of a startability rank correction coefficient Ksr.
FIG. 7 is a waveform diagram for explaining the operation of the present invention.
FIG. 8 is a diagram corresponding to a claim of the first invention.
[Explanation of symbols]
1 Motor
2 Engine
16 controller
27 Crank angle sensor
32 Variable valve gear

Claims (5)

Means for measuring the time required for restart after engine warm-up is completed;
Means for determining a startability rank representing the startability of the startability based on the measured value;
Means for storing the startability rank; and means for performing control at restart after the determination of the startability rank using the stored startability rank ;
When the engine water temperature is equal to or higher than a predetermined value, the engine is stopped when the vehicle is stopped, and then restarted. A vehicle engine start control device.   2. The engine start control device for a vehicle according to claim 1, wherein the timing for measuring the period required for restart is the earliest restart time after completion of engine warm-up.   2. The vehicle engine start control device according to claim 1, wherein a warning device warns when the startability exceeds a limit and is bad as judged from the stored startability rank. 3.   2. The engine start control device for a vehicle according to claim 1, wherein the startability rank determined based on the measurement value is two or more.   2. The engine start control device for a vehicle according to claim 1, wherein the startability rank determined based on the measured value is held even after the ignition key switch is turned off. 3.

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