JP6481544B2 - Vehicle engine control method and vehicle engine control apparatus - Google Patents

Description

  The present invention relates to a vehicle engine control method and a vehicle engine control apparatus.

  As this type of technique, a technique described in Patent Document 1 below is disclosed. This document discloses that the idle engine stop control is prohibited when the remaining capacity of the capacitor is less than or equal to the capacitor capacity necessary for starting the engine.

JP-A-11-257120

In the technique of Patent Document 1, when the remaining capacity of the capacitor is less than or equal to the capacitor capacity necessary for starting the engine, the engine is driven until it exceeds the capacitor capacity necessary for starting the engine even if other engine stop requirements are satisfied. Will continue. Therefore, even when the driver is not operating the accelerator pedal, the engine continues to be driven for a long time, which may cause the driver to feel uncomfortable.
The present invention has been focused on the above problems, and an object of the present invention is to provide a vehicle engine control method and a vehicle engine control device that can shorten the engine drive time when there is an engine stop request. It is to be.

  Using the discharge amount per engine start determined in advance, calculate the number of times the engine can be started from the discharge capacity of the power source that supplies power to the motor that starts the engine to the predetermined discharge capacity, and start the engine When the engine can be started a large number of times, the engine prohibition time is set shorter than when the engine can be started a small number of times.

  Therefore, in the present invention, the engine drive time when there is an engine stop request can be shortened.

1 is a system diagram of a rear-wheel drive hybrid vehicle in Embodiment 1. FIG. 3 is a flowchart showing a flow of processing of engine drive continuation control after engine start in the first embodiment. 2 is a time chart of each device of Example 1. FIG. 6 is a flowchart showing a flow of processing of engine drive continuation control after engine start in Example 2. FIG. 6 is a graph showing the relationship between the discharge capacity of the engine starting power source and the engine drive duration in Example 2. 10 is a flowchart showing a flow of processing of engine drive continuation control after engine start according to a third embodiment. 7 is a graph showing the relationship between the allowable number of start times and the engine drive duration in Example 3. 10 is a flowchart showing a flow of processing of engine drive continuation control after engine start in Example 4. 6 is a graph showing the relationship between the allowable number of start times and the engine drive duration in Example 4. 10 is a flowchart showing a flow of processing of engine drive continuation control after engine start in Example 5. 10 is a graph showing the relationship between the allowable number of start times and the engine drive duration in Example 5.

Example 1
[overall structure]
FIG. 1 is a system diagram of a rear-wheel drive hybrid vehicle to which an engine control method and an engine control apparatus of the present invention are applied.
The hybrid vehicle has an engine 1, a first clutch 2, a high-power motor 3, a second clutch 4, an automatic transmission 5, and drive wheels 6 as drive system devices.

The engine 1 is, for example, a gasoline engine, and the valve opening degree of the throttle valve and the like are controlled based on a control command from the engine controller 13. The engine 1 is started by an SSG (Side mounted Starter Generator) 10. The SSG10 functions as an engine starter as well as an alternator.
The first clutch 2 is a clutch interposed between the engine 1 and the high electric motor 3. The first clutch 2 is controlled to be engaged and disengaged including slip engagement based on a control command from the first clutch controller 15.

  The high electric motor 3 is a synchronous motor generator in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator, and is controlled based on a control command from the motor controller 16. The strong electric motor 3 can operate as an electric motor that is driven to rotate by receiving power supplied from the high electric motor power source 7 (hereinafter, this state is referred to as “power running”). In addition, when the rotor is rotated by an external force, it can function as a generator that generates electromotive force at both ends of the stator coil and can charge the high-power motor power supply 7 (hereinafter, this operation state is referred to as “regeneration”. "). The rotor of the high electric motor 3 is connected to the input shaft of the automatic transmission 5 via a damper (not shown).

The second clutch 4 is a clutch interposed between the high electric motor 3 and the drive wheel 6. The second clutch 4 is controlled to be engaged and disengaged including slip engagement based on a control command from the automatic transmission controller 17.
The automatic transmission 5 is a transmission that automatically switches stepped gear ratios such as forward 6 speed, reverse 1 speed, etc., according to vehicle speed, accelerator opening, and the like. The second clutch 4 is not newly added as a dedicated clutch, but uses some frictional engagement elements among a plurality of frictional engagement elements that are engaged at each gear stage of the automatic transmission 5. In the automatic transmission 5, the engagement / release of each frictional engagement element is controlled based on a control command from the automatic transmission controller 17.
For the first clutch 2 and the second clutch 4 described above, for example, a wet multi-plate clutch capable of continuously controlling the oil flow rate and hydraulic pressure with a proportional solenoid is used.

  The hybrid vehicle has three travel modes according to the engaged / released state of the first clutch 2. The first travel mode is an electric vehicle travel mode (hereinafter abbreviated as “EV travel mode”) as a motor use travel mode in which the first clutch 2 is disengaged and travels using only the power of the high-power motor 3 as a power source. It is. The second travel mode is an engine use travel mode (hereinafter, abbreviated as “HEV travel mode”) in which the first clutch 2 is engaged and the engine 1 is included in the power source. The third travel mode is a slip travel mode in which the second clutch 4 is slip-controlled while the first clutch 2 is engaged and travels while including at least one of the engine 1 or the high-power motor 3 as a power source (hereinafter referred to as “WSC travel mode”). For short). This mode is a mode in which creep running can be achieved particularly when the battery SOC is low or the engine water temperature is low. When transitioning from the EV travel mode to the HEV travel mode, the first clutch 2 is engaged and the engine is started using the torque of the high-voltage motor 3.

  The above-described “HEV travel mode” has three travel modes of “engine travel mode”, “motor assist travel mode”, and “travel power generation mode”. In the “engine running mode”, the drive wheels 6 are moved using only the engine 1 as a power source. In the “motor assist travel mode”, the driving wheel 6 is moved by using the engine 1 and the high electric motor 3 as power sources. In the “running power generation mode”, the driving wheel 6 is moved using the engine 1 as a power source, and at the same time, the high electric motor 3 is caused to function as a generator. During constant speed operation or acceleration operation, the high-power motor 3 is operated as a generator using the power of the engine 1. Further, during deceleration operation, braking energy is regenerated to generate electric power by the high electric motor 3 and used for charging the high electric motor power source 7. Further, as a further mode, there is a power generation mode in which the high-power motor 3 is operated as a generator using the power of the engine 1 when the vehicle is stopped.

Next, the configuration of the control system of the hybrid vehicle will be described.
The hybrid vehicle includes a vehicle control controller 14, an engine controller 13, a first clutch controller 15, a motor controller 16, and an automatic transmission controller 17 as control system devices. The engine controller 13, the first clutch controller 15, the motor controller 16, and the automatic transmission controller 17 are connected to the vehicle controller 14 by a CAN (Controller Area Network) and can exchange information.

The vehicle controller 14 inputs various vehicle information (vehicle speed, engine speed, motor output, accelerator pedal opening, brake switch, discharge capacity of each power source, etc.).
The vehicle controller 14 calculates a target engine torque of the engine 1 and outputs the target engine torque to the engine controller 13. Further, a stop request and a start request for the engine 1 are output to the engine controller 13. The engine controller 13 controls the engine 1 based on a command from the vehicle controller 14.

The vehicle controller 14 outputs a command for engaging / disengaging the first clutch 2 to the first clutch controller 15 according to the travel mode described above. The first clutch controller 15 controls the first clutch 2 based on a command from the vehicle controller 14.
The vehicle controller 14 calculates the target motor torque or the target motor rotation speed of the high-power motor 3 and outputs the target motor torque or the target motor rotation speed to the motor controller 16. The motor controller 16 controls the high electric motor 3 based on a command from the vehicle controller 14.

  The vehicle controller 14 outputs a command for engaging / disengaging the second clutch 4 to the automatic transmission controller 17 when the vehicle starts or when the travel mode is switched. The vehicle controller 14 determines a gear ratio from various information and outputs it to the automatic transmission controller 17. The automatic transmission controller 17 controls the automatic transmission 5 based on a command from the vehicle controller 14.

Next, the configuration of the electric system of the hybrid vehicle will be described.
The hybrid vehicle has a high-electric motor power source 7, a DC / DC converter 8, an auxiliary power source 9, an engine starting power source 11, and a charging relay 12 as electric devices.

  The high-power motor power supply 7 supplies power to the high-power motor 3. The DC / DC converter 8 drops the voltage of the high-power motor power supply 7 to the charging voltage of the auxiliary power supply 9 and the engine starting power supply 11. The auxiliary power source 9 supplies electric power to various auxiliary machines (not shown). The engine starting power supply 11 supplies power to the SSG 10.

  The charging relay 12 connects and disconnects between the engine starting power source 11 and the auxiliary power source 9. When the engine 1 is started by the SSG 10, the charging relay 12 is disconnected. This prevents a voltage drop of the auxiliary power source 9 when starting the engine, and does not affect the operating state of various auxiliary machines. After the start of the engine 1 is completed, the charging relay 12 is connected. As a result, the engine starting power source 11 is charged from the high power motor power source 7 via the DC / DC converter 8.

[Engine drive continuation control after engine start]
If the engine start request is frequently generated, the charging opportunity of the engine starting power supply 11 is reduced. Therefore, the discharge capacity of the engine starting power supply 11 is increased, and the starting performance of the engine 1 by the SSG 10 may be deteriorated. In order to suppress a decrease in the starting performance of the engine 1, in the first embodiment, a stop prohibition period (engine drive duration T) after the engine 1 is started is set.

  Even if an engine stop request is commanded from the vehicle controller 14 until the engine drive duration time T elapses after the engine is started, the engine controller 13 does not stop the engine 1. While the engine 1 is being driven, the charging relay 12 is connected, and the engine starting power source 11 is charged from the high power motor power source 7 via the DC / DC converter 8.

FIG. 2 is a flowchart showing a flow of processing of engine drive continuation control after engine start performed in the engine controller 13.
In step S1, the elapsed time t after engine start is counted, and the routine proceeds to step S2.

  In step S2, the number f of times that the engine 1 can be started (allowable number of times f) is calculated with the current discharge capacity of the engine starting power supply 11, and the process proceeds to step S3. A method of calculating the allowable number of start times f will be described in detail later.

In step S3, it is determined whether or not the allowable number of start times f is smaller than one. When the allowable number of start times f is smaller than 1, the process proceeds to step S4. When the allowable number of start times f is 1 or more, the process proceeds to step S5.
In step S4, the engine drive duration T is set to T1 [s], and the process proceeds to step S8.

  In step S5, it is determined whether the allowable number of start times f is smaller than f2. When the allowable number of start times f is smaller than f2, the process proceeds to step S6. When the allowable number of start times f is equal to or greater than f2, the process proceeds to step S7. For example, set f2 = 2.

In step S6, the engine drive duration T is set to T2 [s] (T2> T1), and the process proceeds to step S8.
In step S7, the engine drive duration T is set to 0 [s], and the process proceeds to step S8.

In step S8, it is determined that an engine stop request is output from the vehicle controller 14 and that the elapsed time t after engine start is equal to or longer than the engine drive duration T. When an engine stop request is output from the vehicle controller 14 and the elapsed time t after engine startup is equal to or longer than the engine drive duration T, the process proceeds to step S9. When an engine stop request is output from the vehicle controller 14 and the elapsed time t after engine startup is not equal to or longer than the engine drive duration T, the process proceeds to step S10.
In step S9, the engine 1 is stopped.
In step S10, the engine 1 is not stopped and the driving state is continued.

[Calculation method of allowable start times]
When the engine is started at a certain timing, the discharge amount Cout [Ah] discharged from the engine starting power supply 11 is measured or calculated by supplying electric power from the engine starting power supply 11 to the SSG 10. The engine is started at a certain timing as described above, and after the SSG 10 is stopped, the charge amount Cin [Ah] charged in the engine starting power supply 11 is measured or calculated until the next engine starting.

The engine start is started from the discharge amount Cout [Ah] and the charge amount Cin [Ah], and the discharge capacity Cr [Ah] of the engine starting power supply 11 until the next engine start is obtained by the following equation (1).

  The amount of discharge C1 [Ah] when the engine is started once is obtained in advance by experiments or the like. The discharge amount C1 [Ah] varies depending on the specifications of the engine 1, the SSG 10, the engine starting power source 11, and the like. The allowable discharge capacity C [Ah] is arbitrarily set from the characteristics of the engine starting power supply 11 and the like. The allowable discharge capacity C [Ah] is an allowable value of the discharge capacity of the engine starting power supply 11, and is set to a value that can suppress deterioration of the engine starting power supply 11 and the like.

The number f of times that the engine 1 can be started (allowable start frequency f) is calculated from the current discharge capacity Cr [Ah] of the engine starting power supply 11 to the allowable discharge capacity C [Ah]. The allowable start frequency f is calculated using the following equation using the allowable discharge capacity C [Ah], the discharge capacity Cr [Ah] of the engine starting power supply 11 and the discharge amount C1 [Ah] when the engine is started once. Obtained by (2).

The allowable start frequency f can also be obtained by the following equation (3) using the allowable start frequency fz obtained at the previous engine start.

  The discharge amount Cout [Ah] at the time of engine start and the charge amount Cin [Ah] to be charged until the next engine start can also be obtained from detection values of a current sensor or the like. In this case, the detection values of the current sensor or the like may be integrated.

以下、この式(4)により求めた許容始動回数fを用いて説明する。 Further, the discharge amount Cout [Ah] at the time of starting the engine is set to the discharge amount C1 [Ah] at the time of starting the engine once obtained in advance by experiments or the like (Cout = C1), and the allowable number of starts f is obtained. You can also. In this case, the charging current time constant τ [s] of the engine starting power supply 11 and the fastening time t [s] of the charging relay 12 after the engine starting can be obtained by the following equation (4). The charging current time constant τ [s] is obtained in advance through experiments or the like. The fastening time t [s] of the charging relay 12 is obtained by measurement.

Hereinafter, description will be made using the allowable number of start times f obtained by the equation (4).

[Action]
As described above, if engine start requests are frequently generated, the discharge capacity of the engine starting power supply 11 is increased, and the starting performance of the engine 1 by the SSG 10 may be deteriorated. In order to suppress a decrease in the starting performance of the engine 1, it is conceivable that the driving of the engine 1 is continued even if there is a request for stopping the engine for a certain time after the engine is started. However, every time the engine 1 is started, the engine 1 continues to be driven for a certain period of time, which may cause deterioration in fuel consumption. Further, since the accelerator pedal operation and the driving / stopping state of the engine 1 do not match, there is a possibility that the driver feels uncomfortable.

  Therefore, in the first embodiment, the engine 1 is started according to the allowable number of times f of starting the engine 1 from the current discharge capacity Cr [Ah] of the engine start power supply 11 to the allowable discharge capacity C [Ah]. The period for prohibiting the stop of 1 (engine drive duration T) was set. The engine drive duration T is set shorter when the allowable number of starts f is large than when the allowable number of starts f is small.

FIG. 3 is a time chart of the engine start request, the engine speed, the SSG 10 drive stop state, the charge relay 12 disconnected state, and the engine start power source 11 discharge capacity.
At time t1, an engine start request is output from the vehicle controller 14. The SSG 10 is driven and the engine 1 is started. At this time, the charging relay 12 is disconnected, and the engine starting power source 11 is not charged. Since the engine starting power supply 11 supplies power to the SSG 10, the discharge capacity rapidly increases.

At time t2, the engine start is completed and the SSG 10 stops. The charging relay 12 is connected, the engine starting power source 11 starts to be charged, and thereafter the discharge capacity decreases. Since the allowable start frequency f obtained based on the discharge capacity of the engine starting power supply 11 when the SSG 10 is stopped is f2 or more, the engine drive duration T is set to 0 [s].
At time t3, an engine stop request is output from the vehicle controller 14. At this time, the engine drive duration time T (= 0) has elapsed from time t2, so the engine 1 is stopped. Even after the engine 1 is stopped, the charging relay 12 is kept connected, and the engine starting power source 11 is charged.

At time t4, an engine start request is output from the vehicle controller 14. The SSG 10 is driven and the engine 1 is started. At this time, the charging relay 12 is disconnected.
Thereafter, when an engine start request is output from the vehicle controller 14 after the engine is started and before the discharge capacity of the engine start power supply 11 before the engine start is restored, the discharge capacity of the engine start power supply 11 increases. Go.

  At time t11, the vehicle controller 14 outputs an engine start request. At this time, the charging relay 12 is disconnected, and the engine starting power source 11 is not charged. Since the engine starting power supply 11 supplies power to the SSG 10, the discharge capacity rapidly increases.

  At time t12, the engine start is completed and the SSG 10 stops. Since the allowable number of start times f obtained based on the discharge capacity of the engine start power supply 11 at this time is less than f2, the engine drive duration T is set to T2 [s].

  At time t13, an engine stop request is output from the vehicle controller 14. However, since the engine drive duration time T (= T2) has not elapsed from time t12, the drive of the engine 1 is continued.

  At time t14, the engine drive duration time T2 elapses from time t12. At this time, since the engine stop request from the vehicle controller 14 is continuously output, the engine 1 is stopped.

  As shown in FIG. 3, the engine 1 is operated at the timing when the engine stop request is output from the vehicle controller 14 until the allowable start frequency f obtained based on the discharge capacity of the engine start power supply 11 is less than f2. Stop. Therefore, fuel consumption can be improved. Further, the accelerator pedal operation and the driving / stopping state of the engine 1 coincide with each other, and the driver's uncomfortable feeling can be suppressed.

  Also, the engine drive duration T2 set when the allowable start frequency f is f2 times (f2> 1) is set shorter than the engine drive duration T1 set when the allowable start frequency f is 1 time. . The condition that the allowable start frequency f is f2 is more frequently established than the condition that the allowable start frequency f is 1 time. By setting the engine drive duration T2 to be shorter than the engine drive duration T1, the engine drive time can be shortened as much as possible. Therefore, fuel consumption can be improved. Further, it is possible to shorten the time during which the accelerator pedal operation and the driving / stopping state of the engine 1 are inconsistent, and to suppress the driver's uncomfortable feeling.

[effect]
(1) Calculate or estimate the discharge capacity Cr [Ah] of the engine start power supply (power supply) that supplies power to the SSG 10 (motor) that starts the engine 1, and the discharge amount C1 [ Ah] is used to calculate the number of times the engine 1 can be started (allowable start frequency f) from the discharge capacity Cr [Ah] to the allowable discharge capacity C (predetermined discharge capacity). When the allowable start frequency f is large, the time during which the engine 1 is prohibited from being stopped (engine drive duration T) is set shorter than when the allowable start frequency f is small.
Therefore, the fuel consumption can be improved. Further, it is possible to shorten the time during which the accelerator pedal operation and the driving / stopping state of the engine 1 are inconsistent, and to suppress the driver's uncomfortable feeling.

(2) Calculate or estimate the discharge capacity Cr [Ah] of the engine start power supply (power supply) that supplies power to the SSG 10 (motor) that starts the engine 1, and the discharge amount C1 [ Ah] is used to calculate the number of times the engine 1 can be started (allowable start frequency f) from the discharge capacity Cr [Ah] to the allowable discharge capacity C (predetermined discharge capacity). When the allowable start frequency f is large, an engine controller 13 (control unit) that sets a time for prohibiting the stop of the engine 1 (engine drive duration T) is set shorter than when the allowable start frequency f is small.
Therefore, the fuel consumption can be improved. Further, it is possible to shorten the time during which the accelerator pedal operation and the driving / stopping state of the engine 1 are inconsistent, and to suppress the driver's uncomfortable feeling.

(Example 2)
In the second embodiment, the allowable discharge capacity C of the engine starting power supply 11 is made variable according to the vehicle speed. The second embodiment will be described below, but is the same as the first embodiment except for the engine drive continuation control of the engine controller 13.

[Engine drive continuation control after engine start]
FIG. 4 is a flowchart showing a flow of processing of engine drive continuation control after engine start performed in the engine controller 13.

In step S11, it is determined whether or not the vehicle speed V is lower than V0 [km / h]. For example, V0 is set to 10 [km / h]. When the vehicle speed V is smaller than V0 [km / h], the process proceeds to step S12. When the vehicle speed V is V0 [km / h] or more, the process proceeds to step S13.
In step S12, the allowable discharge capacity C is set to C0 [Ah].
In step S13, the allowable discharge capacity C is set to C0 ′ [Ah] (C0 ′ <C0).

  In step S14, it is determined whether the allowable discharge capacity C is the same as the previous value Cz. When the allowable discharge capacity C is the same as the previous value Cz, the process proceeds to step S15. When the allowable discharge capacity C is not the same as the previous value Cz, the process proceeds to step S16.

ステップS17では、エンジン始動後の経過時間tをカウントして、ステップS18へ移行する。 In step S15, the previous allowable start frequency fz is maintained.
In step S16, the previous allowable start frequency fz is converted to fz ′. This conversion is performed by the following equation (5).

In step S17, the elapsed time t after engine start is counted, and the routine proceeds to step S18.

In step S18, the number f of times that the engine 1 can be started (allowable start number f) is calculated with the current discharge capacity of the engine starting power supply 11, and the process proceeds to step S19.
In step S19, it is determined whether or not the allowable number of start times f is smaller than one. When the allowable number of starts f is less than one, the process proceeds to step S20, and when the allowable number of starts f is one or more, the process proceeds to step S21.
In step S20, the engine drive duration T is set to T1 [s], and the process proceeds to step S24.

  In step S21, it is determined whether or not the allowable number of start times f is smaller than f2. As the allowable start frequency f, when converted into fz ′ in step S16, the converted value is used. When the allowable start frequency f is smaller than f2, the process proceeds to step S22, and when the allowable start frequency f is equal to or greater than f2, the process proceeds to step S23. For example, set f2 = 2.

In step S22, the engine drive duration T is set to T2 [s] (T2> T1), and the process proceeds to step S24.
In step S23, the engine drive duration T is set to 0 [s], and the process proceeds to step S24.

In step S24, it is determined that an engine stop request is output from the vehicle controller 14 and that the elapsed time t after engine startup is equal to or longer than the engine drive duration T. When an engine stop request is output from the vehicle controller 14 and the elapsed time t after engine startup is equal to or longer than the engine drive duration T, the process proceeds to step S25. When an engine stop request is output from the vehicle controller 14 and the elapsed time t after engine start is not equal to or longer than the engine drive duration T, the process proceeds to step S26.
In step S25, the engine 1 is stopped.
In step S26, the engine 1 is not stopped and the driving state is continued.

[Action]
When driving slowly or when the vehicle is stopped (for example, the vehicle speed is 10 [km / h] or less), the acceleration performance of the vehicle is rarely required, and the drive torque of the engine 1 is rarely required. Therefore, it is not necessary to start the engine 1 in a short time (hereinafter referred to as engine starting performance), and it is allowable that the discharge capacity of the engine starting power supply 11 is slightly increased. The fuel consumption can be improved by stopping the engine 1 with priority given to the engine stop request as much as possible. Further, the time during which the accelerator pedal operation does not match the driving / stopping state of the engine 1 can be shortened, and the driver's uncomfortable feeling can be suppressed. Below, the time of slow running or the time of a vehicle stop is made into the time of low speed driving.

On the other hand, during normal travel (for example, the vehicle speed is greater than 10 [km / h]), the acceleration performance of the vehicle is often required, and the drive torque of the engine 1 is often required. Therefore, it is necessary to avoid as much as possible the increase in the discharge capacity of the engine starting power supply 11 in order to suppress the deterioration of the engine starting performance. After the engine is started, the charging frequency of the engine starting power supply 11 can be increased, and an increase in the discharge capacity of the engine starting power supply 11 can be suppressed.
In Example 2, the allowable discharge capacity C was set to be smaller during normal traveling than during low-speed traveling.

  FIG. 5 shows the discharge capacity of the engine starting power supply 11 and the engine when the allowable discharge capacity C is set to C0 [Ah] and when the allowable discharge capacity C is set to C0 ′ [Ah] (C0 ′ <C0). It is a figure which shows the relationship of the drive continuation time T. FIG. As shown in FIG. 5, when the allowable discharge capacity C is set to C0 ′ [Ah], the engine drive duration T is set compared to when the allowable discharge capacity C is set to C0 [Ah] (engine (Driving duration T is T2 or more) Discharge capacity is small.

  Thereby, the charging frequency of the engine starting power supply 11 can be increased during normal traveling, and deterioration of the engine starting performance can be suppressed. When traveling at a low speed, the engine 1 can be stopped for a longer time to improve fuel efficiency. Further, it is possible to shorten the time during which the accelerator pedal operation and the driving / stopping state of the engine 1 are inconsistent, and to suppress the driver's uncomfortable feeling.

  In step S16 of the flowchart of FIG. 4, the previous allowable start frequency fz is converted to fz ′. Based on the previous allowable start frequency fz obtained from the different allowable discharge capacity C, if the current allowable start frequency f is calculated, the allowable start frequency f cannot be accurately calculated. ing.

[effect]
(3) When the vehicle speed V is equal to or higher than the predetermined vehicle speed V0, the predetermined discharge amount C is made smaller than when the vehicle speed V is lower than the predetermined vehicle speed V0.
During normal running, the charging frequency of the engine starting power source 11 can be increased, the increase in the discharge capacity of the engine starting power source 11 can be suppressed, and the engine starting performance can be ensured. When traveling at low speed, priority can be given to the engine stop request as much as possible to improve fuel efficiency. Further, it is possible to shorten the time during which the accelerator pedal operation and the driving / stopping state of the engine 1 are inconsistent, and to suppress the driver's uncomfortable feeling.

Example 3
In the third embodiment, the engine driving duration T is made variable according to the vehicle speed. The third embodiment will be described below, but is the same as the first embodiment except for the engine drive continuation control of the engine controller 13.

[Engine drive continuation control after engine start]
FIG. 6 is a flowchart showing a flow of processing of engine drive continuation control after engine start performed in the engine controller 13.
In step S31, the elapsed time t after engine start is counted, and the routine proceeds to step S32.

In step S32, the number f of times that the engine 1 can be started (allowable number of times f) is calculated with the current discharge capacity of the engine starting power supply 11, and the process proceeds to step S33.
In step S33, it is determined whether or not the allowable number of start times f is smaller than one. When the allowable number of start times f is smaller than 1, the process proceeds to step S34. When the allowable start frequency f is 1 or more, the routine proceeds to step S35.

  In step S34, it is determined whether or not the vehicle speed V is lower than V0 [km / h]. For example, V0 is set to 10 [km / h]. When the vehicle speed V is lower than V0 [km / h], the process proceeds to step S37. When the vehicle speed V is equal to or higher than V0 [km / h], the process proceeds to step S38.

  In step S35, it is determined whether or not the allowable number of start times f is smaller than f2. When the allowable start frequency f is smaller than f2, the process proceeds to step S36. When the allowable number of start times f is equal to or greater than f2, the process proceeds to step S41. For example, set f2 = 2.

  In step S36, it is determined whether or not the vehicle speed V is lower than V0 [km / h]. For example, V0 is set to 10 [km / h]. When the vehicle speed V is smaller than V0 [km / h], the process proceeds to step S39. When the vehicle speed V is V0 [km / h] or more, the process proceeds to step S40.

In step S37, the engine drive duration T is set to T1 [s], and the process proceeds to step S42.
In step S38, the engine drive duration T is set to T1 ′ [s], and the process proceeds to step S42.
In step S39, the engine drive duration T is set to T2 [s], and the process proceeds to step S42.
In step S40, the engine drive duration T is set to T2 ′ [s], and the process proceeds to step S42.
In step S41, the engine drive duration T is set to 0 [s], and the process proceeds to step S42.
The relationship between T1 ′, T1, T2 ′, and T2 is T1 ′>T1> T2 ′> T2.

In step S42, it is determined that an engine stop request is output from the vehicle controller 14 and that the elapsed time t after engine startup is equal to or longer than the engine drive duration T. When an engine stop request is output from the vehicle controller 14 and the elapsed time t after engine startup is equal to or longer than the engine drive duration T, the process proceeds to step S43. When an engine stop request is output from the vehicle controller 14 and the elapsed time t after engine startup is not equal to or longer than the engine drive duration T, the process proceeds to step S44.
In step S43, the engine 1 is stopped.
In step S44, the engine 1 is not stopped and the driving state is continued.

[Action]
In the third embodiment, as in the second embodiment, the fuel consumption is improved during low-speed driving, the time during which the accelerator pedal operation and the driving / stopping state of the engine 1 are inconsistent is shortened, and the driver's uncomfortable feeling is suppressed. Yes. Further, during normal running, after the engine is started, the charging frequency of the engine starting power supply 11 is increased to suppress an increase in the discharge capacity of the engine starting power supply 11.
In Example 3, the engine drive duration T was set to be longer during normal travel than during low speed travel.

  FIG. 7 is a graph showing the relationship between the allowable number of start times f and the engine drive duration T. As shown in FIG. 7, during normal travel (vehicle speed V ≧ V0), the engine drive duration T is set longer than during low-speed travel (vehicle speed V <V0).

  Thereby, during normal running, the charging time of the engine starting power supply 11 can be lengthened, and deterioration of engine starting performance can be suppressed. When traveling at a low speed, the engine 1 can be stopped for a longer time to improve fuel efficiency. Further, it is possible to shorten the time during which the accelerator pedal operation and the driving / stopping state of the engine 1 are inconsistent, and to suppress the driver's uncomfortable feeling.

[effect]
(4) When the vehicle speed V is equal to or higher than the predetermined vehicle speed V0, the engine drive duration time T is set longer than when the vehicle speed V is lower than the predetermined vehicle speed V0.
During normal running, the charging time of the engine starting power supply 11 can be lengthened, the increase in the discharge capacity of the engine starting power supply 11 can be suppressed, and the engine starting performance can be ensured. When traveling at a low speed, the engine 1 can be stopped for a longer time to improve fuel efficiency. Further, it is possible to shorten the time during which the accelerator pedal operation and the driving / stopping state of the engine 1 are inconsistent, and to suppress the driver's uncomfortable feeling.

(Example 4)
In the fourth embodiment, the allowable start frequency f for setting the engine drive duration T according to the vehicle speed is made variable. Hereinafter, the fourth embodiment will be described, but is the same as the first embodiment except the engine drive continuation control of the engine controller 13.

[Engine drive continuation control after engine start]
FIG. 8 is a flowchart showing a flow of processing of engine drive continuation control after engine start performed in the engine controller 13.
In step S51, the elapsed time t after engine start is counted, and the routine proceeds to step S52.

In step S52, the number f of times the engine 1 can be started (allowable start number f) is calculated with the current discharge capacity of the engine starting power supply 11, and the process proceeds to step S23.
In step S53, it is determined whether or not the vehicle speed V is lower than V0 [km / h]. For example, V0 is set to 10 [km / h]. When the vehicle speed V is smaller than V0 [km / h], the process proceeds to step S54. When the vehicle speed V is equal to or higher than V0 [km / h], the process proceeds to step S56.

  In step S54, it is determined whether or not the allowable number of start times f is smaller than one. When the allowable number of starts f is smaller than one, the process proceeds to step S58. When the allowable start frequency f is 1 or more, the process proceeds to step S55.

  In step S55, it is determined whether or not the allowable number of start times f is smaller than f2. When the allowable start frequency f is smaller than f2, the process proceeds to step S59. When the allowable number of start times f is equal to or greater than f2, the process proceeds to step S60. For example, set f2 = 2.

  In step S56, it is determined whether or not the allowable number of start times f is smaller than f3 times. When the allowable number of start times f is smaller than f3, the process proceeds to step S61. When the allowable number of start times f is equal to or greater than f3, the process proceeds to step S57. For example, set f3 = 3.

  In step S57, it is determined whether or not the allowable number of start times f is smaller than f4 times. When the allowable number of start times f is smaller than f4, the process proceeds to step S62. When the allowable number of start times f is equal to or greater than f4, the process proceeds to step S63. For example, set f4 = 4.

In step S58, the engine drive duration T is set to T1 [s], and the process proceeds to step S64.
In step S59, the engine drive duration T is set to T2 [s], and the process proceeds to step S64.
In step S60, the engine drive duration T is set to 0 [s], and the process proceeds to step S64.

In step S61, the engine drive duration T is set to T3 [s], and the process proceeds to step S64.
In step S62, the engine drive duration T is set to T4 [s], and the process proceeds to step S64.
In step S63, the engine drive duration T is set to 0 [s], and the process proceeds to step S64.
The relationship between T1, T2, T3, and T4 is T1 = T3> T2 = T4.

  In step S64, it is determined that an engine stop request is output from the vehicle controller 14 and that the elapsed time t after engine startup is equal to or longer than the engine drive duration T. When an engine stop request is output from the vehicle controller 14 and the elapsed time t after engine startup is equal to or longer than the engine drive duration T, the process proceeds to step S65. When an engine stop request is output from the vehicle controller 14 and the elapsed time t after engine start is not equal to or longer than the engine drive duration time T, the process proceeds to step S66.

In step S65, the engine 1 is stopped.
In step S66, the engine 1 is not stopped and the driving state is continued.

[Action]
In the fourth embodiment, as in the second embodiment, the fuel consumption is improved during low-speed driving, the time during which the accelerator pedal operation and the driving / stopping state of the engine 1 are inconsistent is shortened, and the driver's uncomfortable feeling is suppressed. Yes. Further, during normal running, after the engine is started, the charging frequency of the engine starting power supply 11 is increased to suppress an increase in the discharge capacity of the engine starting power supply 11.
In Example 4, the value of the allowable number of start times f for setting the engine drive duration T is set larger during normal running than during low speed running.

  FIG. 9 is a graph showing the relationship between the allowable number of start times f and the engine drive duration T. As shown in FIG. 9, during normal travel (vehicle speed V ≧ V0), the value of the allowable start frequency f is set larger than that during low-speed travel (vehicle speed V <V0).

  Thereby, the charging frequency of the engine starting power supply 11 can be increased during normal traveling, and deterioration of the engine starting performance can be suppressed. When traveling at a low speed, the engine 1 can be stopped for a longer time to improve fuel efficiency. Further, it is possible to shorten the time during which the accelerator pedal operation and the driving / stopping state of the engine 1 are inconsistent, and to suppress the driver's uncomfortable feeling.

[effect]
(5) The engine drive duration T is set when the allowable start frequency f is less than or equal to the predetermined number of times, and when the vehicle speed V is equal to or higher than the predetermined vehicle speed V0, the predetermined number of allowable start times f than when the vehicle speed is less than the predetermined vehicle speed V0. Increased the value of.
During normal running, the charging frequency of the engine starting power source 11 can be increased, the increase in the discharge capacity of the engine starting power source 11 can be suppressed, and the engine starting performance can be ensured. When traveling at low speed, priority can be given to the engine stop request as much as possible to improve fuel efficiency. Further, it is possible to shorten the time during which the accelerator pedal operation and the driving / stopping state of the engine 1 are inconsistent, and to suppress the driver's uncomfortable feeling.

Example 5
In the fifth embodiment, the number of allowable start times f for setting the engine driving duration T according to the vehicle speed is made variable. The fifth embodiment will be described below, but is the same as the first embodiment except for the engine drive continuation control of the engine controller 13.

[Engine drive continuation control after engine start]
FIG. 10 is a flowchart showing a flow of processing of engine drive continuation control after engine start performed in the engine controller 13.
In step S71, the elapsed time t after engine start is counted, and the process proceeds to step S72.

In step S72, the number of times f (allowable start frequency f) at which the engine 1 can be started is calculated with the current discharge capacity of the engine starting power supply 11, and the process proceeds to step S73.
In step S73, it is determined whether the allowable number of start times f is smaller than one. When the allowable start frequency f is smaller than 1, the process proceeds to step S77. When the allowable number of start times f is 1 or more, the process proceeds to step S74.

  In step S74, it is determined whether or not the allowable number of start times f is smaller than f2. When the allowable start frequency f is smaller than f2, the process proceeds to step S78. When the allowable start frequency f is equal to or greater than f2, the process proceeds to step S75. For example, set f2 = 2.

  In step S75, it is determined whether or not the vehicle speed V is smaller than V0 [km / h]. For example, V0 is set to 10 [km / h]. When the vehicle speed V is lower than V0 [km / h], the process proceeds to step S79. When the vehicle speed V is V0 [km / h] or more, the process proceeds to step S76.

  In step S76, it is determined whether or not the allowable number of start times f is smaller than f5 times. When the allowable start frequency f is smaller than f5, the process proceeds to step S80. When the allowable start frequency f is f5 or more, the process proceeds to step S81. For example, set f5 = 5.

In step S77, the engine drive duration T is set to T1 [s], and the process proceeds to step S82.
In step S78, the engine drive duration T is set to T2 [s], and the process proceeds to step S82.
In step S79, the engine drive duration T is set to 0 [s], and the process proceeds to step S82.
In step S80, the engine drive duration time T is set to T5 [s], and the process proceeds to step S82.
In step S81, the engine drive duration T is set to 0 [s], and the process proceeds to step S82.
The relationship between T1, T2, and T5 is T1>T2> T5.

In step S82, it is determined that an engine stop request is output from the vehicle controller 14 and that the elapsed time t after engine startup is equal to or longer than the engine drive duration T. When an engine stop request is output from the vehicle controller 14 and the elapsed time t after engine startup is equal to or longer than the engine drive duration time T, the routine proceeds to step S83. When an engine stop request is output from the vehicle controller 14 and the elapsed time t after engine startup is not equal to or longer than the engine drive duration T, the process proceeds to step S84.
In step S83, the engine 1 is stopped.
In step S84, the engine 1 is not stopped and the driving state is continued.

[Action]
In the fifth embodiment, as in the second embodiment, the fuel consumption is improved during low-speed driving, the time during which the accelerator pedal operation and the driving / stopping state of the engine 1 are inconsistent is shortened, and the driver's uncomfortable feeling is suppressed. Yes. Further, during normal running, after the engine is started, the charging frequency of the engine starting power supply 11 is increased to suppress an increase in the discharge capacity of the engine starting power supply 11.
In Example 5, the number of allowable start times f for setting the engine drive duration T during normal driving is set higher than during low-speed driving. Specifically, in the first to fourth embodiments, the number of allowable start times f for setting the engine drive duration T is two, but in the fifth embodiment, the number is three.

  In Example 4, the number of allowable start times f for setting the engine drive duration T is four, but during normal driving, the engine drive duration T is set when the allowable start number is 1 and f2. The engine drive duration time T is set when the allowable number of start times is f3 and f4 during low-speed running. That is, the number of allowable start times f for setting the engine drive duration T during normal travel is two, and the number of allowable start times f for setting the engine drive duration T during low speed travel is two.

  FIG. 11 is a graph showing the relationship between the allowable number of start times f and the engine drive duration T. In Example 5, the value of the allowable start frequency f5 for setting the engine drive duration T increased during normal travel is set larger than the value of the allowable start frequency f2 for setting the engine drive duration T during low speed travel. Further, the engine drive duration T5 set corresponding to the allowable start frequency f5 is made shorter than the engine drive duration T2 set corresponding to the allowable start frequency f2.

  Thereby, the charging frequency of the engine starting power supply 11 can be increased during normal traveling, and deterioration of the engine starting performance can be suppressed. Although the charging frequency of the engine starting power supply 11 has been increased, the engine driving duration T5 is set to be short, so that it is possible to suppress deterioration in fuel consumption and increase in discomfort to the driver. When traveling at a low speed, the engine 1 can be stopped for a longer time to improve fuel efficiency. Further, it is possible to shorten the time during which the accelerator pedal operation and the driving / stopping state of the engine 1 are inconsistent, and to suppress the driver's uncomfortable feeling.

[effect]
(6) The engine drive duration time T is set for each value of the number of times that a plurality of engines 1 can be started. When the vehicle speed V is equal to or higher than the predetermined vehicle speed V0, the engine drive duration time T is lower than when the vehicle speed V is lower than the predetermined vehicle speed V0. The number of allowable start times f for setting is increased.
During normal running, the charging frequency of the engine starting power source 11 can be increased, the increase in the discharge capacity of the engine starting power source 11 can be suppressed, and the engine starting performance can be ensured. When traveling at low speed, priority can be given to the engine stop request as much as possible to improve fuel efficiency. Further, it is possible to shorten the time during which the accelerator pedal operation and the driving / stopping state of the engine 1 are inconsistent, and to suppress the driver's uncomfortable feeling.

[Other Examples]
As mentioned above, although the form for implementing this invention was demonstrated by the Example based on drawing, the concrete structure of this invention is not limited to an Example, The design of the range which does not deviate from the summary of invention Any changes and the like are included in the present invention.

The number of allowable start times f for setting the engine drive duration T may be set as appropriate. However, it is necessary to set the engine drive duration T to be shorter as the allowable start frequency f is larger.
In the first embodiment, the engine drive continuation control after the engine is started is applied to the hybrid vehicle. However, the hybrid vehicle may be applied to a vehicle having only the engine without the drive motor.

  In the second to fifth embodiments, the conditions for setting the engine drive duration T are changed according to the vehicle speed, but the methods of the respective embodiments may be combined.

13 Engine controller (control unit)

Claims (5)

Calculate or estimate the discharge capacity of the power source that supplies power to the motor that starts the engine,
Using the predetermined amount of discharge per engine start, calculate the number of times that the engine can be started from the discharge capacity to the predetermined discharge capacity,
When the engine is started, when the number of times that the engine can be started is large, the time for which the engine is stopped is set shorter than when the number of times that the engine can be started is small ,
The vehicle engine control method characterized in that when the vehicle speed is equal to or higher than a predetermined vehicle speed, the predetermined discharge capacity is made smaller than when the vehicle speed is lower than the predetermined vehicle speed . In the vehicle engine control method according to claim 1,
A vehicle engine control method characterized in that when the vehicle speed is equal to or higher than a predetermined vehicle speed, the time during which the engine is stopped is set longer than when the vehicle speed is lower than the predetermined vehicle speed. The vehicle engine control method according to claim 1 or 2,
When the number of times that the engine can be started is less than or equal to a predetermined number of times, a time for prohibiting the engine from stopping is set,
A vehicle engine control method characterized in that when the vehicle speed is equal to or higher than a predetermined vehicle speed, the predetermined number of times is set larger than when the vehicle speed is lower than the predetermined vehicle speed. The vehicle engine control method according to claim 3,
A vehicle engine control method characterized in that a time for prohibiting the engine from stopping is set for each value of the number of times the plurality of engines can be started. Calculate or estimate the discharge capacity of the power source that supplies power to the motor that starts the engine, and start the engine from the discharge capacity to the predetermined discharge capacity using a predetermined discharge amount per engine start. calculating a number of possible, when you start the engine, the when the number of times capable start the engine, the time for prohibiting the stopping of the engine shorter set than when the small number of possible start the engine An engine control device for a vehicle, comprising: a controller that reduces the predetermined discharge capacity when the vehicle speed is equal to or higher than a predetermined vehicle speed than when the vehicle speed is lower than the predetermined vehicle speed .

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