JP2001047890A - Control device for vehicle power plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the load caused by the drag of a torque converter and suppress an increase of fuel consumption by controlling a transmission at a neutral position if engine stop conditions are not met when a vehicle is stopped. SOLUTION: In a power plant controller 24 controlling the operations of an engine 10 and a transmission 14 receiving its output via a torque converter 12, an engine controller 26 controls the fuel injection quantity according to the engine operation state such as engine revolving speed, intake pipe pressure, vehicle speed, and cooling water temperature and the input action of a driver such as an accelerator pedal action. A transmission controller 28 selects the required shift stage based on the selected travel range and engine operation state. The power plant controller 24 controls the transmission 14 at a neutral position if engine stop conditions are not met when a vehicle is judged to be stopped, thereby the load caused by the drag of the torque converter 12 is reduced, and fuel consumption is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for controlling a power plant for a vehicle having a heat engine, a coupling device for transmitting output via a fluid, and a transmission, and more particularly to a control device for controlling a power plant for a vehicle when the vehicle stops. The present invention relates to a control device for stopping a heat engine when a condition is satisfied.

[0002]

2. Description of the Related Art A gasoline engine or a diesel engine, which is a heat engine, usually performs so-called idling even when a vehicle equipped with the engine is stopped. At this time, the consumed fuel does not contribute to the running of the vehicle. That is, the running fuel efficiency at this time is zero. Such idling reduces overall running fuel efficiency, and it is desirable to avoid idling as much as possible in order to improve fuel efficiency.

[0003] Conventionally, when the vehicle stops at a traffic light or the like, the engine is stopped, and when the driver tries to start running, for example, when the accelerator pedal is depressed,
Control devices for starting the engine have been developed and are partly in practical use.

Japanese Patent Application Laid-Open No. Hei 9-310629 describes a control device for a vehicle equipped with a power plant that transmits the output of an engine to a transmission via a torque converter, which is a coupling device for transmitting power via a fluid. Have been. The configuration of the power plant is the configuration of a power plant of a vehicle equipped with an automatic transmission (hereinafter referred to as an AT vehicle) which is currently most widely used. In the device disclosed in the above publication, the range of the automatic transmission is a traveling range (so-called D range) in which all of the forward gears can be used, and the condition that the vehicle is stopped and the foot brake is depressed is satisfied. A technique for stopping the engine when the engine is stopped is disclosed. By stopping the engine, the fuel consumed by idling can be reduced.

[0005]

In the case of an AT vehicle equipped with a torque converter, such as the vehicle disclosed in the above publication, when the vehicle is stopped and the engine is operating, a pump impeller, which is an input-side component of the torque converter, is used. Rotates integrally with the engine, while the turbine liner, which is an output-side component, is stopped like the wheels. Due to the difference between the input and output rotational speeds, the fluid in the torque converter is agitated and the flow is disturbed, which becomes a load (so-called drag torque). Therefore, there is a problem that the AT vehicle consumes more fuel when idling than a vehicle equipped with a manual transmission. If the engine is stopped as in the device of the above publication, no drag torque is generated. However, when the engine stop condition is not satisfied and the engine is running even when the vehicle is stopped, a drag torque is generated, and there is a problem that fuel consumption increases by this load.

The present invention has been made to solve the above-mentioned problem, and suppresses an increase in fuel consumption due to a load on a coupling device via a fluid when a vehicle is stopped and a heat engine is operated. The purpose is to do.

[0007]

In order to solve the above-mentioned problems, a control apparatus for a power plant for a vehicle according to the present invention includes a heat engine mounted on a vehicle and an output of the heat engine via a fluid. A power plant control device for controlling a power plant, comprising: a coupling for transmitting the power to the transmission; and a transmission for shifting the output of the coupling, wherein the control unit controls the selection and switching of the gear position of the transmission. A transmission control unit, a heat engine control unit that controls the operation of the heat engine, a vehicle stop determination unit that determines a substantial stop of the vehicle, and a heat stop unit that determines that the vehicle has stopped. And a heat engine stop determination unit that determines whether a predetermined condition that can stop the operation of the engine is satisfied. When the heat engine stop determination unit determines that the heat engine operation stop condition is satisfied, the heat engine control unit controls the heat engine to stop, and the vehicle is substantially stopped, but the other operation is stopped. When it is determined that the stop condition is not satisfied, the transmission control unit controls the transmission to a neutral state.

Further, after the transmission is controlled to be in the neutral state, the heat engine can be stopped when the heat engine stop determination section determines that the operation stop condition is satisfied.

[0009]

Embodiments of the present invention (hereinafter referred to as embodiments) will be described below with reference to the drawings. FIG.
FIG. 1 is a diagram illustrating a schematic configuration of a power plant of an AT vehicle. The output of the engine 10 is sent to a transmission 14 via a torque converter 12. The transmission 14 changes the speed of the input rotation and sends it out to the propeller shaft 16. The transmission 14
It has a gear transmission mechanism including a planetary gear mechanism, and also includes various engagement mechanisms for selecting a gear ratio. The on / off of a part of the engagement mechanism is controlled by the hydraulic pressure supplied from the hydraulic control unit 18. Details of the shifting operation of the transmission 14 will be described later. The engine 10 has a starter 20 for starting, and the starter 20 is a motor that receives power supply from a battery 22.

The operation of the engine 10 and the transmission 14
It is controlled by the power plant control unit 24. The power plant control unit 24 includes an engine control unit 26 that controls the engine 10 and a transmission control unit 2 that controls the transmission 14.
8 inclusive. The engine control unit 26 controls a fuel injection amount and the like according to an operation state of the engine 10 (for example, a rotation speed, an intake pipe pressure, a vehicle speed, and a coolant temperature) and a driver's input operation (for example, an operation of an accelerator pedal). Then, operation control is performed. Further, the transmission control unit 28 selects an appropriate gear position based on the selected traveling range, engine rotation speed, vehicle speed, accelerator pedal operation amount, and the like.
A command is issued to the hydraulic control unit 18 to control the transmission 14.

FIG. 2 shows main input / output signals to the power plant control unit 24. The left side of the block showing the control unit 24 shows main input signals, and the right side shows main output signals. The signal of the engine rotation speed can be provided as an output signal of a pickup provided on a periphery of a gear-shaped disk that rotates integrally with the crankshaft. The pickup can output an ON signal when a tooth portion of the disc faces the disc, and output an OFF signal when a valley portion between the teeth faces the disc, and can respond to the rotation speed of the disc. A square wave of frequency is output. This square wave is input as an engine speed signal. The signal of the temperature of the engine cooling water can be an output of a thermistor thermometer installed in a cooling water channel of the engine block or the like.
The SOC (charged state) of the battery, that is, the amount of power currently stored with respect to the power stored when the battery is fully charged, can be obtained by integrating the incoming and outgoing power of the battery. In addition, simply, it can be estimated based on at least one of the terminal voltage and the current of the battery. The terminal voltage and the current are converted into input signals of corresponding voltage values, and the current SOC of the battery can be obtained by referring to a previously determined relationship between the voltage and the current. The vehicle speed signal can be obtained based on the rotation speed of the output shaft of the transmission 14 and the rotation speed of the tires of the vehicle. A gear-shaped disk and a pickup are provided on the output shaft as in the case of the engine rotation speed, and the vehicle speed can be calculated based on the output frequency of the pickup. Further, the rotational speed of the tire can be obtained by disposing a gear-shaped disk and a pickup on the axle portion, similarly to the output shaft.
The foot brake signal can be obtained from a sensor that outputs an ON signal when the foot brake is operated. The signal of the throttle valve opening can be obtained from a sensor that detects the rotation angle of the butterfly valve of the throttle valve. The signal of the intake pipe pressure can be obtained from a pressure sensor provided downstream of the throttle valve. As the signal of the amount of intake air, a signal of a sensor that detects a voltage between both ends of the heating wire provided in the intake pipe can be used. A predetermined current flows through the heating wire. The intake air amount is proportional to the intake flow velocity in the intake pipe, and the temperature of the heating wire changes according to the flow velocity.
The change in the temperature changes the resistance of the heating wire, and the change in the resistance, that is, the change in the voltage allows the amount of intake air to be obtained.

The ignition signal is a signal for instructing the timing at which a spark is generated in the spark plug. The injection signal is a signal for instructing a fuel injection timing and an injection amount, and is controlled by designating an injection valve release timing and time. The starter signal is a signal for rotating the starter, specifically, a signal for turning on a relay provided on a power supply line from the battery to the starter. The AT solenoid signal is a signal for instructing the operation of a solenoid valve in the hydraulic control unit 18 of the transmission, and a clutch for supplying oil pressure is selected by the operation of the solenoid valve based on this signal. The AT line pressure control solenoid signal controls the hydraulic pressure supplied to the clutch. This oil pressure is increased at high output to prevent the clutch from slipping. Further, the instruction signal of the automatic stop control execution indicator is a signal for instructing the driver to display an indicator indicating whether the automatic stop control of the engine is performed and the engine is stopped. The automatic stop standby indicator is a signal that indicates a state in which all predetermined engine stop conditions except the vehicle speed (stop) are satisfied and the vehicle is on standby.

FIG. 3 schematically shows a transmission mechanism of the transmission 14. The transmission 14 has a five-speed configuration in which an auxiliary transmission OD and a main transmission M having four forward speeds and one reverse speed formed of a simple connection of three planetary gear trains are combined. FIG. 3 also shows a torque converter 12, which has a lock-up clutch LC as shown. The auxiliary transmission OD includes a sun gear S0, a carrier C0, and a ring gear R0.
In addition, a first one-way clutch F-0, a multi-plate clutch C-0 in parallel with the first one-way clutch F-0, and a multi-plate brake B-0 in series with the first one-way clutch F-0 are provided. On the other hand, the main transmission M includes sun gears S1 to S3, carriers C1 to C3, and a ring gear R1.
3 of the simple connection in which the speed change elements consisting of
A plurality of gear units P1, P2, P3, and multiple disc clutches C-1, C-
2, band brake B-1, multiple disc brakes B-2 to B-
4. A one-way clutch F-1 and a second one-way clutch F-2 are provided. Although not shown, each clutch and brake is provided with servo means having a piston for engaging and disengaging the friction material under control of servo hydraulic pressure. Further, an input rotation sensor 30 is provided on the sun gear S0 of the auxiliary transmission OD to detect the input rotation speed of the transmission 14. The rotation sensor is similar to the sensor that detects the engine rotation speed described above.
It includes a gear-shaped disk and a pickup that is installed on the periphery of the disk and outputs an ON signal and an OFF signal depending on the presence or absence of gear teeth. As will be described later, in the first to fourth speeds, the sun gear S0 rotates integrally with the turbine of the torque converter 12, so that the input rotation speed of the transmission 14 can be detected. Further, in order to detect the output rotation speed of the transmission 14, the propeller shaft 16
Alternatively, the output rotation sensor 32 is provided on a shaft that rotates integrally with the output rotation sensor. The structure of this sensor is the same as that of the input rotation sensor 30.

FIG. 4 is a diagram showing an operating state of each engagement element when a certain gear is selected in the transmission shown in FIG. In the figure, “○” indicates that the engaging element is engaged, and the one-way clutch is locked. “△” indicates that the engagement element is engaged but is not related to power transmission. Note that the range of the selected shift speed is limited according to the position of the shift lever.

Depending on the shift lever, P range or N range
When the range is selected, the clutch C-0 is engaged,
One-way clutch F-0 is locked. As shown in the figure, neither of the clutches C-1 and C-2 is in the engaged state. Therefore, no power is transmitted to the main transmission M, and there is no output from the transmission 14.

When a forward range such as a D range is selected by a shift lever or the like, a shift speed is selected within a range corresponding to the range. For example, when the D range is selected, any one of the first to fifth speeds is selected according to the traveling state and the driver's request. Further, for example, when three ranges are selected, the shift speed is selected in a range from the first speed to the third speed. Further, in the case of the present embodiment, a manual range which is fixed to one shift speed and does not shift to another shift speed is provided. This manual range is provided so that a driving feeling similar to that of a manual transmission can be obtained, so that the input from the propeller shaft is input to the engine or at least to the turbine of the torque converter so that engine braking is also effective. Each engagement element is controlled to reach.

When the first speed is selected, the clutch C
-0 is engaged. When the clutch C-0 is engaged, the sun gear S0 of the auxiliary transmission 0D and the carrier C0 rotate integrally, and accordingly, the ring gear R0 also rotates integrally. Therefore, when the clutch C-0 is engaged, the auxiliary transmission 0D is in a directly connected state, and the input and output rotational speeds match. In main transmission M, clutch C-1 is engaged. Thereby, the sun gear S3 of the gear unit P3 rotates. The sun gear S3 tries to rotate the ring gear R3 via a planetary gear on the carrier C3, and the rotation direction of the ring gear R3 is a direction that is prevented by the one-way clutch F-2. As a result, the ring gear R3 is fixed, and power is transmitted from the carrier C3 to the propeller shaft 16. If it is necessary to apply the engine brake, the brake B-4 is further engaged. When the engine brake is applied, that is, in the reverse driving state, the direction in which the carrier C3 tries to rotate the ring gear R3 is the direction in which the one-way clutch F-2 becomes free. If this state is not maintained, the sun gear S3 is not driven and the engine brake does not work. Then, the brake B-4 is engaged to fix the ring gear R3. As a result, the driving force is transmitted to the sun gear S3, and the clutches C-1 and C-0 are engaged, so that the turbine of the torque converter 12 is driven and the engine brake operates.

When the second speed is selected, the auxiliary transmission O
D is in a directly connected state as in the case of the first speed. In the main transmission M, the clutch C-1 and the brake B-3 are engaged. The power input via the clutch C-1 drives the ring gear R2 of the gear unit P2. On the other hand, in the gear unit P1, since the carrier C1 is fixed by the brake B-3, the movements of the ring gear R1 and the sun gear S1 are in the opposite directions of rotation, and the absolute of the peripheral velocity at the contact point with each planetary gear. It is limited to movements where the values are equal. As illustrated, the sun gear S2 of the gear unit P2 rotates at the same speed because it is integral with the sun gear S1. Further, the ring gear R1 and the carrier C
2 also rotates at the same speed. From the above, the gear unit P2
The rotation speed of the carrier C2 and the rotation speed of the sun gear S2 have a predetermined relationship based on the gear ratio. Further, there is a relationship that the peripheral speed at the planetary gear support point of the carrier C2 is an average value of the peripheral speeds of the contact points of the ring gear R2 and the sun gear S2 with each planetary gear. Here, since the rotation speed of the ring gear R2 is determined as an input from the clutch C-1, the variable is the rotation speed of the carrier C2 and the sun gear S2. The relationship between the rotation speed and the peripheral speed is a fixed value determined by the pitch circle radius of each gear. Since there are two functional relationships between the carrier C2 and the sun gear S2, which are variables, the two variables are uniquely determined. This rotation is output to the propeller shaft 16. At the time of reverse driving driven from the propeller shaft side, the driving force is transmitted in the above-described path in the reverse direction, the turbine is driven, and the engine brake operates.

When the third speed is selected, the auxiliary transmission O
D is in a directly connected state as in the case of the first speed. In the main transmission M, the clutch C-1 and the brake B-2
Are brought into the engaged state. The input from the clutch C-1 drives the ring gear R2. Ring gear R2 is sun gear S
2 is to be rotated in the one-way clutch F
The direction -1 is locked, and the sun gear S2 is fixed. Therefore, the carrier C2 rotates, causing the propeller shaft 16 to rotate. At the time of reverse drive driven from the propeller shaft side, the one-way clutch F-1 becomes free, so that the brake B-1 is engaged to fix the sun gear S2. As a result, the driving force is transmitted in the direction opposite to the above-described path, the turbine is driven, and the engine brake operates.

When the fourth speed is selected, the auxiliary transmission O
D is in a directly connected state as in the case of the first speed. In main transmission M, clutches C-1 and C-2 are engaged. Thereby, the sun gear S2 of the gear unit P2
And the ring gear R2 have the same rotation speed, and the carrier C
2 also rotates at the same speed. This rotation is transmitted to the propeller shaft 16. When driven from the propeller shaft 16, the driving force is transmitted in the opposite direction as described above, the turbine is driven, and the engine brake operates.

When the fifth speed is selected, the auxiliary transmission O
In D, the clutch C-0 is released, and the brake B-0 is engaged instead. As a result, the sun gear S0 is fixed, and the rotation of the carrier C0 is increased and transmitted to the ring gear R0. The main transmission M is the same as in the case of the fourth speed. When driven from the propeller shaft 16, the driving force is transmitted in the opposite direction to drive the turbine, and the engine brake operates.

The engine brake is a torque converter 1
Engaging the second lock-up clutch LC can make it stronger.

When the reverse gear is selected, separate control is performed when the reverse gear is selected and when the vehicle is not actually traveling and when the vehicle is actually traveling. When the reverse is selected by the shift lever but is stopped, the sub-transmission O
D clutch C-0 is engaged. In the main transmission M, the clutch C-2 and the brake B-4 are engaged. During reverse travel, the clutch C-0 of the auxiliary transmission is released and the brake B-0 is engaged instead, as in the case of selecting the fifth speed. In the main transmission M, the engagement of the clutch C-2 and the brake B-4 is maintained. The rotation transmitted via the clutch C-2 is transmitted to the gear unit P
2 is input to the sun gear S2. Gear unit P2, P
The relationship between the three elements is the same rotation speed because the ring gear R2 and the sun gear S3 are integrated, and the carrier C2
Since C3 is integrated, the rotation speed is the same. further,
The peripheral speed at the planetary gear support point of the carrier C3 is an average value of the peripheral speeds at the contact points of the sun gear S3 and the ring gear R3 with each planetary gear. Also,
The peripheral speed at the planetary gear support point of the carrier C2 is an average value of the peripheral speeds at the contact points of the sun gear S3 and the ring gear R3 with each planetary gear. The rotation speed of the sun gear S2 is determined by the input, and the ring gear R3 is fixed by the brake B-4. The relationship between the peripheral speed and the rotation speed of each element is a fixed value that is geometrically determined from the pitch circle radius and the like. From the above, the variables in the two gear units P2 and P3 are the carriers C2 and
The rotational speeds of the carrier C2, C3, and the rotational speeds of the ring gear R2 and the sun gear S4 are geometrically determined among the four rotational speeds of C3, the ring gear R2, and the sun gear S3. Therefore, it can be regarded as one variable. Accordingly, there are two variables, and the peripheral speed of each element in the gear units P2 and P3 is represented by two equations, so that the variables are uniquely determined.

Since there are four of these relationships as described above, each value is uniquely determined. In addition, since the ring gear R2 and the sun gear S3 have the same rotational speed, the carriers C2 and C3 rotate in the reverse direction, thereby allowing the carriers C2 and C3 to retreat.

As can be understood from the above description, when both the clutches C-1 and C-2 of the main transmission are released, the rotation on the engine side and the rotation on the propeller shaft side are cut off. That is, the transmission 1 is released by releasing these two clutches.
4 is controlled to a neutral state. In the present embodiment, when it is determined that the vehicle is substantially stopped, but when the engine cannot be stopped, the transmission 14 is controlled to a neutral state, and control is performed to reduce the load due to drag of the torque converter 12. The clutches C-1 and C-2 are released regardless of the range selected by the shift lever in order to achieve the neutral state.

FIG. 5 is a schematic diagram of a circuit for supplying hydraulic pressure to the clutch C-1. The oil pump 50 is a gear pump driven by the engine 10. More specifically, the transmission 14 includes a gear that is disposed closest to the torque converter 12 of the transmission 14 and is driven by a part that is formed integrally with the pump impeller of the torque converter, and a gear that follows the gear. 14 each clutch, each brake, and the lock-up clutch L of the torque converter 12
Supply hydraulic pressure to C. The transmission 14 and the torque converter 12 are lubricated by oil supplied by the oil pump 50. The pressure from oil pump 50 is regulated by primary regulator valve 52. This pressure is changed by the line pressure control solenoid 54 based on the operation state. For example, when the accelerator pedal is greatly depressed, the output torque of the engine increases, and it is necessary to engage each engagement element more firmly. Further, when it is determined that the output torque of the engine is small, the hydraulic pressure is set to a lower value so that each of the engagement elements does not suddenly engage to reduce the shock during shifting.

The manual valve 56 sends the hydraulic pressure supplied from the primary regulator valve 52 to a predetermined engagement element corresponding to the selected range. That is, the manual valve 56 is mechanically linked with the shift lever operated by the driver, and opens and closes a predetermined hydraulic circuit according to the position of the shift lever, that is, the travel range. Although FIG. 5 shows only the hydraulic circuit for the clutch C-1, a hydraulic circuit for another engagement element actually exists downstream of the manual valve 56.

The hydraulic pressure from the manual valve 56 is
Or the circuit including the first orifice 58 and the switching valve 60, or the circuit including the first orifice 58 and the second orifice 62 arranged in parallel with the switching valve. The selection of the two circuits is made by opening and closing a switching valve by a switching valve solenoid 64. The diameter of the first orifice 58 is larger than the diameter of the second orifice 62, so that when a circuit is formed that passes through the second orifice 62, the flow rate of oil is substantially determined by the second orifice. You. An accumulator 66 is arranged immediately before the clutch C- 1, and a third orifice 68 is arranged on a circuit branched to the accumulator 66. In addition, the second orifice 6
The check valve 70 is arranged in parallel with the valve 2 in such a manner that the direction from the clutch C-1 to the manual valve 56 is set as the forward direction.

In normal control, the switching valve 60 is controlled to be closed. That is, when the driver operates the shift lever to select a travel range such as the D range, the hydraulic pressure from the manual valve 56 passes through the second orifice 62 and is sent to the clutch C-1. At this time, since the accumulator 66 is provided in front of the clutch C-1, while the accumulator 66 is performing a stroke, the engagement of the clutch C-1 is executed by the hydraulic pressure determined by the spring. Since the diameter of the second orifice 62 is small, the supply amount of oil is limited, and the time until the stroke of the piston of the accumulator 66 ends is relatively long. This prevents the clutch C-1 from being suddenly connected and causing a shift shock.

The reason why the switching valve 60 is controlled to the open state is as follows.
This is when it is desired to rapidly engage the clutch C-1. Such a case is, for example, when the engine is restarted after stopping the engine while the vehicle is stopped in order to suppress fuel consumption. The first orifice 58 has a second orifice 62
When the switching valve 60 is open, the flow rate to the clutch C-1 increases, and the piston of the accumulator 66 moves faster. However, if oil is supplied only through the first orifice 58,
Since the flow rate is large but a large shock occurs, the switching valve 60 is closed immediately before the piston moves. Therefore, the time until the clutch C-1 is completely engaged can be shortened, and the shock can be reduced.

When the supply of the hydraulic pressure to the clutch C-1 becomes unnecessary, the check valve 70 releases the oil in the clutch C-1 earlier.

FIG. 6 is a flowchart showing control of the power plant when the vehicle stops.
This control is achieved by the power plant control unit 24 operating according to a predetermined program. When this routine is started, the input signal is processed and converted into necessary data (S100). Next, it is determined whether the vehicle has substantially stopped (S102). Further, the stop state of the vehicle can be determined based on a speed signal from a vehicle speed sensor. The stop of the vehicle can be determined based on the fact that the frequency of the square wave signal from the vehicle speed sensor has fallen below the predetermined position.

If it is determined that the vehicle has not stopped, this routine ends. If it is determined that the vehicle has stopped, it is next determined whether the engine stop condition is satisfied (S104). The engine stop condition is, for example, that the temperature of the engine coolant is within a predetermined range, the accelerator pedal is fully returned, and the state of charge of the battery (SO
C) is at an appropriate level and the brake pedal is being depressed. The cooling water temperature is
If the temperature is too high, it is necessary to cool, and if the engine is stopped, the cooling fan driven by the engine cannot be rotated, and cooling cannot be performed. Further, even in a cooling fan (electric fan) that is not directly driven by the engine, it is necessary to keep the engine running in order to consume the battery power and replenish the battery. Therefore, if the cooling water temperature is too high, stopping the engine is not preferable. Also, when the cooling water temperature is low, to raise the temperature to the normal operation temperature,
It is necessary to warm up the engine. If the accelerator pedal is depressed, the driver is considered to have a will to drive, so it is not preferable to stop the engine at this time as well. Also, when the battery charge is low,
It needs to be charged and the engine must be running. In addition, if the amount of stored power is small, it may be difficult to restart the engine, so it is not preferable to stop the engine. Furthermore, if the brake is depressed, the driver's intention to stop is apparent, and in this case, the engine can be stopped.

When the engine stop condition is satisfied, the engine is stopped (S106). On the other hand, if the engine stop condition is not satisfied, the clutches C-1 and C-2 of the transmission 14 are released while the engine is running, and the transmission 14 is brought into the neutral state (S108). By controlling to the neutral state, the engine side and the propeller shaft side can be separated, and the load due to drag of the torque converter can be reduced. And fuel consumption can be reduced.

In step S104, if the engine stop condition is not satisfied and the clutch C-1 is released,
It is also possible to determine whether or not the brake pedal is depressed, and release the clutch C-1 only when the brake pedal is depressed.

The routine shown in FIG. 6 is executed at predetermined intervals, and after the transmission is controlled to the neutral state without satisfying the engine stop condition, if the stop condition is satisfied,
Engine stop control is executed. When the stop condition is not satisfied during the stop of the engine, the starter 20 is driven to start the engine.

In the above embodiment, a power plant using a torque converter as a transmission means via a fluid has been described. However, other means, for example, a device having a fluid coupling having no torque amplification function, can be similarly used. Can be adopted.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of a power plant according to an embodiment.

FIG. 2 is a diagram illustrating input / output signals of a control unit according to the embodiment.

FIG. 3 is a diagram showing a schematic internal structure of a transmission and the like.

FIG. 4 is a diagram showing an operating state of an engagement element of the transmission at each shift speed.

FIG. 5 is a circuit diagram for supplying hydraulic pressure to a clutch C-1 of the transmission.

FIG. 6 is a control flowchart relating to engine stop control and transmission neutral state control when the vehicle is stopped.

[Explanation of symbols]

10 engine, 12 torque converter, 14 transmission, 18 hydraulic control unit, 20 starter, 22 battery, 24 power plant control unit, 26 engine control unit, 28 transmission control unit.

Continued on the front page F-term (reference) HE01Z HF08Z HF12Z HF25X HF26Z 3G093 AA05 BA03 BA19 BA22 CA10 CB01 DA01 DA05 DA06 DA09 DB05 DB11 DB15 EA01 EA05 EA13 EB03 EB04 EC01 FB02 3J052 AA11 AA14 CB07 CB11 EA04 FB31 GC04 GC32 GC01

Claims (2)

[Claims] 1. A power plant, comprising: a heat engine mounted on a vehicle; a joint for transmitting an output of the heat engine via a fluid; and a transmission for shifting the output of the joint. A control device for a vehicle power plant, comprising: a transmission control unit that controls selection and switching of a gear position of the transmission; a heat engine control unit that controls operation of the heat engine; A vehicle stop determination unit that determines stop, whether a predetermined condition that can stop the operation of the heat engine in addition to the determination that the vehicle stop is satisfied,
And a stop condition determining unit that determines whether the stop condition of the heat engine is satisfied when the stop condition determining unit determines that the stop condition of the heat engine is satisfied. When it is determined that the operation has been substantially stopped but other operation stop conditions are not satisfied,
The control device for a vehicle power plant, wherein the transmission control unit controls the transmission to a neutral state. 2. The control apparatus for a vehicle power plant according to claim 1, wherein when the stop condition determination unit determines that the operation stop condition is satisfied after the transmission is controlled to the neutral state, A control device that stops the engine.