JP2001012269A - Engine automatic stop / start device - Google Patents

Abstract

(57) [Summary] [Problem] To automatically stop and restart the engine,
Provided is an engine automatic stop / start device that enables more accurate automatic stop / restart of an engine. An engine automatic stop / start apparatus for automatically stopping / starting an engine under predetermined conditions including at least the presence / absence of a brake operation is provided. The configuration is such that the presence or absence of the brake operation can be determined in combination with the signal from the above sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention saves fuel consumption by executing automatic stop and start of an engine.
Alternatively, the present invention relates to a control device for a transmission including an engine automatic stop / start device that reduces exhaust emissions.

[0002]

2. Description of the Related Art Conventionally, when a vehicle stops at an intersection or the like during traveling, the engine is automatically stopped under a predetermined stop condition, and then the engine is started under a predetermined start condition, for example, when an accelerator pedal is depressed. An automatic engine stop / start system that saves fuel or reduces exhaust emissions by starting the engine is disclosed in
For example, it is known in US Pat.

On the other hand, in recent years, many automobiles have an automatic transmission (hereinafter referred to as A / T), and it is expected that the engine automatic stop / start device will be provided in an automobile having an automatic transmission.

[0004] Conditions for the automatic stop / start device to stop the engine include, for example, first, the shift lever is located in a drive range (hereinafter, referred to as D) or a neutral range (hereinafter, referred to as N). Second, that the vehicle speed is 0 (zero), third, that the brake switch detects when the brake is depressed, that the brake pedal signal (STP signal) is ON, etc. It is. When all of the above conditions are satisfied, the engine is automatically stopped by the automatic engine stop and start device.

[0005] Further, the predetermined conditions for the engine automatic stop / start device to restart the engine include, for example, first, that the shift lever is located at a position other than D or N, and, second, that the vehicle speed is constant. Over speed (vehicle speed is 0 (zero)
Third, the brake pedal signal is in an OFF state. When any of the above conditions is satisfied, the automatic engine stop / start device operates, and the engine restarts.

As described above, when the traveling vehicle satisfies the predetermined condition, the automatic engine stop / start device operates, and the engine is temporarily stopped or the engine is stopped even when the ignition switch is ON. Or restart. This has made it possible to reduce fuel consumption and exhaust emissions.

[0007]

However, in the above-mentioned conventional automatic engine stop / start system, the information that the brake pedal is stopped by depressing the brake pedal is relying solely on the brake switch. Occurs, it is expected that the brake pedal signal will remain OFF and the engine will not stop automatically even if the predetermined condition for automatic stop is satisfied.
Conversely, there is a possibility that the predetermined condition for the automatic stop is satisfied even though the brake pedal is not depressed, the brake pedal signal is turned on, and the engine is automatically stopped.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an automatic engine stop / start apparatus capable of avoiding such a problem and enabling more accurate automatic stop and automatic start of the engine.

[Means for Solving the Problems]

According to the present invention, in an automatic engine stop / start system for automatically stopping and restarting an engine under predetermined conditions including at least the presence or absence of a brake operation, two or more sensors for detecting the presence or absence of a brake operation, and each sensor And determining means for determining the presence / absence of a brake operation based on a plurality of brake operation presence / absence signals. The two or more sensors include a brake switch that senses at least the presence or absence of a brake operation. According to the present invention, as a sensor other than the brake switch, a pedal stroke sensor for detecting a change in stroke when a brake is depressed, and a brake pressure sensor for detecting a change in pressure in a brake device of a hydraulic or pneumatic brake (In case of hydraulic brake: brake oil pressure sensor,
Pneumatic brake: at least one of a brake air pressure sensor). That is, a combination of a brake switch and a brake pressure sensor, a combination of a brake switch and a pedal stroke sensor, and a combination of a brake switch, a brake pressure sensor, and a pedal stroke sensor can be exemplified.

Therefore, the presence or absence of the brake operation has been determined only by the signal from the brake switch.
The presence / absence of a brake operation can be determined by combining with a signal detected from another sensor.

Thus, even if a failure occurs in the brake switch, the other sensors detect the presence or absence of the brake operation and accurately stop the engine automatically.
Enables automatic restart.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The automatic engine stop / start system according to the present invention can be used for hydraulic and pneumatic brakes. Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

<Embodiment 1> In this embodiment, an automatic engine stop / start device is mounted on an automobile equipped with an automatic transmission equipped with a hydraulic brake. [Overview of System Configuration] FIG. 1 is a configuration diagram showing an overall image of an apparatus according to the present invention. As shown in FIG. 1, an internal combustion engine 1 (hereinafter, referred to as an engine) is connected to an automatic transmission 2 (hereinafter, referred to as an automatic transmission: A / T) and functions as a motor and a generator. Motor generator 3 (hereinafter, referred to as M / G). The M / G 3 is connected to a crankshaft of the engine via a pulley 4, a belt 5, and a pulley 6. Between the pulley 6 and the crankshaft, there is provided an electromagnetic clutch 7 capable of switching between transmission and non-transmission of power.

Further, as accessories driven by the power of the engine, for example, a pump 8 for power steering and a compressor 9 for air conditioner are provided, and a crankshaft of the engine 1 and a pulley 10 are connected to the M / G 3 respectively. ,
11 and the belt 5. Although not shown, an oil pump for the engine, a water pump for cooling the engine, and the like are also connected as auxiliary equipment in addition to the above. An inverter 12 is electrically connected to the M / G3. The inverter 12 changes the number of revolutions of the M / G3 from a battery 13 as a power source. Further, switching is performed so that electric energy is charged from the M / G 3 to the battery.

Further, in addition to the engine control, a controller (electronic control unit: ECU) comprising a computer is provided for controlling the on / off of the electromagnetic clutch and the switching control of the inverter.
4, a M / G rotation speed and an air conditioner operation switch signal are input as input signals.

The controller is a well-known central processing unit CP.
In addition to U, a logical operation circuit including input support and the like, such as a ROM storing a control program, a RAM for writing operation results, and a backup RAM for backing up data. These are connected by a bus.

The controller includes various sensors (crank angle sensor, cooling water temperature sensor, intake pressure sensor, accelerator sensor (throttle opening sensor), air-fuel ratio sensor, fuel pressure sensor, and a brake oil pressure sensor (master cylinder pressure sensor). ) 15a, pedal stroke sensor 1
6) are connected, and a detection signal from each is input.

Various switches (range switch 20, brake switch 18) are connected to the controller.

[Automatic Transmission] As shown in FIG. 2, the automatic transmission 2 transmits the power of the engine 1 to the drive wheels through the pump impeller 20 which is directly connected to the drive wheels. Is converted into kinetic energy of the fluid by the rotation of the
1, a torque converter 23 for transmitting power by rotating an output shaft to a turbine runner 22 and transmitting a driving force transmitted by the torque converter 23 to a driving force required for a vehicle. I have. The torque converter 23 includes a lock-up clutch 24,
When the vehicle speed exceeds a certain level, the output shaft of the engine 1 and the output shaft of the torque converter 23 are directly connected.

Next, an input shaft (input shaft) 25 of the transmission is connected to an output shaft connected to the turbine runner 22. The transmission 2 includes a gear train, and usually combines a planetary gear mechanism, a clutch, a brake, and the like, and selects a plurality of shift speeds and selects between forward and reverse. Hereinafter, the details will be described with reference to FIG. FIG.
It is a figure showing an example of a gear train of the above-mentioned automatic transmission 2, and in the composition shown here, it is constituted so that the speed of four steps of forward and one reverse may be set. The input shaft 25 of the transmission connected to the turbine hub 26 of the torque converter 23 is connected to the sun gear 29 of the first planetary gear mechanism 27 via the forward clutch C1.

The first planetary gear mechanism 27 is provided with a ring gear 28, a sun gear 29 disposed at the center of the ring gear 28, and disposed between the sun gear 29 and the ring gear 28 and held by a carrier 30. It has a pinion gear, and the pinion gear is configured to relatively rotate around the sun gear while meshing with the sun gear 29 and the ring gear 28.

On the other hand, the input shaft 25 of the transmission 2 is C2
Carrier 3 of second planetary gear set 31 via clutch
2 and to the sun gear 33 of the second planetary gear set 31 via a C3 clutch. The ring gear 34 of the second planetary gear set 31 and the carrier 30 of the first planetary gear set 27 are connected.

The band brake B1 for stopping the rotation of the sun gear 33 of the second planetary gear set 31 is
And the casing 35. Further, a band brake B2 for selectively stopping the rotation of the sun gear is provided in parallel between the sun gear 33 and the casing 35 via a one-way clutch.

The engine output input via the input shaft 25 is finally output from the output shaft 36 connected to the carrier 30 of the first planetary gear set 27 and transmitted to the drive wheels.

In the above automatic transmission, four forward speeds and one reverse speed can be set by engaging and disengaging each clutch and brake as shown in the operation table of FIG. In FIG. 3, a circle indicates an engaged state, a double circle indicates an engaged state during engine braking, and a blank indicates a released state.

The above-described control of the torque converter 23,
The engagement and disengagement of the clutch and the brake is performed by an actuator that operates by hydraulic pressure (fluid pressure), and a hydraulic control device including a hydraulic circuit for driving the actuator is provided.

[Automatic Stopping / Starting Device of Engine] The automatic stopping device of the engine 1 is realized on the controller 14 in accordance with the control program stored in the ROM.
As shown in FIG. 4, the apparatus includes an automatic stop determination unit 101 for determining an execution condition of the automatic stop of the engine 1 and a fuel supply to the engine when the automatic stop determination unit 101 determines that the automatic stop condition is satisfied. When the fuel cut command means 102 for cutting off the supply, the automatic return determination means 103 for determining the execution condition of the restart of the engine 1, and the automatic return determination means 103 determine that the engine should be restarted, M / And a return command means 104 for driving G3 and restarting the fuel supply to restart the engine.

The automatic stop / automatic return determination of the engine by the automatic stop determination means 101 and the automatic return determination means 103 is performed by a signal from a vehicle speed sensor, a signal indicating a position of a shift lever, a signal from an accelerator sensor, a brake operation, This is executed by a presence / absence signal or the like.

The brake operation presence / absence signal is not only information (signal) from the brake switch 18 but also a brake oil pressure sensor (master cylinder pressure sensor) for detecting a change in oil pressure in a master cylinder constituting the brake device.
The signal from the engine 15 and at least one of the signals from the pedal stroke sensor 16 for detecting a change in stroke when the brake is depressed are used as a material for determining the automatic stop / return of the engine.

FIG. 5 shows the conditions for judging the automatic stop of the engine. First, the shift lever position is in the D or N range. Second, the accelerator pedal is not depressed and the vehicle speed is 0 km / h. Third, the brake operation presence / absence signal is ON. Other conditions include that the engine water temperature and the operating oil temperature of the A / T are within a predetermined range, and the SOC (St) of the battery.
ate of Change) is within a predetermined range.

On the other hand, the condition for determining the automatic return of the engine is that the accelerator pedal is depressed or the brake is off.

The execution of the automatic stop / start control of the engine at the D or N position is referred to as D eco-run. The automatic stop / start control of the engine is performed only at the N position, and the automatic stop / start control of the engine is performed at other positions. Control that does not perform stop / start control is called N eco-run. It is also possible to select and control whether to use D eco-run or N eco-run.

As described above, in the example, the presence or absence of the brake operation can be determined without relying only on the brake switch.
By making a determination in conjunction with other information, it is possible to accurately determine whether or not a brake operation has been performed, and thereby it is possible to accurately perform automatic stop / restart of the engine.

Further, since the presence or absence of a brake operation is determined from a plurality of information (signals), the determination is more accurate, and even if a failure occurs in the brake operation presence / absence signal, information from other sensors (signals) is obtained. Signal), the system can back up the judgment of the presence or absence of the brake operation.

When the automatic stop determination means 101 determines that the automatic stop conditions are satisfied, the engine automatic stop / start device includes a control execution indicator provided in the driver's seat.
For example, an automatic stop display unit 105 that lights a lamp and indicates to the driver that the engine is being automatically stopped is provided.

Further, the automatic engine stop / start device includes an automatic stop prohibiting means 107 for prohibiting the automatic stop control when the transmission is at a high speed. For example, when various valves of the transmission do not operate and the transmission fails, and the transmission is in a high speed stage.

Further, also in the snow mode in which the second transmission is performed, the automatic stop prohibiting means prohibits the automatic stop control. When changing to the snow mode, it may be performed at the N position. When changing to the snow mode at the N position, the automatic stop state is immediately stopped. Conversely, it is conceivable as an embodiment that the snow mode is not received unless the automatic stop control is stopped. The reason for this is that the automatic stop / start control in this example operates only when the first start is performed, and therefore cannot be incompatible with the snow mode in which the second start is contradictory. In the snow mode, the automatic stop determination means may determine that “it should not be stopped automatically” and the automatic engine stop and start device may not be operated.

[Hill Hold Control Means] If the engine is running even when the vehicle is stopped, a creep force is applied to move the vehicle forward as long as the shift lever is in the D position. Therefore, it is possible to prevent the vehicle from moving backward by the creep force on a gentle slope.

However, in the present invention, when the vehicle stops, the engine stops, so that no creep force works.
Therefore, when the stopped position is on a slope, the vehicle will retreat unless the brake is continuously depressed.

Therefore, as shown in FIG. 4, when the automatic stop determination means 101 determines that the automatic stop conditions are satisfied, the hill which holds the master cylinder hydraulic pressure contained in the brake device 17 to maintain the braking force is provided. Hold control means 106 is provided. This hill hold control means 106
Is also realized on the controller by a program. Note that the hill hold control is preferably performed by driving an actuator for an anti-lock brake device (ABS). Further, the rotating shaft connected to the wheels may be mechanically locked.

<Embodiment 2> This embodiment relates to an automatic engine stop / start system according to the present invention for a pneumatic brake.

The pneumatic brake mainly includes a compressor (not shown) for compressing air, an air tank (not shown) for storing compressed air, and sends the compressed air to a brake system. And a brake chamber (not shown) for converting the pressure of the compressed air into mechanical force.

Therefore, instead of a brake oil pressure sensor for detecting a change in the hydraulic pressure in the master cylinder used for the hydraulic brake, an air pressure sensor 15b for detecting a change in the air pressure in the air tank is used.

Thereafter, the same stroke as in the case of the hydraulic brake is followed, and the automatic stop and start of the engine can be performed more accurately.

The combination of sensors for implementing the present invention includes a combination of a brake switch and a stroke sensor, a combination of a brake switch and a pneumatic sensor 15b, and a combination of a brake switch, a stroke sensor and a pneumatic sensor 15b. Examples can be given.

According to the present invention, not only the brake switch but also other sensors are used as the sensor for detecting the presence or absence of the brake operation. Thus, the presence or absence of the brake operation can be detected. Therefore, even if the predetermined condition for the automatic stop is satisfied, the brake pedal signal remains OFF, and the engine does not stop automatically or the predetermined condition for the automatic stop is satisfied even if the brake pedal is not depressed. As a result, it is possible to avoid such a disadvantage that the brake pedal signal is turned on and the engine is automatically stopped. As described above, since the automatic stop and start of the engine can be performed more accurately, it is also possible to more reliably reduce the fuel and the exhaust emission.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an entire system according to the present invention.

FIG. 2 is a schematic diagram showing a gear train of a transmission.

FIG. 3 is a diagram showing an operation state of a transmission.

FIG. 4 is a block diagram of an automatic stop / start device realized by a CPU of a controller;

FIG. 5 is a block diagram showing automatic stop of the engine.

[Explanation of symbols]

 Reference Signs List 1 internal combustion engine (engine) 2 automatic transmission 3 motor / generator 4, 6 pulley 5 belt 7 electromagnetic clutch 8 pump 9 compressor 10, 11 pulley 12 inverter 13 battery 14 controller 15a brake oil pressure sensor 15b brake air pressure sensor 16 pedal stroke sensor Reference Signs List 17 brake device (hydraulic pressure or air pressure) 18 brake switch 19 brake pedal 20 range switch 21 stator 22 turbine runner 23 torque converter 24 lock-up clutch 25 input shaft 26 turbine hub 27 first planetary gear device 28, 34 ring gear 29, 33 Sun gear 30, 32 Carrier 31 Second planetary gear unit 35 Casing 36 Output shaft 101 Automatic stop determination means 102 Fuel cut command means 103 Automatic return determination Stage 104 return command means 105 automatically stops displaying means

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Claims (3)

[Claims] 1. An engine automatic stop / start apparatus for automatically stopping / restarting an engine under predetermined conditions including at least the presence or absence of a brake operation, comprising: two or more sensors for detecting the presence or absence of a brake operation; An automatic stop / start device for an engine, comprising: a determination unit configured to determine the presence or absence of a brake operation based on a brake operation presence / absence signal. The two or more sensors include a brake switch for detecting at least the presence or absence of a brake operation when the brake is of a hydraulic type, and a master cylinder pressure for detecting a change in hydraulic pressure in a master cylinder of the brake. 2. The automatic engine stop / start system according to claim 1, further comprising at least one of a sensor and a pedal stroke sensor for detecting a change in a stroke of a brake pedal. 3. The two or more sensors include, when the brake is a pneumatic type, a brake switch for detecting at least the presence or absence of a brake operation, and a pneumatic pressure for detecting a pneumatic change in an air tank of the pneumatic brake. 2. The automatic engine stop / start system according to claim 1, further comprising at least one of a sensor and a pedal stroke sensor for detecting a change in a stroke of a brake pedal.