JPH1047105A - Automatically starting/stopping device of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of battery exhaustion by comparing a battery voltage value at the time of engine start with a judging value which is set beforehand, and prohibiting automatically stopping control of an engine in the case where the battery voltage value is lower than the judging value. SOLUTION: In a computer 4, various kinds of signals are inputted, a signal for injecting fuel to an injector 26 and a signal for igniting an ignitor 24 are stopped in the case where a prescribed engine stopping condition is set up during operation of an engine, automatically stopping of the engine is controlled, and the automatically starting of the engine is controlled in the case where a prescribed engine start condition is set up during stopping of the engine. The voltage value of a battery 22 at the time of start of the engine and the judging value which is set beforehand are compared with each other, and automatically stopping control of the engine is prohibited in the case where the voltage value of the battery 22 is lower than its judging value. It is thus possible to prevent generation of battery exhaustion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic stop / start system for an engine, and more particularly to an improvement in fuel efficiency when an electric load is small, and an increase in a battery when the electric load is large. The present invention relates to a device for automatically starting and stopping an engine, which can prevent the occurrence.

[0002]

2. Description of the Related Art Vehicles such as automobiles are frequently stopped by a red light or the like at an intersection while traveling in an urban area. Even when the vehicle is stopped, fuel is consumed as long as the engine is running. Therefore, there is a problem that the fuel consumption rate is reduced due to the idle operation during the stop. Therefore, by stopping the engine when stopping the vehicle and starting the engine when starting the vehicle, unnecessary fuel consumption during the temporary stop is eliminated, and the fuel consumption rate is improved. Automatic start and stop devices have been proposed.

In an automatic start / stop device for an engine,
The control means controls the automatic stop of the engine when a predetermined engine stop condition is satisfied while the engine mounted on the vehicle is operating, and automatically starts the engine when the predetermined engine start condition is satisfied while the engine is stopped. To control.

In this automatic start / stop device, a detecting means for detecting a charged state which is a value of a battery voltage of a battery is provided. As shown in FIG. 21, when a program is started by a control means (step 902), first, the battery is started. The charge amount is compared with a preset judgment value (step 90).
4) If the battery charge is larger than the determination value, and if step 904 is YES, the program returns (step 906). On the other hand, if the battery charge amount is smaller than the determination value, and if step 904 is NO, a setting is made to prohibit the automatic engine stop (step 908), and the program is returned (step 906).

In the automatic start / stop device, a detecting means for detecting a charged state which is a value of a battery voltage of a battery is provided, and as shown in FIG. 22, when a program is started by the control means (step 1002), first, The value of the battery voltage when the engine is started is compared with a preset engine stop prohibition determination value (Bsta) (step 1).
004), when the battery voltage value at the time of starting is larger than the engine stop prohibition determination value, and when step (1004) is YES, the program is returned (step 1).
006). On the other hand, when the value of the battery voltage at the time of starting is smaller than the engine stop prohibition determination value (Bata),
If step 1004 is NO, a setting is made to prohibit automatic stop of the engine (step 1008), and the program is returned (step 1006).

Further, such an automatic start / stop device for an engine is disclosed, for example, in Japanese Utility Model Laid-Open Publication No. Sho 59-28644 and Japanese Utility Model Laid-Open Publication No. Sho 58-191347. Japanese Unexamined Utility Model Publication No. 59-28644 discloses a vehicle having a control circuit that shuts off fuel to an engine during a temporary stop after traveling and restarts the stopped engine during the temporary stop. In the engine, means for detecting the power state of the battery and means for operating the control circuit only when the power is equal to or more than a predetermined value are provided. Japanese Unexamined Utility Model Publication No. 58-191347 discloses a system canceling means for canceling the system when the battery voltage is equal to or lower than a predetermined set voltage at the time of cranking, and a predetermined method after the system is canceled by the system canceling means. System return means for returning the system when a predetermined time has elapsed, and rotation speed increasing means for increasing the engine rotation speed from when the system is released by the system release means to when the system is restored by the system return means Are provided.

[0007]

However, in the conventional automatic stop and start device, if the determination value (threshold) for determining the state of charge of the battery is set to a high value, the number of engine stops is reduced. However, there is an inconvenience that a great improvement in fuel efficiency cannot be achieved.

[0008] Further, if the judgment value (threshold value) is set low, there is an inconvenience that the occurrence of a dead battery increases.

Further, as a method for determining the state of charge of the battery, when the determination is made based on the value of the battery voltage at the time of starting the engine, the value of the battery voltage at the time of starting the engine is determined by the presence or absence of an electric load on the engine and the warm-up state of the engine. And so on, there is a disadvantage that when the determination is made based on one predetermined value, an accurate determination cannot be made.

Furthermore, despite the fact that the battery has a sufficient charge, the automatic stop of the engine is prohibited or, conversely,
There is a disadvantage that the engine is stopped even though the charge amount of the battery is small.

[0011]

SUMMARY OF THE INVENTION In order to eliminate the above-mentioned disadvantages, the present invention provides an automatic stop control for an engine mounted on a vehicle when a predetermined engine stop condition is satisfied during operation of the engine. In addition, when a predetermined engine start condition is satisfied while the engine is stopped, an automatic start / stop device for the engine that automatically starts the engine controls the battery voltage at the time of start of the engine and a predetermined determination. A control means for comparing the value with the battery voltage and prohibiting the automatic stop control of the engine when the value of the battery voltage is lower than the determination value.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, the engine is automatically stopped when there is no electric load on the engine and the state of the battery voltage is smaller, so that the fuel efficiency can be improved. In addition, when the electric load of the engine is present and the voltage of the battery is relatively high, the automatic stop of the engine is prohibited, so that the occurrence of the dead battery can be prevented.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; 1 to 6 show a first embodiment of the present invention. 6, reference numeral 2 denotes an automatic start / stop control device for an engine (not shown) mounted on a vehicle;
Reference numeral 4 denotes control means.

The control means 4 includes a water temperature sensor 6 for detecting a cooling water temperature, a clutch upper switch 8 which is turned on when a clutch pedal (not shown) is lightly depressed, and a fully depressed clutch pedal. Clutch lower switch 10, head lamp switch 12, heater fan switch 14, turn switch 16, radiator fan switch 18, idle switch 20
, A battery 22, an igniter (ignition device) 24,
Injector (fuel injection valve) 26 and vehicle speed sensor 28
, An engine speed sensor 30 and an engine start signal detection sensor 32 are provided in communication with each other.

The control means 4 receives various signals and receives predetermined engine stop conditions during operation of the engine (see FIG. 4).
Is satisfied, the fuel injection signal to the injector 26 and the ignition signal to the igniter 24 are stopped to automatically stop the engine, and a predetermined engine start condition (see FIG. 5) is satisfied while the engine is stopped. In such a case, the engine is automatically started, and the value of the battery voltage at the time of starting the engine is compared with a predetermined judgment value (threshold). When the value of the battery voltage is lower than the judgment value, Prohibits automatic stop control of the engine.

As shown in FIG. 4, the engine stop condition is that the engine speed is below a predetermined value, the clutch upper switch 8 and the clutch lower switch 10 are off, the coolant temperature is above a predetermined value, and the vehicle is stopped. Is satisfied when all the conditions of the stop state are satisfied.

As shown in FIG. 5, the above-described engine start condition is satisfied when all the conditions that the clutch lower switch 10 is ON while the engine is stopped are satisfied.

The control means 4 includes, as shown in FIG.
As the determination value of the battery voltage value of the battery 22, a first determination value of the charge amount of the battery 22 and a second determination value that is larger than the first determination value by a predetermined amount are set in advance.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG.

When the program is started by the control means 4 (step 102), it is first determined whether or not an engine stop prohibition condition is satisfied (step 104).

Whether or not the engine stop prohibition condition is satisfied is determined based on the flowchart of FIG.

That is, in FIG. 2, when the program is started (step 202), it is determined whether or not the charge amount of the battery 22 is smaller than a first charge value (step 204).

If YES in step 204,
It is determined that the engine stop prohibition condition is satisfied (step 2
06), the program is returned (step 20)
8).

On the other hand, if NO in step 204,
It is determined whether or not the battery charge amount <the second determination value (step 210).

If YES in step 210,
It is determined whether or not the headlamp, the heater fan, the radiator fan, etc. are operated to have an electric load (step 21).
2).

If YES in step 212,
The engine stop prohibition condition is set (step 206), and the program returns (step 208).

NO at step 210, step 21
If NO in step 2, the program immediately returns (step 208).

That is, when the state of charge of the battery 22 as the battery voltage is equal to or less than the first determination value, the stop of the engine is always prohibited. When the charge amount of the battery 22 is equal to or more than the first determination value and equal to or less than the second determination value, the automatic stop of the engine is prohibited only when there is an electric load.

In FIG. 1, if NO in step 104, it is determined whether an engine stop condition (see FIG. 4) is satisfied (step 106).

If YES in step 106,
The engine is automatically stopped (step 108).

Then, it is determined whether an engine start condition (see FIG. 5) is satisfied (step 110). Also,
If NO in step 106, this step 1
Go to 10 immediately.

If YES in step 110,
The engine is automatically started (step 112).

If the answer is YES in step 104, the answer is NO in step 110, and after the processing in step 112, the program returns (step 114).

Thus, conventionally, the state of charge of the battery 22 is determined by one determination value. However, in the first embodiment, the state of charge of the battery 22 is determined by two first and second states.
The first determination value is set smaller than the second determination value, and the automatic stop control of the engine is always prohibited when the state of charge of the battery 22 is equal to or less than the first determination value.
When the state of charge of the battery 22 is greater than or equal to the first determination value and less than or equal to the second determination value, the automatic stop control of the engine is prohibited only when there is an electric load.

When the state of charge of the battery 22 is equal to or lower than the first judgment value, the stop of the engine is prohibited. Stops the engine after
Further, the engine is started after engine start conditions are satisfied after the engine is stopped.

As a result, when there is no electric load, the engine is stopped in a state where the state of charge of the battery is smaller, so that fuel efficiency can be improved.

When there is an electric load, the automatic stop of the engine is prohibited in a state where the charge of the battery 22 is relatively large, so that the occurrence of the dead battery can be prevented.

FIGS. 7 to 12 show a second embodiment of the present invention. 12, reference numeral 302 denotes an automatic start / stop control device for an engine (not shown) mounted on a vehicle;
04 is control means.

The control means 304 includes a water temperature sensor 306 for detecting the temperature of the cooling water, and a clutch pedal (not shown).
Clutch upper switch 3 that turns on when lightly depressed
08, a clutch lower switch 310 that is turned on when the clutch pedal is fully depressed, a head lamp switch 312, a heater fan switch 314, a turn switch 316, and a radiator fan switch 318.
An idle switch 320, a battery 322, an igniter 324, an injector (fuel injection valve) 326,
A vehicle speed sensor 328, an engine speed sensor 330,
An engine start signal detection sensor 332, a brake lamp switch 334, and a rear deogger switch 336 are provided in communication with each other.

The control means 304 receives various signals and receives predetermined engine stop conditions (see FIG. 1) during operation of the engine.
0), the fuel injection signal to the injector 326 and the ignition signal to the igniter 324 are stopped to automatically stop the engine, and a predetermined engine start condition while the engine is stopped (see FIG. 11). Is satisfied, the engine is automatically controlled to start, the value of the battery voltage at the time of starting the engine is compared with a predetermined judgment value (threshold), and the magnitude of the electric load of the engine is further increased. And a plurality of determination values corresponding to the above-mentioned values, and the value of the above-described determination value decreases as the magnitude of the electric load increases (see FIG. 9), thereby prohibiting the automatic stop control of the engine.

As shown in FIG. 10, the engine stop conditions are as follows: the engine speed is lower than a predetermined value, the clutch upper switch 308 and the clutch lower switch 310 are off, the coolant temperature is higher than a predetermined value, and the vehicle is stopped. Is satisfied when all the conditions of the stop state are satisfied.

The above-described engine starting conditions are as shown in FIG.
As shown in (2), the condition is satisfied when all the conditions that the clutch lower switch 310 is ON while the engine is stopped are satisfied.

In changing the value of the judgment value of the battery 22, as shown in FIG. 9, assuming that the judgment value of the normal battery voltage is Bx, when there is an electric load such as a headlight, a predetermined value is obtained. Bx−Bh, which is reduced by the value Bh, is used as the determination value.
Bx- (Bh + Bb) lowered by b as a determination value, and when there is a rear defogger load, a predetermined value Bd
Bx− (Bh + Bb + Bd) in which is reduced is used as the determination value.

Next, the operation of the second embodiment will be described with reference to the flowchart of FIG.

When the program is started by the control means 304 (step 402), it is first determined whether or not an engine stop prohibition condition is satisfied (step 404).

The engine stop prohibition condition is determined based on the flowchart of FIG.

That is, in FIG. 8, when the program starts (step 502), initialization is performed with the correction value B of the battery voltage value of the battery 22 as zero and the battery voltage determination value Bx (step 504).

Then, it is determined whether or not the headlamp switch 312 is on (step 506).

If YES in step 506,
The correction value B is set to B = Bh (step 508).

Then, it is determined whether or not the brake lamp switch 334 is on (step 510). If the result of step 506 is NO, the process immediately proceeds to step 510.

If YES in step 510,
The correction value B is set to B = B + Bb (step 512).

Then, it is determined whether or not the rear defogger switch 336 is on (step 514). If NO in step 510, this step 514 is immediately executed.
Move to

If YES in step 514,
The correction value B is set to B = B + Bd (step 516).

Then, the actual battery voltage (Bs) <
(Bx-B) is determined (step 518). If NO in step 514, this step 51
Go to 8 immediately.

If YES in step 518,
An engine stop prohibition condition is set (step 520).

After the processing in step 520 and in the case of NO in step 518, the program is returned (step 522).

In FIG. 7, if NO in step 404, it is determined whether an engine stop condition (see FIG. 10) is satisfied (step 406).

If YES in step 406,
The engine is automatically stopped (step 408).

Then, the engine starting conditions (see FIG. 11)
Is determined (step 410). If the result of step 406 is NO, the process immediately proceeds to step 410.

If YES in step 410,
The engine is automatically started (step 412), and the value of the battery voltage is measured (step 414).
YES in step 404, N in step 410
O, after the processing in step 414, the program returns (step 416).

Thus, conventionally, the value of the battery voltage of the battery 22 is determined by one determination value (Bsta). However, according to the second embodiment, the determination value of the engine stop prohibition is changed to the determination value of the engine stop. Depending on the state of the electric load at the time of starting, the value of the determination value of the automatic stop prohibition is set lower as the electric load is larger.

As a result, the value of the battery voltage at the time of starting the engine is accurately determined based on the electric load state at the time of starting the engine. Therefore, the engine stop function is sufficiently operated, and the fuel consumption is improved while preventing the battery from running down. be able to.

FIGS. 13 to 20 show a third embodiment of the present invention. 20, reference numeral 602 denotes an automatic start / stop control device for an engine (not shown) mounted on a vehicle;
604 is control means.

The control means 604 includes a water temperature sensor 606 for detecting a cooling water temperature, a clutch upper switch 608 which is turned on when a clutch pedal (not shown) is lightly depressed, and a full depression of the clutch pedal. The clutch lower switch 610, the head lamp switch 612, the heater fan switch 614, the turn switch 616, and the radiator fan switch 618
, An idle switch 620, a battery 622, an igniter 624, and an injector (fuel injection valve) 626.
, A vehicle speed sensor 628 and an engine speed sensor 630
, An engine start signal detection sensor 632, an engine oil temperature sensor 634, and an outside air temperature sensor 636 are provided in communication with each other.

The control means 604 receives various signals and receives predetermined engine stop conditions (see FIG. 1) during operation of the engine.
8) is satisfied, the fuel injection signal to the injector 626 and the ignition signal to the igniter 624 are stopped to control the automatic stop of the engine, and a predetermined engine start condition while the engine is stopped (see FIG. 19). Is established, the engine is automatically started, and the value of the battery voltage at the time of starting the engine and a predetermined determination value (B
sta), and further, to the ambient temperature of the engine,
For example, the value of the determination value (Bsta) is changed according to the engine water temperature, the engine oil temperature, and the outside air temperature, and the automatic stop control of the engine is prohibited based on the battery voltage value.

As shown in FIG. 18, the engine stop conditions are as follows: the engine speed is below a predetermined value, the clutch upper switch 608 and the clutch lower switch 610 are off, the coolant temperature is above a predetermined value, and the vehicle is stopped. Is satisfied when all the conditions of the stop state are satisfied.

The above-described engine starting conditions are as shown in FIG.
As shown in FIG. 7, the condition is established when all the conditions that the clutch lower switch 610 is ON are satisfied while the engine is stopped.

The value of the above-mentioned determination value (Bsta) is shown in FIG.
As shown in FIGS. To 17, the ambient temperature of the engine is changed depending on the water temperature, the oil temperature, and the outside air temperature. That is, the determination value (Bsta) is set to a lower value as the water temperature, the oil temperature, and the outside air temperature are lower.

Next, the operation of the third embodiment will be described with reference to the flowchart of FIG.

When the program is started by the control means 604 (step 702), it is first determined whether or not an engine stop prohibition condition is satisfied (step 704).

The engine stop prohibition condition is determined based on the flowchart of FIG.

That is, in FIG. 14, when the program starts (step 802), it is determined whether or not the value of the battery voltage at the start> the determination value (Bsta) (step 804). This determination value (Bsta) is changed according to the water temperature, the oil temperature, and the outside air temperature as the ambient temperature, as shown in FIGS.

If YES in step 804,
The program returns (step 806).

On the other hand, if NO in step 804,
The engine automatic stop prohibition is set (step 808), and the program ends (step 806).

Then, in FIG.
If NO in step 706, it is determined whether the engine stop condition (see FIG. 18) is satisfied (step 706).

If YES in step 706,
The engine is automatically stopped (step 708).

Then, the engine starting conditions (see FIG. 19)
Is determined (step 710). If NO in step 706, the process immediately shifts to step 710.

If YES in step 710,
The engine is automatically started (step 712), and the battery voltage is measured (step 714). Step 7
04, YES in step 710, and after the processing in step 414, the program returns (step 716).

Thus, when the engine is started by operating the ignition key, the value of the battery voltage is detected, and if the battery voltage value is equal to or less than the determination value, the automatic stop control of the engine is prohibited.

At this time, since the value of the determination value is changed depending on the ambient temperature, the battery voltage at the time of starting the engine can be accurately determined based on the warming-up state of the engine. Fuel efficiency can be improved while preventing the battery from running down.

[0081]

As apparent from the above detailed description, according to the present invention, the value of the battery voltage at the time of starting the engine is compared with a predetermined judgment value, and the value of the battery voltage is compared with the judgment value. By providing a control means for prohibiting the automatic stop control of the engine when it is low, the engine is stopped in a state where the battery is less charged when there is no electric load on the engine, thereby improving the fuel efficiency. be able to. In addition, when the electric load of the engine is present and the state of charge of the battery is relatively large, the stop of the engine is prohibited, so that the occurrence of a dead battery can be prevented.

[Brief description of the drawings]

FIG. 1 is a flowchart of an automatic start / stop control according to a first embodiment.

FIG. 2 is a flowchart of an engine stop prohibition determination routine.

FIG. 3 is a diagram illustrating first and second determination values.

FIG. 4 is a diagram illustrating an engine stop condition.

FIG. 5 is a diagram illustrating an engine start condition.

FIG. 6 is a block diagram of the automatic start / stop control device of the first embodiment.

FIG. 7 is a flowchart of an automatic start / stop control according to a second embodiment.

FIG. 8 is a flowchart of an engine stop prohibition determination routine.

FIG. 9 is a diagram illustrating a change in a determination value.

FIG. 10 is a diagram illustrating an engine stop condition.

FIG. 11 is a diagram illustrating engine start conditions.

FIG. 12 is a block diagram of an automatic start / stop control device according to a second embodiment.

FIG. 13 is a flowchart of the automatic start / stop control of the third embodiment.

FIG. 14 is a flowchart of an engine stop prohibition determination routine.

FIG. 15 is a diagram illustrating a relationship between a water temperature and a determination value.

FIG. 16 is a diagram showing a relationship between an oil temperature and a determination value.

FIG. 17 is a diagram illustrating a relationship between an outside air temperature and a determination value.

FIG. 18 is a diagram illustrating an engine stop condition.

FIG. 19 is a diagram illustrating engine start conditions.

FIG. 20 is a block diagram of an automatic start / stop control device according to a third embodiment.

FIG. 21 is a flowchart of a conventional engine stop prohibition determination routine.

FIG. 22 is a flowchart of another conventional engine stop prohibition determination routine.

[Explanation of symbols]

 2 Automatic start / stop device 4 Control means 6 Water temperature sensor 8 Clutch upper switch 10 Clutch lower switch 22 Battery 30 Engine speed sensor

Claims (3)

[Claims] An automatic stop control is performed when a predetermined engine stop condition is satisfied during operation of an engine mounted on a vehicle, and when a predetermined engine start condition is satisfied while the engine is stopped. In the automatic start and stop device for the engine that automatically controls the engine, a value of the battery voltage at the time of starting the engine is compared with a predetermined determination value, and the value of the battery voltage is lower than the determination value. A control means for prohibiting the automatic stop control of the engine. 2. The control means has a plurality of determination values according to the magnitude of the electric load of the engine, and decreases the value of the determination value as the magnitude of the electric load increases. The automatic start / stop device for an engine according to claim 1, wherein: 3. The engine start / stop device according to claim 1, wherein the control unit changes the value of the determination value according to an ambient temperature of the engine.