JPS6230292B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic engine stop/start device for automatically stopping or restarting an engine.

Generally, when we are driving on the road and encounter road congestion due to an accident with another car or someone holding a traffic light, and we are forced to stop for a long time, we stop the engine.
Performs an operation to restart the engine when traffic congestion is cleared. This is to avoid wasteful fuel consumption due to long periods of idling.

On the other hand, if the engine is stopped when stopped at a traffic light at an intersection in a city, the engine must be restarted each time the vehicle starts, which is not only troublesome but also lacks the speed of starting.

However, stoppage time during city driving occupies a considerable proportion of the total operating time, and the amount of exhaust gas emitted and the amount of fuel consumed due to idling cannot be ignored.

Therefore, recently, automatic engine stop/start has been developed that automatically stops the engine under certain conditions, such as when the car stops at an intersection etc. while driving in the city, and automatically starts the engine when the normal starting operation (depressing the clutch pedal) is performed. A device has been developed.

In a conventional engine automatic stop/start device, after setting the engine automatic stop/start function, the engine is automatically stopped or started when a predetermined condition is met.

Therefore, even if there is an improbable change in vehicle speed due to a malfunction of the vehicle speed sensor while the vehicle is running (for example, a sudden change from 50 km/h to 0 km/h), other stoppages will be taken. When the conditions are met, the engine will be automatically stopped. When the engine is stopped, there is no negative pressure source for the brake booster, so if the negative pressure stored in the booster is used up, the effectiveness of the brakes may deteriorate.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automatic engine stop/start device that ensures safety when a vehicle is running.

In order to achieve the above object, the present invention provides conditions for automatically stopping or restarting the engine based on detection outputs from a sensor group that includes a vehicle speed sensor that detects the vehicle speed and detects the operating state of each part of the vehicle. and automatically stops the engine when the vehicle is stopped and it is determined that the first condition is satisfied, and automatically restarts the engine when it is determined that the second condition is satisfied. The automatic engine stop/start device includes a detection means for detecting whether or not the vehicle speed sensor output suddenly changes from a state where the vehicle speed is higher than a predetermined vehicle speed to a state where the vehicle is stopped; and a prohibition means for prohibiting the engine from automatically stopping even if it is determined that the first condition is satisfied when a sudden change from the state to the vehicle stop state is detected. Features.

The automatic engine stop/start device of the present invention determines a condition for automatically stopping or restarting the engine based on detection outputs from a sensor group including a vehicle speed sensor, and determines a condition for automatically stopping or restarting the engine when the vehicle is stopped and the first condition is satisfied. When it is determined that the automatic stop condition is satisfied, the engine is automatically stopped, and when it is determined that the second condition is satisfied, that is, it is determined that the automatic restart condition is satisfied. The engine is restarted automatically. The detection means detects whether or not the vehicle speed sensor output suddenly changes from a state where the vehicle speed is higher than a predetermined vehicle speed to a vehicle stopped state, that is, whether or not the vehicle speed sensor output indicates a vehicle stopped state while the vehicle is running. The prohibition means is configured to control the prohibition means when it is detected by the detection means that the vehicle speed sensor output suddenly changes from a state where the vehicle speed is higher than a predetermined vehicle speed to a state where the vehicle is stopped, even if it is determined that the first condition is satisfied, i.e. To prohibit automatically stopping an engine even if it is determined that an automatic stop condition is satisfied. This prevents the engine from being automatically stopped when the vehicle speed sensor output becomes abnormal while the vehicle is running, the vehicle speed sensor output indicates the vehicle is stopped, and the automatic stop condition is satisfied.

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 shows the overall configuration of an automatic engine stop/start device according to the present invention. In the figure, 1 is a control circuit including a central processing unit (CPU), random access memory (RAM), It consists of a microcomputer consisting of memory (ROM), input/output interface (I/O), etc. Detection outputs from various sensors are input to the control circuit 1.

10 is a main switch for setting or canceling a function to automatically stop or start the engine (hereinafter referred to as ERS); when the main switch 10 is pressed after starting the engine by normal operation, ERS is set. be done. Further, after setting the ERS, if the main switch 10 is pressed again, the ERS is canceled. The ERS setting is automatically canceled under other predetermined conditions, which will be described later.

Furthermore, 12 is a vehicle speed sensor, and the vehicle speed sensor 1
Reference numeral 2 detects whether the vehicle is in a running state or in a stopped state, and the detection output of the sensor 12 is used to determine whether the engine is automatically stopped.
14 is an ignition circuit, and the control circuit 1 processes an ignition pulse signal outputted from the ignition circuit 14 as an engine rotation speed signal. As will be described later, this engine rotational speed signal is used to determine conditions for ERS setting, automatic engine stop, automatic engine start, and ERS setting cancellation. 16 is a clutch pedal, and 18A and 18B are clutch pedals 16, respectively.
This is a clutch upper switch and clutch lower switch that operates in conjunction with the on/off operation. Each of these switches detects the amount of depression of the clutch pedal 16, and the clutch overpass switch 18A is turned on when the clutch pedal 16 is depressed by a certain percentage of the full stroke (for example, 30% or more), and the control circuit is activated. 1, and the control circuit 1 controls the engine so as not to stop. Further, the clutch lower switch 18B is turned on when the clutch pedal 16 is fully depressed, and sends a signal thereof (a signal for permitting automatic engine start) to the control circuit 1.

Further, the engine 20 is provided with a water temperature sensor 22 for detecting the engine cooling water temperature and a hydraulic pressure switch 24 for detecting the oil pressure of the engine oil, and these detection outputs are input to the control circuit 1. 26
is a changeover switch for charging the battery with the output of the alternator, and the switch 26 is turned on when the alternator is generating power. 28 is a battery voltage input, and 30 is a magnetic switch that controls the operation of the air conditioner, which is turned on when the air conditioner is operated.

Furthermore, 32 is a headlamp switch that switches the headlamp on or off, and 34 is a wiper switch that detects the operating state of the wiper.These switches 30, 32, and 34 detect whether or not the electrical load is high. It is something to do. Also 3
6 is a turn signal switch that detects the right turn state of the vehicle, and 38 is a door switch that detects the open/close state of the driver's side door. Of these detection outputs, the former is the engine automatic stop condition, and the latter is the ERS
It is used as a judgment input for setting conditions and setting cancellation conditions.

Further, 50 is a slope sensor that detects whether the slope of the slope on which the vehicle is stopped is at least a predetermined value (for example, 2 degrees) and turns on when the slope is at least a predetermined value;
Reference numeral 52 is an idle switch that detects whether the engine is in an idle state (turns ON when the engine is in an idle state), and 54 is a defogger switch that detects whether or not a defogger is being used.

Now, after the predetermined conditions are satisfied and the ERS is set by the main switch 10, automatic stopping and automatic starting of the engine 20 are performed as follows. That is,
When the conditions for stopping the engine 20 are met, the control circuit 1
An engine stop signal (low level) 44 is output to the fuel cut relay 40, and as a result, a fuel cut signal 51 is output from the fuel cut relay 40 to a fuel cut solenoid (not shown) in the fuel supply system in the engine 20, and a fuel cut signal 51 is output to the ignition circuit 14. An ignition cut signal 60 is output to stop the engine. However, in order to achieve the automatic engine stop function, it may be configured to only cut off the ignition without cutting off the fuel, but in this case, the engine runs on, which worsens the driving feeling. There are drawbacks to doing so.

On the other hand, if the ERS is in the setting state and the clutch pedal 16 is fully depressed while the engine is stopped,
Clutch lower switch 18B is turned on,
When other conditions are satisfied (described later), the engine starting signal 4 is sent from the control circuit 1 to the starter relay 41.
6 is output, and as a result, starter signal 70 is output from starter relay 41 to starter 42, and engine 20 is started.

Next, the operation modes of ERS setting, engine stop after ERS setting, and engine start of the automatic engine stop/start device shown in FIG. 1 will be explained based on FIGS. 2 to 4. FIG. 2 shows the operation mode for ERS setting, and as shown in the figure, ERS setting becomes possible when the following five conditions are ANDed.

(1) ERS settings must be canceled.

(2) The main switch for ERS settings is in the on state.

(3) While the engine is rotating (for example, the engine speed is
400±50rpm).

(4) The alternator is generating power.

(5) The driver's side door is closed (detected by the door switch).

Here, the cancellation of the ERS setting (1) may be performed manually by pressing the main switch or automatically, but this will be described later. Further, to detect whether or not the engine is rotating, it is determined based on (3) the engine rotation speed and (4) the power generation state of the alternator. This is to accurately detect whether or not the engine is rotating.

Next, Fig. 3 shows the operating mode of automatic engine stop using ERS. As shown in the figure, the following (1) ~
If the AND of the conditions (13) is satisfied, the engine will be automatically stopped.

(1) ERS must be set.

(2) When the engine speed reaches a specified speed (e.g.
850rpm) or less.

(3) Clutch lift, lower switch 18A, 18
Both B are in the OFF state, that is, the clutch pedal 16
has not been stepped on.

(4) Turn signal switch 36 is OFF,
In other words, the right turn signal is not output.

(5) The headlamp switch 32 is in the OFF state.

(6) The wiper switch 34 is in the OFF state.

(7) The water temperature sensor 22 is in the OFF state, that is, the engine cooling water temperature is within a specific temperature range (for example, 75°C to 105°C).
℃).

(8) The air conditioner magnetic switch 30 is in the OFF state.

(9) A predetermined period of time (for example, 4 seconds) has elapsed after the engine was started by ERS.

(10) The vehicle is stationary.

(11) The slope sensor 50 is in the OFF state.

(12) Idle switch 52 is in the OFF state.

(13) Defogger switch 54 is in the OFF state.

As mentioned above, among the conditions (2) above, the engine speed must be 850 rpm or less to take into account engine stoppage due to stalling, and (4) was used as the judgment condition. This is because when the vehicle turns right, the driver needs to pay attention to checking for oncoming vehicles, etc., and it is not preferable to stop the engine in such a state. Further conditions
The reason why (5), (6), (8), and (13) are used to determine whether or not to stop the engine is to avoid over-discharge of the battery due to stopping the engine when the electrical load is high. .

Condition (7) is such that the engine is difficult to start when the engine cooling water temperature is low or high, so the engine was not stopped in these temperature ranges.
This is because condition (9) is satisfied because the engine is automatically stopped only after the engine is started by ERS. Furthermore, condition (10) “the vehicle is in a stopped state”
is determined based on the presence or absence of a level change in the detection output (pulse train signal) of the vehicle speed sensor 12. Condition (3) was established because the clutch pedal cannot be depressed except when starting the engine or changing gears, and this device is configured to start the engine by depressing the clutch pedal. It is from.

As explained above, the engine rotational speed signal and the clutch signal interlocked with the clutch pedal are used as criteria for automatically stopping the engine.

Next, FIG. 4 shows the operating mode of automatic engine start using ERS. As shown in the figure, the following (1) to (4)
The engine is automatically started when the AND conditions are met.

(1) ERS must be set.

(2) The engine speed is the set speed (e.g.
50rpm) or less.

(3) The alternator is in a state where power generation is stopped.

(4) The clutch lower switch is in the ON state, that is, the clutch pedal is fully depressed.

Among the above conditions, (2) and (3) are used to determine whether the engine is in a stopped state, but the reason why both the engine rotation speed signal and the alternator power generation state signal are used for this determination is because both of them are used. This is to enable reliable determination even when one of the signals is not input to the control circuit 1.

On the other hand, canceling the ERS after setting it is done as follows.

A. When manually canceling: Press the main switch 10 once and then press it again to cancel the ERS setting.

B Cases in which it is automatically released (1) When the ignition switch is manually operated and the engine is restarted.

(2) When the driver's side door is opened.

(3) When the battery voltage drops.

(4) When restarting, it takes a certain amount of time (e.g. 2 seconds) for the engine speed to reach a certain speed (e.g. 550 rpm) or higher.

In the above cases, the ERS setting will be automatically canceled.

Among the above conditions, (1) is because the driver may forget that the engine has automatically stopped due to ERS and restart it using the key switch out of habit, and (2)
This is to take driver changes into consideration and to avoid confusion among people who are unfamiliar with ERS. In addition, for (3) and (4), restarting will be difficult if the ERS is activated when the battery capacity is low, so it is recommended to use the ERS to start the engine only that time, and to cancel the ERS setting at the same time as the start. ing.

Next, prohibition of ERS when the vehicle speed sensor is abnormal will be explained based on FIGS. 5 to 7. Figure 5 shows the running pattern of the vehicle, in which the vehicle is in an accelerated running state in section AB and in section BE.
The vehicle is now running at a constant speed. For example, FIG. 6A shows how the vehicle speed pulse signal changes when the vehicle speed V temporarily changes to an impossible speed due to a failure of the vehicle speed sensor 12 in the section CD where the vehicle is traveling at a constant speed. In the figure, the vehicle speed is V ₁ (>V REF ) from the vehicle speed pulse signal taken into the control unit 1 until time T ₁ , and thereafter no vehicle speed pulse signal is detected until time T ₂ (vehicle speed 0), and therefore the time is V 1 (>V _REF ).
Assume that at T ₁ the vehicle speed decreases at a rate of change V ₁ /sec equal to or higher than a predetermined value (V _REF /sec), and at time T ₃ returns to the vehicle speed V ₁ equal to or higher than the set vehicle speed V _REF . However, the time △t (=T ₂ −
T ₁ ) is the time △t ₀ preset in control circuit 1
be longer.

During this time, an ERS control prohibition command is output from the CPU in the control circuit 1 to the I/O during the period T ₂ tT ₃ , and the engine stop signal 44 and engine start signal 46 are not output.

Next, FIG. 7 shows the processing contents of the control circuit 1 when the vehicle speed change as described above is abnormal.
In the figure, when a task is activated in step 100, ERS is set in step 102 when the above-mentioned certain conditions are met. Furthermore, in the next step 104, it is determined whether or not the conditions for starting the engine by ERS are satisfied, and the process proceeds to step 104.
If it is determined in step 4 that the engine starting condition is not satisfied, the same determination is repeated.

On the other hand, if it is determined in step 104 that the engine starting conditions are satisfied, the next step 106 is performed.
The engine is started and the vehicle is ready to run.
Furthermore, in the next step 108, the vehicle speed V becomes the set vehicle speed V.
It is determined whether the vehicle speed V is equal to or higher than _REF (for example, V _REF =32.8 Km/h), and if it is determined in step 108 that the vehicle speed V is equal to or lower than the set vehicle speed V _REF , the same determination is repeated. On the other hand, in step 108, the vehicle speed V
If it is determined that the vehicle speed V is equal to or higher than the set vehicle speed V _REF , it is determined in step 110 whether the vehicle speed V has suddenly changed, that is, whether there has been a change in the vehicle speed that is actually impossible. Here, as shown in FIG. 6, the time Δt from the time when the vehicle speed pulse signal is no longer detected after the vehicle speed V becomes equal to or higher than V _REF until the vehicle speed V returns to the vehicle speed equal to or higher than V _REF If △t△t is _{0 with respect to the set time △t 0 ,} the control operation by ERS is prohibited for the time △t, and △t
When <△t ₀ , the control operation by ERS shall not be prohibited.

Now, if the determination in step 110 is "No", the process jumps to step 118, and the execution of the task is terminated.

On the other hand, if the determination in step 110 is "Yes", the process moves to step 112, and the process proceeds to step 1.
12, the control operation by ERS is prohibited. That is, the CPU in the control circuit 1 issues an ERS control prohibition command. Then, in the next step 114, it is determined whether the vehicle speed V is equal to or higher than V _REF.In other words, after the vehicle speed pulse signal is no longer detected, it is determined whether a vehicle speed pulse signal corresponding to a vehicle speed equal to or higher than V _REF is detected again. be done.

If it is determined in step 114 that the vehicle speed V is less than V _REF , the same determination is repeated. on the other hand,
If it is determined in step 114 that the vehicle speed V is equal to or higher than V _REF , the process moves to the next step 116,
The prohibition of control operations by ERS is lifted. That is, the sending of the ERS control prohibition command from the CPU to the I/O is stopped, and the execution of the task ends at step 118.

As explained above, according to the present invention, the engine is not automatically stopped even if the automatic stop condition is satisfied when the vehicle speed sensor output suddenly changes to the vehicle stop state while the vehicle is running. This provides the effect that the engine is prevented from being stopped while the vehicle is running, thereby further improving safety when the vehicle is running.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall configuration of an automatic engine stop/start device according to the present invention, and FIGS.
The figure shows the operation mode in the control circuit 1, and the second
The figure shows the operating mode when ERS is set, Fig. 3 shows the operating mode when the engine is automatically stopped, Fig. 4 is an explanatory diagram showing the operating mode when the engine automatically starts, and Fig. 5 shows the vehicle driving pattern. Figure 6 showing
The figure is a timing chart showing the relationship between the vehicle speed pulse signal and the ERS control prohibition command, and FIG. 7 is a flow chart showing the processing content of the control circuit 1 when the vehicle speed change is abnormal. 1...Control circuit, 10...Main switch, 1
2...Vehicle speed sensor, 14...Ignition circuit, 18A,
18B...Clutch switch, 28...Battery voltage sensor, 40...Fuel cut relay, 41...
...Starter relay, 42...Starter.

Claims (1)

[Claims] 1 Determine conditions for automatically stopping or restarting the engine based on detection outputs from a sensor group that includes a vehicle speed sensor that detects the vehicle speed and detecting the operating state of each part of the vehicle, and determines the conditions for automatically stopping or restarting the engine when the vehicle is stopped and
In the engine automatic stop/start device that automatically stops the engine when it is determined that a second condition is satisfied and automatically restarts the engine when it is determined that a second condition is satisfied, the vehicle speed sensor a detection means for detecting whether the output changes suddenly from a state where the vehicle speed is higher than a predetermined vehicle speed to a state where the vehicle is stopped; an automatic engine stop/start device comprising: a prohibition means for prohibiting the engine from automatically stopping even if it is determined that the first condition is satisfied when it is detected that the first condition has been met.