JPS5823250A - Control method of automatic engine stop/restart - Google Patents

Abstract

PURPOSE:To prevent an engine from failing to restart due to overdischarge of a battery by releasing the automatic stop/restart function after confirming the starting condition if there is a lapse of a certain interval from the output of an engine start signal before the engine is started. CONSTITUTION:An automatic engine stop/restart function ERS of a control circuit 1 is executed in such a manner that if a car is stopped at the crossing point, for example, the engine is automatically stopped under a certain condition and then restarted by the normal starting operation. Releasing of the function ERS after setting is alternatively performed by manual or automatic operation. The manual release is completed by redepressing a main switch 10 and so done the automatic release if a detected value of a voltage sensor 28 is reduced or if a time for increasing up to a demanded engine speed exceeds a certain period at restart. The latter case assumes the engine defective so that the releasing is performed after restart of the engine is completed. Hence, the engine may be prevented from failing to restart due to a reduction in potential of battery.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control method for automatically stopping and starting an engine to automatically stop or start an engine.

Generally, when we are driving on a road and encounter road congestion due to an accident with another vehicle or waiting at a traffic light, and are forced to stop for a long time, we stop the engine and then restart it when the congestion clears. conduct.

This is to avoid wasteful fuel consumption due to long periods of idling.

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

However, the stop time during city driving accounts for a small proportion of the total driving 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 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 with the normal start operation (depressing the clutch pedal). Starting devices have now been developed.

In conventional devices of this type, when the engine is started after the engine automatic stop/start function is set, the starter continues to be driven until the engine is started, so if the starter is driven for a long time due to an engine malfunction or other cause. There was a possibility that the battery would become over-discharged, making it impossible to restart the engine the next time the engine was started.

One object of the present invention is to provide a control method for automatically stopping and starting an engine, which prevents the engine from being unable to restart due to over-discharging of the battery due to prolonged driving time of the starter due to engine malfunction, etc. .

A feature of the present invention is that it captures the detection outputs of various sensors that detect the operating state of each part of the vehicle, and automatically stops or starts the engine under predetermined conditions based on these detection outputs, and outputs an engine start signal. Another feature of the present invention is that, when a predetermined period of time elapses before the engine starts, the setting of the automatic engine stop/start function is canceled after checking the starting state of the engine.

EMBODIMENT OF THE INVENTION Hereinafter, one embodiment of the present invention will be specifically described based on the drawings. FIG. 1 shows the overall configuration of an automatic engine stop/start device to which the present invention is applied. In the figure, numeral 1 denotes a control circuit, which is composed of a microcomputer and the like. 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 ER8); when the main switch 10 is pressed after starting the engine by normal operation, ER8 is set. be done. Furthermore, when the main switch 10 is pressed again after setting E'fLS, ER8 is canceled. The setting of ER8 is automatically canceled under other predetermined conditions, which will be described later.

Furthermore, 12 is a vehicle speed sensor, and this vehicle speed sensor 12 detects whether the vehicle is in a running state or a stopped state, and the detection output of this sensor 12 is used to determine whether the engine automatically stops. It will be done. 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 setting ER8, automatically stopping the engine, automatically starting the engine, and canceling the setting of ER8. 16 is the clutch pedal, %j5.18
A and 18B are a clutch upper switch and a clutch lower switch, respectively, which are turned on and off in conjunction with the clutch pedal 16. Each of these switches detects the amount of depression of the clutch pedal 16, and the clutch upper switch 18A is turned on when the clutch pedal 16 is depressed by a certain percentage of the full stroke (for example, 30 degrees or more). A signal is sent to circuit 1, and 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.

The LC engine 20 is provided with a water temperature sensor 22 for detecting the engine cooling water temperature and an oil pressure switch 24 for detecting the oil pressure of the engine oil, and these detection outputs are input to the control circuit 1. Reference numeral 26 denotes 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 magnet switch that controls the operation of the near conditioner, which is turned on when the near conditioner is operated.

Furthermore, 32 is a headlamp switch that switches on and off the headlamp, and 34 is a wiper switch that detects the operating state of the wiper.These switches 30, 32
．． Reference numeral 34 detects whether or not the electrical load is high. Further, 36 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 ER8 It is used as a judgment input for setting conditions and setting cancellation conditions. Further, 50 is a slope sensor that detects whether the gradient of the slope on which the vehicle is stopped is greater than a predetermined value (for example, 22ρ') and turns on when the gradient is greater than the predetermined value, and 52 is a slope sensor when the engine is in an idle state. An idle switch 54 detects whether a defogger is in use (turned ON in an idle state), and a defogger switch 54 detects whether a defogger is being used.

Now, the predetermined conditions are met, and ER8 switches to main switch 10.
After the settings are made, automatic stopping and automatic starting of Edge/20 is performed as follows. In other words, when the condition for stopping the engine 20 is met, the control circuit 1 releases fuel (IJ 7)
As a result, the fuel cut relay 40 sends the fuel cut signal 5) to the fuel cut solenoid (not shown) of the fuel supply system in the engine 20, and the ignition circuit 14 An ignition cut signal 60 is output to the EDGE/, and the EDGE/ is stopped. However, in order to achieve the engine automatic stop function, it may be configured to only cut the ignition without cutting the fuel, but in this case, the driving feeling may be affected because the engine runs on. There are drawbacks that worsen.

On the other hand, when the ER8 is in the setting state and the clutch pedal 16 is fully depressed during edge/stop, the clutch lower switch 18B is turned on, and when other conditions are met (described later), the control circuit 1 More starter relay 41
An engine start signal 46 is output, and as a result, the starter 42 is energized and the engine 20 is started.

Next, E B of the engine automatic stop/start device shown in Figure 1.
, S setting, engine stop and engine start after setting ER8 will be explained based on FIGS. 2 to 4. FIG. 2 shows the operation mode for setting ER8, and as shown in the figure, setting of ER8 becomes possible when the following five conditions are ANDed.

(1) Erts settings must be canceled.

(2) The main switch for the E-S setting is in the ON state. - (3) The edge is rotating (for example, the engine speed is ±5 Orpm or more).

(4) The alternator is generating power.

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

Here, the cancellation of the ER8 setting in (1) may be performed manually by suppressing the main switch or automatically, and this will be described later.

Also, to detect whether or not the engine is running and crashes (3
) The determination is made based on the engine rotation speed (4) and the power generation state of the alternator (4). This is to accurately detect whether or not the engine is rotating.

Next, FIG. 3 shows the operation mode of automatic stop of edge/ by ER8fC. As shown in the figure, the following (1) to (13)
When the AND of the conditions is satisfied, the engine is automatically stopped.

(1) ER8 must be set.

(2) When the engine speed is at a specified speed (e.g. 85
0 rpm) or less.

(3) Clutch upper and lower switch 1sA,
Both IgBs are in the OFF state, that is, the clutch pedal 16 is not depressed.

(4) The tar/signal switch 36 is in the OIi'F state, that is, 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 magnet switch 30 is in the OFF state.

(9) A predetermined period of time (for example, 4 seconds) has elapsed since the start of work/work by ER8.

(10) The vehicle is in a stopped state.

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

(12) The idle switch 52 is in the OFF' state.

(13) The defogger switch 54 is turned off.

The above is based on condition (2) above, which takes into consideration engine stoppage due to engine stalling, with the condition that the engine speed is 850 rpm or less, and condition (4) is considered as a judgment condition. This is because when the vehicle turns right, the driver needs to pay attention to checking for oncoming vehicles, and it is not desirable to stop the engine in such a situation. Furthermore, conditions (5), (6), (8)
This is to avoid over-discharge of the battery due to stopping the engine while the electrical load is high by using (1-3) in determining whether to stop the engine.

Furthermore, condition (7) is such that when the engine cooling water temperature is low or high, it is difficult to start the engine/engine, so the engine/engine is not stopped in these temperature ranges.

This is because condition (9) is such that the automatic stop of the engine is performed only after the engine is started by the E engine S.

Furthermore, condition (10), ``the vehicle is in a stopped state'', is determined based on the detection output of the vehicle speed sensor 12 (the presence or absence of a change in the level of the Hals train (No. i). Condition (3) was established because the clutch The pedal cannot be depressed except when starting the engine or changing gears.

This is also because the present device is configured to start the engine by pressing the clutch pedal.

As explained above, the engine rotational speed signal and the clutch signal interlocked with the clutch pedal are used as conditions for determining automatic stop of the engine.

Next, FIG. 4 shows the operation mode of automatic engine start (11) by ER8. As shown in the figure, the following (1) to (4)
) The engine is automatically started when the AND conditions are satisfied.

(1,) B RS is set (2)
The engine rotation speed is the set rotation speed (for example, 50rpln)
(3) The alternator must be in a state where power generation has 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 for determining 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, to cancel the setting of ER,S, proceed as follows.

A) In the case of manual release: If the main switch 10 is pressed once and then pressed again, the setting of ER8 will be released.

(12) B) When automatically released (1) When the ignition switch is manually operated to restart the engine (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 (for example, 2
seconds) or more.

In the above cases, the ER8 setting is automatically canceled.

Among the above conditions, (1) is because the driver may forget that the engine has automatically stopped due to ER8 and restart it by using the key switch out of habit, and (2) considers changing the driver. This is to avoid confusion among people who are unfamiliar with EbenS. In addition, (3) and (4) if the ER8 is operated with the Vi battery capacity reduced, it will be difficult to restart it, so the ER8 will be used for starting only that time, and the engine will start at the same time as the start.
Cancel the setting of 几S. That's what I do.

Next, FIG. 5 shows the relationship between the battery voltage change characteristics and the starter signal when starting the engine.

When the engine starting conditions are met and the clutch pedal is depressed as described above, the engine starting signal 46 is output to the starter relay 41, and as a result, the starter signal 70 (see @ in the figure) is sent to the starter 42. This starter signal 7
At the start-up time of 0 (time t, 1), the battery voltage sensor 2
The battery voltage detected by 8 drops extremely and gradually recovers as time passes ((C) in the same figure).

As shown in FIG.
It becomes OFF state.

Next, FIG. 6 shows the control contents of the control circuit 1 at the time of starting the engine, which is an embodiment of the control method for automatically stopping and starting the engine according to the present invention. In the figure, when the task is activated in step 60, it is determined in the next step 62 whether or not engine starting conditions are satisfied. If it is determined that the engine starting condition is not satisfied, the same determination is repeated.

On the other hand, if it is determined in step 62 that the engine/engine starting conditions are satisfied, the process moves to step 64, and the process proceeds to step 64.
The control circuit 1 outputs the engine/engine start signal 46 to the starter relay 41 (at the same time, the starter signal 70 is output), and a timer is set for setting the starter driving time from the time when the starter signal is output. TM (provided within the control circuit 1) is activated. Furthermore, in the next step 66, it is determined whether the engine has started or not.
If it is determined in step 66 that the engine has not started, the same determination is repeated. On the other hand, if it is determined in step 66 that the engine has started, the next step 6 is performed.
8, and in step 68 it is determined whether the contents of the timer TM have reached a set value, that is, whether a predetermined time T (2 seconds in this embodiment) has elapsed after the starter signal was output. This starter drive time is selected to be a value that is slightly more generous than the limit value that allows the engine to be restarted. If it is determined in step 68 that the timer TMO Uchitani has not reached the set value, the process moves to step (15) 70, where the timer TMld is reset, and then the process moves to step 62, where the above-mentioned steps are performed. Similar processing is performed.

On the other hand, if it is determined in step 68 that the contents of the timer TM have reached the set value, the process moves to step 72, in which the ESR setting is canceled, then in step 74 the timer TM is reset, and in step 76 The task ends.

As explained above, in the present invention, when a predetermined period of time elapses after the engine start signal is output until the engine starts, the setting of the engine automatic stop/start function is canceled after checking the engine starting state. According to the present invention, it is possible to prevent the engine from being unable to restart due to overdischarge of the batch IJ.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the overall configuration of an automatic engine stop/start device to which the present invention is applied, FIGS. 2 to 4 show operating modes in the control circuit 1, and FIG. 3 is an explanatory diagram showing the operating mode when the engine is automatically stopped, and FIG. 4 is an explanatory diagram showing the operating mode when the engine is automatically started (16).
FIG. 5 is a timing chart showing the relationship between the battery voltage change characteristics and the starter signal when starting the engine, and FIG. 6 is a flowchart showing an embodiment of the control method for automatically stopping and starting the engine according to the present invention. 1... Control circuit, 10... Main switch, 12.
...Vehicle speed, 14...Ignition circuit, ISA, 18B
...Clutch switch, 28...Battery voltage control/
41...Starter relay, 42...Starter agent' Tatsuno Unuma (1 or 2 people). Figure 1: Mountain V%, J-1

Claims (1)

[Claims] (1) In a device that captures the detection outputs of various sensors that detect the operating status of each part of the vehicle and automatically stops or starts the engine under predetermined conditions based on these detection outputs, after outputting an engine start signal, A method for controlling automatic stop and start of an engine, characterized in that when a predetermined period of time elapses before the engine starts, the setting of an automatic stop and start function of the engine is canceled after confirming the starting state of the engine.