JPH0315018B2 - - 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 a traffic jam caused by an accident with another car or waiting at a traffic light, and 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 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, 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, an automatic engine stop/start device 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 vehicle starts normally (depressing the clutch pedal). has been developed.

In conventional devices of this kind, when automatically stopping the engine, the power supply to the ignition circuit that sends the ignition signal to the engine is cut off, and when the engine is restarted, the power supply to the ignition circuit is restored.

On the other hand, the ignition signal output from the ignition circuit is also used as engine rotation speed data. This engine rotation speed data serves as basic data for various engine controls, and in particular, serves as a basic judgment condition for control operations in automatic engine stop/start control. As mentioned above, in the conventional device, the power supply to the ignition circuit is restored when the engine is restarted, so the acquisition of engine speed data is started at the time when the engine is restarted, and the engine speed is determined from various data including this engine speed data. Starting control was performed when the starting conditions were met.

Therefore, it takes a certain amount of time until the engine starting conditions are met, which has the disadvantage of deteriorating the restartability of the engine.

An object of the present invention is to provide an automatic engine stop/start device that improves engine restartability.

In order to achieve the above object, the present invention provides an automatic engine stop/start control that automatically stops the engine when the vehicle is stopped by stopping or returning at least the ignition control means, and automatically starts the engine when the vehicle starts. In the apparatus, the engine rotation speed calculation means calculates the engine rotation speed based on the ignition signal outputted by the ignition control means, and the engine rotation speed calculated by the engine rotation speed calculation means is below a predetermined rotation speed. The engine automatic start control means automatically starts the engine under one of the conditions, and the ignition priority return means returns the ignition control means when the engine is completely stopped.

Embodiments of the present invention will be specifically described below based on 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, and detection outputs from various sensors or circuits are input to the control circuit 1. be done. 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 turns on when the clutch pedal 16 is depressed by a certain percentage of the full stroke (for example, 30% or more), and controls the 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.
The signal (a signal that permits automatic engine starting) is sent 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 displaying the power generation state of the alternator, and this switch 26 is turned off 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.

Furthermore, 50 is a slope sensor that detects whether or not the slope of the slope on which the vehicle is stopped is equal to or higher than a predetermined value (for example, 2°), and turns ON when the slope is equal to or higher than the predetermined value.
2 is an idle switch that detects whether the engine is in an idle state (turns ON when the engine is in an idle state);
54 is a defogger switch that detects whether or not the 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
Fuel cut relay 40, ignition cut relay 4
5, control signals 44 and 47 are output, respectively, and as a result, the fuel cut solenoid (not shown) of the fuel supply system in the engine 20 is output from the fuel cut relay 40.
The fuel cut signal 51 is outputted from the ignition cut relay 45, and the ignition cut signal 60 is outputted from the ignition cut relay 45 to the ignition circuit 14, and the ignition signal and fuel are respectively cut off and the engine is stopped. 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. In order to eliminate this drawback, it is better to cut the fuel and cut the ignition at the same time.

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, the starter 42 is energized and the 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 the engine rotation speed (3) 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 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 attachment, 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, (2) of the above conditions requires that the engine speed be 850 rpm or less, in order to prevent the engine from automatically stopping during racing, and (4) is selected as the determination condition because when the vehicle turns right, the driver needs to pay attention to checking for oncoming vehicles, etc., and it is not desirable to stop the engine in such a state. Furthermore, conditions (5), (6), (8), and (13) are used to determine whether to stop the engine in order to avoid over-discharge of the battery due to stopping the engine when the electrical load is high. It is.

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 such that 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.

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.

Of 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) 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 the engine is restarted, when it takes a certain amount of time (e.g. 2 seconds) for the engine speed to reach a certain speed (e.g. 550rpm) or higher.The ERS setting is automatically canceled in the following cases.

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)
The purpose of this is to take into account driver changes and to avoid confusion among people who are unfamiliar with ERS. In addition, (3) and (4) are difficult to restart 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, FIG. 5 shows the configuration of the main parts of the automatic engine stop/start device according to the present invention, and FIG. 6 shows the details of its operation.

In FIG. 5, the anode of the battery _VB is connected to one end of the fuel cut solenoid _LFC via the ignition switch S1 and the contact 40A of the fuel cut relay 40, and the other end of the solenoid _LFC is grounded. Further, the connection point between the ignition switch S1 and the contact 40A is connected to the ignition circuit 14 via the contact 45A of the ignition cut relay 45. Note that both relays 40 and 45 are normally closed relays.

Furthermore, the connection points are the relay coils 40B of the fuel cut relay 40 and the ignition cut relay 45,
45B to the output terminals T ₁ and T ₂ of the control circuit.

On the other hand, output transistors Q 1 and Q 2 are connected to the output terminals T _{1 and} T ₂ of the control circuit ₁ , and the base of the transistor Q ₁ receives a control signal for causing fuel cut, and the base of the transistor Q ₂ receives a control signal for causing fuel cut. The base of the control signal for making the ignition cut.
IGC is configured to be input.

In the above configuration, when the ignition switch S1 is closed when starting the engine and power is supplied to each part, the starter is driven and the engine is started. Thereafter, when the engine stop condition described above is satisfied, the output transistors Q ₁ ,
Control signals for Q ₂ , respectively (Fig. 6 A, C)
is output at time t ₁ , and as a result, relay coil 40
B, 45B are energized, so contacts 40A, 45A
is open, and the fuel cut solenoid _LFC ,
The power supply to the ignition circuit 14 was cut off (B, D in the same figure),
The engine will stop.

Here, cutting off the ignition and cutting off the fuel at the same time when the engine is stopped is called a run on.
This is to prevent this and stop the engine smoothly.

On the other hand, the control signal for cutting the ignition is generated for a predetermined period of time T from the time when the power supply to the fuel cut solenoid _LFC and the ignition circuit 14 is simultaneously cut off (time t ₁ ).
The signal is output until the elapsed time (time t ₂ ), and since the power supply to the ignition circuit 14 is restored from time t ₂ , the ignition signal (engine rotation speed signal) is taken into the control circuit 1 via the input terminal T ₃ . The predetermined time T is the time from when the power supply to the fuel cut solenoid _LFC and the ignition circuit 14 is cut off until the engine rotates due to inertia and stops. This is the time required to confirm that the engine has stopped. To restore the ignition circuit and supply power after a predetermined time T, the ignition signal, that is, the engine speed, which is basic data for various engine controls, is input into the control device, and the engine starting conditions are set by the fuel cut solenoid L _FC. This is because restarting the engine does not take much time and the engine can be restarted quickly any time after the vehicle has stopped by restarting the engine when power is restored or immediately after that time.

On the other hand, the control signal for fuel cut is output until the next engine restart, that is, the time when the starter is driven (time _t3 ), and at time _t3 , the fuel cut relay 40, which controls the power supply to the fuel cut solenoid _LFC , is output. Since the relay coil 40B is de-energized, the contact 40A is closed and fuel supply to the engine is started.

In this embodiment, the starter drive start point (time t ₃ )
The power supply to the fuel cut solenoid is restored at the time _t2 .
The configuration may be such that the recovery is performed in the subsequent steps).

Further, in this embodiment, the ignition is cut off by cutting off the ignition power supply, but the ignition may be cut off by other methods, such as cutting off the signal that controls the ignition timing.

As explained above, in the present invention, the ignition cut is returned after a predetermined period of time after the engine has stopped, and the ignition signal (engine speed signal) is input into the control circuit. The engine starting conditions can be established simply by returning the fuel supply from the fuel cut, and the engine can be started quickly without taking the time required with conventional devices, improving engine restartability. .

[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, and Fig. 4 is an explanatory diagram showing the operating mode when the engine automatically starts.
FIG. 5 is a block diagram showing the configuration of the main parts of the automatic engine stop/start device according to the present invention, and FIG. 6 is a time chart showing the details of its operation. 1...Control circuit, 10...Main switch, 1
4...Ignition circuit, 18A, 18B...Clutch switch, 40...Fuel cut-off relay, 41...Starter relay, 42...Starter, 45...Ignition cut-off relay.

Claims (1)

[Scope of Claims] 1. An automatic engine stop/start device that is controlled to automatically stop the engine when the vehicle is stopped by stopping or returning at least the ignition control means, and to automatically start the engine when the vehicle starts, comprising: the ignition control means; An engine rotation speed calculation means for calculating an engine rotation speed based on an ignition signal outputted by the means, and one of the conditions is that the engine rotation speed calculated by the engine rotation speed calculation means is equal to or less than a predetermined rotation speed. An automatic engine stop/start device comprising: automatic engine start control means for automatically starting an engine; and ignition priority return means for restoring the ignition control means when the engine has completely stopped.