JPH0442540B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply control device for an internal combustion engine, and more particularly to a fuel supply control device that significantly suppresses fuel supply during engine deceleration to reduce fuel consumption.

In this type of fuel supply control device, it is advantageous in terms of fuel efficiency to suppress the fuel supply to a lower speed during deceleration, but when the fuel supply is resumed after deceleration operation is completed, combustion is resumed smoothly. In order to do so, it is better not to suppress the fuel to low speeds. Therefore, in the fuel supply control device described in Utility Model Application Publication No. 54-113922, when the brake operation is not performed, that is, when transitioning from deceleration to acceleration, a relatively high speed of about 2000 [rpm] is applied. The fuel supply is restarted at the engine speed, and when the brakes are being operated, that is, when transitioning from deceleration to idling, the fuel supply is suppressed to a lower engine speed of around 1000 rpm.

However, in such a fuel control system, if the clutch is disengaged in a decelerating state, the internal combustion engine will no longer be driven from the wheels, causing a sudden deceleration and possibly stopping the internal combustion engine.

Therefore, in the fuel cut device described in Japanese Utility Model Publication No. 53-53010, fuel supply is restarted at the same time as the clutch is released, thereby preventing the internal combustion engine from stopping.

However, in this fuel cut device, if the clutch is once disengaged and then immediately reconnected, the rotational speed of the internal combustion engine may not fall to the rotational speed at which fuel supply is resumed, and there is a risk that fuel supply will be suppressed. In this case, a sudden load is applied to the low-speed rotating internal combustion engine, which may cause the internal combustion engine to stop. In particular,
In a configuration such as the fuel control device in Publication No. 113922, which suppresses fuel supply to low rotational speeds when the brake is operated, if the clutch is operated while the brake is depressed and the transmission is set to neutral, resulting in idling. Since a load is applied when the clutch is re-engaged, and no driving force is transmitted from the drive wheels to the internal combustion engine, the rotational speed of the internal combustion engine rapidly decreases. In addition, since the fuel supply is not restarted until the speed is reduced to about 1000 [rpm], there is a risk that the internal combustion engine may stop because the decrease in rotational speed cannot be suppressed completely after the fuel supply is restarted.

The present invention was devised to solve these conventional problems, and it is an object of the present invention to provide a fuel supply control device that can prevent an unexpected stoppage of an internal combustion engine while reducing fuel consumption as much as possible.

A fuel supply control device according to the present invention includes a deceleration state detector that detects a deceleration state of an internal combustion engine, a brake detector that detects a brake operation state, and a rotation speed detector that detects the rotation speed of the internal combustion engine. A clutch switch detects the engagement state of the clutch, a fuel cut valve opens and closes a fuel passage of a fuel supply system of the internal combustion engine, a signal state corresponding to deceleration is inputted from the deceleration state detector, and a signal state corresponding to the deceleration is inputted from the brake detector, and a signal state corresponding to the deceleration is inputted from the brake detector. A corresponding signal state is input during non-operation, or a signal state corresponding to a clutch disengaged state is input from the clutch detector, and a signal state corresponding to a clutch disengagement state is input from the rotation speed detector, and the rotation speed corresponds to a first set rotation speed or higher. When a detection signal is input, or a signal state corresponding to deceleration is input from the deceleration state detector, a signal state corresponding to the brake operation is input from the brake detector, and the clutch is engaged from the clutch detector. When a signal state corresponding to the state is input and a detection signal corresponding to a rotation speed equal to or higher than a second set rotation speed lower than the first set rotation speed is input from the rotation speed detector, the fuel cut valve is closed. a controller for suppressing the fuel supply, and a time delay for detecting a change in the signal state when the signal state from the clutch detector changes from a signal state corresponding to a clutch disengaged state to a signal state corresponding to a clutch engaged state. and a delay circuit that also inputs input to the controller.

The fuel supply suppression may be performed by controlling a solenoid valve that introduces atmospheric air into the fuel supply system of the carburetor. In other words, the second configuration of the present invention includes a deceleration state detector that detects the deceleration state of the internal combustion engine. , a brake detector that detects the operation state of the brake, a rotation speed detector that detects the rotation speed of the internal combustion engine, a clutch switch that detects the engagement state of the clutch, and atmospheric air introduced into the fuel supply system of the carburetor. A signal state corresponding to deceleration is inputted from the solenoid valve and the deceleration state detector, a signal state corresponding to the brake non-operation is inputted from the brake detector, or a signal state corresponding to the clutch disengaged state is inputted from the clutch detector. when a signal state corresponding to the rotation speed is inputted from the rotation speed detector, and a detection signal corresponding to the rotation speed equal to or higher than the first set rotation speed is input from the rotation speed detector, or when a signal state corresponding to the rotation speed from the brake detector is input during a brake operation. A signal state corresponding to a clutch engaged state is input from the clutch detector, and a detection signal corresponding to a rotation speed equal to or higher than a second set rotation speed lower than the first set rotation speed is input from the rotation speed detector. When the controller controls the solenoid valve to introduce atmospheric air into and a delay circuit that inputs a change in the signal state to the controller with a time delay.

The deceleration state detector may be a negative pressure switch that detects the intake negative pressure of the internal combustion engine, and the negative pressure switch may output a detection signal when the intake negative pressure becomes higher than a predetermined value. .

Next, a first embodiment of the fuel supply control device according to the present invention will be described based on the drawings.

1 and 2, the fuel supply suppressing device includes a fuel cut valve 3 capable of opening and closing a slow system 2 of a carburetor 1, which is a fuel passage of a fuel supply device of an internal combustion engine. CPU4 is connected as a device. CPU4
includes an idle switch 5, a brake detector 6 for detecting the operation state of the brake, a rotation speed detector 7 for detecting the rotation speed of the internal combustion engine, a clutch switch 8 for detecting the engagement state of the clutch, and a vehicle speed detector 9. are connected.

The idle switch 5 outputs a detection signal S1 when the throttle valve 10 of the carburetor 1 reaches the idle opening position, that is, when the internal combustion engine is in a deceleration state.
Input to CPU4.

The brake detector 6 inputs a detection signal S2 to the CPU 4 when the brake pedal is depressed.
The clutch switch 8 inputs a detection signal to the CPU 4 when the clutch pedal is not depressed.

The rotation speed detector 7 inputs a detector signal S3 corresponding to the rotation speed of the internal combustion engine to the CPU 4, and the vehicle speed detector 9 outputs a detection signal S5 when the vehicle speed becomes below a predetermined value.

The CPU 4 includes a logic circuit 11 that outputs a predetermined logic value L1 when the detection signal S1 is input, and a logic circuit 11 that outputs a predetermined logic value L1 when the detection signal S3 is higher than a first set rotation speed of 2100 [rpm], for example. For example, the logic circuit 12 outputting the value L2 and the detection signal S3
Logic circuit 1 that outputs a predetermined logical value L3 when the rotation speed is higher than the second set rotation speed of 1000 [rpm]
3, an OR circuit 15 is connected to the logic circuit 11 via a delay circuit 14, and an OR circuit 15 is connected to the logic circuit 11 via a delay circuit 14.
is connected to the OR circuit 15 via the changeover switch 16. The changeover switch 16 connects one of the logic circuits 12 and 13 to the OR circuit 15 by switching. The OR circuit 15 outputs an output signal SOUT when one of the logic outputs L2 or L3 and the logic output L1 are input.

The CPU 4 further includes a logic circuit 17 that outputs a predetermined logic output L4 when the detection signal S5 is input, a logic circuit 18 that outputs a predetermined logic output L5 when the detection signal S2 is input, and a logic circuit 18 that outputs a predetermined logic output L5 when the detection signal S2 is input. A delay circuit 1 that outputs a predetermined logic output L6 after a certain delay time Δt ₁ when the signal S4 is input.
9, and logic circuits 17 and 18 and a delay circuit 19 are connected to an OR circuit 20. The OR circuit 20 is connected to the changeover switch 16, and the logical output L
4, switching signal when L5 and L6 are input
Input the SCO to the changeover switch 16. The changeover switch 16 connects the logic circuit 13 to the OR circuit 15 when the changeover signal SCO is input, and connects the logic circuit 12 to the OR circuit 15 in other cases.

As shown in FIG. 3, the delay circuit 19 of this embodiment has one terminal grounded and the other terminal connected to the variable resistor R1.
capacitor C connected to reference voltage VCC through
The connection point between the capacitor C and the variable resistor R1 is the output terminal VOUT. Output terminal VOUT
is connected to the clutch switch 8 through a resistor R2 and a diode D in this order, and the diode D is arranged in the forward direction toward the clutch switch 8. The clutch switch 8 has one terminal connected to the diode D and the other terminal grounded, so that when the clutch switch 8 is closed, both terminals of the capacitor C are grounded. When clutch switch 8 is opened, capacitor C is at the reference voltage.
It is charged by VCC, and a reference voltage VCC is generated at the output terminal VOUT.

FIG. 4 shows the relationship between the voltage V at the output terminal VOUT and time t. When the clutch switch 8 is closed, the voltage V drops rapidly (curve A). When clutch switch 8 is subsequently opened, capacitor C is charged to VCC with a time constant determined by its capacitance and variable resistor R1 (curve B). The delay circuit 14 outputs a logic output L when V is higher than the judgment voltage VD which is lower than VCC.
6, and a time delay of Δt ₁ occurs until the curve B reaches VD from zero. There is also a time delay of Δt ₂ when the curve A reaches from VCC to VD, but the resistance value of the resistor R1 is set to be sufficiently low, and Δt ₅ is small enough to be ignored.

When the internal combustion engine is driven, when the accelerator pedal is stopped and the deceleration state is entered, the logical output L1 is input to the OR circuit 15, and after that, the rotation speed of the internal combustion engine becomes higher than the first set rotation speed or the second set rotation speed. When the rotation is occurring, the logic output L2 or L3 is input to the OR circuit 15. At this time, OR circuit 1
5 outputs an output signal SOUT to drive the fuel cup valve 3 and stop the fuel supply. When the vehicle speed is above a predetermined value, the brake is being operated, and the clutch is engaged, the changeover switch 16 is connected to the logic circuit 13, and the fuel supply is stopped until the second set rotation speed is reached. Ru. When a brake operation is performed, idling is generally performed after deceleration, so even if fuel supply is stopped until lower speed rotation, there is no adverse effect on driving performance. By stopping the fuel supply until the rotation speed is lower, fuel consumption can be reduced. Also, if the vehicle speed is low but the internal combustion engine rotation speed is higher than the second set rotation speed,
Engine racing, commonly known as racing, is generally performed, and the vehicle speed detector 9 prevents the internal combustion engine from unexpectedly stopping due to the fuel supply being stopped up to 1000 [rpm] immediately after racing. The delay circuit 14 also prevents the internal combustion engine from stopping immediately after racing, and the OR circuit 1 of the logic output L1
5 is delayed by a predetermined period of time, and the fuel supply is stopped after the rotational speed has sufficiently decreased. For example, if the fuel supply is stopped immediately after racing while the air conditioner is running, the internal combustion engine's rotational speed will rapidly drop and stop.
The logic output L1 is input to the OR circuit 15 after waiting for the rotation speed to decrease to a speed lower than the first set rotation speed. This completely prevents the internal combustion engine from stopping immediately after racing. Even when the clutch is disengaged, the rotation speed of the internal combustion engine rapidly decreases, so the changeover signal SCO output causes the changeover switch 1 to
6 is connected to a logic circuit 12, so that fuel supply is restarted when the rotation speed is lower than the first set rotation speed. After the clutch is disengaged, when the clutch is reconnected, the logic output L6 is output with a time delay of Δt ₁ , so that the logic circuit 1 of the changeover switch 16
The switching to the third side is delayed, and immediately after the clutch is reconnected, the fuel supply execution range remains below the first set rotation speed (2100 rpm).

Therefore, when stopping a vehicle at a traffic light, etc.,
When operating the clutch while stepping on the brake to put the transmission into neutral, do so at a speed slightly higher than idling (e.g.
2000 rpm, etc.), the fuel supply will not be interrupted. This also prevents the internal combustion engine from stopping.

FIG. 5 shows a second embodiment of the present invention, in which a solenoid valve 21 for introducing atmospheric air into the slow system 2 is used in place of the fuel cutoff switch 3 of the first embodiment. The solenoid valve 21 outputs a signal
When SOUT is input, atmospheric air is introduced into the slow system 2, greatly suppressing fuel supply. This embodiment also provides the same effects as the first embodiment.

FIG. 6 shows a delay circuit 22 corresponding to the delay circuit 19 in a third embodiment of the present invention, and an arithmetic circuit 23 that sets the judgment voltage VD corresponding to the rotation speed r based on the detection signal S3. It is equipped with The delay time Δt ₁ should be set to the time to decelerate from the rotation speed r to the second set rotation speed,
Under normal operating conditions, if the delay time is set to about 2 to 3 seconds, the rotational speed will be reduced to below the second set rotational speed within the delay time. However, in order to take into account deceleration from an abnormally high rotational speed and to reduce fuel consumption as much as possible, Δt ₁ should be set to an optimal value depending on the rotational speed r. In this embodiment, VD is changed in order to set the optimum Δt ₁ according to the rotation speed r. Furthermore, VD
A similar effect can be obtained by changing the resistance R1 without changing the resistance R1.

As described above, according to the present invention, when the engine shifts to idling due to brake operation, fuel supply is suppressed until the rotational speed of the internal combustion engine becomes equal to or lower than the relatively low second set rotational speed. Consumption is suppressed. In addition, when the clutch is in the disengaged state, the suppression of fuel supply is stopped when the rotational speed of the internal combustion engine is below the first set rotational speed, which is relatively high. , it is possible to prevent a sudden drop in rotational speed. Further, according to the present invention, the clutch is deemed to be disengaged for a predetermined period of time after the clutch is re-engaged due to the operation of the delay circuit, and the suppression of fuel supply is stopped when the rotation speed is below the first set rotation speed. Even when shifting to idling with a neutral shift, it is possible to prevent a sudden drop in rotation speed that would cause the internal combustion engine to stop, and even during the period when the clutch is considered to be disengaged due to the operation of the delay circuit. If the fuel supply suppression condition is satisfied, such as during deceleration at a rotation speed higher than the first set rotation speed, fuel supply is immediately suppressed, so that unnecessary fuel consumption can be reduced. Furthermore, the third effect can be achieved by simply adding a simple delay circuit that delays the clutch engagement state and inputs it to the controller to the configuration for obtaining the first effect and the second effect. It is possible to achieve the following effects, such as being able to suppress cost increases.

Note that the present invention is not limited to the above-mentioned embodiment, and instead of the idle switch, a negative pressure switch may be used to determine that the deceleration state is present when the intake negative pressure becomes higher than a predetermined value.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a first embodiment of a fuel supply control device according to the present invention, FIG. 2 is a logic circuit diagram of the same embodiment, and FIG. 3 is a circuit diagram showing a delay circuit in the same embodiment. 4 is a graph showing the characteristics of the delay circuit in FIG. 3, FIG. 5 is a block diagram showing the second embodiment, and FIG. 6 is a circuit diagram showing the delay circuit in the third embodiment. It should be noted that the same or corresponding parts in the figures are indicated by the same reference numerals. 1... Carburetor, 2... Slow system, 3... Fuel cut valve, 4... CPU, 5... Idle switch, 6... Brake detector, 7... Rotation speed detector, 8... Clutch switch, 9...Vehicle speed detector, 10...Slot valve, 11, 12, 13
... logic circuit, 14 ... delay circuit, 15 ... OR circuit, 16 ... changeover switch, 17, 18 ... logic circuit, 19 ... delay circuit, 20 ... OR circuit,
21...Solenoid valve, 22...Delay circuit, 23...Arithmetic circuit.

Claims (1)

[Scope of Claims] 1. Connection of a deceleration state detector that detects the deceleration state of the internal combustion engine, a brake detector that detects the operation state of the brake, a rotation speed detector that detects the rotation speed of the internal combustion engine, and a clutch. A clutch switch detects the state, a fuel cut valve opens and closes a fuel passage of a fuel supply system of the internal combustion engine, a signal state corresponding to deceleration is input from the deceleration state detector, and a signal state corresponding to the deceleration is input from the brake detector, and a signal state corresponding to the brake is not operated is input from the brake detector. or a signal state corresponding to a clutch disengaged state is input from the clutch detector, and a detection signal corresponding to a rotation speed equal to or higher than the first set rotation speed is input from the rotation speed detector. or a signal state corresponding to deceleration is input from the deceleration state detector, and a signal state corresponding to the brake operation is input from the brake detector,
When a signal state corresponding to a clutch engaged state is input from the clutch detector, and a detection signal corresponding to a rotation speed equal to or higher than a second set rotation speed lower than the first set rotation speed is input from the rotation speed detector. ,
a controller that drives the fuel cut valve to suppress fuel supply; and a signal when the signal state from the clutch detector changes from a signal state corresponding to a clutch disengaged state to a signal state corresponding to a clutch engaged state. A fuel supply control device for an internal combustion engine, comprising a delay circuit that inputs a change in state to the controller with a time delay. 2. The deceleration state detector is a negative pressure switch that detects the intake negative pressure of the internal combustion engine and outputs a detection signal when the intake negative pressure becomes higher than a predetermined value. A fuel supply control device for an internal combustion engine according to claim 1. 3. A deceleration state detector that detects the deceleration state of the internal combustion engine, a brake detector that detects the operation state of the brake, a rotation speed detector that detects the rotation speed of the internal combustion engine, and a clutch switch that detects the engagement state of the clutch. a solenoid valve that introduces atmospheric air into the fuel supply system of the carburetor; a signal state corresponding to deceleration is input from the deceleration state detector; and a signal state corresponding to the brake non-operation is input from the brake detector. or a signal state corresponding to a clutch disengaged state is input from the clutch detector, and a detection signal corresponding to a rotation speed equal to or higher than the first set rotation speed is input from the circuit rotation detector, or A signal state corresponding to the brake operation is input from the brake detector, a signal state corresponding to the clutch engagement state is input from the clutch detector, and a second setting lower than the first set rotation speed is input from the rotation speed detector. When a detection signal corresponding to a rotation speed equal to or higher than the rotation speed is input, a controller for controlling the solenoid valve to introduce atmospheric air into An internal combustion engine characterized by comprising: a delay circuit that inputs a change in a signal state from a signal state corresponding to a engaged state to a signal state corresponding to a clutch engaged state to the controller with a time delay. fuel supply control device. 4. The deceleration state detector is a negative pressure switch that detects the intake negative pressure of the internal combustion engine and outputs a detection signal when the intake negative pressure becomes higher than a predetermined value. A fuel supply control device for an internal combustion engine according to claim 3.