JPH0416624B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention stops the supply of fuel during deceleration,
The present invention relates to an engine deceleration fuel stop device for improving fuel efficiency.

(Conventional technology) Conventionally, as a means of improving fuel efficiency,
Various deceleration fuel stop devices have been proposed that stop the supply of fuel during deceleration. This type of deceleration fuel stop device, as shown in Japanese Patent Application Laid-open No. 59-162327, stops the fuel when the engine speed is higher than the high speed setting during deceleration when the throttle valve is fully closed. is configured to run. That is, in the conventional configuration, a rotation speed detector detects a rotation speed of a predetermined number or higher, and a throttle valve opening degree detector detects that the throttle valve is fully closed, thereby executing deceleration fuel stop.

(Problems to be Solved by the Invention) In such a conventional deceleration fuel stop device, the throttle opening degree detector is normally set to detect the fully closed position of the throttle valve.
In reality, due to the nature of the mechanical switch, the switch is set to turn on and off at a position slightly open from the fully closed position of the throttle valve. Therefore, even if you lightly press the accelerator pedal to accelerate again from a fuel stop state during deceleration, the throttle opening detector detects that the fuel supply will be restarted unless the throttle opening exceeds a predetermined opening. Since the engine was not started, it was not possible to immediately return to the fuel supply state, resulting in poor drivability.

This invention was made in view of the above-mentioned circumstances, and the purpose of this invention is to
To provide a deceleration fuel stop device for an engine which can smoothly transition from a fuel supply stop state to a fuel supply state in response to depression of an accelerator pedal without impairing acceleration performance when fuel supply is restored.

(Means for Solving the Problems) In order to solve the above-mentioned problems and achieve the purpose, the engine deceleration fuel stop device according to the present invention stops the fuel supply to the engine during deceleration. The stop device includes a first detection means for detecting whether the engine rotation speed is equal to or higher than a set rotation speed, a second detection means for detecting whether the engine throttle valve is in a fully closed position, and a throttle valve. The third detection means detects whether the intake negative pressure downstream of the valve is below the set pressure, and the first to third detection means detect whether the engine rotation speed is higher than the set rotation speed and the throttle valve is fully closed. stop means for stopping the fuel supply to the engine when it is detected that the throttle valve is in the position and that the intake negative pressure downstream of the throttle valve is below the set pressure, and the stopping means is configured to meet a fuel stop release condition. In the high speed range of the engine,
defined by detecting a position other than the fully closed position of the throttle valve in the second detection means,
Further, in the low rotation range, the set pressure in the third detection means is set by the boost pressure at medium rotation of the engine when the throttle valve is in the fully closed position, and the set pressure is determined by detecting the set pressure or higher. It is characterized by

(Embodiment) An embodiment of the engine deceleration fuel stop device according to the present invention will be described in detail below with reference to the accompanying drawings.

As shown in Fig. 1, the engine carburetor 1
An air cleaner 12 is attached to the inlet portion 10a of the engine 0, and an intake manifold 14 is connected to the outlet portion 10b. Further, an end of the intake manifold 14 is connected to a cylinder 18 via an intake valve 16. This cylinder 18 is connected to an exhaust manifold 22 via an exhaust valve 20.

In the carburetor 10 described above, the main nozzle 10d opens in the ventilate portion 10c, and the slow port 10 is located on the side of the throttle valve 10e.
f and idle port 10h are open. This slow port 10f and idle port 10h
A slow cut solenoid 10g is configured to cut off and cut off fuel supply between the fuel tank and a float chamber (not shown). This slow cut solenoid 10g is connected to an engine control unit (hereinafter simply referred to as ECU) 24 that controls the drive of the engine, and is controlled intermittently (excitation/demagnetization control) by this ECU 24.

On the other hand, this ECU 24 includes a boost switch 26 that detects the intake negative pressure of the intake manifold 14, a throttle opening switch 28 that detects the opening of the throttle valve 10e, a clutch switch 30 that detects the on/off state of the clutch, and a shift knob. A neutral switch 32 is connected to detect the neutral state of the engine, and a no-load switch 34 detects the no-load state of the engine. A rotation speed detection switch 40 for detecting the rotation speed is connected.

This boost switch 26 outputs an "H" level signal when the detected boost pressure is less than a predetermined value on the negative pressure side, and outputs an "L" level signal when it is greater than the predetermined value. Further, the throttle opening switch 28 outputs an "H" level signal when the detected throttle opening is at the fully closed position, and outputs an "L" level signal when it is larger than the fully closed position.

On the other hand, the no-load detection switch 34 detects whether or not the engine is in a no-load state based on the signals from the clutch switch 30 and the neutral switch 32, and outputs an "H" level signal when the detected state is no-load. If there is no load, that is, if there is a load, an "L" level signal is output. Further, the rotation speed detection switch 40 outputs an "H" level signal when the detected rotation speed is above a predetermined value, and outputs an "L" level signal when the detected rotation speed is less than the predetermined value.

In addition, the aforementioned slow cut solenoid 10g
is demagnetized when an “L” level signal is input to it, stops fuel supply, and turns “H”
It is configured to be excited and supply fuel when a level signal is input.

Here, the ECU 24, as shown in FIG.
In order to control the slow cut solenoid 10g intermittently, one AND gate circuit 24a and two inverters 24b and 24c are provided. That is,
The aforementioned no-load detection switch 34 connects the AND gate circuit 24a via one inverter 24b.
The rotation speed detection switch 40, the boost switch 26, and the throttle opening switch 28 are connected to the second, third, and fourth input terminals of the AND gate circuit 24a, respectively. In addition, this AND gate circuit 24a
The output end of is connected to the slow cut solenoid 10g via the other inverter 24c.

In this way, the ECU 24 determines that the vehicle is in a deceleration state when "H" level signals are output from the boost switch 26, the throttle opening switch 28, and the rotation speed detection switch 40. Then, when the "L" level signal is output from the no-load detection switch 34, that is, when there is a load and there is a deceleration state, the ECU 24 demagnetizes the slow cut solenoid 10g to stop the fuel supply.

In other words, in this ECU 24, the third
As shown in the figure, a fuel supply stop region is defined, and when the operating state is in this fuel supply stop region, the slow cut solenoid 10g is demagnetized and the fuel supply is stopped. That is, this fuel supply stop region is defined by the range surrounded by three straight lines l, m, and n, where the straight line l is determined by the set rotation speed of the rotation speed detection switch 40, and the straight line m is determined by the setting of the boost switch 26. It is determined by the boost pressure, and the straight line n is determined by the set opening of the throttle opening switch 28.

In this way, in this embodiment, as shown in FIG. 4, in a low rotation state, the boost switch 26, which can implement/stop the fuel supply more precisely than the throttle opening switch 28, is used for control. I try to do that. In this way,
The fuel supply stop region in the low rotation state can be set accurately and freely.

Here, if the boost switch 26 is used to uniformly set this fuel supply range even in a high rotational state, an undesirable situation will arise because the actual demand will differ depending on the rotational speed. However, in this embodiment, as shown in FIG. 3, the fuel supply stop region is defined by the throttle opening switch 28 in the high rotation state. This throttle opening switch 28 is a mechanical switch that can be turned on and off in a high-speed state in a manner similar to the operation sense of the operator.It also regulates the boost pressure corresponding to each rotation speed, so it can better meet the demands. This defines a fuel supply stop area that can be accommodated.

In addition, in a low rotation state, the fuel supply stop region is defined by the boost switch 26, so even if the driver lightly depresses the accelerator pedal to accelerate again, boost is immediately applied as the intake negative pressure changes. Since the switch 26 is now capable of responsive operation, drivability is considerably improved.

This invention is not limited to the configuration of the one embodiment described above, and can be modified in various ways without departing from the gist of the invention.

(Effects of the Invention) As described in detail above, the engine deceleration fuel stop device according to the present invention is an engine deceleration fuel stop device that stops fuel supply to the engine during deceleration, when the engine speed is set to a set speed. a first detection means for detecting whether the throttle valve of the engine is in the fully closed position; and a second detection means for detecting whether the throttle valve of the engine is in the fully closed position; a third detection means for detecting the
The first to third detection means detect that the engine speed is above the set speed, the throttle valve is in the fully closed position, and the intake negative pressure downstream of the throttle valve is below the set pressure. and stop means for stopping fuel supply to the engine when the fuel stop release condition is set to a state other than a fully closed position of the throttle valve in the high engine speed range by the second detection means. In addition, in the low rotation range, the set pressure in the detection means 3 above is set by the boost pressure at medium rotation of the engine when the throttle valve is in the fully closed position. The feature is that it is specified by detecting the above.

Therefore, according to the present invention, over a wide rotation range, the fuel supply state can be smoothly transitioned from the fuel supply stop state to the fuel supply state according to the depression of the accelerator pedal, so that the acceleration performance when the fuel supply is restored is not impaired. An engine deceleration fuel stop device will be provided.

[Brief explanation of drawings]

FIG. 1 is a front view schematically showing the configuration of an embodiment of an engine deceleration fuel stop device according to the present invention;
FIG. 2 is a block diagram showing the control contents of the deceleration fuel stop device, and FIG. 3 is a diagram showing the fuel supply stop area defined by the deceleration fuel stop device. In the figure, 10... Carburetor, 10a... Inlet section, 10b... Outlet section, 10c... Ventilation section, 10d... Main nozzle, 10e... Throttle valve, 10f... Slow port, 10e...
...Slow cut solenoid, 12...Air cleaner, 14...Intake manifold, 16...
...Absorption valve, 18...Cylinder, 20...Exhaust valve, 22...Exhaust manifold, 24...
ECU, 24a...AND gate circuit, 24b, 2
4c...Inverter, 26...Boost switch, 28...Throttle opening switch, 30...
Clutch switch, 32...neutral switch, 34...no-load detection switch, 36...distributor, 38...ignition coil, 40...rotation speed detection switch.

Claims (1)

[Scope of Claims] 1. An engine deceleration fuel stop device that stops fuel supply to the engine during deceleration, comprising: a first detection means for detecting whether the engine rotation speed is higher than a set rotation speed; a second detection means for detecting whether the throttle valve is in the fully closed position; a third detection means for detecting whether the intake negative pressure downstream of the throttle valve is below a set pressure; When the detection means detects that the engine speed is above the set speed, the throttle valve is in the fully closed position, and the intake negative pressure downstream of the throttle valve is below the set pressure, fuel is not supplied to the engine. and a stop means for stopping the fuel supply, and the stop means detects a position other than the fully closed position of the throttle valve in the high engine speed range when the fuel stop release condition is detected by the second detecting means. In addition, in the low rotation range, the set pressure in the third detection means is set by the boost pressure at mid-engine rotation with the throttle valve in the fully closed position, and a pressure equal to or higher than this set pressure is detected. An engine deceleration fuel stop device characterized by the following: