JPS60222548A - Fuel cut device for engine for vehicle - Google Patents

Abstract

PURPOSE:To provide a fuel cut device which controls cutting of fuel during deceleration of an engine without using various switches, reads out a decelerating condition from memory, based on a change rate of the number of revolutions, cuts fuel according to the result, and is easy to maintain and is reliably operated. CONSTITUTION:A valve 5, which cuts the fuel system of an evaporator 1, inputs the value of a detector 25 for the number of revolutions of an engine into a controlling device 7, and when it is decided that engine is in a decelerating condition, the valve 5 is actuated by means of an output therefrom to cut fuel. When it is decided that deceleration is completed, with an electromagnetic pump 6 actuated, stopgap fuel is supplied. The number of revolutions 25 is inputted at 23 within a controlling device 7, an arithmetic unit 21 compares a change rate of the number of revolutions with the value of a change rate stored when a wheel driving system is not connected, detects that a driving system is connected, finds whether a deceleration rate is a given value, and cuts the fuel when the number of revolutions exceeds a given value. Thereafter, when the number of revolutions is decreased to below a given value, the pump 6 is actuated.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a fuel cut device for a vehicle engine used primarily in automobiles.

(B) Prior Art In order to improve fuel economy, many recent automobile engines are equipped with a fuel cut device that cuts fuel during deceleration.

As a prior art related to this type of fuel cut device, there is one as shown in the previously filed Japanese Patent Application No. 190903/1983. In other words, this device includes a fuel cut valve to cut off the fuel passage, a rotation speed detector to detect the engine speed, a clutch switch to detect clutch engagement, and a detection to detect whether the transmission is dual-coatral or not. an idle switch that detects whether the throttle valve of the carburetor is closed more than a set opening degree, and an idle switch that detects whether the vehicle is in a deceleration state based on signals from the rotation speed detector and each of the switches. Some devices are equipped with a control mechanism that outputs a fuel cut command signal to the tsuyu-12 cut pulp when it is determined that the fuel is in a deceleration state.

However, since these devices use a large number of switches as mentioned above to detect the deceleration state of the vehicle, they have a large number of parts, making assembly and adjustment complicated, and making maintenance and inspection difficult. There is also the problem that it is time consuming. In addition, when using ON/OFF switches to define the fuel cut range, only relatively rough settings can be made, making it difficult to reasonably expand the fuel cut range. There is also.

(c) Purpose The present invention was made with attention to such circumstances,
This fuel cutter for vehicle engines eliminates the inconvenience of requiring time and effort for assembly, adjustment, maintenance, inspection, etc. due to the small number of parts, and also allows for relatively easy expansion of the fuel power/power range. [The purpose is to provide equipment.]

(d) Structure In order to achieve the above object, the present invention eliminates the flange switch, neutral switch, idle switch, etc., and instead uses only the engine rotation speed detected by the rotation speed detection means to be processed by the arithmetic processing device. This arithmetic processing unit calculates the rate of change of the engine speed per unit time, detects a deceleration state based on whether or not this calculated rate of change shows a negative value, and By comparing the value with a reference rate of change stored in a memory device in advance, it is detected whether the transmission state between the engine and the driving wheels is disconnected, and based on these detection results, the fuel cut valve is installed. It is characterized in that it is configured to control the fuel adjustment rod PL.

(e) Examples Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a system explanatory diagram of a fuel cut device according to the present invention, in which 1 indicates a carburetor of an automobile engine;
2 is a throttle valve of this carburetor 1, 3 is a float chamber, 4
is a fuel adjustment means for adjusting the amount of fuel supplied to the carburetor l. The fuel adjustment means 4 includes a fuel cut valve 5 interposed in the middle of a fuel passage (not shown) of the carburetor 1, and a pump 6 for supplying auxiliary fuel to the intake passage 1a of the carburetor 1. It is equipped with the following. The fuel adjusting means 4 is controlled by a microcomputer 7.

Tsuyu 12 Lucut Pulp 5 is the fuel cut signal A
The on-off valve is configured to close the fuel passage when a fuel cut release signal B is received, and open the fuel passage when a fuel cut release signal B is received.

In addition, the pop 6 has an inlet 9 having a check valve 8.
It is an electromagnetic type that is connected to the float chamber 3 via a solenoid passage 11 and has an outlet 12 opened into the intake passage la of the carburetor 1 via an outlet passage 14 in which a check valve 13 is broken. It is driven by a pump drive circuit 15 which receives a fuel discharge signal C from the microcomputer 7 and outputs pulsed electricity K a number of times according to the signal C.

Specifically, this pump 6 houses a piston 17 in a cylinder 16 that forms a pump chamber 15.
7 is moved forward by the biasing force of a spring 18 and the electromagnetic attraction force of a solenoid 19 excited by the pulse voltage, thereby performing a pumping function.

On the other hand, the microcomputer 7 has the central processing unit 2
1, a storage device 22, and an input/output interface 2
3.24, and the number 4F+ is sequentially inputted to the interface 23 from a rotation speed detection means 25 for detecting the rotation speed of the engine. Further, from the interface 24,
As will be described later, a fuel cut command signal A or a fuel cut release signal B is output to the fuel car/to valve 5, and a fuel discharge signal C is output.
is output to the pump drive circuit 15. Then, the storage device 22 of this microcomputer 7 stores the rate of change in the engine speed, which is the criterion for determining whether or not the transmission state between the engine and the driving wheels is disconnected, as a reference rate of change N1. The engine rotation speed that defines the lower limit of the fuel cut region is stored as the lower limit rotation speed N7, and furthermore, the engine rotation speed that defines the lower limit of the region where stable operation of the engine can be always guaranteed without supplying auxiliary fuel is stored as the safe rotation speed N1. Let me remember it as. Note that the reference rate of change N1 is actually determined as follows. First, the change in engine speed per unit time when the transmission state between the engine and the driving wheels is cut off and the engine enters a racing (idling) state. 1. :Measure the rate (ΔN/ΔT). This is called the "rate of change during racing (a)." Next, the vehicle is actually driven, and the accelerator is released from an arbitrary vehicle speed in the actual running state to shift to coasting. Then, the rate of change in engine speed during coasting is measured. This measurement is performed by sequentially switching the transmission up to Low-Top (fourth speed). This is called the rate of change during coasting (b). Further, the vehicle is actually driven, and the brake is depressed to the maximum from an arbitrary vehicle speed in the actual traveling state to rapidly decelerate the vehicle.

And the engine speed during sudden deceleration.

Change = measuring the cup. This measurement also takes the transmission to L.
Change sequentially up to o w-T o-p (4th speed) and carry out each one. This is called "change during sudden deceleration J(c)j. After determining each change rate (a), 0 mouth), and (c) as described above, change during coasting*(b) Define a value that is between the rate of change during sudden deceleration (c) and that can be determined to be definitely not during racing.Then, the rate of change in the determined chain is the rate of change during racing. The value as close as possible to (a) is set as the reference rate of change.Here, the reason for choosing the value as close as possible to the rate of change during racing (a) is to increase the fuel cut area as much as possible.On the other hand, The above-mentioned lower limit rotation speed N1 is determined by experimenting with the engine rotation speed at which the engine can continue to operate reliably without stalling, and selects the lower limit value among them.The above-mentioned safe rotation speed N1 is , is determined as follows. First, the vehicle is decelerated by engine braking while the vehicle is in the 2-knee cut state. Then, when the engine speed has decreased to a certain value, the clutch is depressed or the shift lever is shifted to neutral. The transmission state between the engine and the drive wheels is cut off by the shift operation, and the fuel cut is canceled.At this time, it is checked whether the engine can return to normal operation without stalling.This investigation is carried out when the fuel cut is canceled. When the engine speed is varied and carried out, it can be seen that if the fuel cut is canceled when the engine speed is below a certain number, the fuel cannot be restored in time and the engine starts to stop. Therefore, this specific engine rotational speed or a value near it is defined as the safe rotational speed N1.

The microcomputer 7 has a built-in program as shown in FIG.

More specifically, first, the actual engine rotation speed N detected by the rotation speed detection means 25 is sequentially read. Then, the rate of change ΔN/ΔT of the engine speed N per unit time is calculated in the central processing unit Nzt, and
It is determined whether this calculated rate of change ΔN/ΔT is a negative value. Then, if the calculated rate of change ΔN/ΔT is a negative value, the process moves to step (a), and if it is zero or positive, the process moves to a new cycle. In step (a), next, the calculated rate of change ΔN/ΔT is determined by the reference rate of change N
It is determined whether the value is between + (for example, -38 Orpm/sec) and zero. If so, it is determined that the transmission pipe between the engine and the driving vehicle is not disconnected, and the process proceeds to step (b). Conversely, if it is determined that this is not the case, that is, ΔN/ΔT<-38O
rpm/sec, it is determined that the transmission state between the engine and the drive wheels has been cut off, and step (
Move to C). In step (b), next, the engine rotation speed N is set to the lower limit rotation speed Nt (for example, 900
rpm), and if it is determined to be low, proceed to step (d), and when the fuel cart signal A is output, that signal is used as the fuel cart release signal B. Switch. If it is determined that this is not the case, that is, is the engine rotation speed N the lower limit rotation speed N? If it is recognized that the above is the case, proceed to step (e) and output the fuel cut signal A, or
) Maintain the output state of signal A. On the other hand, it is determined that the transmission state between the engine and the driving wheels is cut off, and step (C)
), first the engine speed N is the lower limit speed N? Compare whether or not it is lower than , and if it is determined to be lower, proceed to step (f), and
If you are at the river at traffic light A, you can easily use that traffic light for a fuel car.
switch to the reset signal B. Then, at the same time as outputting a fuel cant release signal B, a fuel discharge signal C is outputted,
Operate the pump a predetermined number of times ('N7 times) to make up for the lack of fuel. If it is determined otherwise, that is, if it is determined that the engine rotational speed N is equal to or higher than the lower limit rotational speed N7, the process moves to step (g). In Ste Tubu (g),
Next, the engine rotation speed N is equal to the lower limit rotation speed N1 and the above-mentioned safe rotation speed N (for example).

1800 rpm),
If it is determined that this is the case, the process moves to step (h), and if it is determined that this is not the case, the process moves to step C+). In step (h), it is determined whether or not the fuel cut signal output A is being outputted, and if it is being outputted, that state is maintained, and if it is not being outputted, the fuel cut signal A is outputted. At this time, the fuel cut signal A is output, and at the same time, the fuel discharge signal C is also output, and the pump is operated a predetermined number of times (Cn+times) to make up for the lack of fuel. In addition, when moving to step (i), it is determined whether or not the fuel cut h g A is being outputted, and if it is being outputted, that state is maintained, and if it is not being outputted, the fuel cut signal A is outputted. Output.

The table for the lower leg shows the above procedures in an organized manner, and this table also includes control details that are omitted in FIG. 2. In other words, in this table, if the transmission state between the engine and the drive wheels is cut off before 1 second has elapsed since the engine speed N has fallen below the lower limit speed N1, the fuel cant is When the fuel cant is released, the pump 6 is driven to replenish fuel, but if the transmission state is cut off after one second or more has elapsed, the fuel cant is only released and no fuel is refilled.

With such a configuration, when the transmission state between the engine and the driving wheels is not disconnected, that is, when the clutch is connected and the transmission is running in a state other than neutral, the lower limit Rotation speed N7
The fuel cut is simply turned ON and OFF at the boundary. That is, the reference rate ΔN/Δ of the engine speed N
When T shows a negative value, it is determined that the vehicle is in a deceleration state, and a fuel cut is performed on the condition that the engine rotation speed N exceeds the lower limit rotation speed N1. Even if ΔN/ΔT is negative, when the engine speed N falls below the lower limit speed N2, the fuel cut is canceled and engine stall is avoided. On the other hand, if the power transmission between the engine and the drive wheels is suddenly cut off by pressing the clutch or neutral shifting the shift lever, in addition to the basic fuel cut control described above, more detailed control is required. It is done. In other words, when the vehicle is decelerating, the engine is forcibly rotated by the rotational force of the drive wheels, but if the transmission relationship between the engine and the drive wheels is suddenly severed at this time, the urging force on the engine will be reduced. It may suddenly disappear and the engine may stop. However, in this device, fuel is replenished from the pump 6 in areas where there is a risk of engine stalling, so engine stalling can be effectively avoided.

In this way, the engine speed control can be performed, but this device calculates the rate of change in the engine speed and determines the deceleration state depending on whether the calculated value shows a negative value or not. It also detects whether or not the transmission state between the engine and the driving wheels is cut off by comparing the calculated value with a predetermined reference rate of change, and based on these detection results, the fuel cut valve 5 The fuel adjusting means 4 including the fuel adjusting means 4 is controlled. Therefore, as long as the engine speed is detected, the necessary minimum control is possible, and there is no need for a clutch switch, neutral switch, idle switch, etc. that are essential in conventional devices.

Therefore, the number of parts can be reduced, assembly and adjustment can be simplified, and troublesome maintenance and inspection can be eliminated. Furthermore, if the above-mentioned values N1, Nt, and N1 are determined in advance through careful experiments, it will be easier to define the region where fuel can be cut than by using ON/OFF switches. It becomes possible to expand without difficulty. Therefore, fuel economy can be effectively improved.

Note that the configuration of the fuel adjustment means is of course not limited to that of the above embodiment. It is also possible to add an idle up mechanism that temporarily opens the throttle valve by a small amount when replenishing the fuel.

Further, the control of the fuel adjustment means by Mr. B is not limited to the above-mentioned method, and the determination result of whether or not the engine and the driving wheels are in a transmission state may be used as one piece of information when canceling the fuel cut. good. Specifically, if it is determined that the power transmission relationship between the engine and the drive wheels has been severed, it is possible to perform control such that the fuel cut is canceled regardless of the engine speed.

(F) Effects Since the present invention has the above-described configuration, it is possible to eliminate the inconvenience that the number of parts is small and that assembly, adjustment, maintenance, inspection, etc. are time-consuming. It is possible to provide a fuel cut device for a vehicle engine that can be easily expanded.

[Brief explanation of the drawing]

Fig. 1 is a system explanatory diagram showing one embodiment of the present invention;
The figure is a flowchart showing the control procedure of the same embodiment. l...Carburetor 2111111 Throttle valve 3...Float chamber 4...Fuel adjustment means 5ΦΦΦFuel cut/help 6...Pump 21...Arithmetic processing unit 22...Storage device 25゛Φ...Rotation Detection means agent Patent attorney Hiroshi Akazawa Figure 1

Claims (2)

[Claims] (1) The transmission state between the fuel adjustment means that is equipped with a fuel cut valve and adjusts the amount of fuel supplied to the carburetor, the rotation speed detection means that detects the engine rotation speed, and the engine and the drive wheels is cut off. a storage device that stores a rate of change in engine speed as a reference rate of change, which is a criterion for determining whether or not the engine speed is The deceleration state is detected based on whether the calculated value is indicated or not, and whether or not the transmission state between the engine and the driving wheels is disconnected is detected by comparing the calculated value with the reference rate of change, and based on these detection results. 1. A fuel cut device for a vehicle engine, characterized in that the fuel cut device for a vehicle engine is equipped with an arithmetic processing device that controls the fuel adjusting means. (2) The fuel regulating means is provided with a fuel intake valve for shutting off a fuel passage and a pump for supplying auxiliary fuel to the carburetor. A fuel cut device for a vehicle engine according to item 1.