JPS63239330A - Fuel supply shutdown device for internal combustion engine - Google Patents

Abstract

PURPOSE:To aim at control over a decelerating shock, by stopping a fuel supply after the elapse of the delay time set according to an opening or closing state of an on-off valve, at the time of a fuel cut under the specified decelerating driving conditions, in case of a device which installs the on-off valve in one side of two suction ports. CONSTITUTION:In case of a device which has two suction ports A and B at each cylinder, and installs an on-off valve C to be opened or closed by a valve driving device D, in the suction port B on one side, there is provided with a fuel stop condition judging device F which judges whether a fuel stop condition is materialized or not when the decelerating driving of an engine is detected by a detecting device E. Also, there is provided with a valve opening-closing detecting device G which detects an opening or closing state of the on-off valve C at time of decelerating drive starting, and according to the detected result, delay time ranging from fuel stop condition materialization to fuel supply stopping is set by a delay time setting device H. And, when the fuel stop condition is materialized, actuation of a fuel supplying device I is stopped after the said set delay time, by a fuel supply stopping device J.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a fuel supply stop device for an internal combustion engine that stops the fuel supply under predetermined deceleration operating conditions.
Relating to one with two intake ports.

<Prior art> Conventionally, in an internal combustion engine equipped with an electronically controlled fuel injection device, fuel injection is stopped in a predetermined deceleration operating state (when the throttle valve is fully closed and the engine speed is above a predetermined value N1). There is one that aims to improve exhaust emission characteristics and fuel efficiency during deceleration (see Japanese Patent Laid-Open No. 59-203827).

In addition, when fuel supply is stopped immediately after deceleration operation, sudden torque fluctuations may occur, which may worsen riding comfort.To prevent this, the deceleration operation detection means is delayed by a predetermined delay time to reduce the torque. Some models also stop fuel injection after the

Here, the delay time is changed and set based on the engine cooling water temperature and the engine rotation speed.

<Problems to be Solved by the Invention> However, in such a conventional fuel supply stop device, the delay time is set based on the engine cooling water temperature and the engine rotation speed, so the following problems occur. was there.

That is, during low load operation, there is less liquid fuel (hereinafter referred to as wall flow fuel) flowing along the walls of the intake passage, while during high load operation, there is more wall flow fuel. For this reason, when decelerating from a low load range, the air-fuel ratio tends to become lean, causing deceleration wrinkles due to over-leaning. On the other hand, when decelerating from a high load range, the room-fuel ratio tends to become over-rich, causing deceleration shock due to over-richness. There is a problem that ・・・・ri occurs and deceleration drivability deteriorates.

In particular, the above-mentioned problems are noticeable in engines that are equipped with two intake ports for each cylinder, and in which an on-off valve installed in one of the ports is opened in a high-speed, high-load operating range.

The present invention was made in view of the above-mentioned circumstances, and has two
An object of the present invention is to provide a fuel supply stop device that can improve deceleration drivability while improving exhaust emission characteristics and fuel efficiency in an internal combustion engine equipped with an on-off valve on one of two intake ports.

Means for Solving the Problems〉 Therefore, as shown in FIG.
two intake ports A, B, and an on-off valve C interposed in one of these intake ports A, B.
and a deceleration operation detection means E for detecting deceleration operation of the engine.

When deceleration is detected, the engine operating status is ff! j
&',''IS A fuel stop condition determining means F for determining whether a fuel stop condition is satisfied; and a valve opening/closing detection means G for detecting the open/close state of the on-off valve C at the start of deceleration operation. ,
A delay time setting means I for setting a delay time from the time when the fuel stop condition is met until the fuel supply is stopped according to the detected open/close state of the on-off valve C (and the delay time from when the fuel stop condition is met until the fuel supply is stopped). a fuel supply stop means J that stops the operation of the fuel supply means (■) after the delay time elapses;
We prepared the following.

Effect> In this way, the delay time is changed depending on the open/close state of the on-off valve, and it is possible to cope with wall flow fuel.

<Example> An example of the present invention will be described below based on FIGS. 2 to 4.

In Figure 2, each cylinder has the first and second intake bow) IA
, IB are formed, and these first and second intake ports],
A, iB are interposed with first and second intake valves 2A, 2B. A butterfly-type on-off valve 3 is interposed in the second intake port 2B, and this on-off valve 3 is driven to open and close by a valve driving device 4 comprising a negative pressure actuator or the like.

Further, a fuel injection valve 5 is provided so as to inject fuel toward the first intake port 18, which is always open. The fuel injection valve 5 and the valve driving device 4 are driven and controlled by a control device 6 consisting of a microcomputer or the like.

The control device 6 includes a rotational speed sensor 7 that detects the engine rotational speed, an air flow meter 8 that detects the intake air flow rate, and an intake throttle valve opening sensor that serves as a deceleration operation detection means that detects the intake throttle valve opening degree. Detection signals are input from the sensor 9 and the sensor 9, respectively.

Here, the control device 6 operates according to the third flower 1 and controls the fuel injection valve 5.

Here, the control device 6 constitutes a deceleration operation detection means, a fuel stop condition determiner j], a valve opening/closing detection means, and a fuel supply stop means, and the valve drive device 4 and the control device 6 constitute a valve drive means. do.

Note that 1.10 is the combustion chamber, Xl is the spark plug, 12A, 12
B is the first and second exhaust valves.

Next, the operation will be explained according to the flowchart shown in FIG.

Sl reads various signals from the rotational speed sensor 7, etc.

In S2, it is determined whether or not deceleration operation is being performed, and if YES, the process proceeds to S3, and if NO, the routine is ended. This deceleration operation is determined based on the rate of change in the intake throttle valve opening detected by the intake throttle valve opening sensor 9.

In S3, it is determined whether the fuel stop condition is satisfied, and Y
When the answer is ES, the process advances to S4, and when the answer is NO, the process advances to S11. This fuel stop condition is determined by comparing the lower limit value of the engine rotation speed for the stop condition stored in the map as a function of the engine cooling water temperature with the actual engine rotation speed.

In S4, it is determined whether the fuel stop condition is satisfied for the first time,
When the answer is YUS, the process proceeds to S5, and when the answer is NO, the process proceeds to S6.

In S5, it is determined whether the on-off valve 3 is opened or closed at the start of deceleration, and when it is fully closed, the process proceeds to S7, and when it is fully open, the process proceeds to S8.

Here, the on-off valve 3 controls the engine rotation speed and the basic injection ITp (
= load) and are driven to open and close according to another routine. Specifically, as shown in FIG. 4, the on-off valve 3 is fully opened in a high-speed, high-load operating range where both the engine rotational speed and the basic injection amount Tp are above a predetermined value, while the on-off valve 3 is fully opened in a low-speed, low-load operating range where the engine rotational speed and basic injection amount Tp are both above a predetermined value. The opening/closing valve 3 is controlled to be fully closed in the load operating range.

In S7, the delay time Tt when the on-off valve 3 is fully closed is set to, for example, 600 m5ec, while in S8, the on-off valve 3
For example, the delay time T when fully opened is set to 0 m5ec.

In this way, the delay time is set the first time the fuel stop condition is met.

In S6, from the time when the fuel stop condition is satisfied for the first time, in S7
Alternatively, it is determined whether the delay time set in S8 has elapsed, and if YFS, the process advances to S9, and if NO, the process advances to 310.

In S9, the output of the actuation signal to the fuel injection valve 5 is stopped,
While the injection operation of the fuel injection valve 5 is stopped, the injection operation of the fuel injection valve 5 is continued in SIO.

In SLL, it is determined whether the recovery condition is satisfied or not,
If YES, proceed to S12; if NO, proceed to S9
Proceed to continue the fuel supply stop operation. This recovery condition is determined by comparing the lower limit value of the engine rotation speed for recovery stored in the map as a function of the engine cooling water temperature with the actual rotation speed.

In S12, the injection operation of the fuel injection valve 5 is restarted.

In this way, when the fuel stop condition is met during deceleration driving, the fuel stop operation is performed after the delay time set in S7 or S8 has elapsed until the fuel stop condition is satisfied, so that It is possible to improve exhaust emission characteristics and fuel efficiency. At this time, since the delay time is set to be extremely short (Qn+5ec in this example) during deceleration operation from the high speed, high load operation range where the on-off valve 3 is fully opened, the fuel stop operation is started immediately after the fuel stop condition is satisfied. . Therefore, even if there is a large amount of wall flow fuel, the air-fuel ratio can be prevented from becoming overrich, and deceleration shock can be suppressed. In addition, the delay time is made relatively long during deceleration operation from the low-speed, low-load operation range where the on-off valve 3 is fully closed.
Even if the fuel stop condition is met, fuel supply continues during the delay time. Therefore, even if the wall flow fuel is small, the air-fuel ratio can be prevented from becoming overly lean, and deceleration lock can be suppressed.

<Effects of the Invention> As explained above, the present invention changes the delay time according to the opening/closing state of the on-off valve, so it is possible to maintain an appropriate air-fuel ratio during deceleration operation from a wide range of operating ranges. It is possible to suppress deceleration shock.

[Brief explanation of the drawing]

Fig. 1 is a claim correspondence diagram of the present invention, Fig. 2 is a configuration diagram showing an embodiment of the present invention, Fig. 3 is a flowchart of the same as above,
FIG. 4 is a diagram for explaining the same effect as above.

Claims (1)

[Claims] In an internal combustion engine, each cylinder is provided with two intake ports, an on-off valve separated into one of these intake ports, and a valve driving means for driving the on-off valve to open and close depending on the engine operating state. a deceleration operation detection means for detecting deceleration operation; a fuel stop condition determination means for determining whether a fuel stop condition is satisfied according to the engine operating state when deceleration operation is detected; valve opening/closing detection means for detecting the open/closed state of the on-off valve; and delay time setting means for setting a delay time from the time when a fuel stop condition is satisfied until the fuel supply is stopped according to the detected open/closed state of the on-off valve. and a fuel supply stop means for stopping the operation of the fuel supply means after the set delay time elapses from the time when the fuel stop condition is satisfied.