JPS60247033A - Electronically controlled fuel injection device in internal-combustion engine - Google Patents

Abstract

PURPOSE:To set the recovery rotational speed to a low value to enhance the fuel consumption rate, by providing an interrupt pulse delivering means for delivering an interrupt pulse to a fuel injection valve when a recovering means detects such a condition that fuel injection is restarted. CONSTITUTION:A recovering means D restarts the operation of a fuel injection pulse delivering means B when the rotational speed of an engine becomes below the recovery rotational speed during resting of fuel injection by a fuel-cut means C. When the recovering means D detects the condition of starting of fuel injection, an interrupt pulse delivering means E delivers an interrupt signal to a fuel injection valve A. Thus, the recovery rotational speed may be set to a lowermost value, thereby it is possible to enhance the fuel consumption rate.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electronically controlled fuel injection device for an internal combustion engine that has a function of stopping the supply of fuel to the engine under predetermined operating conditions of the engine.

<Prior Art> Conventionally, in internal combustion engines for vehicles, fuel supply to the engine has been stopped when engine output is not required, such as when decelerating or dismounting, in order to improve fuel efficiency. (Refer to Japanese Patent Application Laid-Open No. 107927/1984, etc.).

In other words, for example, when decelerating, the throttle valve is fully open (
If the engine speed is equal to or higher than the preset fuel cut speed Nc when the idle switch is turned ON, the fuel supply will be stopped and the throttle valve will open or the engine speed will be set in advance. Cover rotation speed N, (however, N r
When the vehicle has descended to <N c ), fuel supply is restarted.

<Problems to be solved by the invention> However, in electronically controlled fuel injection devices for internal combustion engines,
A fuel injection valve is provided for each cylinder in the intake manifold or commonly for all cylinders upstream of the throttle valve, and a fuel injection pulse corresponding to the engine operating state is sent to the fuel injection valve at a predetermined timing in synchronization with the engine rotation. In this way, in an intermittent injection system that injects fuel at a predetermined timing in synchronization with engine rotation, the fuel injection starts after the fuel injection valve stops supplying fuel. The condition for restarting is that even if the engine speed falls below the recovery speed N, fuel injection will not be performed until the predetermined timing arrives, and even if the engine speed drops during that time, and even if fuel injection is restarted. Since the mixture ratio will not reach normal explosion until several revolutions are made, the revolution speed will drop due to this, and considering engine stall, the recovery revolution speed N must be set high. However, there was a problem in that it was disadvantageous in terms of fuel efficiency.

Therefore, the present invention enables prompt resumption of fuel injection in an electronically controlled fuel injection device for an intermittent injection system, and
The purpose is to make it possible to reduce the recovery rotation speed Nr to the lowest possible level, thereby further improving fuel efficiency.

Means for Solving the Problems> For this reason, the present invention, as shown in FIG. A fuel injection pulse output means B that outputs a fuel injection pulse, a fuel cut means C that stops the operation of the fuel injection pulse output means B when the throttle valve is fully closed, and a fuel cut means C that stops the operation of the fuel injection pulse output means B, and when the fuel cut means C stops fuel injection, the engine speed increases and the cover rotation speed increases. In addition to being provided with a recovery means for restarting the operation of the fuel injection pulse output means BQ when the fuel injection pulse output means BQ becomes lower than or equal to An interrupt pulse output means E is provided which outputs an output to the fuel injection valve A regardless of the fuel injection valve A.

According to this, when the operation of the fuel injection pulse output means B is stopped by the fuel cut means C and the fuel injection is stopped, the engine speed reaches the recovery speed at time t in FIG. When the number of revolutions is below N1, the operation of the fuel injection pulse output means B is restarted by means of recovery, but at this time, that is, at time t1 when the number of rotations of the cover becomes equal to or less than N1, the operation of the fuel injection pulse output means B is activated by the interrupt pulse output means E. An interrupt pulse is output, an interrupt injection is performed, and thereafter, a normal fuel injection pulse is output at a predetermined timing in synchronization with the engine rotation by the fuel injection pulse output means B, and normal fuel injection is performed.

<Example> Examples will be described below.

In Fig. 3, 1 is the engine, 2 is the intake pipe, and 3 is the intake pipe 2.
4 is an electromagnetic fuel injection valve that injects and supplies fuel to the engine 1, and 5 is a fuel pipe that supplies fuel from a fuel pump (not shown) to the fuel injection valve 4.

6 is a microcomputer, an air flow meter 7 for measuring the flow rate of intake air flowing through the intake pipe 2, and an engine 1.
Signals are input from a crank angle sensor 8 that outputs a pulse signal according to the rotation of the crankshaft, an idle switch 9 that detects the fully closed state of the throttle valve 3, etc., and based on these, calculations and processing are performed to drive the Driving power is supplied to the fuel injection valve 4 via the circuit 1o.

Here, normally (other than during fuel cut), according to the following formula,
Determine the fuel injection amount and generate the corresponding fuel injection pulse T
are applied to the fuel injection valve 4 via the drive circuit 10 at a predetermined timing in synchronization with the engine rotation (for example, once per rotation) to inject fuel.

T = = to - (Q/N) ・C0EF+T.

However, K is a constant, Q is the intake air flow rate, N is the rotation speed, and C0
EF is various correction coefficients, and Tr is voltage correction.

Fuel cut and fuel cover control are performed based on the flowchart shown in FIG.

At Sl, it is determined whether the throttle valve 3 is fully closed or not based on 0N10FF of the idle switch 9, and if it is fully closed, the process advances to s2.

In S2, it is determined whether the fuel is being cut or not, and if the fuel is not being cut, the process proceeds to S3.

In S3, it is determined whether or not the engine speed N is equal to or higher than the fuel cut rotation speed NC at which fuel cut can be started. If it is higher than Nc, the process proceeds to S4 and the output of the fuel cut (normal fuel injection pulse T) is determined. (prohibited) and does not perform fuel cut if it is less than Nc.

If it is determined in S2 that the fuel is being cut, the process proceeds to S5 where it is determined whether the engine speed N is equal to or less than the recovery rotation speed Nr.If not, the fuel cut is continued, but the recovery rotation speed N, In the following cases, proceed to S6.

In S6, an interrupt pulse is output to cause the fuel injection valve 4 to perform an interrupt injection. Incidentally, the interrupt pulse may be predetermined as a constant value so that the optimum mixture ratio is achieved in one shot, or may be determined by search or calculation depending on the operating state.

Then, in the next step 87, the fuel cut is canceled, and thereafter, fuel injection is performed by a fuel injection pulse at every predetermined timing.

If the throttle valve 3 is not fully open as determined by Sl,
The process proceeds to step S8 to determine whether or not the fuel cut is in progress, and if the fuel cut is in progress, the process proceeds to step S7 to cancel the fuel cut. still,
At this time, the process may proceed to 86 to perform interrupt injection.

It is preferable that the fuel cut rotation speed Nc and the recovery rotation speed N are set according to the engine cooling water temperature as shown in FIG.

<Effects of the Invention> As explained above, according to the present invention, after fuel power and
Since the interrupt injection is performed the moment the engine speed falls below the recovery speed, the recovery speed can be kept as low as possible, which is advantageous in terms of fuel efficiency.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is a time chart showing the operation of the present invention, FIG. 3 is a schematic diagram showing an embodiment of the present invention, FIG. 4 is a flowchart of the same, and FIG. FIG. 5 is a characteristic diagram of the fuel cut rotation speed and the recovery rotation speed. 1... Engine 3... Throttle valve 4... Fuel injection valve 6... Microcomputer 9... Idle switch 10... Drive circuit

Claims (1)

[Claims] The fuel injection pulse output means outputs a fuel injection pulse according to the engine operating state to the fuel injection valve at a predetermined timing in synchronization with engine rotation, and the operation of the fuel injection pulse output means is stopped when the throttle valve is fully closed. and a recovery means for restarting the operation of the fuel injection pulse output means when the engine rotation speed becomes equal to or less than a predetermined recovery rotation speed while fuel injection is stopped by the fuel cut means. An internal combustion controlled fuel injection device, characterized in that an interrupt pulse output means is provided for outputting an interrupt pulse to the fuel injection valve regardless of the timing when the recovery means detects a condition for restarting fuel injection. The engine's electronically controlled fuel injection system.