JPS5919797Y2 - fuel injected internal combustion engine - Google Patents

Description

[Detailed description of the invention] This invention is applicable to automobiles that have a power steering device and a fuel-injected internal combustion engine (hereinafter also referred to as the engine).
The present invention relates to an engine equipped with a power steering device that has a mechanism that prevents the engine rotational speed from becoming unstable or prevents the occurrence of engine stalling when power steering is performed during a fuel cut.

Generally, when an engine is decelerating, when the engine speed exceeds a certain set rotation speed and the throttle valve is close to being fully closed, fuel is cut in order to improve fuel efficiency and reduce emissions.

Therefore, in order to improve fuel efficiency, it is desirable to set the fuel cut return (cancellation) rotation speed low and to lengthen the fuel cut.

However, if the fuel cut return rotation speed is set too low, the idle rotation speed immediately after the fuel cut return will undershoot, causing rough idling or even stalling in some cases.

Therefore, the fuel cut return rotation speed is set to the lowest possible rotation speed without causing the rough idle or engine stall.

Furthermore, conventionally, automobiles have been equipped with a so-called power steering device that uses the engine to drive a power steering pump (hereinafter also referred to as PS pump) and uses the hydraulic pressure generated by the engine to drive a power cylinder to assist the driver in steering the vehicle. There is.

In a vehicle equipped with the above-mentioned engine and such a power steering device, when the driver turns the power steering, the PS pump is activated, and the frictional horsepower of the entire engine is increased by adding the driving horsepower of the PS pump to the power steering. It increases compared to when there is no device.

Particularly when the engine is stationary, the drive horsepower of the PS pump becomes a very large proportion of the friction horsepower of the entire engine.

Therefore, if the fuel cut return speed of an engine without a power steering device is set as the fuel cut return speed of an engine with power steering, the engine speed will drop quickly even if the engine returns from fuel cut during PSS shift operation. Problems such as rough idling and engine stalling occur.

If the fuel cut return rotation speed is set at a high rate in a vehicle equipped with power steering to prevent this problem from occurring, another problem occurs in that the fuel cut period becomes shorter and fuel efficiency worsens.

This invention aims to eliminate the above-mentioned drawbacks in engines with power steering devices.

This invention will be explained below based on drawings showing embodiments.

FIG. 1 shows a block diagram of a first embodiment. In the figure, 1 indicates a PS pump.

1 communicates with a steering gear box (not shown) through a pressure oil passage 2 and a return passage 3.

A pressure sensor 4 of the ON-OFF type (ON when the oil pressure is below a set value, OFF when the oil pressure is at or above the set value) is attached to the pressure oil path 2 of the PS pump 1.

Reference numeral 5 denotes a cut release circuit, which is composed of an engine speed conversion circuit 6 and an AND circuit 7.

The engine rotation speed conversion circuit 6 is connected to the engine rotation speed output from the waveform shaping frequency dividing circuit 10 via the electric line 11 and the electric line 9.
The oil pressure signal of the PS pump 1 is input through the circuit 6, and the circuit 6 changes the fuel cut return rotation speed n in stages as shown in FIG. n is compared with the engine speed taken in from the waveform shaping frequency dividing circuit 10, and when the fuel cut return speed n is larger, the engine speed conversion circuit 6 outputs "'l".

An electrical circuit connects the AND circuit 7 to the throttle position switch 8 (which is turned on when the throttle valve is close to fully closed and "l"
The output signal from the engine speed conversion circuit 6 and the output signal from the engine rotation speed conversion circuit 6 are input.

When the output of the engine speed conversion circuit 6 and the output of the throttle position switch 8 are both 1, the AND circuit 7 issues a fuel cut release signal.

(Conversely, when the output of the AND circuit 7 is O, fuel cut is performed.

) The ignition-next signal is input to the waveform shaping/frequency dividing circuit 10, which circuit 10 shapes this to calculate the engine speed and outputs it to the AND circuit 6 via the electric line 11 as described above. 12 to the divider circuit 13.

An air flow rate signal air flow rate from an air flow meter (not shown) is input to the division circuit 13, and the division circuit 13 calculates the air flow rate and inputs the signal to the multiplication circuit 15 via the electric line 14.

A correction signal based on, for example, engine water temperature and intake air temperature is input to the multiplication circuit 15.

On the other hand, a cut release signal from the AND circuit 7 is transmitted to the electric line 14 via the electric line 16.

As a result, the multiplier circuit 15 corrects the signal from the divider circuit 13 using the increase correction signal and outputs it to the output stage 17.
7 operates the fuel injection valve 18.

Note that when the cut release signal is not transmitted to the electric line 14, the multiplier circuit 15 does not operate, so the fuel injection valve 18 also does not operate.

Furthermore, the area within the frame of the two-dot chain line indicated by arrow A1 indicates a fuel injection controller.

The operation of the above configuration will be explained as shown in the following table under the condition that the throttle position switch is ON.

Further, as a second embodiment, an 0N-OFF type pressure sensor 4
Instead, a pressure sensor 4 that outputs a linear output according to the output of the PS pump 1 is used.

In the engine speed conversion circuit 6, the fuel cut return speed n is linearly changed according to the PS pump pressure as shown in FIG. , controls the fuel cut return rotation speed.

The following details are the same as those in the first embodiment and will therefore be omitted.

As described above, by using the present invention, when the power steering is activated, the fuel cut recovery rotation speed becomes high, and problems such as rough idling and engine stalling do not occur when the fuel cut is restored, and when the power steering is not activated, the fuel cut recovery speed is increased. This has the excellent effect of keeping the cut return rotation speed low and preventing deterioration of fuel efficiency.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an embodiment of this invention including an engine speed conversion circuit, and Figs. 2 and 3 show P on the horizontal axis.
FIG. 3 is a characteristic diagram of the engine rotational speed conversion circuit in which the S pump oil pressure and the fuel cut return rotational speed are plotted on the vertical axis. 1...PS pump, 5...Fuel cut release circuit.

Claims (1)

[Scope of utility model registration request] A power steering device that assists steering operation,
Fuel is cut when the engine speed is above the first set speed with the throttle valve closed, and when the engine speed falls from the first set speed to the second set speed while fuel is being cut, the fuel is cut. A fuel injection type internal combustion engine is provided with a fuel cut device for releasing the power steering device, the engine having a mechanism for increasing the second set rotation speed in response to an increase in oil pressure of a power steering pump that operates the power steering device. Features a fuel-injected internal combustion engine.