JPS60159348A - Electronic-control type fuel injection device - Google Patents

Abstract

PURPOSE:To prevent any drop in an engine speed and the occurrence of an engine stall in spite of sudden deceleration in time of extremely low temperature, by setting a water temperature compensation factor to the smaller a value, the lower a colling water temperature at a time when the cooling water temperature comes under the extremely low temperature range. CONSTITUTION:In time of engine operation, a value this time is subtracted from the last value of throttle opening and thereby finds its deceleration at a throttle opening deceleration detecting device A, and when the value is positive, it is judged as being in deceleration and, according to the deceleration at that time, decrement is found at a decrement setting device D. Likewise, according to output of a cooling water temperature detecting device B, a water temperature compensation factor is found at a water temperature compensation factor setting device E, and a compensating fundamental injection quantity is calculated on the basis of the value and a fundamental injection quantity by the decrement value and a fundamental injection quantity operating device C. At this time, a water temperature compensation factor is to be set to the smaller a value, the lower a cooling water temperature when the cooling water temperature is below the specified, extremely low temperature range (for example, -20 deg.C).

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to an electronically controlled fuel injection device for an internal combustion engine installed in a vehicle such as an automobile. The present invention relates to an electronically controlled fuel injection device that can prevent the occurrence of engine depression or engine stall.

[Prior Art] As is well known, the electronically controlled fuel injection system determines the basic injection amount based on the engine speed and the intake air amount, and adds corrections to this basic injection amount according to other engine operating conditions. , determines the final fuel injection amount (valve opening time) by the injector.

As one of these corrections, when decelerating while driving in the D (drive) range, a fuel reduction value is calculated based on this deceleration and the engine cooling water temperature, and this reduction value is subtracted from the basic injection amount. There is deceleration reduction control that improves fuel efficiency by reducing fuel consumption.

However, according to an electronically controlled fuel injection system that performs this type of deceleration reduction control, when the cooling water temperature is in the extremely low temperature range of -20°C, for example, the engine speed may drop or the engine speed may drop during sudden deceleration. There were times when a stall occurred.

OBJECT OF THE INVENTION 1 The present invention aims to solve the above-mentioned problems, and aims to prevent the occurrence of engine stall when the engine speed drops by properly performing deceleration reduction control at extremely low temperatures. .

[Structure of the Invention] Therefore, on the electronic type 1111 fuel injection device side of the present invention, as shown in FIG. C, a reduction value setting means for determining a reduction value according to the throttle opening deceleration, and a water temperature correction coefficient according to the cooling water temperature, which is smaller as the cooling water temperature is lower when the cooling water temperature belongs to a predetermined extremely low temperature range. a main correction coefficient setting means E that determines what will be the value, and a corrected basic injection amount calculation means that calculates the corrected basic injection amount by subtracting the multiplication value of the decrement value and the water temperature correction coefficient from the basic injection 1'l amount. It is characterized by comprising F and.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 2 to 5.

FIG. 2 shows a schematic electrical block diagram of the electronically controlled fuel injection system of this embodiment. In the figure, 1 is a rotation sensor, 2 is an air 70 meter, 3 is a throttle position sensor, and 4
5 is a cooling water temperature sensor, 5 is another operating state detection means such as an intake air temperature sensor, 6 is an arithmetic control circuit with a built-in microcomputer, 7-1, . . . , 7-n are injectors, 8 is a battery, and 9 is a Represents the ignition switch.

The arithmetic control circuit 6 includes a CPU 6-1, a ROM 6-2, and an RA.
Equipped with a microcomputer consisting of M6-3, input port row 4, etc., and a drive circuit 6-5 for driving injectors 7-1, . . . 7-n, which are electrically connected to each other via a common bus 6-6. has been done.

When the ignition switch 9 is turned on, the cpus-i periodically executes the process shown in FIG. 3, which is a process according to the present invention.

This process subtracts the current value TA now from the previous value TA old of the throttle opening to obtain the throttle opening deceleration ΔTA, and then determines whether or not this ΔTA is positive, that is, whether or not it is during deceleration. If it is determined that it is the time of deceleration, the decrement value is determined from the requested throttle opening deceleration ΔTA, and the water temperature correction coefficient K is determined from the cooling water temperatures TH and W, and the basic injection amount T+1 is determined. The corrected basic injection amount, that is, the corrected basic injection II4! by subtracting the multiplication value KD of the reduction value and the water temperature correction coefficient from ! The main content is to understand T″p.

Here, the reduction value is determined to have the characteristics shown in Fig. 4 with respect to the throttle opening deceleration ΔTA.
The larger the TA, the larger the value. In addition, the water temperature correction coefficient is determined to have the characteristics shown in Fig. 5 with respect to the cooling water temperature THW, and when TI-IW is in the temperature range Z1 higher than a predetermined value THWo, for example -20°C, , takes a larger value as the temperature decreases, and on the other hand, when THW is in the extremely low temperature region z2 of 120 degrees Celsius or less, it takes a smaller value as the temperature decreases, contrary to the above temperature region Z1. Ru. The weight loss value and water temperature correction coefficient having such characteristics are each stored in the ROM 6-2 as a map. However, it is free to determine it by calculation using an approximation formula of this characteristic.

Therefore, during rapid deceleration in the extremely low temperature range, the water temperature correction coefficient K becomes a small value, so the corrected reduction value KD becomes a sufficiently small value, and the corrected basic injection amount TD is compared with the basic injection amount Tp. The value is close to the target.

This prevents the combustion energy in the cylinder from dropping below the desired level, ensuring sufficient combustion energy to overcome the relatively large engine load at extremely low temperatures, thereby preventing a drop in engine speed and the occurrence of engine stall. can do. Note that the water temperature correction coefficient may have a characteristic as shown by the dashed-dotted line in FIG. 5 in the extremely low temperature range.

[Effects of the Invention] As explained above, according to the present invention, when the cooling water temperature belongs to a predetermined extremely low temperature range, the water temperature correction coefficient is set to a smaller value as the cooling water temperature becomes lower. At times, sufficient injection quantity is secured to generate combustion energy sufficient to overcome relatively large *lQ loads, and II
It is possible to prevent the A engine rotational speed from dropping and the occurrence of engine stall. Therefore, it can be expected that drivability will be improved and deterioration of the m-rings will be prevented.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram for clearly explaining the present invention, FIGS. 2 to 5 are one embodiment of the present invention, and FIG. 2 is an electrical block diagram schematically showing the overall configuration. FIG. 3 is a flow chart showing the processing according to the present invention, and FIGS. 4 and 5 show characteristic diagrams of the reduction mIt1 and the water temperature correction coefficient, respectively. A...Throttle opening deceleration detection means B...Cooling Honpo detection means C...Basic injection amount calculation means D...Reduction value setting means E...Water temperature correction coefficient setting means F...Correction Basic injection amount calculation means Agent: Patent attorney Tsutomu Sadatsu and one other person Figure 1 Figure 3

Claims (1)

[Scope of Claims] Throttle opening deceleration detection means, cooling water temperature detection means, basic injection amount calculation means, and a reduction value that determines a reduction value according to throttle opening deceleration! a water temperature correction coefficient setting means for determining a water temperature correction coefficient according to the cooling water temperature, which becomes a smaller value as the cooling water temperature is lower when the cooling water temperature belongs to a predetermined extremely low temperature range; An electronically controlled fuel injection device comprising: corrected basic injection amount calculation means for calculating a corrected basic injection amount by subtracting the sum of the reduced m value and a water temperature correction coefficient from the amount.