JPH04203229A - Fuel injection control device - Google Patents

Abstract

PURPOSE:To precisely suppress increase of an engine speed by judging operation modes of fuel supply situation under a low speed condition of an engine, and outputting a correction signal of fuel injection so as to decrease an output temporarily when an air conditioner is set OFF under the low speed condition of the engine. CONSTITUTION:A fuel injection system has a control unit 20 including a fuel injection control part 21 in which an engine speed Ne, a water temperature Tw, an intake amount Q of an air flow meter 6 and the like are input to calculate a reference injection pulse width Tp, the pulse width Tp is corrected by the requirement of the water temperature Tw or the like to obtain a fuel injection pulse width Ti, and the pulse width Ti is optimumly set. An output lowering correction part 24 is further provided on the control unit 20. The correction part 24, which has an air conditioner setting OFF detecting part 25, a fuel cut setting part 30, a fuel gradual-decrease setting part 31 and a fuel decrease setting part 32, sets gradual-decrease of the fuel when an air conditioner setting OFF signal is input and an operation mode detected by an operation mode judging part 23 is a low speed running mode, while sets decrease of fuel with deceleration under a low speed.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a fuel injection control device that electronically controls fuel injection in a vehicle engine according to each operation and various conditions. Air conditioner O under driving conditions
This relates to measures to prevent a momentary increase in engine speed during FF.

[Conventional technology]

In the intake system of vehicle engines, a method has become popular in which the number of intake valves is increased to improve charging efficiency and engine output under medium and high loads. The volume of the F flow is set to be large due to the intake chamber, intake manifold, etc. In this type of engine, when the engine is running at low speeds, even if the intake air volume is reduced by turning off the air conditioner, a large amount of air remains in the intake manifold of the throttle body, so there is no substantial response to reduce the air volume. There is a relatively large delay. Coupled with this, the amount of fuel injected into the cylinder does not decrease due to a delay in the amount of fuel injected from the injector, a delay in the amount of injection due to the slowing of the measurement of the amount of intake air, and a delay in evaporation of the amount of fuel 01 arriving. This causes an instantaneous increase in the engine speed immediately after the air conditioner is turned off, which may cause discomfort and a feeling of stiffness due to increased vibrations while the vehicle is stopped or driving at low speeds. Therefore, in engines whose intake system volume is increased, it is necessary to appropriately prevent the engine speed from increasing by 11-1 when the air conditioner is turned off at low engine speeds using the engine's control system such as fuel injection. desired.

Conventionally, there is a prior art technique for controlling fuel injection in relation to an air conditioner, for example, as disclosed in Japanese Unexamined Patent Publication No. 59-65080. Here, the basic fuel injection amount according to the engine speed and suction pipe pressure is corrected based on information from sensors that detect the operating status of auxiliary equipment such as car coolers, and the opening time of the fuel injection valve is controlled. It has been shown that

[Problem to be solved by the invention]

By the way, in the prior art described above, when the load on the engine increases due to the operation of auxiliary equipment such as a car cooler, the amount of fuel injection is increased to increase output, and when the auxiliary equipment is not activated, the amount of fuel injection is reduced. It is assumed that it will return to normal. Therefore, with such fuel injection control, it is not possible to forcibly prevent the engine rotation from increasing.

The present invention has been made in view of these points.
The target is turning off the air conditioner when the engine speed is low.
An object of the present invention is to provide a fuel injection control device that can appropriately control fuel injection and reduce engine rotation during engine rotation in a responsive manner.

[Means to solve the problem]

In order to achieve the above object, the fuel injection control device of the present invention provides a fuel injection control system that electronically sets and controls the fuel injection pulse width according to various operating conditions. It is equipped with an operation mode determination means for determining each operation mode, and an output reduction compensation means for outputting a fuel injection correction signal that temporarily lowers the output when the air conditioner is turned off at low engine speed. It is.

[For production]

Based on the above configuration, the conditions of low engine speed when stopping or driving are determined, and when the air conditioner is turned off at this time, the fuel injection pulse width is corrected and controlled to reduce the output, thereby increasing the volume of the intake system. It is large and a large amount of air remains when the air conditioner is turned off, increasing the amount of evaporation of adhering fuel, preventing the engine output from increasing by 1, and effectively reducing the engine speed.
It becomes possible to suppress the rise by 1.

〔Example〕

Hereinafter, embodiments of the present invention will be described based on the drawings.

In FIG. 1, the configuration of the electronic control system for the air conditioner and fuel injection will be explained as follows: air conditioner switch 1, engine rotation sensor 2. Throttle opening sensor 3. Vehicle speed sensor 4
．． It has human power information detection means such as a water temperature sensor 5. To explain the air conditioner control system, the actuation signal of the air conditioner switch 1 is input to the driving means 10, and in the case of an ON signal, at least the capacitor fan motor 11. The electromagnetic clutch 13 of the compressor I2 is operated to cool the passenger compartment.

In addition, the operation signal of this air conditioner switch 1, each sensor 2
．． Signals of the engine rotational speed Ne, throttle opening α, and vehicle speed V of 3.4 are manually input to the air conditioner control unit 14 to determine the driving state of idling when the vehicle is stopped or low-speed driving. The air conditioner control system in these low engine speed operating states opens the idle control valve 18 provided in the bypass passage 17 of the throttle valve 16 of the throttle body 15 to prevent engine stalling and improve cooling capacity. It is composed of

Next, the fuel injection control system will be explained. Signals such as engine speed Ne, water temperature Tw, and intake air amount Q of the air flow meter 6 are sent to the fuel injection control section 21 of the control unit 20.
Enter. Then, the basic injection pulse width Tp is calculated based on these signals, and this basic injection pulse width Tp is calculated based on the water temperature T.
Find the fuel injection pulse width T1 by correcting it with factors such as w, and optimally set the fuel injection pulse width Ti under all engine operating conditions, including when the above-mentioned eye control valve 18 is opened. This fuel injection signal is then output to the injector 22.

Therefore, in an engine in which the volume of the intake system downstream of the throttle valve is set to be large, measures to prevent the engine speed from increasing when the air conditioner is turned off will be explained.
It has an output drop correction section 24 at F time.

The control in this case is to control the idle control valve i when the air conditioner is turned on.
8 targets low-speed engine operation and running conditions in which the valve is opened, so the operating modes include a warm-up idle stop determination unit 27, a low-speed running determination unit 28, and a low-speed deceleration running determination unit 29.
has. The warm-up idle stop determination unit 27 determines ■=α-0 degrees in the fuel supply state.

When Ne≦11000rp and Tw≧90°C, the warm-up idle stop is interrupted by 1'11. The low-speed running determination unit 28 determines that V≦20 Km/h, 0 degrees and α≦10 in the fuel supply state.
Low-speed running is determined when Ne≦1.500 rpm and Tw≧60°C. The low-speed deceleration running determination unit 29 determines that in the fuel supply state, VS20 K m /h, a=O degree, N
When e≦1500 rpm and Tw≧80° C., low-speed deceleration running is determined.

On the other hand, the output reduction correction section 24 includes an air conditioner OFF detection section 25 to which the operation signal of the air conditioner switch 1 is input, and a fuel correction means corresponding to each operation mode.

Here, since it is necessary to quickly reduce the idle speed to a low idle speed when the vehicle is stopped, a fuel cut setting section 30 is provided in response to the warm-up idle speed. Then, when the air conditioner OFF signal from the air conditioner OFF detection section 25 is input, a fuel cut is set by setting the correction coefficient K to K = 0 for the set number of times, and this correction signal is output to the fuel injection control section 21 . Since it is necessary to secure a certain level of engine output during low-speed running, a fuel cut setting section 31 is provided in response to this requirement. Then, when the air conditioner OFF signal is input, the correction coefficient is set to 0<
K+Δ is set to ≦1.0, and after fuel decreases according to K, △
This supplementary 1F signal is output by setting a gradual decrease in fuel such that the fuel returns slowly with K.

Since the engine speed is higher during low-speed deceleration than when the vehicle is stopped, a fuel reduction setting section 32 is provided in response to this.

Then, when the air conditioner OFF signal is input manually, the correction coefficient K
O<K<1 for a set number of times. ．． The injected fuel is set to 0 and this correction signal is output. Fuel injection control section 21
is set to a predetermined injection amount by multiplying the fuel injection pulse width Ti by each of the above-mentioned correction coefficients K.

Next, the operation of this embodiment will be explained using the flowchart in FIG. 2 and the time chart 1 in FIG. 3.

First, when stopping or running when the engine is running, each switch and sensor signal is sent to the air conditioner and fuel injection control unit [4].
, 20 and processed. Therefore, when the air conditioner switch 1 is turned on, the fan motor 1 is activated by the drive means 10.
．． The L electromagnetic clutch I3 is activated to provide cooling. At this time, when the engine is in a high speed state where the throttle opening is greater than or equal to a predetermined throttle opening, the idle control valve 18 is closed and the compressor 12 is also sufficiently driven by the engine power in this case.

On the other hand, when the air conditioner is turned on, under conditions of low engine speed such as stopping or driving at low speed, the control unit 14 opens the idle control valve 18 and bypasses the throttle valve 16 to increase the intake air amount and control the engine output. increases, and the compressor is sufficiently driven to provide cooling. Also, when the air conditioner is turned off, the fan motor 11
stops, the electromagnetic clutch 13 is turned off, the cooling action is stopped, and the idle control valve 18 is closed, returning to the original low engine output state.

On the other hand, when switching to the air conditioner OFF, Fig. 2 (a,
) is executed, and in the case of a fuel supply state, each operation mode under low rotation conditions is determined. Therefore,
In the warm-up idle stop mode, the mode shifts to (+) fuel cut correction control, and the fuel injection is corrected to be cut a set number of times. Immediately after, the engine enters an operating state in which the injection signal is output intermittently, and the output is forcibly reduced. Therefore, in an engine with a large intake system volume, in situations where a large amount of air remains downstream of the throttle valve when the air conditioner is turned off, the intermittent injection signals cause a relatively large amount of air to be decimated and burned. The output will drop significantly and the actual amount of air used will also gradually decrease. Therefore, as shown in FIG. 3(c), the engine speed Ne is suppressed from increasing as indicated by the dashed line, and immediately drops to the idle speed due to a significant reduction in engine output.

Furthermore, when the low-speed driving mode is selected in the main routine of FIG. 2(a), the process shifts to the fuel reduction control of FIG.
As shown in Figure (e), fuel injection is controlled to decrease a set number of times. Therefore, the engine output is reduced, although not in duplicate, and the engine speed is similarly reduced to the level corresponding to the driving conditions. Furthermore, when the low speed deceleration driving mode is selected, (c
1), the fuel injection is reduced by a predetermined amount within a set time, as shown in FIG. 3(d), and then returned to the predetermined amount.

Therefore, in this case, the engine rotational speed Ne is similarly reduced while preventing a reduction in engine output that would impair driving.

Although the embodiments of the present invention have been described above, the present invention is not limited thereto. Further, any of the controls in the above embodiments may be selected and used.

〔Effect of the invention〕

As explained above, according to the present invention, when the air conditioner is turned off while the engine is stopped or running at low engine speeds, the fuel injection control system corrects the fuel injection so that it is temporarily cut or reduced, so that the intake system To surely prevent an instantaneous increase in engine speed by 1'' when the air conditioner is turned off in the case of a large-capacity engine, and to eliminate unpleasant sensations such as vibrations, feeling of starting to run, etc.

The operating mode for low engine speeds is determined to be warm-up idle stop, low-speed running, or low-speed deceleration, and fuel injection is cut or reduced for each mode, so engine stalling may occur under each condition. It is possible to optimally lower the engine speed without any problems.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an electronic control system of an embodiment of the fuel injection control device of the present invention, FIG. Figures 3 (a,) to e) do not show the same time chart 1. 1... Air conditioner switch, 20... Control unit l-
121...Fuel injection control unit, 23...Operation mode determination unit, 24...Output reduction correction unit, 25...Air conditioner O
FF detection section. Patent Applicant: Fuji Heavy Industries Co., Ltd. Agent Patent Attorney: Nobu Kobashi Ukiwa Patent Attorney: Wataru Ogura April 20, 1991 Commissioner of the Japan Patent Office Toshihiko Ue 1, Indication of Case 1990 Patent Application No. 33212/1 No. 2, Name of the invention Fuel injection control device 3, Relationship to the case of the person making the amendment Patent Applicant: 1-7-2-4, Nishi-Shinjuku, Shinjuku-ku, Tokyo, Agent 6, Subject of amendment - Drawing No. 3. Corrections will be made as shown in Figure 7, details of correction attached.

Claims (3)

[Claims] (1) In a fuel injection control system that electronically sets and controls the fuel injection pulse width according to various operating conditions, an operation mode determination means for determining each operation mode in a low engine rotation fuel supply state; 1. A fuel injection control device comprising: output reduction correction means for outputting a fuel injection correction signal to temporarily reduce output when the air conditioner is turned off at low engine speeds. (2) The fuel injection control device according to claim 1, wherein the operation mode determining means includes determining means for warm-up idle stop, low-speed running, and low-speed deceleration running in the fuel supply state. (3) The output reduction correction means includes setting means for setting correction amounts for fuel cut, slow reduction in fuel injection, and reduction by a predetermined amount for each operation mode when the air conditioner is turned off. (1) The fuel injection control device as described.