JPS6079131A - Fuel control device in engine - Google Patents

Abstract

PURPOSE:To make it possible to obtain satisfactory drive feelings in every decelerating operating condition, by changing the width of hysteresis between the stop and return of fuel supply in accordance with a time for changing the opening degree of the throttle valve upon delerating operation. CONSTITUTION:A fuel control means 17 compares an engine operating condition detected by an engine operating condition detecting means 15, with a fuel return line which has been beforehand is set in accordance with the operating condition, and a fuel stop line which is shifted toward the fuel stopping range from the fuel return line by a predetermined hysteresis, and controls a fuel supply means 7 so that fuel supply to one part of cylinders is returned or stopped. A measuring means 18 detects such that the operating condition of the engine is in the vicinity of the fuel return line to measure the time of duration. When this condition lasts for a prede termined time, a hysteresis increasing means 19 increases the width of a predetermined hysteresis between the above-mentioned both lines of the fuel control means 17 toward the fuel stopping range.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in the fuel control side of an engine, in particular, in which fuel supply to at least some cylinders is stopped during deceleration operation of the engine. , alternately repeating the stop and return of the fuel supply between stopping the fuel supply when the engine is in a decelerating operating state and restoring the fuel supply when the engine shifts to an idling operating state after the decelerating operating state. This article concerns measures to prevent the so-called hunting phenomenon.

(Prior Art) Conventionally, as a fuel control device for this type of engine, one disclosed in Japanese Patent Publication No. 53-42854, for example, has been known. This is especially true when the engine is in deceleration mode, when the throttle valve installed in the engine intake passage is fully opened, or when the engine is in the deceleration mode from idling mode. ! the standard engine rotation speed (hereinafter referred to as -2- stop reference rotation speed), and the second engine rotation speed (hereinafter referred to as return reference rotation speed) when the engine transitions from the deceleration operation state to the idle operation state. The stop reference rotation speed is set higher than the return reference rotation speed by a predetermined rotation speed (hysteresis) with hysteresis between Accordingly, even if the engine speed increases and reaches the return reference speed, the fuel supply is prevented from being stopped again unless the stop reference speed is reached, and the hunting phenomenon occurs in which the fuel supply is alternately stopped and restored. This is designed to prevent the occurrence of

However, in recent years, in order to improve fuel efficiency and the durability of exhaust gas purification devices, the reference rotation speeds for return and stop are both set low and close to each other, that is, the rotation speed difference between the two rotation speeds is There is a tendency to set the hysteresis small. Therefore, in this case, the above-mentioned conventional method still tends to cause the hunting phenomenon and cannot effectively prevent the occurrence of torque shock caused by repeated stop and return of fuel supply, resulting in poor driving performance. We definitely tried to improve the ring (there was a drawback that there was no koto).

Therefore, as disclosed in Japanese Unexamined Patent Publication No. 54-7021, a second stop reference rotation speed that is higher than the stop reference rotation speed by a predetermined number of rotations has been set to restore fuel supply to the engine. After the idle operating state, when the engine speed increases with the return of this fuel supply and reaches the return reference speed, the second stop reference speed is set as the reference engine speed at which the fuel 1 supply is stopped. By temporarily setting a large hysteresis, in other words, temporarily expanding the range of engine speeds to which fuel should be supplied, it is possible to stop fuel supply to the engine while sacrificing fuel efficiency.
Even when the hysteresis during return is set small, a system has been proposed that prevents the hunting phenomenon as reliably as possible, reduces the tendency of torque shock to occur, and improves the driving feeling. .

However, since the above proposal is applied to engine deceleration operating conditions based on the throttle valve being fully opened, it is not possible to open the throttle valve to a predetermined degree on a gentle downhill slope, etc. When applied to a device in which fuel supply is stopped even when the engine is decelerated, the hysteresis increases even though a good driving feeling is maintained. It may waste fuel and cannot be adopted immediately. In other words, during engine deceleration operation in which the throttle valve is held fully open or approximately at a predetermined opening, torque shock due to the hunting phenomenon described above frequently occurs against the driver's will to maintain the same engine operating state. Since this deteriorates the driver's driving feeling, it is necessary to set a large hysteresis between the stop and return of fuel supply to prevent the above hunting phenomenon. During engine deceleration operation, in which the driver increases or decreases the throttle valve in small increments every five hours, in order to finely adjust the deceleration changes, the driver does not have to worry about driving performance even if a torque shock occurs due to his/her own driving operation. Ring-5- does not feel bad, so if you set a large hysteresis between the stop and return of fuel supply as above, the engine rotation at which fuel should be supplied will be lower even though the driving feeling is good. As the number range increases, you end up wasting fuel by that much.

(Objective of the Invention) The object of the present invention is to maintain the hysteresis between the stop and return of fuel supply to a small level without increasing it during engine deceleration operation in which the throttle valve is frequently increased and decreased in a short period of time as described above. By increasing the hysteresis during deceleration operation in which the throttle valve is fully opened or continuously held at a predetermined opening, it is possible to improve fuel efficiency while improving the driving feeling in any engine deceleration operation state. be.

(Configuration of the Invention) In order to achieve the above object, the configuration of the present invention includes a fuel supply means 7 for supplying fuel to the engine 1, as shown in FIG.
An engine-6 engine operating state detecting means 15 detects the engine operating state, and the engine operating state detected by the engine operating state detecting means 15 is connected to a fuel return line and a fuel stop line set in advance according to the engine operating state. Compared to a fuel stop line spaced apart by a predetermined hysteresis on the side of the fuel stop area, the fuel supply means 7 is activated or stopped so as to restore or stop the fuel supply to at least some cylinders of the engine. a control means 17; a measuring means 18 for detecting that the engine operating state is near the fuel return line and measuring the duration of the state; When the engine operating state continues for a predetermined period of time, hysteresis increasing means 19 is provided to increase the width of a predetermined hysteresis between the fuel return line and the fuel stop line of the fuel control means 17 toward the fuel stop region. The width of the hysteresis is increased toward the fuel stop region -7- only when the engine operating state near the line continues for a predetermined period of time, that is, during engine deceleration operation with the throttle valve fully open or almost maintained at a predetermined opening. This is what I did.

Here, the cylinders to which fuel supply is stopped during engine deceleration operation may be some or all cylinders,
The point is that at least some cylinders are sufficient.

(Effects of the Invention) Therefore, according to the present invention, the width of the hysteresis between the stop and return of fuel supply is not increased during engine deceleration operation in which the throttle valve is frequently increased or decreased in a short period of time, and the throttle valve is This is done only when the engine is decelerating when the engine is fully opened or maintained at a predetermined opening, thereby reducing fuel consumption as much as possible while improving the driving feeling when the engine is decelerating. Therefore, it is possible to achieve both improvement in driving feeling and improvement in fuel efficiency.

(Example) Hereinafter, an example as a specific example of the technical means of the present invention will be described based on the drawings from FIG. 2 onwards.

-8- In FIG. 2, 1 is an engine, 2 is a combustion chamber formed by a cylinder 3 formed in the engine 1, and a piston 4 slidably inserted into the cylinder 3, and 5 is a combustion chamber formed by a cylinder 3 formed in the engine 1 and a piston 4 slidably inserted into the cylinder 3. An intake passage whose one end opens to the atmosphere via an air cleaner (not shown) and whose other end opens into the combustion chamber 2 to supply intake air to the combustion chamber 2. A throttle valve 6 for controlling the amount of air and a fuel injection valve 7 as a fuel supply means for injecting and supplying fuel downstream of the throttle valve 6 are provided. Further, reference numeral 8 denotes an exhaust passage that opens into the combustion chamber 2 at one end and opens into the atmosphere at the other end for discharging exhaust gas from the combustion chamber 2. Note that 9 is an intake valve provided at the opening of the intake passage 5 to the combustion chamber 2, and 10 is an exhaust valve provided at the opening of the exhaust passage 8 to the combustion chamber 2.

Further, 11 is a throttle opening sensor that detects the opening degree of the throttle valve 6, 12 is an air sensor 70 that measures the amount of intake air upstream of the throttle valve 6 in the intake passage 5, and 13 is the throttle valve 6 in the intake passage 5. A negative pressure sensor -9- 14 detects the downstream intake negative pressure, and an engine rotation speed sensor detects the rotation speed of the engine 1. The throttle opening sensor 11 and the engine rotation speed sensor 14 detect the engine rotation speed. The engine operating state detecting means 15 is configured to detect the operating state. Detection signals from the four sensors 11 to 14 are input to a control unit 16 comprised of a microcomputer that drives and controls the fuel injection valve 7, respectively.

Inside the control unit 16, as shown in FIG. ! I m TV
The fuel return line Fre is connected across the O+ hysteresis.
A first fuel stop line Fcut+ is set parallel to t, and a first fuel stop line Fcut I is similarly set below the first fuel stop line 1:cutl with a hysteresis of a predetermined throttle opening value T V O2. and a second fuel stop line Fcut 2 set parallel to the line Fcut 2 are respectively input and stored. Note that the curve NL shown by a broken line in the figure is a no-load curve.

-10- Then, the control unit 16 first calculates the fuel injection amount according to the intake air amount signal from the air flow sensor 12 and the negative pressure signal from the negative pressure sensor 13 during the operating state of the engine 1 except during deceleration operation. Then, an injection pulse signal with a pulse width corresponding to the fuel injection amount tJJ is output to the fuel injection valve 7 at each predetermined injection timing (for example, piston top dead center), and the injection pulse signal is output from the fuel injection valve 7 according to the engine operating state. When the engine 1 is injected and supplied with fuel and the engine 1 shifts from this state to a deceleration operation state, when the engine operation state belongs to the fuel stop region located below the first fuel stop line Fcu1 in FIG. , stops outputting the injection pulse signal to the fuel injection valve 7, and then resumes outputting the injection pulse to the fuel injection valve 7 when moving the fuel return line F re' to the fuel return region located above. , and the engine operating state is again at the fuel return line F.
When moving beyond ret and moving below it, the first or second fuel stop line Fcut
,.

Injection pulse signal-1 to the fuel injection valve 7 based on FcUj2
It is configured to restart the output of No. 1-. Therefore,
The control unit 16 controls the engine operating state to the fuel return line F ret and the first fuel stop line FCut.
A fuel control means 17 is configured to control the operation or stop of the fuel injection valve 7 (fuel supply means) so as to stop or restore fuel supply to at least some cylinders of the engine 1. .

Next, the stop control of the fuel injection valve 7 after the fuel supply is restored by the control unit 16 will be explained based on the flowchart of FIG. 3.

First, in step S+, the current throttle opening value TVoo and engine speed R are determined based on the throttle opening signal from the throttle opening sensor 11 and the engine speed signal from the engine speed sensor 14.
After reading o, the current throttle opening difference T V O
o is compared in magnitude with the throttle opening value TVO+ corresponding to the current engine speed Ro at the first fuel stop line FcLItl in FIG. 4, and the difference ΔT V O (= T
V Oo -T-12- (101) is calculated. Then, in step S2, the difference ΔTVO is converted to a predetermined value a (
-2・ΔTVO+), and if YES is larger than the predetermined value a, that is, if there is no need to increase the hysteresis between stop and return of fuel supply, the throttle opening difference ΔTVO is determined in step S3. After setting the zone flag FzO, which indicates that the throttle opening is within the predetermined throttle opening range, to "0", the fuel stop line change flag FdC is set to "0" in step S4, and the process ends.

On the other hand, in step S2, the throttle opening difference ΔTVO
If the answer is No, the zone flag FZO is set to "1" in step S5, and then
In step S6, the throttle opening difference ΔTVO is "0".
” or more. If YES, which is 0 or more, the current throttle opening value ΔT
If V Oo is within the predetermined throttle opening range corresponding to the predetermined value a near the fuel return line Frat, the moment the zone flag l"zo is set to "1" in step S7, YE, which is the moment when it is determined whether or not and is set to [1]
In the case of S, it is determined that this is the moment when the current throttle opening ΔT V Oo moves within the predetermined throttle opening range near the fuel return line Fret, and the timer TMZ for measuring the predetermined time T is set in step S8. After clearing to 'OJ', the process proceeds to step S9, while if the answer is No, which is not the moment when it is set to "1", the process immediately proceeds to step S8.

Then, in step S9, after applying rIJ to the timer TMZ to measure time, in step 810, whether or not the timer TMZ has completed measuring the predetermined time T (
TMZ≧T) is determined, and if the measurement is not completed (No), the process is immediately terminated, while if the measurement is completed (YES), the throttle valve 6 is operated all the time or almost at a predetermined interval near the fuel return line F ret. It is determined that the engine operating state is maintained, and the fuel stop line change flag l"dc is set to "1" in step S++, and the process ends.

-14- Also, in step S6, the throttle opening/injection difference ΔTVO
If "No" is not greater than "01", that is, if the current throttle opening is below the first fuel stop line Fcu1, it is further determined in step 812 whether or not the fuel stop line change flag Fdc is NJ. Then, “1
”, in step S+a, the output of the injection pulse to the fuel injection valve 7 is stopped by the second fuel injection valve 7.
1 stop line FCtlt2! ! However, if the fuel stop line change flag Fdc is not "1" but is No, it is determined that the engine is in deceleration operation where the throttle valve 6 is frequently increased or decreased in a short period of time to adjust the deceleration gain. Then, in step S14, the output of the injection pulse to the fuel injection valve 7 is stopped based on the first fuel stop line Fcut+, and the process ends. Therefore, the throttle opening difference ΔT
It is detected that VO has shifted within a predetermined throttle opening range corresponding to a predetermined value a near the fuel return line F ret (82, Ss, Ss).

S7), the engine operating state -15 is set by starting the measurement of the engine speed at a predetermined time using the timer TMZ (Ss, Ss).
- Measuring means 1 that detects that the state is near the fuel return line l: ret and measures the duration of that state.
8, and when the measurement of the predetermined time T by the timer TMZ is completed, the fuel stop line change flag Fdc should be set to "1" S+o, 511)
In this state, when the throttle opening difference ΔTVO becomes smaller than rOJ, that is, the engine operating state moves into the fuel stop region of the first fuel stop line FcutlT, the fuel supply is stopped based on the second fuel stop line Fcut2. By (Ss-+8+2→S+a), when the engine operating state near the fuel 111 return line F ret continues for a predetermined period of time, the hysteresis increasing means 19 is configured to increase the width of the hysteresis toward the fuel stop region side. There is.

Therefore, in the above embodiment, the operating state of the engine 1 changes depending on the deceleration operation of the engine 1 on the fuel return line F in FIG.
When moving to the fuel return region above ret, fuel injection from the fuel injection valve 7 is restored, but in this state, the opening degree -16- of the throttle valve 6 is kept fully open or almost at a predetermined opening degree. If the throttle opening is within the predetermined throttle opening range near the fuel return line F ret for a predetermined time 1 or more, the fuel stop line change flag Fdc is set to "1" and the fuel The reference line for restarting the supply is from the first fuel stop line Fcut+ to the second fuel stop line l"clJ
tz, the hysteresis between the stop and return of fuel supply changes from the predetermined throttle opening value ΔTVO+ to (ΔTvOL+
ΔTVO2). Therefore, if the driver intends to maintain the same engine operating state by fully opening the throttle opening or maintaining a predetermined opening, fuel supply is frequently stopped and restored despite this intention. This makes it possible to prevent the occurrence of torque shock as much as possible, thereby improving the driving feeling.

On the other hand, when the opening degree of the throttle valve 6 is frequently increased or decreased in a shorter time than the predetermined time T in order to adjust the deceleration curve on a downhill slope with many ups and downs, the fuel stop line change flag Fdc is set to [0 ], the reference line for restarting fuel supply is the 1st line.
The fuel stop line Fcut+ is maintained, and the hysteresis between stopping and returning fuel supply is still small at the predetermined throttle opening value ΔTVO+.

Therefore, when the opening of the throttle valve 6 decreases and exceeds the narrow predetermined throttle opening value ΔTVO+ and moves below the first fuel stop line Fcutl, the engine operating state immediately shifts to the fuel stop region and fuel injection is started. Fuel injection from valve 7 will be stopped immediately. Therefore,
Fuel consumption can be reduced and fuel efficiency can be improved. At this time, the fuel supply is repeatedly stopped and restored in response to increases and decreases in the throttle opening, causing the driver to feel torque shock, but this is not due to the increase or decrease in the throttle opening caused by the driver's own operation. Because of this, you won't feel that the driving feeling is bad.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIGS. 2 to 4 show embodiments of the present invention, and FIG. 2 is an overall configuration diagram,
FIG. 3 is a flowchart showing the operation of the control unit, and FIG. 4 is a diagram showing the memory contents of the control unit. DESCRIPTION OF SYMBOLS 1... Engine, 7... Fuel injection valve (fuel supply means), 15... Engine operating state detection means, 17...
Fuel control means, 18... Measuring means, 19... Hysteresis increasing means. -19- 1st plan 8^

Claims (1)

[Claims] (1) A fuel supply means for supplying fuel to the engine, an engine operating state detecting means for detecting the engine operating state, and a fuel set in advance according to the engine operating state detected by the engine operating state detecting means. activating the fuel supply means to restore or stop fuel supply to at least some cylinders of the engine in comparison with a return line and a fuel stop line spaced apart by a predetermined hysteresis on the fuel stop region side with respect to the fuel return line; or a fuel control means for controlling the stop, a measuring means for detecting that the engine operating state is near the fuel return line and measuring the duration of that state, and receiving a measurement signal from the measuring means to perform the fuel return. hysteresis increasing means for increasing the width of the predetermined hysteresis of the fuel control means toward the fuel stop region when the engine operating state near the line continues for a predetermined period of time; m device.