JPS59226238A - Fuel injection apparatus for engine - Google Patents

Abstract

PURPOSE:To improve the performance of an engine at the time of accelerating the same after deceleration, by changing the reset engine speed for recommencing fuel supply or increasing the fuel supply rate according to the rate of rise in the engine speed at the time when the enine operation is changed from deceleration to acceleration in a fuel injection apparatus including a fuel supply interrupting means. CONSTITUTION:An apparatus of this invention comprises a first detecting means for detecting that an engine is in deceleration and a second detecting means for detecting the rate of rise in the engine speed at the time when the engine operation is changed from deceleration to acceleration. The fuel supply rate is decreased to a level lower than the ordinary level or otherwise fuel supply is stopped by operating a fuel supply interrupting means in response to the output of the first detecting means. Subsequently, if the engine is accelerated, a reset engine speed is changed by a reset engine speed changing means according to the rate of rise in the engine speed detected by the second detecting means, and the rest engine speed is used at the time of next deceleration. In case that the rate of rise in the engine speed exceeds a reference value, the reset engine speed is lowered. On the other hand, in case that the rate of rise in the engine speed is lower than the reference value, the reset engine speed is raised.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel injection device for an engine, and more particularly to a fuel injection device equipped with a fuel cut means for reducing the amount of fuel to be injected during engine deceleration.

(Prior Art) In order to improve the fuel efficiency of automobiles, during engine deceleration, when the engine speed is above a certain set point, the fuel is cut, i.e., the fuel supply is reduced or stopped, and the engine speed is reduced to the set speed. It is known to perform fuel supply control such that when the rotational speed drops to a different set rotational speed or less, the fuel is restored, that is, the fuel supply is restarted or increased (see, for example, Japanese Patent Laid-Open No. 7027). In this type of control, keeping the rotational speed at which fuel recovery occurs low is effective in improving fuel efficiency, but there is a problem in that a shock occurs when reaccelerating.

(Objective of the Present Invention) Therefore, an object of the present invention is to provide a fuel injection device for an engine that can improve fuel efficiency and obtain appropriate acceleration performance after deceleration. .

(Configuration of the present invention) In order to achieve the above object of the present invention, the present invention is configured as follows. That is, the first detection means detects that the engine is decelerating, and the fuel cut means reduces the amount of fuel supplied, and the fuel cut means is activated when the engine speed is decelerated from a predetermined value or higher. In such a fuel injection device, the second detection means detects the rate of increase in rotational speed when changing from deceleration to acceleration, and when the rate of increase in rotational speed is less than a reference value, restarting or increasing fuel supply is performed. The present invention is characterized in that it includes return rotation speed changing means for determining the return rotation speed and lowering the return rotation speed when the rotation speed increase rate exceeds a reference value.

The configuration of the present invention will be explained with reference to FIG.

If the first detection means detects that the engine is in a deceleration state and there is a danger, the fuel cut means is activated to reduce the amount of fuel supplied than normal or to cut off the fuel supply. As a result, when the rotational speed drops to a low T'L/tlQ rotational speed, fuel supply is restarted or gH is increased. That is, fuel restoration is performed. When the next acceleration operation is performed, engine rotational melting is restored, but
Then @the increase in rotational speed detected by the second detection means -
The return rotation speed is changed by the return rotation speed changing means according to the magnitude of the rotation rate. When the rotational speed increase rate exceeds the reference value, the fuel return is performed; the recovery rotational speed is lowered,
If it is below the reference value, the return rotation speed is increased. The fuel return rotation θ determined in this manner will be used during the next deceleration.

(Effect of non-invention) As mentioned above, the return rotation speed is determined each time depending on the magnitude of the increase rate of rotation speed at low speed after deceleration, and the rotation speed increase rate during acceleration is large. In some cases, the fuel return speed is set low, which can improve fuel efficiency.
When the rate of increase in rotational speed is small, the return rotational speed is increased, eliminating the sluggishness caused by the next acceleration. That is, the control according to the present invention makes it possible to always maintain the return rotation speed at an appropriate value.

(Description of Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

a) System configuration Referring to FIG. 2, the engine body 10 includes a cylinder block 17 having a cylinder 14 in which a piston 12 slides, and a combustion chamber 1 attached to the upper part of the cylinder 14.
8 and a cylinder head 20 forming a cylinder head 8. An intake pipe 22 and an exhaust pipe 24 are connected to the cylinder head 20, respectively. Further, a portion of an intake passage 26 and a portion of an exhaust passage 28 communicating with the intake pipe 22 and exhaust pipe 24 are formed in the cylinder head 2o. Intake passage 26
An intake valve 82 is combined with the opening of the exhaust passage 28 to the combustion chamber 18, that is, an intake port 80, and an exhaust valve 86 is combined with the opening of the exhaust passage 28 to the combustion chamber 18, that is, an exhaust port 84. An air cleaner 88 is provided at the tip of the intake passage 26. An air flow meter 4o is provided to measure the air pressure on the downstream side, and further downstream thereof, a throttle valve 42 is provided. A combustion injection nozzle 44 is disposed in the intake passage 26 near the intake port 80'. In addition, the intake passage 26 is provided with a bypass passage 46 for bypassing the throttle valve 42, and a core passage 46 is provided in the intake passage 26.
6 is provided with a proportional solenoid valve 48 that adjusts the amount of air flowing through the passage 46. Furthermore, the intake passage 2
6 is provided with a throttle valve opening degree safe t50 for detecting the opening degree of the throttle valve 42.

In order to control the fuel injection nozzle 44 and the proportional solenoid valve 48, a control unit 52, preferably consisting of a microcomputer, is installed. The device of this example is equipped with a crank angle sensor 54 that calculates the engine speed,
A signal from this sensor 54 is input to the control unit 52. Signals from the air flow meter 40 and throttle opening sensor 5o are also input to the control unit 52. Further, a signal from a water temperature sensor 56 that detects the cooling water temperature is also input to the control unit 52. Furthermore, the control unit 5
2 is input with an ON-OFF signal of various engine accessories such as a cooler, that is, an engine load 58.

Furthermore, an intake negative pressure sensor 60 is provided in the intake passage 26 to detect the entire intake negative pressure, and signals from the sensor 60 are also input to the control unit 52.

b) Flow 1 The control GLODARAM of the present invention includes a main routine that calculates the return rotation speed and an interrupt processing routine that performs processing to determine the fuel injection amount, and the interrupt processing routine executes the main routine at a predetermined timing. K is set to interrupt and process the process. The main routine includes a rotation speed increase rate calculation subroutine and a throttle opening change rate calculation subroutine.

FIG. 3 shows a flowchart of the main routine. In the first stage, each variable is initialized (Sl). Next, ^10 conversion of the manifold pressure, that is, the intake negative pressure signal is performed (S2). Next, the throttle opening change rate dθ/dt is calculated (S5). this is,
Calculations are processed by subroutines,
FIG. 7 shows the flowchart.

In this routine, first, A/D conversion of the throttle opening signal is performed (351). Next, the converted value is stored in memory (S52). Then, the throttle changed once [
C3ss) where the Hi rate (Z) is calculated. In this case, the rate of change (Z) is given by the difference between the throttle opening when the interrupt routine was executed M times ago and the throttle opening when the interrupt routine was last executed. Rate of change 2 is then compared to a predetermined positive value X (354). That is, when 2 is greater than x, it is determined that an acceleration operation is being performed, and in that case, 2 is stored in the memory (S3s). With this, the execution of the throttle opening change rate calculation subroutine is ended, and the execution of the main routine is continued again. That is, in the main routine, next, a mode determination is performed (S4).

At this stage, based on the engine speed, intake negative pressure, throttle opening, etc., it is possible to determine whether the engine is at least decelerating and is in a state where fuel cut can be performed, that is, it is in F/C mode.
It is determined whether the state of acceleration is in acceleration mode.

Next, the rotational speed increase rate and the corresponding return rotational speed are determined (S5). This step is processed by the rotational speed increase rate calculation subroutine. A flowchart of this subroutine is shown in Figure i5.

In this routine, first, when this routine was executed last time, F
/C mode and it is determined whether fc or not ("s+
,). If it was in the F/C mode last time, then the current engine rotation aN is set in advance to the first set rotation speed 01.
It is determined whether or not the following is true (S52). If the rotation speed is less than or equal to the first set rotation speed, it is determined whether the rotation speed is equal to or higher than the λ-th set rotation speed n2, which is lower than the rotation speed by a predetermined value υ (Ss3). A case where the engine is operated at a rotation speed between the first set rotation speed and the second set rotation speed is subject to fuel cut control. If N≧02, it is then determined whether the mode is acceleration mode (554). In the case of acceleration mode, the current rotational speed N is stored in the memory as N (Sss).

Next, 1 is placed in the memory T indicating whether the mode has changed to the acceleration mode (Ss6). Next, 1 is placed in the caranta memory k that measures the time in acceleration mode (S5.)
. If the rotational speed N is greater than 01, or smaller than 02, or if the acceleration mode is not in effect, execution proceeds to the main routine. Also, stainless steel 7”
If 'IMJ is disconnected with No in 51, that is, this routine was executed last time (also, if it was not in FIG mode, it is determined whether the memory T is 1 or not (Ssa)
.

If T=/, then it is determined whether the mode is acceleration mode (859). If the mode is the acceleration mode, / is added to the counter k (S6o).

Next, it is determined whether a predetermined time to has elapsed since the value on the counter changed to the acceleration code (ral).

If the value in the counter is the time to KJ,
Store the current rotation speed N in the memory as N1 (S62
). Next, the rotational speed N immediately after changing from F/C mode to acceleration mode, and the time t after changing to acceleration mode. The rotational speed N after .

It is determined whether the difference is greater than or equal to a predetermined value n5 (S6). That is, it is determined whether the rotation speed increase rate is equal to or greater than a predetermined value. (predetermined value) is the rotation speed No.
and throttle opening change dθ/dt, and is stored in advance as a chart in the memory. N1-No, that is, the rotation speed increase rate is the predetermined value 03
If it is above, the return rotation speed 05 is lowered by a predetermined value Δn (S64). If the rotational speed increase rate does not exceed the predetermined value, the return rotational speed ns is increased by a predetermined value Δn (S6s). Next, memories T and kKO are entered (S661S47), and No and N are cleared (568), and the process returns to the main routine. In addition, if it is determined in step (S59) that the VC is not in the acceleration mode and the value is 7, 0 is stored in memories T1 and k without changing the return rotation speed, N0sN1 is cleared (S7o), and the main routine returns. will be returned to. The main routine is repeatedly executed from steps S2 to s5.

During execution of the main routine, an interrupt routine is executed at a predetermined timing.

When an interrupt routine is executed, execution of the main routine is interrupted. A flowchart of the interrupt routine is shown in FIG. In the first step of the interrupt routine, the period of the engine is measured based on signals from the comb/yield angle sensor and the like.

(SS1), then the rotation a N calculation fill 7) (
SS2).

Next, all operating conditions such as throttle opening and intake negative pressure are detected (SS5). Then, it is determined whether the mode is F/C mode (SS4).

In the case of F/C mode, it is further determined whether the rotation speed N is equal to or higher than the return rotation speed ng (SSs).
. If the rotation speed N exceeds the return rotation speed n5, F
/C processing is performed (SS6). That is, the fuel injection amount is reduced or the injection is stopped. F/
C-[If not need, and rotation speed N is return rotation speed n
If sj and i7 are also small, the injection amount is calculated from a predetermined MAP based on the operating state (SSy). Next, it is determined whether the injection timing matches the injection timing (SSa
), if the injection timing matches, the button issues an injection command (SS9).

C) Control example In the fuel injection device of this example, the rotation speed N is the return rotation speed n5.
If it is in a deceleration state with the speed exceeding
If the vehicle descends further than that, fuel reversion will occur automatically.

Referring to FIG. 7, the rotation speed N is the first set rotation speed 01.
and the second set rotation speed, T1
If an acceleration operation is performed at this point and the rotational speed starts to increase, the return rotational speed changes depending on the value of the rotational speed increase rate. In this case, as mentioned above, when the rate of increase in rotational speed is large, the return rotational speed 05 is set low, and when the rate of increase is small, it is set high. Therefore, when the rate of increase in rotational speed is large, the fuel cut time is maintained for a relatively long time during deceleration, so fuel efficiency can be improved, and when the rate of increase in rotational speed is small, the fuel cut is relatively long. Since it is released at an early stage, re-acceleration performance can be improved. That is, the control of this example makes it possible to obtain appropriate acceleration performance and to improve fuel efficiency. In order to prevent hunting, it is preferable to set the rotation speed at which fuel is cut and the rotation speed at which fuel is restored separately.

[Brief explanation of the drawing]

Fig. 1 is a claim correspondence diagram of the present invention, Fig. 2 is a system configuration diagram according to the embodiment of the present invention, Fig. 3 is a flowchart of the main routine of control according to the present invention, Fig. 4 and Fig. S t:j A flowchart of a subroutine of the routine in FIG. 3, FIG. 6 is a flowchart of a refined interrupt processing routine that performs interrupt processing for the main routine,
FIG. 7 is a graph showing the relationship between rotation speed change and time. Description of symbols IO...Engine body, 12...Piston, 14...
...Cylinder, 26...Intake passage, 28...Exhaust passage, 88...Air cleaner, 40...Air flow meter, 42...Throttle valve, 44...Fuel injection nozzle, 48...・Proportional solenoid valve, 50... Throttle valve opening sensor, 52... Control unit, 54...
・Crank angle sensor, 56...Water mud sensor, 60...
・Negative pressure sensor patent applicant Toyo Kogyo Co., Ltd.

Claims (1)

[Claims] The first detection means detects that the engine is decelerating, and the fuel cut means reduces the amount of fuel supplied, and the fuel cut means is operated when the engine speed is decelerated from a predetermined value or higher. In the fuel injection device which has become a new fuel injection device, there is a λ-th detection means for detecting the rate of increase in rotational speed when changing from deceleration to acceleration, and a return rotation for restarting or increasing fuel supply when the rate of increase in rotational speed is less than a basic value. 2. A fuel injection device for an engine, comprising: a return rotation speed changing means for increasing the rotation speed and lowering the return rotation speed when the rotation speed increase rate exceeds a reference value.