JPH03242446A - Fuel injection control device - Google Patents

Abstract

PURPOSE:To improve stability of an engine speed, even when an engine is at a low speed, by changing a voltage value of an injection pulse only for a very little time after the predetermined time elapsed from starting to apply the injection pulse, and applying voltage again only for a very little time after the predetermined time from the end of applying the injection pulse. CONSTITUTION:A core member 7 is excited by a first injection pulse, being applied till a protrusion 5B of a needle valve 5 touches a stopper 4 by detaching the needle valve 5 from a valve seat 3A, and thereafter soon pulse-cut, so that a rebound between the protrusion 5B and the stopper 4 is relaxed by decreasing a speed at which the protrusion 5B hits the stopper 4. Further a speed of a valve unit 5A to hit the valve seat 3A is decreased to relax a rebound between the valve unit 5A and the valve seat 3A by applying a third injection pulse after the pulse cut time after a second injection pulse is cut, and thus stabilizing a fuel flow amount at low speed time of an engine so as to prevent dispersion of the engine speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel injection control device suitably used in, for example, an electronically controlled fuel injection device.

[Conventional technology]

6 to 9 show prior art fuel injection control devices.

First, in FIG. 6, l indicates an injection valve, 2 is a stepped cylindrical valve body constituting the injection valve 1, and 3 is provided on the tip side of the valve body 2, and is made of stainless steel ( SUS30
4) shows an injection nozzle formed in a stepped cylindrical shape, and a valve seat 3A and an injection port 3B are formed on the inner periphery of the tip side of the injection nozzle 3, and a needle valve described later is formed on the valve seat 3A. 5 is designed to separate and deposit dust. Further, a stopper 4 formed of a substantially U-shaped or C-shaped plate is provided at the base end of the injection nozzle 3 and positioned between the step part 2A of the valve body 2, and the stopper 4 is connected to the needle valve 5. The valve opening position is regulated.

Reference numeral 5 designates a needle valve that is movable in the axial direction within the injection nozzle 3 and is made of stainless steel (SUS304) or the like like the injection nozzle 3. It extends into the portion 2A and is fixed to the anchor 10 so as to be displaced integrally with the anchor 10, which will be described later. The tip side of the needle valve 5 extends inside the injection nozzle 3 with a fuel passage 6 secured between it and the injection nozzle 3, and its tip becomes a valve body 5A that is seated on and off the valve seat 3A. The injection port 3B is opened and closed by moving the valve body 5A to and from the valve seat 3A. Also,
An annular projection 5B is formed in the axially intermediate portion of the needle valve 5, and the projection 5B comes into contact with the stopper 4 when the needle valve 5 is opened, thereby regulating the valve opening position. . Here, the tip side of the needle valve 5 has an injection port 3B.
A bottle 5C, which is formed to have a smaller diameter than the injection port 3B and projects in the axial direction from the injection port 3B, is integrally provided, and the bottle 5C injects fuel from the injection port 3B in a predetermined injection pattern.

Reference numeral 7 indicates a cylindrical core member provided extending in the axial direction within the valve body 2. The core member 7 is formed into a stepped cylindrical shape from a magnetic material such as electromagnetic stainless steel, and is located on the proximal end side. death,
A protrusion 7A protruding upward in the figure from the valve body 2 and a protrusion 7A located in the axially intermediate portion, and a protrusion 7A protruding upward in the figure from the valve body 2, and a protrusion 7A provided at the proximal end of the valve body 2 by means such as caulking in order to cover the proximal end of the valve body 2. It is generally composed of a fixed flange portion 7B and a core portion 7D extending downward in the figure from the flange portion 7B and having an enlarged diameter hole 7C formed on the inner periphery of the distal end. A coil bobbin 9 around which an electromagnetic coil 8 is wound is attached to the outer periphery of the core portion 7D.
These constitute an electromagnetic actuator that attracts the anchor 10 upward in the figure to open the needle valve 5.

Reference numeral 10 denotes an anchor movably disposed within the valve body 2 and located between the core member 7 and the needle valve 5, and the anchor 10 is formed in the shape of a covered cylinder from the same magnetic material as the core member 7. , a needle valve 5 is installed on the inner periphery of its tip (lower end side).
The base end side of is fixed using means such as caulking. The proximal end surface of the anchor 10 faces the distal end surface of the core portion 7D with a gap of a predetermined size interposed therebetween, and is attracted upward in the figure by the magnetic force from the core portion 7D. Further, a coil bobbin 9 is provided on the outer peripheral side of the anchor 10.
, a small gap is formed between the stepped portion 2A of the valve body 2,
Fuel from a fuel vibrator 11, which will be described later, flows into the fuel passage 6 through this gap.

Reference numeral 11 denotes a fuel vibrator which is inserted and fixed in the axial direction into the core member 7, and 12 refers to the tip of the fuel vibrator 11 and the anchor'-
The valve spring 12 presses the anchor 10 downward in the drawing, thereby normally urging the needle valve 5 in the valve-closing direction. The spring load of the valve spring 12 is adjusted by the fuel vibrator 11, and after the spring load is adjusted, the fuel vibrator 11 is fixed to the core member 7 by means such as caulking.

Reference numeral 13 indicates a fuel hose connected to the protrusion 7A of the core member 7, and the hose 13 is configured to supply fuel pumped from a fuel pump (not shown) into the fuel vibrator 11 etc. through a filter 14. It has become. Reference numeral 15 denotes a connector located on the proximal end side of the valve body 2 and integrated with the outer periphery of the protrusion 7A. It is designed to generate magnetic force on the surface side.

Furthermore, as shown in FIG. 7, the injection valve 1 is connected to a battery 16 as a DC power source via a connector 15. A switching transistor 17 and a protection resistor 18 are connected in series in this order, and each is connected to ground 19. The base side of the switch ink transistor 17 is connected to an injection amount calculating device 20, which will be described later.

Reference numeral 20 denotes an injection amount calculation device as a control device composed of a microcomputer or the like that calculates the fuel injection amount, and the injection amount calculation device 20 is provided with a storage area 20A consisting of RAM, ROM, etc. inside. . The input side of the injection amount calculation device 20 includes a start switch 21,
It is connected to the crank angle sensor 22, air flow meter 23, oxygen sensor 24, etc., and its output side is connected to the base side of the switching transistor 17.

Here, the injection amount calculation device 20 calculates the fuel injection amount T, as follows: T+=TpXαx ax Cozy + Ts −
(1) However, L2,'r, : Basic injection plate α : Air-fuel ratio feedback correction coefficient α' : Basic air-fuel ratio learning correction coefficient Co□ : Various correction coefficients TII : Calculated as battery voltage correction coefficient, and apply it to the relevant injection 11T. It is designed to output an injection pulse with a corresponding pulse width. In addition, for convenience of explanation below, fuel injection is used! 1T, injection pulse T,
It is stated as follows.

The conventional fuel injection control device has the above-mentioned configuration, and the injection I! The arithmetic unit 20 performs the calculation of equation (1) based on the detection signals from each sensor, outputs an injection pulse T to the switching transistor 17, and applies it to the electromagnetic coil 8 of the injection valve 1. As a result, the core part 7 is energized, the anchor 10 is attracted against the valve flap 12, the needle valve 5 is opened, and fuel is injected outward from the injection port 3B of the injection nozzle 3. . When the injection pulse T is stopped, the anchor 10 is pressed by the valve spring 12, and the valve body 5A of the needle valve 5 is seated on the valve seat 3A, stopping fuel injection.

[Problem to be solved by the invention]

By the way, in the above-mentioned prior art, the actual movement of the needle valve 5 after receiving the application of the injection pulse T exhibits the valve characteristics as shown in FIG. That is, the injection pulse T is applied to the injection valve 1, the core part 7 is energized, and the needle valve 5 is moved to the valve seat 3.
Time 1+ (for example, 1.2 to 1.4 ms) until the protrusion 5B of the two dollar valve 5 hits the stopper 4 after leaving the seat A.
The protrusion 5B of the needle valve 5 is
Since there is a considerable speed when it hits stopper 4, it does not stop at stopper 4 immediately but for a minute time t! (For example, 0.05m
During 5), the protrusion 5B rebounds to the stopper 4. Then, during time t3, the needle valve 5 remains stationary on the stopper 4, and the application of the injection pulse T1 is canceled, so that the power supply to the electromagnetic coil 8 is canceled A1, and the needle valve 5 is moved from the stopper 4 to the valve seat 3A. Direction 1. 'j is moved by the spring force of the spring 12 and the valve is closed. In this case, it takes 1A for the valve body 5A of the needle valve 5 to hit the valve seat 3A (for example, 0.7 m
S) is required, and the valve body 58 of the needle valve 5 is connected to the valve seat 3A.
Since the contact point also has a considerable speed, it does not immediately sit on the valve seat 3A and waits for a short time t5 (for example, 0.05 m).
During 5), the valve body 5A rebounds onto the valve seat 3A and then seats on the valve seat 3A. Then, while the next injection pulse T is applied at j:, the valve body 5A is seated on the valve seat 3Ai, and
Stop fuel injection.

Here, the relationship between the pulse width of the injection pulse T and the combustion injection dissipation shows the characteristics as shown in Fig. 9, and when the engine speed is high and the pulse width of the injection pulse T is long, (i, time t3 In order to become longer, the rebound times ta and t
The influence of s is almost tJ.

However, when the engine speed is low, that is, when the pulse width of the injection pulse T is short, the time t3 becomes short, so the influence of the rebound times t2 and t6 becomes large, and the stability of the injection plate deteriorates. , injection pulse T
When the width of , is short, the fuel injection plate is extremely lowered, causing variations in engine rotation, which has the disadvantage of reducing the stability of engine rotation.

The present invention has been made in view of the two drawbacks of the prior art, and an object of the present invention is to provide a fuel injection control device that can improve the stability of engine rotation even at low engine speeds.

[Means to solve the problem]

The feature of the configuration of the present invention configured to solve the above-mentioned problems is that the control system includes the step of slightly reducing the voltage value of the injection pulse after a predetermined time from the start of application of the injection pulse according to the fuel injection condition. The present invention is provided with a voltage changing means that varies by time, and a voltage reapplying means that reapplies the voltage for a minute time after a predetermined period of time has elapsed after the application of the injection pulse has ended.

[Function] With the above configuration, when the protrusion of the two-dollar valve hits the stopper, it is possible to alleviate the rebound that occurs when the valve body of the needle valve hits the valve seat.

[Example] Hereinafter, an example of the present invention will be described based on FIGS. 1 to 5. Note that the same reference numerals are given to the same components as those of the prior art described above, and the explanation thereof will be omitted.

A first embodiment will be described based on FIGS. 1 to 3.

In the figure, reference numeral 31 indicates an injection amount calculation device as a control device according to the present embodiment, and the injection amount calculation device 31 is composed of a microcomputer, etc., like the injection amount calculation device 20 according to the prior art, and has internal RAM and ROM. A storage area 31A consisting of the following information is provided, and the fuel injection amount according to the above-mentioned formula (1) is stored. In addition to the calculation function, the adjustment injection pulse T shown in FIG.

It has the function to calculate.

Here, the injection pulse T1 and the adjusted injection pulse T output from the injection amount calculation device 31. have the relationship as shown in Figure 2. That is, based on the injection pulse T1, the first injection pulse T0, the second injection pulse T1m, and the third injection pulse T+' are calculated, and the pulse cut times T1 and T2 at which the voltage application is stopped are calculated. It is something that calculates
The width of the injection pulse T, 1°T, □, Tl' and the pulse cut time T, , T, is the same as the time t, ~t in the prior art.
, that is, the width of the first injection pulse T=time, the width of the second injection pulse "r+a=time t3, the width of the third injection pulse T1'=time t.

Pulse cut T, = time t2 Pulse cut Tz = time t4 There is a relationship between

As a result, the injection pulse T, is: T I = T + + + T + + T + z
," (2), and the adjusted injection pulse T. is T o = T + + + T + + T r x
+ T z + T += T + + T 2 +
T I'...The relationship is as shown in (3).

As a result, it is only the width of the second injection pulse T1□ that changes the pulse width of the adjusted injection pulse T0 calculated by the injection amount calculation device 31, and other time widths etc. are stored as constant values in the storage area 31A. has been done.

Here, the process for forming the adjusted injection pulse T0 will be explained with reference to FIG.

By turning on the start switch 21, the processing program is started and the timer t is activated.

In step 1, the injection pulse T is calculated based on the data detected from each sensor.

In step 2, the first injection pulse T, is read out from the storage area 31A, and in step 3, the first injection pulse T,
is applied, and in step 4 it is determined whether the timer t is greater than or equal to T11, and if rNOJ, the process returns to step 3 and rYES.
If J, move to step 5, and spend time T between steps 3 and 4.
11, voltage is applied to the injection valve 1.

Then, in step 5, the pulse cut time T1 is read from the storage area 31A, in step 6, the pulse is cut, and in step 7, it is determined whether or not the timer t is greater than or equal to T1, and the rNO
If J, the process returns to step 6, and if rYESJ, the process moves to step 8, and the voltage is cut for a time T1 between steps 6 and 7.

In step 8, the second injection pulse T1□ is set to T l 2 =
T + (T + + + T + )'
...(5), apply the second injection pulse T1□ in step 9, determine whether the timer t is equal to or greater than T12 in step 10, return to step 9 if rNOJ, and return to step 9 if rYEsJ. Go to step 11, step 9,
Voltage is applied to the injection valve 1 for a time Ti2 of 10 hours.

In step 11, the pulse cut time T2 is read from the storage area 31A, in step 12 the pulse is cut, and in step 13 it is determined whether the timer t is 72 or more, and the rNO
If J, the process returns to step 12; if rYESJ, the process proceeds to step 14; between steps 12 and 13, for a time T2;
It is designed to cut the voltage.

Furthermore, in step 14, the third injection pulse T,' is read from the storage area 31A, in step 15, the third injection pulse T1' is applied, and in step 16, it is determined whether the timer t is greater than or equal to Tl', and if rNOJ is If it is rYEsJ, it returns to step 15, and if it is rYEsJ, it moves to return, and steps 15.16
A voltage is applied to the injection valve 1 for a time T + ' between the two.

Here, steps 5 to 7 are specific examples of voltage changing means according to the present invention, and steps 14 to 16 are specific examples of voltage reapplying means according to the present invention.

The fuel injection control device according to this embodiment is configured as described above, but the adjustment injection pulse T is used. is applied to the injection valve 1 in the same way as the injection pulse T and the injection pulse in the prior art, and there is no particular difference in their basic operations.

However, in this embodiment, the core member 7 is excited by the first injection pulse T,1, and the pulse is applied until the needle valve 5 is separated from the valve seat 3A and the protrusion 5B of the needle valve 5 hits the stopper 4, and then immediately thereafter Since the pulse cut T1 is reached, the speed at which the protrusion 5B of the needle valve 5 hits the stopper 4 can be reduced, and the rebound between the protrusion 5B and the stopper 4 can be alleviated. Furthermore, after the pulse cut time T2 after cutting the second injection pulse T, 2, the third injection pulse
By applying the injection pulse T, the speed at which the valve body 5A of the needle valve 5 hits the valve seat 3A can be reduced,
The rebound between the valve body 5A and the valve seat 3A can be alleviated, the fuel flow rate can be stabilized at low engine speeds, and variations in engine speed can be prevented. Furthermore, wear of the valve body 5A, protrusion 5B, valve seat 3A, and stopper 4 of the needle valve 5 can be prevented, and the performance of the injection valve 1 can be prevented from deteriorating and its life can be extended. At this time, the pulse cut time T1 is set to 0.05 m, for example.
5, and the third injection pulse T
By also setting l' to 0.05 m5, it is possible to eliminate the influence on actual injection accuracy when actually injecting fuel.

In the above-mentioned embodiments, the case where the injector l is an injector 1 that opens inward is used, but it is also possible to use an injector that opens outward.

Furthermore, FIGS. 4 and 5 show a second and third embodiment of the present invention. In the second embodiment shown in FIG. 4, a voltage is applied in reverse during the pulse cut time T1, and the rebound between the projection 5B of the needle valve 5 and the stopper 4 can be further reduced. Further, the third embodiment shown in FIG. 5 has a pulse cut time T1 and a third injection pulse T.
Sufficient effects can also be obtained by arranging l' with an applied voltage that is half of the applied voltage.

〔Effect of the invention〕

The present invention is as described above in detail, and includes a voltage changing means for changing the injection pulse applied to the injection valve from the control device by a minute time after a predetermined time from the start of application, and a voltage changing means for changing the injection pulse for a predetermined time after the application of the injection pulse ends. By comprising a voltage reapplying means for reapplying the voltage for a minute time after the elapse of time,
The voltage changing means prevents the protrusion of the valve in the injection valve from rebounding to the stopper, and the voltage reapplying means prevents the valve body of the valve from rebounding to the valve seat,
It is possible to stabilize the amount of fuel injected when the engine rotates at low speeds, prevent engine variations, and extend the life of the injection valve.

[Brief explanation of drawings]

1 to 5 relate to embodiments of the present invention, FIG. 1 is a circuit configuration diagram of a fuel injection control device, and FIG. 2 is the relationship between injection pulses, adjusted injection pulses, and valve characteristics according to the first embodiment. FIG. 3 is a flowchart showing the shaping process program of the adjusted injection pulse T0, and FIG.
Waveform diagram similar to that shown in Fig. 5 c# (7) Second waveform diagram according to the embodiment
Waveform diagrams similar to those shown in the figure, Figures 6 to 9 show the prior art, Figure 6 is a vertical cross-sectional view of the injection valve, Figure 7 is a circuit diagram of the fuel injection control device, and Figure 8 is the injection pulse. FIG. 9 is a waveform diagram showing the valve characteristics, and FIG. 9 is a characteristic diagram showing the characteristics of the fuel injection amount with respect to the injection pulse. l...Injection valve, 31...Injection amount calculation device (control device), TI...Injection pulse, To...Adjusted injection pulse, T,...First injection pulse, T11...Second Injection pulse, T,'...Third injection pulse (voltage reapplying means),
T,, T2...Pulse cut time (voltage changing means). Figure 1 Figure 2--1-21 TI+ Ti T, 2 T2 Tl' Figure 4 M □ ■ 1 2 T2 T. Brush drawing ■ Han 12 2T Diagram

Claims (1)

[Claims] A fuel injection control device comprising an injection valve that opens and closes a valve body in response to input of an injection pulse, and a control device that calculates a fuel injection amount and outputs an injection pulse to the injection valve. Voltage changing means for changing the voltage value of the injection pulse for a minute time after a predetermined time has elapsed from the start of application of the injection pulse according to the injection amount, and applying the voltage again for a minute time after the elapse of a predetermined time after the application of the injection pulse ends. A fuel injection control device characterized in that it is provided with a voltage reapplying means for reapplying a voltage.