JPS61106946A - Fuel injection timing control device - Google Patents

Abstract

PURPOSE:To promote carburetion and atomization and improve responsiveness of fuel supply by providing a changing ratio detecting means outputting changing ratio of charging amount of combustion air and a fuel injection timing changing means changing fuel injection timing. CONSTITUTION:A changing ratio detection means outputting a signal concerning changing ratio of charging amount of combustion air and a discriminating means discriminating a normal running condition and a transient running condition by an output oft he changing ratio detecting means are provided. a fuel injection timing changing means making injection timing of a fuel injection valve to a timing except suction stroke in normal running condition and making it to a suction stroke in transient running condition based on the output of the discriminating means is also provided. Thus, carburetion and atomization can be promoted and responsiveness of fuel supply can also be improved.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an engine fuel injection timing control device.

(Prior art) Conventionally, in order to precisely control the amount of fuel injected to each cylinder of an engine, an injector was provided in the intake path of each cylinder on the downstream side of the intake manifold, and fuel was injected at appropriate timing. For example, Japanese Patent Laid-Open No. 57-108428 describes a fuel injection supply for an engine in which fuel is injected into the intake passage at the end of each cylinder's intake stroke to promote fuel vaporization. The equipment is described.

However, as long as fuel is injected into the intake passage, if fuel is injected at an early point, such as at the end of the intake stroke, a considerable portion of the injected fuel will adhere to the wall of the intake passage, and this will occur with a time delay. A phenomenon occurs in which the liquid is sucked into the cylinder.

However, during steady operation, no particular problem arises because the fuel adhering to the wall is sucked in in fixed amounts with a certain delay, but during transient operating conditions such as during acceleration, the fuel supply response is proportional to the amount of fuel adhering to the wall. A delay occurs, and furthermore, it is not possible to respond to changes in the required amount from the time when the injection amount is determined to the time when the amount is inhaled. As a result, there is a problem that acceleration performance deteriorates. In other words, there will be a shortage of the required fuel.

Further, the same problem of response delay as described above occurs during a transient operating state such as when returning from a fuel cut.

(Object of the Invention) The present invention has been made to solve the above problems, and it is possible to improve the vaporization of fuel during steady operation, and to provide a fuel that does not cause a delay in the response of fuel supply during transient operation. An object of the present invention is to provide an injection timing control device.

(Structure of the Invention) As shown in FIG. 1, the fuel injection timing control device according to the present invention includes a fuel injection valve, an operating state detecting means for detecting an operating state, and a fuel injection timing control device according to the output of the operating state detecting means. an injection amount setting means for determining the amount of fuel injection, a fuel injection timing control means for controlling the fuel injection timing, and a fuel injection amount setting means for determining the fuel injection amount; a change rate detection means for outputting a signal related to the rate of change of the fuel injection valve; a discrimination means for discriminating between a steady operating state and a transient operation state based on the output of the change rate detection means; The fuel injection timing changing means sets the injection timing to a timing other than the intake stroke during a steady operating state, and sets the injection timing to a timing other than the intake stroke during a transient operating state.

(Effects of the Invention) In the present invention, as described above, the determining means receives a signal related to the rate of change of the charging amount of combustion air from the rate of change detecting means to determine whether the operating state is a steady state or a transient operating state, The fuel injection timing changing means that receives the output of the determination result sets the fuel injection timing to a timing other than the intake stroke when the operating state is steady, and to the timing of the intake stroke when the operating state is transient. In this case, it is possible to promote vaporization and atomization of the fuel by injecting it at a time other than the intake stroke, and in transient operating conditions, by injecting it during the intake stroke, most of the injected fuel is carried on the intake airflow. By sending the injection amount into the cylinder, it is possible to supply a highly accurate injection amount according to the request without delay in response.

In other words, in steady-state operating conditions, where delay in fuel supply response due to fuel adhesion to walls is not a problem, fuel is injected at times other than the intake stroke to promote vaporization and atomization of the fuel, but response delay in fuel supply becomes a problem. During transient operating conditions, the fuel can be injected during the intake stroke to improve the responsiveness of fuel supply.

(Example) Hereinafter, an example in which the present invention is applied to a vertical four-cylinder fuel injection engine will be described with reference to the drawings.

The fuel injection timing control system in this embodiment has a second
As shown in the figure, four injectors 31 to 3 each inject fuel into the intake passage 2 of each cylinder 11 to 14 of the engine E.
4, a control unit 4 that outputs drive signals to these injectors 3, to 34, and various sensors described below that output various detection signals to the control unit 4.

The throttle opening sensor 5 is connected to the throttle valve 6, detects the opening of the throttle valve 6, and outputs a throttle opening signal TH.

The manifold negative pressure sensor 7 is provided downstream of the throttle valve 6 and upstream of the intake manifold 8, detects the negative pressure of the intake manifold 8, and outputs a manifold negative pressure signal (2).

The crank angle sensor 9 is provided in conjunction with the crankshaft 10, and outputs a rank angle signal C as shown in FIG. 4(a).

The cylinder identification sensor 11 is provided in conjunction with the distributor 12, and as shown in FIG.
Intake TDC (intake top dead center) and its ATDC90@ (
A cylinder identification signal K is output at a high level to cover the range (90° after top dead center).

The control unit 4, as shown in FIG.
A computer consisting of a human output port 13, a central processing value f (CPU) 14, a read only memory (ROM) 15, a random access memory (RAM) 16, and a free running counter 17, a manifold negative pressure sensor 7, Output signal V-T from throttle opening sensor 5
an A/D converter that receives the manifold negative pressure signal V and the throttle opening signal TH from the first input circuit 18, converts them into A/D, and outputs them to the input/output port 13. 19, a second input circuit 20 which receives the output signals C and K from the crank angle sensor 9 and the cylinder identification sensor 11, shapes their respective waveforms, and outputs them to the input/output port 13; Crank angle signal C
A rising/falling detection circuit 22 detects the rising/falling of the crank angle signal C and outputs a corresponding interrupt signal I to the CPU 4, and a computer detects the rising/falling of the crank angle signal C. Timers 211 to 21.21. to 34 receive fuel injection signals to output fuel injection pulses f having timing and duration corresponding to the signals. and each timer 21
．． ~214, each drive circuit 231-23 receives the fuel injection pulse f, amplifies it, and outputs it to each injector 31-34.
It consists of 4 parts.

Here, the basic idea of this fuel injection timing control system will be explained.

First, during steady operation, during the exhaust stroke (exhaust AB
By injecting fuel at DC90° (90° after the exhaust bottom dead center), the time from injection to intake is slightly longer and the vaporization and atomization of the fuel in the intake passage 2 is promoted. In principle, during transient operating conditions such as immediately after the recovery of the
) to improve the responsiveness of fuel supply.

When switching from exhaust ABDC 90° injection to intake TDC injection or from intake TDC injection to exhaust BTr) C90°
When switching to injection, in order to prevent duplicate fuel injection (injection twice per cylinder stroke cycle), cylinder 1, which has completed its intake stroke,
1-1. The new injection timing after switching is applied sequentially, but since there is no possibility of duplicate injection immediately after returning from a fuel cut, the new timing after switching is applied immediately.

The fuel injection timing is determined by the main routine shown in the flowchart of FIG. 6 based on various detected data indicating the operating state of the engine E, and the fuel injection from each injector 3I to 34 is determined by the main routine. Based on the requested fuel injection timing, the interrupt processing routine shown in the flowchart of FIG. 7 is executed during execution of the main routine.

However, the above-mentioned interrupt processing is executed based on the interrupt signal (2) outputted from the rise/fall detection circuit 22 to the CPU 14 at the rise and fall of the crank angle signal.

The main routine program, the interrupt processing routine program, and other necessary constants are input and stored in the ROM 15 of the computer in advance.

Next, the main routine (steps s1 to 516) for determining the fuel injection timing will be explained with reference to the flowchart of FIG.

First, the input/output port 13 and RAM 16 are activated by the start signal.
When the necessary data stored in memory is initialized, S
At l, the throttle opening signal TH is read, and at S2, this throttle opening signal TH and the previous throttle opening T are read.
H is compared, and based on this comparison result, it is determined in S3 whether or not it is in an acceleration state. If it is in an acceleration state, the process moves to S8 via 84 to S6, and if it is not in an acceleration state, it moves to S8 via S5. Transition.

In S4, it is determined whether the acceleration flag FACC is 1 or 0, and F
When ACC=0, that is, when acceleration starts, the process moves to S6;
In step S7, the acceleration flag FACC is set to 1, and in step S7, the number of intake top injections NTDC is set in the intake top injection counter CINJ. When the acceleration flag FACC=1 in S4, that is, when acceleration is in progress since the previous time, the process moves to S8.

S5 is a case where the vehicle is not in an acceleration state, and the acceleration flag FACC is reset in S5.

88~Sll is for determining the fuel cut condition.
In S8, the manifold negative pressure signal ■ is read, and in S9, the manifold negative pressure is the fuel cut judgment vacuum F.
It is determined whether or not it is larger than CV'AC. If it is larger, the process moves to 311, and if it is not larger, the process moves to S13.

At Sll, it is determined whether the throttle valve 5 is fully closed or not based on the throttle opening signal TH, and if it is fully closed, the process moves to S'12, and if it is not fully closed, the process moves to S13.

Si2 is a case where all fuel cut conditions are satisfied, and in step 312, the fuel cut flag FFC is set to 1.

S13 is a case where fuel cut does not apply, and 3
In step 13, it is determined whether the fuel cut flag FFC is 1 or 0, and if FFC=1, that is, it was a fuel cut last time and it is not a fuel cut this time, it is 3.
At 14, the fuel cut flag FFC is reset, and at 315, the intake top injection counter CINJ is reset.
The number of intake top injections NTDC is set in
lH:c! ! IUIEg;=l! to % I-,y 7
'Each injector 3 at 316 to transition to injection. Injection timing flag F I corresponding to ~34
N+''F I All N4 are set to FIN=1.

When the fuel cut flag is FFC-0 in S13, the process returns directly.

In the above main routine, the fuel injection timing is set to exhaust ABDC 90° or intake top injection counter CI.
It is set to the intake TDC via NJ.

Next, the determination of the order of fuel injection of each injector 31 to 34, the determination of whether to actually inject or not, and the fuel injection, which are made in the interrupt processing at the time of rising or falling of the crank angle signal C, are shown in FIG. The explanation will be based on a flowchart.

First, when interrupt processing is started by the interrupt signal ■ from the rising/falling detection circuit 22, the time is read from the free running counter 17 in S21, and the S
In step 22, the interrupt period is determined from the previous interrupt time and the current interrupt time, and the engine speed is calculated.In step S23, the level of the crank angle signal c is read, and in S24, it is determined whether the level of the crank angle signal C is rHJ or rLJ. judged,
When the level of crank angle signal C is rHJO, that is, intake TD
When it is C, it goes to S25, and when it is “L”, that is, ATDC90.
When it is °, the process shifts to 351.

325 is the case of intake TDC, the cylinder identification signal K is read in S25, and the cylinder identification signal K is read in in S26.
It is determined whether it is HJ or rLJ, and when it is rHJO, it is determined that it corresponds to the intake TDC of No. 1 cylinder 11, and 32
7, and when it is I''LJ, it moves to 328.
In 1S27, the injector counter N is set to 1, and in 328, the injector counter N is set to 1.
is added by 1.

In this way, it is determined by 325 to 32B which of 1 to 4 the value of the injector counter N indicating the ignition order corresponds to.

Incidentally, this injector counter N corresponds to the injectors 31 to 3. in FIG. When the value of this injector counter N is determined tomorrow, the corresponding cylinder number is also determined, and it can be seen that it corresponds to the intake TDC of the cylinders 1° to 14 (see FIG. 5).

In S29, it is determined whether the intake top injection counter CINJ is 0 or not. When CINJ = 0, that is, if it does not correspond to intake top injection, the process moves to S30, and in 330, it is determined which of 1 to 4 the injector counter N corresponds to. and moves to any one of 831 to S34 depending on the value of N,
In each of 331 to 334, each injection timing flag II
N is reset and set to inject at normal exhaust ABDC 90°.

In 330 to 334 above, for example, when N=2, 33
2, the injection timing flag FIN.

The reason for resetting is that when N=2, it corresponds to the intake TDC of the No. 3 cylinder 13, and the intake stroke of the No. 1 cylinder 11 has been completed at this point.

In S29, when the intake top injection counter CINJ is not O, that is, when intake top injection is set, S
35, the intake top injection counter CINJ is counted down in S35, and in S36 it is determined which of 1 to 4 the injector counter corresponds to, and N
337 to S40 depending on the value of
In each of ~S40, each injection timing flag FIN is 1.
The engine is set to inject at the intake top TDC.

Even at the time of transition from S36, the correspondence between the injector counter N and the injection timing counters FIN+ to FIN4 is the same as described above, and the cylinders 11 to 14 whose intake strokes have finished at that point are switched to intake top injection in order. become.

In S24 above, the level of the crank angle signal C is rLJ.
At O time, the process moves to 551, and from each of the above 331 to 334 and each of the above 837 to S40, the process moves to S71.

351 to S59 are normal injection timings, that is, exhaust AB
Judgment 9 is the intake TDC to determine whether or not to actually inject at 90° DC.
This routine determines whether or not to actually inject the fuel and executes it.

In S51, the value of the injector counter N is determined, and the process moves to one of 352 to 555 depending on the value of N at that time, and in each of 352 to S55, it is determined whether each injection timing flag FIN is 1 or 0. Ru.

When transitioning from S51 above, for example, when N=2, 353
As can be seen from FIG. 5, what is determined about the injection timing flag FIN3 in this case is that when N=2, the intake air ATDC of the No. 3 cylinder 13 corresponds to 900, and at this time, the No. 4 cylinder 14 (corresponding to the injector 33) is the exhaust gas. ABDC
This is because it matches the fuel injection timing of 90°.

In each of 352 to S55, it is determined whether each injection timing flag FIN is 1 or 0, and only when FIN=0, the process moves to 356 to S59, and in each of 856 to S59, the corresponding injector 31 to 3 a (I N
Fuel is injected from J + = I N J a ).

That is, since 351 to S59 are injected at the timing of exhaust ABDC90', they are injected on the condition that FIN=O.

Therefore, when it is determined that FIN=1 in each of steps 352 to S55, the process returns to the main routine without injecting.

Next, after S'71, the injection is performed at the timing of intake TI)C, and in S71, the value of the injector counter N is determined, and the process moves to one of 372 to S75 depending on the value of N. In each of the above, it is determined whether each injection timing flag FIN is 1 or 0.

For example, when transitioning from 371 to S72 to S75, N
= 2, the injection timing flag F T at 373
Nz is determined because the current interrupt point corresponds to the intake TDC, so when it is N-2, as can be seen from Fig. 5, the number 3 cylinder 1 corresponding to this injector 3□
．． This is because it corresponds to the intake TDC and may be immediately injected from the injector 3□ on the condition that FINg=1.

Only when the determination result FIN=1 in each of 372 to S75, the corresponding injector 3. Fuel is injected from ~34 (INJ, ~IN, J4). On the other hand, when it is determined that FIN=O in each of steps 372 to S75, the injection is not performed and the process returns to the main routine.

FIG. 5 shows each cylinder 1.0 when fuel is injected at a timing of exhaust ABDC 90° in a steady operating state, the state shifts to a transient operating state of an acceleration state, and then shifts to a steady operating state again. It is an operation time chart showing the suction, compression, explosion, and exhaust strokes and fuel injection timing (indicated by arrows in the figure) of 1 to 14.

The above interrupt processing routine will be explained in relation to FIG. 5 above.

Assuming that the state shifts to the acceleration state at the time point C1 in FIG.
The process moves from 29 to S71 via S35, S36, and S37, and then from 371 to 372. However, since the injection timing flag FIN+ was previously set to FINl=0 in 332 during the steady operating state, the process from S72 to 876 Injector 3I (T
NJ+) will return without being injected.

Therefore, it is not injected at the intake TDC of the first intake stroke after the injection timing change determination at the time of code CI, and at 838 at the time of the second intake TDC, FrNI −
Since it has been set to 1, the injection will proceed from 372 to 376.

This also applies to the other injectors 3□ to 34.

Next, the same applies when switching from intake TDC injection to exhaust ABDC 90'' injection, and injection will continue at the original injection timing until the first intake stroke after the injection timing change determination is completed. I'm here.

Of course, the injection timing during the steady operation state may be other than 90° at the exhaust ABDC, and may also be during the compression stroke or the explosion stroke.

In the flowcharts in Figures 6 and 7 of Section 2,
Although the setting of the fuel injection amount is not explained, the fuel injection amount is set in ROM1 based on the engine speed and throttle opening or the intake air amount detected by an intake air sensor (not shown).
The fuel injection timing is determined by the CPU 14 using a predetermined arithmetic expression, map, etc. manually entered in advance in the CPU 14, and is output to the timers 211 to 214 as the fuel injection timing.

As described above, it is possible to prevent duplicate injections and injection errors (omissions) due to injection timing switching.

According to the fuel injection timing control device of the above embodiment, in a steady operating state, fuel vaporization and atomization can be promoted by injecting at a timing of 90° exhaust BTDC, and in a transient operating state, fuel is injected at a timing of intake TDC. By causing the injected fuel to flow along with the intake air flow, adhesion to the wall surface of the intake passage can be minimized, thereby increasing the responsiveness of fuel supply.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a functional block diagram of the present invention, FIG. 2 is an overall configuration diagram of a fuel injection timing control system, FIG. 3 is a basic configuration diagram of a control unit, and FIG. Figures (a) and (b) are waveform diagrams of the crank angle signal and cylinder identification signal, Figure 5 is an operation time chart showing the relationship between the stroke, fuel injection timing, and required injection timing of each cylinder, and Figure 6 is the fuel FIG. 7 is a flowchart of the main routine for determining the injection timing, and FIG. 7 is a flowchart of the interrupt processing routine. 31 to 34... Injector, 4... Control unit, 5... Throttle opening sensor, 7... Manifold negative pressure sensor, 9... Crank angle sensor,
11... Cylinder identification sensor. Patent applicant: Engraving of drawings by Mazda Motor Corporation (no changes to content) Figure 1*! Injection II! 'tR Shamote role. Procedural amendment document March 15, 1988 Patent Application No. 229954 2, Name of the invention 猃牉 i1+1 Jtl JI Temple Kan Sosukawa Ino Old Shikaoki 3, Distance between the person making the amendment and Hanyu Patent applicant address Hiroshima 3-1 Shinchi, Fuchu-cho, Aki-gun, Prefecture Name
(313) Mazda Motor Corporation Representative Ken Yamamoto - 4, Agent Address 4-5-5 Nishitenma, Kita-ku, Osaka 530
No. Tokyu Marquis Umeda 5, Date of amendment order Vol. 6, Subject of amendment Column for detailed explanation of the invention in the specification and Drawing 7, Contents of amendment (1) Page 8, line 16 of the specification "(Cylinder 1 stroke cycle) ``To prevent double injection)'' has been corrected to ``To prevent (double injection per cylinder stroke cycle) and injection omission''. ” and “large′
Insert the following phrase between "If necessary, go to Sll." Note: “If it is large, go to SIO; if it is not large, go to S1.”
Move to 3. 310, it is determined whether the engine speed is greater than the fuel cut judgment rotation speed FORPM. (3) Figure 3 of the drawing has been corrected as shown in Figure 3 of the attached appendix. (4) Figure 4 of the drawings will be corrected as shown in Figure 4 of the attached appendix. (5) Figure 5 of the drawings will be corrected as shown in Figure 5 of the attached appendix. [ [ rtsu rtsu r') rQl (J ~ formula% formula% □-mouth Hero 8 6 Go to 1 〇 Procedural amendment (flag) May 25, 1985

Claims (1)

[Claims] (1) A fuel injection valve, an operating state detection means for detecting the operating state, an injection amount setting means for determining the fuel injection amount according to the output of the operating state detection means, and a fuel injection timing control for controlling the fuel injection timing. a rate-of-change detection means for outputting a signal related to a rate of change in the charging amount of combustion air; and a rate-of-change detection means for detecting a steady state of operation and a state of transient operation based on the output of the rate-of-change detection means. a discriminating means for discriminating; and a fuel injection timing changing means for changing the injection timing of the fuel injector to a timing other than the intake stroke in a steady operating state and to a timing other than the intake stroke in a transient operating state, based on the output of the discriminating means. A fuel injection timing control device characterized by comprising: