JP2935630B2 - Engine control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control device, and more particularly to an electronic control fuel injection device for a multi-cylinder engine.

[0002]

2. Description of the Related Art Conventionally, there is known an internal combustion engine in which fuel is injected by a fuel injection valve and ignited by an ignition plug, in which the timing of fuel injection is switched in accordance with an engine load factor ( Tokuhei 4
-67578).

[0003]

In such an engine, even if the load is the same, immediately after the fuel injection timing is switched to the delay side (the intake stroke side), the injection timing and the intake valve timing are changed. Due to the timing of opening, a case may occur in which all the injected fuel cannot enter the cylinder in the corresponding intake stroke, and the fuel that cannot enter enters the cylinder in the next intake stroke. After that, the fuel that did not fit into the cylinder in the current injection is supplemented with the fuel that did not fit in the cylinder in the previous injection. Becomes equal to the fuel amount before switching.

[0004] Therefore, the fuel temporarily becomes lean only immediately after switching the injection timing, and a step in torque occurs. Therefore, when the fuel injection timing is continuously changed for all cylinders, the torque steps of the respective cylinders are added to generate a large torque step, and as a result, a large torque shock occurs. When the fuel injection timing is switched to the advanced side (explosion stroke side), the torque step generated immediately after the switching is smaller than in the case of switching to the delayed side described above.

The present invention has been made to solve such a problem, and provides an engine control device capable of preventing occurrence of a large torque shock when switching the fuel injection timing to a delay side. The purpose is to:

[0006]

According to a first aspect of the present invention, there is provided an engine control device for determining whether an engine speed is greater than a predetermined speed, and an operating state of the engine. A signal generating means for generating a fuel injection timing switching request signal in accordance with the control signal, and a switching direction determining means for determining whether to switch the fuel injection timing to the leading side or the lagging side when the switching request signal is generated, When the switching speed of the fuel injection timing at the time of generation of the switching request signal is on the delay side when the rotation speed of the cylinder is equal to or higher than a predetermined rotation speed, an interval of a predetermined stroke number or more is provided between the switching of the cylinders. Is what you do.

[0007] the engine control system according to the invention of claim second term, when the rotational speed of the engine is switched direction delayed side of the fuel injection timing at the time of occurrence of the change request signals below a predetermined rotational speed, total The cylinders are switched continuously.

[0008] the engine control system according to the invention of claim 3, wherein, the time of switching the direction leading side of the fuel injection timing at the time of occurrence of switching Rikae request signal, which was switched in succession all the cylinders It is.

[0009]

According to the first aspect of the present invention, when the engine speed is equal to or higher than the predetermined engine speed and the fuel injection timing is switched to the delay side, an interval equal to or longer than the predetermined stroke number is provided between the switching of the cylinders. To do. As a result, it is possible to prevent a torque step generated immediately after the fuel injection timing is switched to the delay side in each cylinder from being added, and to avoid a large torque shock.

In the second aspect of the present invention, when the engine speed is equal to or lower than the predetermined speed and the fuel injection timing is switched to the delay side, all the cylinders are switched continuously. As a result, it is possible to prevent a torque step occurring immediately after switching the fuel injection timing to the delay side in each cylinder from being added without the air-fuel ratio becoming lean, and to avoid a large torque shock. Become.

In the third aspect of the invention, when switching the fuel injection timing to the advanced side substantially irrespective of the engine speed, all the cylinders are switched continuously. As a result, the air-fuel ratio of each cylinder becomes slightly lean, but the torque step at this time is smaller than when the air-fuel ratio becomes lean. As a result, generation of a large torque shock can be avoided, and smooth fuel injection control can be performed.

[0012]

【Example】

Embodiment 1 FIG. Hereinafter, a case will be described in which the engine control device according to the present invention is applied to an electronic control fuel injection device of a multi-cylinder engine. FIG. 1 is a configuration diagram showing one embodiment of the present invention. In the figure, reference numeral 1 denotes an engine having first to fourth four cylinders (only one cylinder is shown), and an intake pipe 2 and an exhaust pipe 3 are connected to each cylinder. Throttle valves 4 a and 4 b are arranged at the gathering portion of the intake pipe 2, and the upstream end thereof reaches an air cleaner 5.

Each of the intake pipes 2 is provided with a fuel injection valve 6 adjacent to an intake port, and each fuel injection valve 6 is connected to a fuel tank (not shown) via a regulator. The fuel is supplied to the fuel injection valve 6 via a regulator at such a pressure that the pressure difference from the intake pipe pressure is always constant.

Reference numeral 8 denotes a pressure sensor for detecting the pressure of the intake pipe 2 downstream of the throttle, reference numeral 9 denotes a water temperature sensor for detecting the temperature of cooling water of the engine 1, and reference numeral 10 denotes a crank angle of the engine based on the rotation angle of the distributor and the first cylinder. , A crank angle sensor for detecting the piston top dead center TDC, 11 an ignition switch, and 12 a starter motor. Reference numeral 13 denotes a fuel injection control circuit including an interface 14, a CPU 15, and a memory 16.
Stored therein are programs and the like for the arithmetic processing of the CPU 15 shown in the flowcharts of FIGS.

Here, the schematic operation of this embodiment will be described. In this example, when the fuel injection timing of each cylinder is continuously switched to the delay side, a step of the torque generated in each cylinder is added to prevent a large torque shock from occurring. For this reason, in this example, when switching the fuel injection timing of each cylinder to the delay side, the engine speed is detected, and this speed is set to a predetermined value (for example, 2000 to 3000).
(about rpm) or more, the switching of the fuel injection timing of each cylinder is sequentially performed at intervals of four strokes. Thus, the switching of the fuel injection timing does not concentrate at one time, and the occurrence of a large torque shock can be prevented.

In this embodiment, when the fuel injection timing of each cylinder is switched to the delay side, if the engine speed is less than the predetermined value, the switching is performed successively and sequentially. That is, if the engine speed is less than the predetermined value, the period during which the intake valve is open is long, so that even if the fuel injection timing is switched to the delay side, all the fuel injected this time is drawn into the cylinder during the current intake stroke. be able to. Therefore, even immediately after switching to the lag side, the air-fuel ratio does not become lean and a torque step does not occur. In this case, switching of the fuel injection timing of each cylinder is performed promptly.

Further, in this embodiment, when the fuel injection timing of each cylinder is switched to the advanced side, this switching is performed continuously and sequentially. That is, when the fuel injection timing is switched to the advanced side, the air-fuel ratio of the cylinder becomes rich by Δα shown in FIG. However,
At this time, the torque step generated in the engine is smaller than when the air-fuel ratio becomes lean. Therefore, when switching the fuel injection timing to the advanced side, it is not necessary to particularly consider the torque shock, so that the fuel injection timing is switched continuously and sequentially.

Next, a specific operation of this embodiment will be described with reference to FIGS. 2 to 4 are flowcharts showing the operation of switching the fuel injection timing. CP
A program stored in the memory 16 is configured so that the U15 performs a predetermined crank angle routine for each predetermined crank during the main routine processing. In step S1, for example, the output of the crank angle sensor 10
Is calculated.

In step S2, it is determined whether or not the rotation speed Ne is equal to or greater than a predetermined rotation speed Ne0. If it is determined in step S2 that the rotation speed is equal to or higher than the predetermined rotation speed Ne0, the flow proceeds to step S3, where "1" is set in FLAGA, and the flow proceeds to step S5. If it is determined in step S2 that the rotation speed is less than the predetermined rotation speed Ne0, the flow proceeds to step S4, where "0" is set in FLAGA, and the flow proceeds to step S5. Here, FLAGA indicates whether or not the rotation speed Ne is equal to or higher than a predetermined rotation speed Ne0.

In step S5, an intake air amount Qa to be taken into the engine 1 is calculated. In step S6, it is determined whether the intake air amount Qa is equal to or greater than a predetermined value Qa0. If it is determined in step S6 that the value is equal to or larger than the predetermined value Qa0, the process proceeds to step S7, where "1" is set in FLAGB, and the process proceeds to step S9. If it is determined in step S6 that the value is less than the predetermined value Qa0, the process proceeds to step S8, where "0" is set in FLAGB, and the process proceeds to step S9. Where FL
AGB indicates whether the intake air amount Qa is equal to or greater than a predetermined value Qa0.

In step S9, the value of FLAGB ', which was obtained when the predetermined crank angle routine was previously processed, is fetched. In step S10, the value of FLAGB is set to FL
It is stored in the RAM in the CPU 15 as the value of AGB '.
In step S11, the previous FLAGB value FL
It is determined whether or not the value of AGB 'matches the value of the current FLAGB. In step S11, FLAGB ≠ FLAG
If it is determined to be B ', the process proceeds to step S12 and FLA
GC is set to "1", and the process proceeds to step S14. If it is determined in step S11 that FLAGB = FLAGB ', the flow advances to step S13 to set "0" to FLAGC, and then to step S14. Where FLAGC
Indicates whether the load of the engine has changed, that is, whether to switch the fuel injection timing.

In steps S14 to S16, the fuel injection timing is switched depending on whether or not the intake air amount Qa is equal to or more than a predetermined value Qa0. In step S14, FLAGB =
If "1", that is, if the intake air amount Qa is equal to or more than the predetermined value Qa0, the process proceeds to step S15 and the injection start timing IN
The value of T1 is set in JS, and the process proceeds to step S17. If it is determined in step S14 that FLAGB = "0", the process proceeds to step S16, and the injection start timing INJ
The value of T2 is set in S, and the process proceeds to step S17. That is, the fuel injection timing is switched according to the intake air amount Qa. In step S17, the previous injection start timing INJS 'taken in the previous processing of the predetermined crank angle routine is taken. Then, in step S18, INJS is stored in the RAM as INJS '.

In steps S19 to S23, it is determined whether the fuel injection timing is switched to the leading side or the lagging side. In step S19, it is determined whether or not FLAGC is "1", that is, whether or not to switch the fuel injection timing. When FLAGC = "1", that is, when there is a request to switch the fuel injection timing, the process proceeds to step S20, and ΔINJS = INJS-I.
NJS 'is calculated, and in step S21, the sign of ΔINJS is determined.

In step S21, when it is determined that ΔINJS> 0, that is, when the fuel injection timing is switched to the delay side (when the previous time is T1 and the current time is T2), the process proceeds to step S22, and FLAGD is set to "1". Then, the process proceeds to step S24. In step S21, ΔINJS ≦
0, that is, when it is determined to switch the fuel injection timing to the leading side (when the previous time is T2 and the current time is T1)
Proceeds to step S23, sets "0" to FLAGD, and proceeds to step S24. Where FLAGD is
This indicates whether the fuel injection timing is switched to the leading side or the lagging side. Step S19
When it is determined that FLAGC = "0", the process proceeds to step S24 without performing any operation.

In step S24, if FLAGC = "1", there is a request to switch the fuel injection timing, so the process proceeds to step S25. If FLAGC = "0", there is no request to switch the fuel injection timing, so there is no request. Proceed to step S28. In step S25, when FLAGA = "1", there is a switching request,
In addition, since the rotational speed is equal to or more than the predetermined value, the process proceeds to step S26. If FLAGA = "0", a switching request is made, but since the rotational speed is less than the predetermined value, the process directly proceeds to step S28.

In step S26, FLAGD =
In the case of "1", there is a switching request, and the number of rotations is equal to or more than the predetermined value, and the switching is to the delay side, so that the process proceeds to step S27. In step S26, FLAGD = "0"
In the case of (2), there is a switching request and the number of revolutions is equal to or higher than the predetermined value. Therefore, the process proceeds to step S27 only when there is a request for switching the fuel injection timing, the rotational speed is equal to or more than the predetermined value, and the switching of the fuel injection timing is on the delay side.

In step S27, COUNT1
Is a counter for switching the fuel injection timing, and corresponds to each cylinder. In this example, a four-cylinder engine is assumed, so that COUNT1 is a count of free run for each injection stroke, such as 3 → 2 → 1 → 0 → 3 → 2 → 1 →. Works as COUN
T2 is a judgment value for COUNT1.
This COUNT2 is subtracted by 1 when COUNT1 is 0. Therefore, COUNT2 is 4
It is subtracted one by one in the process. The value of COUNT2 is set to 0 when the power is turned on.

In step S27, after both COUNT1 and COUNT2 are preset to 3,
Proceed to 28. In step S28, a cylinder for fuel injection is selected, and the process proceeds to step S29. In step S29, the values of COUNT1 and COUNT2 are compared, and
If the value of NT1 is equal to or greater than the value of COUNT2, step S
Proceed to step S30, otherwise proceed to step S31.

In step S30, the value stored in INJS is set in fuel injection timing INJT, and the flow advances to step S32. In step S31, INJS
The value obtained by subtracting the value stored in ΔINJS from the value stored in is set as the fuel injection timing INJT, and the process proceeds to step S32. In step S32, COUNT1
Is determined to be 0 or not. If the value is not 0, the process proceeds to step S33, in which the value of COUNT1 is subtracted by 1. If the value is 0, the process proceeds to step S34 to preset the value of COUNT1 to 3. As a result, COUNT1 is decremented by one each time this flowchart is started, and
When the count content becomes 0, the count content is preset to 3 again.

After COUNT1 is preset to 3, the process proceeds to step S35, where it is determined whether COUNT2 is 0 or not. Here, if the value of COUNT2 is 0, the process proceeds directly to step S37.
After the value of OUNT2 is decremented by 1, after step S37
Proceed to. The above steps S35 and S36 are performed in COUNT1.
This is the step to proceed when the value of is zero. Therefore, C
The value of OUNT2 will be decremented by one every four strokes. In step S37, the fuel injection timing INJT
The fuel injection is started at the timing stored in, and a series of processing ends.

Up to this point, the flowcharts of FIGS. 2 to 4 have been generally described. Next, the case where the fuel injection timing is not changed, delayed, or advanced will be described. First, a case where the fuel injection timing is not changed will be described. The case where the fuel injection timing is not changed is when there is no change in the intake air amount. At this time, FLAGC = "0" in steps S11 and S13.
It has become. Therefore, steps S24 to S28
The value of COUNT2 remains at the value at the time of turning on the power, that is, 0.

Therefore, in step S29, CO
Since it is determined that UNT1 ≧ COUNT2, step S3 is performed.
Therefore, the value of INJS determined in step 15 or S16 is stored in the fuel injection timing INJT. Here, step S14 is a step of selecting any one of the fuel injection timings T1 and T2 in accordance with the intake air amount. Therefore, the fuel injection timing at which no change in the intake air amount is selected becomes the same as the previous time.

Next, a case where the fuel injection timing is delayed from T1 to T2 will be described. The fuel injection timing is delayed when the rotational speed is equal to or greater than a predetermined value and the intake air amount was equal to or greater than a predetermined value last time but is now less than the predetermined value. In this case, steps S2 and S3
FLAGA = "1" at step S6, FLAG at steps S6 and S8
B = “0”. In step S11, if the previous fuel injection timing was T1, the previous FL
FLAGB ', which is the AGB, should have been "1", so that FLAGB ≠ FLAGB', and step S12
Becomes FLAGC = "1".

In steps S14 and S16, INJS =
It is T2. Since FLAGC = “1”, the process proceeds to steps S19 and S20, and in step S20, ΔINJS
= T2−T1 and T2> T1 so that step S
At 21, S22, FLAGD becomes "1". Thereafter, the process proceeds to steps S24, S25, S26, S27, and COU
NT1 and COUNT2 are both preset to 3. In step S28, a cylinder for injecting fuel this time is selected. In step S29, COUNT1 and COUNT
Since both T2 is 3, the process proceeds to step S30.

In step S30, the fuel injection timing determined in step S16 is set to INJT as the current fuel injection timing.
2 is stored, and the process proceeds to step S32. In step S32, since COUNT1 = 3, the process proceeds to step S33, where COUNT1 is subtracted to 2 and then step S3.
Go to 7. In step S37, fuel is injected into the cylinder selected in step S28 (tentatively, the first cylinder) at the timing of T2 as shown in FIG.

In the next predetermined crank angle routine, FLAGB is set to "0" at steps S6 and S8, and FLAGC is set to "0" at step S13 because FLAGB is set to FLAGB 'in step S11. Therefore,
In the next routine, INJS is performed in steps S14 and S16.
= T2, in step S19, steps S20 to S23
Is jumped, so that ΔINJS remains T2−T1 obtained in the previous routine. Thereafter, the process proceeds from step S24 to S28, where COUNT1 and COUNT are set.
The value of T2 is not preset, COUNT1 is 2, CO
3 is stored in UNT2. In step S28, the second cylinder is selected as the next fuel injection cylinder.

In step S29, since COUNT2 is larger, the process proceeds to step S31 in the next routine. In step S31, INJS = T2- (T2-T
1) is calculated to obtain T1. Then, step S32,
Proceeding to S33, after subtracting COUNT1 by 1 to 1 and proceeding to step S37, fuel injection is performed in the second cylinder at the timing of T1. The third cylinder is calculated similarly to the first cylinder and the second cylinder, and the fuel injection timing is both T1.

In the fourth cylinder, up to step S32, the operation is the same as in the first to third cylinders. However, since the value of COUNT1 is 0 in step S32, step S34 is executed.
Proceed to. In step S34, COUNT1 is preset to 3, and in steps S35 and S36, COUNT1 is set.
The value 2 is subtracted by 1 and the value is rewritten from 2 to 3 and fuel is injected into the fourth cylinder at the timing of T1 in step S37.

In the next predetermined crank angle routine for the first cylinder, COUNT1 = 3 and COUNT2 = 2. Therefore, the process proceeds to steps S29 and S30, and IN
After setting JT = T2 and subtracting COUNT1 by 1 in step S33 and setting it to 2, fuel is injected into the first cylinder at the timing of T2 in step S37. Similarly, in the next second cylinder, since COUNT1 = 2 and COUNT2 = 2, the process proceeds to steps S29 and S30, and INJT = T
After setting it to 2, COUNT1 = 1 is subtracted by 1 and rewritten from 2 to 1, and fuel is injected into the second cylinder at the timing of T2.

In the next third cylinder, COUNT1 = 1,
Since COUNT2 = 2, the process proceeds to steps S29 and S31 to set INJT = T1.
Since NT1 = 0 and COUNT2 = 2, step S2
9, the process proceeds to S31 to set INJT = T1. That is,
The transition of the fuel injection timing of each cylinder when the fuel injection timing is delayed from T1 to T2 is as shown in FIG. As is clear from the figure, the fuel injection timing of each cylinder is sequentially switched every four strokes.

FIG. 5 is a time chart showing the operation of this embodiment. In FIG. 5, the fuel injection timing is changed from T1 to T2.
In the case of switching to the first cylinder, it means that the switching is performed to T2 in the case of the first cylinder, and the subsequent third cylinder is not switched to T1. In this case, the fuel in the first cylinder immediately after the switching is reduced by Δα. However, in this example, it is prohibited to continuously switch the fuel injection timing of each cylinder. As a result, the fuel is reduced only in the switched cylinder during the four strokes, so that the fuel in all the cylinders is reduced by Δα to prevent a large torque shock.

When the rotation speed Ne is less than the predetermined rotation speed Ne0 and the fuel injection timing is delayed from T1 to T2, FLAGA is set to "0" in steps S2 and S4. S27
Will jump. Therefore, COUNT1
Since RESET2 and COUNT2 are not preset, the process always proceeds to steps S29 and S30, and the switching of the fuel injection timing of each cylinder is performed continuously without waiting for four strokes.

Next, a case where the previous fuel injection timing is advanced from T2 to T1 will be described. Since the previous fuel injection timing INJS ′ is T2 and the current fuel injection timing INJS is T1, ΔINJS = T1−T2 in step S20, and steps S21 and S21
At 23, FLAGD becomes "0". As a result, step S27 is jumped in step S26, so that CO
UNT1 and COUNT2 are not preset, and in step S29, the process always proceeds to step S30.
Therefore, the switching of the fuel injection timing of each cylinder is performed successively without waiting for four strokes.

Embodiment 2 FIG. In the above embodiment,
In the case where the rotation speed of the engine 1 is equal to or higher than the predetermined rotation speed and the fuel injection timing is switched to the delay side, an example is shown in which four strokes are provided between the switchings of the cylinders, but the stroke number is not limited thereto. It is needless to say that it can be set arbitrarily so as not to cause a large torque shock.

[0045]

According to the first aspect of the present invention, a rotational speed determining means for determining whether or not the rotational speed of the engine is higher than a predetermined rotational speed, and switching of fuel injection timing according to the operating state of the engine. A signal generating means for generating a request signal; and a switching direction determining means for determining whether to switch the fuel injection timing to a leading side or a lagging side when a switching request signal is generated, wherein the engine speed is equal to or higher than a predetermined engine speed. When the switching direction of the fuel injection timing at the time of generation of the switching request signal is on the lag side, an interval of a predetermined number of strokes or more is provided between the switching of the cylinders. It is possible to prevent a torque step generated immediately after switching to the delay side from being added, and to avoid the occurrence of a large torque shock.

[0046] According to the present invention the second term, when the rotational speed of the engine is switched direction delayed side of the fuel injection timing at the time of occurrence of the change request signals below a predetermined rotational speed,
Since all cylinders are switched continuously, it is possible to prevent the torque step that occurs immediately after switching the fuel injection timing to the delay side in each cylinder from being added without the air-fuel ratio becoming lean, and to prevent a large torque shock. There is an effect that generation can be avoided.

[0047] According to the invention of claim 3, wherein, when the switching direction of the fuel injection timing at the time of occurrence of switching Rikae request signal leading side of, since the switched continuously all the cylinders, each cylinder Although the air-fuel ratio becomes slightly lean, the torque step at this time is smaller than when the air-fuel ratio becomes lean, so that it is possible to switch continuously and continuously without special consideration of the torque shock, and to obtain a large torque shock. There is an effect that generation can be avoided and smooth fuel injection control can be performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an engine control device according to the present invention.

FIG. 2 is a flowchart (part 1) illustrating a switching operation of fuel injection timing.

FIG. 3 is a flowchart (part 2) illustrating a switching operation of fuel injection timing.

FIG. 4 is a flowchart (part 3) showing a switching operation of fuel injection timing.

FIG. 5 is a timing chart showing a fuel injection timing switching operation.

FIG. 6 is a diagram showing a transition of the fuel injection timing of each cylinder when the fuel injection timing is delayed from T1 to T2.

[Explanation of symbols]

 Reference Signs List 1 engine 2 intake pipe 3 exhaust pipe 4a, 4b throttle valve 5 air cleaner 6 fuel injection valve 8 pressure sensor 9 water temperature sensor 10 crank angle sensor 11 ignition switch 12 starter switch 13 fuel injection control circuit 14 interface 15 CPU 16 memory

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F02D 41/34 F02D 41/36

Claims (3)

(57) [Claims] 1. A number-of-revolutions determining means for determining whether or not the number of rotations of an engine is greater than a predetermined number of rotations; a signal generating means for generating a fuel injection timing switching request signal in accordance with the operating state of the engine; Switching direction determining means for determining whether to switch the fuel injection timing to the leading side or the lagging side when the switching request signal is generated, and to generate the switching request signal when the engine speed is equal to or higher than a predetermined speed. An engine control device characterized in that when the switching direction of the fuel injection timing at the time is a delay side, an interval of a predetermined number of strokes or more is provided between switching of the cylinders. 2. The engine according to claim 1, wherein the engine speed is equal to or less than a predetermined speed.
At the time of generation of the switching request signal.
When the switching direction of the engine is on the delay side, all cylinders
The engine control device according to claim 1, wherein the switching is performed . 3. The fuel supply system according to claim 1, wherein the fuel is supplied when the switching request signal is generated.
When the direction of switching the fuel injection timing is
The cylinders are switched continuously.
The control device for an engine according to claim 1 .