JP2964053B2 - Engine ignition timing 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 ignition timing control device for an engine.

[0002]

2. Description of the Related Art For example, when the engine is in a deceleration operation state, the required output is small, and stable operation is possible even if the supplied fuel is cut for a predetermined period. Therefore, the fuel cut is more advantageous in terms of fuel economy. For this reason, in recent electronically controlled fuel injection type engines, deceleration fuel cut control is generally adopted.

[0003] In an engine employing the deceleration fuel cut control, when the fuel return condition is satisfied (the engine speed drops to a predetermined speed or less), the fuel itself is removed in order to prevent the occurrence of torque shock. The first method for gradually obtaining a target air-fuel ratio by gradually returning from the small amount state and the fuel itself as disclosed in Japanese Patent Publication No. 61-6262, for example, immediately after the above conditions are satisfied, On the other hand, the ignition timing is set to be greatly retarded in accordance with that, and the retard value of the ignition timing is gradually decreased from the large state to maintain the ignition timing finally corresponding to the target output. There are two control methods, two methods.

[0004] Above all, the method of retarding the second ignition timing has a higher control response than the first method of controlling the fuel supply amount, and is suitable for the control of the above transient state. There is an advantage.

[0005]

In the above-described electronic fuel injection type engine, a fuel amount (basic injection amount) corresponding to an intake air amount per one stroke of the engine is defined as a difference between the engine speed and the engine speed. The relationship is calculated and this is injected from the fuel injector to the intake system. In such a fuel supply system, it is assumed that the entire amount of fuel originally injected into the intake system is directly drawn into the combustion chamber of the engine.

However, in the fuel supply system of the fuel injection system, since the fuel is not always sufficiently vaporized and atomized, part of the fuel injected from the fuel injector into the intake system is directly introduced into the combustion chamber. Just by being inhaled, the other part adheres and remains on the intake passage wall, and is vaporized and inhaled at the next injection. That is, a fuel transportation delay occurs. Accordingly, a difference occurs between the amount of fuel actually sucked into the combustion chamber and the required amount of fuel of the engine (that is, the basic injection amount), thereby deteriorating the operability of the engine.

[0007] This is exactly the same when the fuel is returned after the deceleration fuel cut, and in this case, in particular, because the fuel has been cut so far, there is no adhesion amount for the previous time, so the above-mentioned transportation delay causes The effect is significant.

For example, looking at the misfire limit ignition timing Igt ₁ (at the time of low intake charge) and Igt ₂ (at the time of high intake charge) of the above ignition timing, the results are as shown in FIG. At this time, the generated torque of the engine is substantially proportional to the difference between the ignition timing and (Igt) and misfire limit ignition timing Igt _1, Igt ₂ is the control. Therefore, the torque shock is less likely to occur if the difference between the ignition timings changes gradually with time.

[0009] However, when attempting to lowest possible fuel return speed after deceleration fuel cut as described above (Nfc), eventually intake air charging amount Ce becomes high, the misfire limit ignition timing as shown, as described above Igt ₂ The shift is further to the retard side. As a result, assuming that the characteristics of the ignition timing Igt are the same, the ignition timing Igt and the misfire limit ignition timing
The time characteristic of the difference from (Igt ₂ ) becomes steep, causing a problem that the torque shock becomes large. On the other hand, since the distributor has an ignition guarantee limit, the retard amount itself cannot be too large.

[0010]

Means for Solving the Problems Each of the inventions according to claims 1 to 3 of the present invention has been made for the purpose of solving the above problems, and has the following structures.

(1) Structure of the invention according to claim 1 The engine ignition timing control apparatus according to the present invention comprises a deceleration fuel cut means, a fuel return means for returning fuel by the deceleration fuel cut means, and the fuel return means. When the fuel is returned after the deceleration fuel cut, the ignition timing of the engine is retarded by a predetermined value from the required ignition timing, and thereafter, the retard value is gradually reduced to return to the required ignition timing. The engine is characterized in that control timing delay control means is provided for delaying the retard value attenuation control start timing of the ignition timing control means as the parameter amount related to fuel transport delay increases.

(2) Structure of the invention according to claim 2 The ignition timing control device for an engine according to the invention is configured as described in claim 1 above.
The invention according to the invention has a basic configuration, and a parameter relating to a fuel transport delay in the configuration is a parameter relating to a fuel amount attached to an intake pipe.

(3) Structure of the invention according to claim 3 The engine ignition timing control device according to the invention is characterized in that:
The invention according to the invention has a basic configuration, and a parameter related to fuel transport delay in the configuration is an engine water temperature.

[0014]

The inventions according to the first to third aspects have the following configurations and, as a result, have the following operations corresponding to the respective configurations.

(1) The operation of the invention according to the first aspect of the invention In the engine ignition timing control apparatus according to the invention, first, at the time of fuel return after deceleration fuel cut, the ignition timing of the engine is set to be larger than the original required ignition timing by a predetermined value. Retarding reduces the engine output and cancels the sudden increase in torque due to fuel return.After that, by gradually reducing the retard value, it converges to the original target ignition timing, enabling stable running. Control so that

Next, there is provided control timing delay control means for delaying the start of the retard value attenuation control of the ignition timing control means in the ignition timing control as the parameter amount related to the fuel transport delay increases. As a result, the retard control of the ignition timing is started in accordance with the actual supply timing of the fuel in consideration of the transport delay, so that the ignition timing is retarded earlier than the fuel supply timing and the engine is started. A misfire state can be reliably prevented.

(2) The operation of the invention according to claim 2 In the ignition timing control apparatus for an engine according to the invention, the same operation as that of the invention according to the above-described claim 1 is performed by the basic components of the ignition timing control apparatus. Is appropriately realized based on a parameter related to the amount of fuel adhering to the intake pipe of the same fuel, which indicates

(3) Effect of the Invention According to Claim 3 In the engine ignition timing control device according to the invention, the same operation as that of the invention described in the above-mentioned claim 1 is performed by the basic components of the ignition timing control device. It is properly realized based on the engine water temperature.

[0019]

As described above, according to the ignition timing control apparatus for an engine of the present invention, it is possible to smoothly and appropriately realize fuel return after deceleration fuel cut without causing torque shock.

[0020]

2 and 3 show an ignition timing control device for an automobile gasoline engine when the present invention is applied to the engine. FIG. 2 schematically shows a control system of the above-mentioned embodiment device. FIG. 3 and FIG. 3 are flowcharts showing the ignition timing control operation of the engine control unit in the control system.

First, an outline of the control system according to the embodiment of the present invention will be described with reference to FIG. 2, and then control of main parts will be described.

In FIG. 2, reference numeral 1 denotes an engine main body. Intake air is taken in from the outside via an air cleaner 30, and then supplied to each cylinder via an air flow meter 2 and a throttle chamber 3. The fuel is supplied from the fuel tank 12 to the engine side by the fuel pump 13 and is injected by the fuel injector 5.

This embodiment employs a so-called split injection system in which the fuel injection is divided into both an intake stroke and a combustion stroke of the engine.

In this embodiment, fuel injection is performed as an external factor that affects the degree of evaporation of fuel.
It is assumed that a part of the fuel adheres to the intake passage wall surface and then evaporates and evaporates and is taken into the combustion chamber. This is in view of the fact that the earlier the injection timing, the larger the amount of evaporation of the attached fuel, and as a result, the ratio of the carry-out amount to the total fuel taken into the combustion chamber increases.

The fuel injection is performed by an engine control unit 9 to be described later based on input signals such as an intake air amount, a water temperature, and a crank angle. Hereinafter, this is referred to as the amount of adhered intake manifold), the fuel supply amount is calculated in accordance with the degree of evaporation of the fuel, and the like, and the valve opening time of the fuel injector 5 is controlled.

By the way, The fuel injected from the fuel injector 5 is divided into a direct input fraction F ₂ taken into the combustion chamber of the deposition amount F ₁ directly engine adheres to the wall surface of the intake passage 7. The fuel F ₁ adhering to the wall surface of the intake passage 7, this is the carry-off component F ₁₁ taken into the combustion chamber is vaporized, as it remains without vaporized is inhaled vaporized at the next injection residual divided into fuel amount F _12.
Therefore, when performing intake manifold wet correction considering the carry-off component F ₁₁ is attached to the intake manifold adhesion amount τn underlying the calculation of the carry-away amount F _11, the intake passage wall of the fuel previously injected It is necessary to calculate on the basis of the attached amount and the remaining fuel amount which was not removed by vaporization in the previous attached amount. In this embodiment, an arithmetic method based on such a concept is employed.

Further, the intake manifold wet correction, as described above, direct input component ratio of F ₂ and the carry-off component F ₁₁ of the fuel, that is, those carried out on the basis of direct input rate α and carry-off ratio beta, also Both the direct entry rate α and the carry-out rate β are determined based on experimental data. In this case, the ratio between the direct entry rate α and the carry-out rate β is also affected by the length of the fuel evaporable period, and therefore, if this fuel evaporable period is not considered at all, an appropriate This means that wet correction cannot be performed.

Therefore, in this embodiment, the prediction of the direct entry rate and the removal rate is changed according to the fuel injection timing which affects the nourishment possible period, so that more realistic control can be performed.

The engine control unit 9
Has a deceleration fuel cut control function, and has an engine speed N
When e is equal to or higher than a predetermined number of revolutions and the throttle valve 6 is fully closed, fuel cut control is executed.

The amount of air taken into the cylinder during traveling is controlled by a throttle valve 6 provided in the throttle chamber 3. The throttle valve 6 is operated in conjunction with the accelerator pedal, and is maintained at the minimum opening degree in the idling operation state.

The throttle chamber 3 is provided with a bypass intake passage 7 which bypasses the throttle valve 6. The bypass intake passage 7 has an intake air amount adjusting means for controlling the engine speed during idling. A current control type solenoid valve (ISC valve) 8 is provided. Therefore, in the idle operation state, the intake air passing through the air flow meter 2 is supplied to each cylinder via the bypass intake passage 7, and the supply amount is adjusted by the electromagnetic valve 8. The open / close state of the solenoid valve 8 is controlled by the duty ratio D of a control signal supplied from the engine control unit 9.

Reference numeral 10 denotes a three-way catalytic converter 1
1 shows an exhaust pipe provided with an exhaust pipe 1.

On the other hand, reference numeral 14 denotes an ignition plug provided on the cylinder head of the engine body 1 so that a predetermined ignition voltage is applied to the ignition plug 14 via a distributor 17 and an igniter 18. The ignition voltage application timing, that is, the ignition timing is controlled by an ignition timing control signal Igc supplied from the ECU 9 to the igniter 18. Reference numeral 19 denotes a knock sensor provided in the cylinder block of the engine body 1, which outputs a voltage output Vo corresponding to the strength of occurrence of knocking of the engine and inputs the voltage output Vo to the ECU 9. Further, reference numeral 20 denotes a boost pressure sensor 20, which detects an engine boost pressure B corresponding to an engine load and inputs it to the ECU 9.

The ECU 9 is mainly composed of, for example, a microcomputer (CPU) as an arithmetic unit, and includes a knock determination circuit, memories (ROM and RAM), and an interface (I / O).
/ O) circuit and the like. In addition to the above detection signals, the interface circuit of the ECU 9 includes, for example, an engine start signal (ECU trigger) from a starter switch (not shown), an engine speed detection signal Ne from the engine speed sensor 15, a water temperature thermistor. Various detections such as a detection signal Tw of the engine cooling water temperature detected by the throttle valve 16, a throttle opening detection signal TVO detected by the throttle opening sensor 4, an intake air amount detection signal Q detected by the air flow meter 2, and the like. Each signal is also input.

Next, the operation of controlling the ignition timing of the engine of this embodiment by the engine control unit 9 will be described.

[0036] First, at a step S _1, reads the various data necessary for the following ignition timing control. Then, the subsequent current deceleration fuel cut return state (at fully closed throttle, below a predetermined speed) at Step S ₂ determines whether it is, YES
Reads the initial value Igtr (n) to be subjected to retarding control than retard map A of the ignition timing shown in FIG. 4, for example the routine proceeds to step S ₃ when. In the retard map A, the retard value of the ignition timing is determined using the intake air charge amount Ce and the engine coolant temperature Tw as parameters. The retard value increases as the coolant temperature Tw decreases (the fuel transport delay increases as the coolant temperature decreases. Is also set), and the data is set such that the larger the intake filling amount Ce, the larger the retard value. On the other hand, when the result is NO, the routine proceeds to step S ₆ will be described later. Then, the initial value of the retard amount of the intake air charging amount Ce in step S ₃ Igt
When the reading of r (n) is completed, step S ₄ in the initial timer value T (n to retard tailing running timer T for executing the retard tailing control of the ignition timing caused by the fuel recovery after deceleration fuel cut as described above ) Is set. And further, then, turn to set the initial retard value of the read ignition timing itself in step S ₃ Igtr (n) to the ignition timing control unit proceeds to step S _5. Thus, the initial value setting of the ignition timing retard control corresponding to the fuel return at the initial stage of the deceleration fuel cut release is completed.

Next, in the next control cycle, not a time fuel recovery after longer deceleration fuel cut, since it is determined as NO in step S _2, followed by the procedure proceeds to step S _6, S _7, the step S ₅ is set in the ignition timing retard amount Igtr (n) is whether a Igtr (n) = 0, i.e. set the ignition timing (n times) the targeted to whether finished retarded, also the retard that has been set in step S ₄ ·
The set timer value T (n) of the tailing execution timer T is T
(n) = 0, that is, whether or not the set time T (n) has elapsed is sequentially determined. Then, when the results are both NO, first willing the retard tailing run timer T set value T (n) a dose decrement of the step S ₈ (T (n)
-1) with at Step S ₉ on which the retard amount of the initial value Igtr (n) is hold processing returns to the control of the next period. On the other hand, when NO in step S _6, S _7, to perform the retard tailing of the ignition timing in step S _10. That is, in this embodiment, until the set time T (n) of the retard / tailing control execution timer T elapses, the tailing control of the ignition timing retard amount Igtr accompanying the fuel return is executed as shown in FIGS. The actual fuel supply timing T as shown in the characteristic of FIG.
Only when the set time T (n) corresponding to m has elapsed, retard tailing of the ignition timing is started. Therefore, unlike the related art, the fuel is started when the retard tailing of the ignition timing advances earlier than the fuel supply timing to be in the advanced state, and the occurrence of torque shock does not occur.

On the other hand, retard tailing of the ignition timing is executed in accordance with the fuel transport delay time Tm as described above, and when the set retard amount Igtr (n) is reached,
To end the control is determined as YES in the step S _6.

(2) Second Embodiment By the way, in the ignition timing control of the first embodiment, a considerable man-hour is required to create a control map of a timer set time. Therefore, there is a problem that the cost is high.

Therefore, the second embodiment is the same in that the retard map A based on the intake air charge amount Ce and the engine coolant temperature Tw is used, but the timing for executing the retard tailing at the same ignition timing is shown in FIG. As shown in the flow chart of FIG. 8, it is characterized in that it can be easily performed by deciding according to the amount of change in the amount of adhered intake manifold (wet correction amount).

That is, in this embodiment, first, step S
_{In step 1} , various data required for the following ignition timing control are read. Then, the subsequent current (at fully closed throttle, below a predetermined rotational speed) deceleration fuel cut return state at Step S ₂ determines whether it is, for example, similar to the first embodiment proceeds to step S ₃ when the YES The initial value Igtr (n) for performing the retard control is read from the retard map A of the ignition timing shown in FIG. In the retard map A, as described above, the retard value Igtr (n) of the ignition timing corresponding to the fuel return is determined using the intake air charge amount Ce and the engine coolant temperature Tw as parameters, and as the coolant temperature Tw becomes lower, the retarder becomes smaller. The data is set such that the value is large (the lower the water temperature, the longer the fuel transport delay is), and the larger the intake charge Ce, the larger the retard value. On the other hand, when the result is NO, the routine proceeds to step S ₇ described later.

Next, the read initial value Igtr (n) of the retard amount of the intake air charging amount Ce in step S ₂ is completed,
Step S ₄ in the value of the retard tailing execution flag FOK for executing the retard tailing control of the ignition timing caused by the fuel recovery after deceleration fuel cut as described above FO
Set K = 0 (retard prohibition). And then,
Proceed to step S _5, FOK = 1? After performing determination of (retard tailing executable?), Tailing of the initial retard value of the set the ignition timing to the ignition timing control unit in the step S ₃ when the YES Igtr (n) (Igtr ( n ) -1) is executed.

On the other hand, if NO, the process returns to the control of the next cycle.

Next, in the next control cycle, not a time fuel recovery after longer deceleration fuel cut, since it is determined as NO in step S _2, followed by the procedure proceeds to step S _7, the step S ₃ It is determined whether or not the initial retard amount Igtr (n) of the ignition timing set in (1) is equal to Igtr (n) = 0, that is, whether or not the retard has been completed to the target set ignition timing.

As a result, if NO is determined, step S
_8, also when it is determined YES, and the process proceeds respectively to the step S _11.

[0046] In step S _8, the intake manifold wet weight τn
Is calculated based on the following equation (1).

Τn = (1−α) · τen + (1−β) τmn (1) where τen: injection pulse width α: direct insertion ratio β: carry-out ratio τmn: total amount of intake manifold afterwards followed the routine proceeds to step S ₉ and, based on the amount of change Derutatauenu the calculated value .tau.n, variation Derutatauenu of the operation value is determined whether or not lower than a predetermined set value Derutatauenu _1, intake manifold attached amount YE in which the amount of change Δτn has decreased below the set value Δτn ₁
The value of the retard tailing executable flag FOK of the ignition timing for the first time in step S ₁₀ when the S FOK = 1
(Execution permission) on set at the process proceeds to step S _5, S ₆ described above, to perform the retard tailing of the ignition timing (Igtr (n) -1).

[0048] On the other hand, when NO in the determination in step S ₉ continues the control described above (Step S ₁ to S ₉₎ until is YES.

As a result, in this embodiment, the tailing control of the ignition timing retard amount Igtr accompanying the fuel return until the tailing control execution flag FOK is set to the execution permission state of FOK = 1 as shown in FIG. The ignition timing is not executed, and the retard tailing of the ignition timing is started only when the change amount Δτn of the intake manifold attachment amount corresponding to the actual fuel supply timing decreases to the set value Δτn ₁ or less. Therefore, unlike the related art, the fuel is started when the retard tailing of the ignition timing advances earlier than the fuel supply timing to be in an advanced state, and the occurrence of torque shock does not occur.

On the other hand, retard tailing of the ignition timing is executed in accordance with the fuel transport delay time Tm as described above, and when the ignition timing reaches the set retard amount Igtr (n),
The process proceeds to step S ₁₁ it is determined YES in step S _6, the control is ended reset to retard tailing execution flag FOK = 0.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims of the present invention.

FIG. 2 is a control system diagram of the ignition timing control device for the engine according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing an ignition timing control operation of the same device.

FIG. 4 is an ignition timing retard map used in the control of FIG. 3 of the same device.

FIG. 5 is a graph showing a set time characteristic of an ignition timing retard / tailing execution timer used in the control of FIG. 3 of the apparatus.

FIG. 6 is a time chart showing ignition timing control characteristics of the same device.

FIG. 7 is a graph showing the ignition timing control characteristics of FIG. 6 of the same device in relation to the fuel return timing and the misfire limit ignition timing.

FIG. 8 is a flowchart showing an ignition timing control operation of the engine according to the second embodiment of the present invention.

FIG. 9 is a graph showing an ignition timing control characteristic of the same device in relation to a fuel intake amount and a change of the fuel intake amount.

FIG. 10 is a graph showing a problem of ignition timing control characteristics of a conventional engine.

[Explanation of symbols]

1 is an engine body, 2 is an air flow meter, 5 is a fuel injector, 14 is a spark plug, 15 is an engine speed sensor, and 18 is an igniter.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-40055 (JP, A) JP-A-3-81566 (JP, A) JP-A-61-283748 (JP, A) JP-A-54- 145819 (JP, A) JP-A-3-81566 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F02P 5/15 F02D 43/00 301 F02D 45/00 364

Claims (3)

(57) [Claims] A deceleration fuel cut means; a fuel return means for returning fuel by the deceleration fuel cut means; and a fuel return after the deceleration fuel cut by the fuel return means. An ignition timing control means for retarding the retard value by a predetermined value and thereafter gradually attenuating the retard value to return to the required ignition timing. An ignition timing control device for an engine, further comprising control timing delay control means for delaying the parameter amount when the parameter amount related to the transport delay is large. 2. The engine ignition timing control device according to claim 1, wherein the parameter related to the fuel transport delay is a parameter related to the amount of fuel attached to the intake pipe. 3. The engine ignition timing control device according to claim 1, wherein the parameter related to the fuel transport delay is the engine water temperature.