JPH08303337A - Engine ignition time controller - Google Patents

Abstract

PURPOSE: To promote warming up without deteriorating fuel efficiency by retarding an ignition time according to the temperature of an engine when the engine is in its idle driving condition and returning the ignition time to a basic ignition time when the idle driving condition is released. CONSTITUTION: ECU 32 for inputting output signals from an ignition switch 34, an idle switch 36, a water temperature sensor 38, a crank angle sensor 40, etc., reads a basic ignition time θB from the basic ignition time map of ROM based on the revolving speed and load of an engine 2 when the engine 2 is placed in a starting condition. This basic ignition time θB is outputted to an ignition time adjuster 30 and the igniting operation of an ignition plug 28 is controlled. Then, when the completion of engine starting is determined, a retarded ignition time is read according to an engine temperature detected by the water temperature sensor 38, and when an idle driving condition is released, the ignition time is returned to the basic ignition time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
An object of the present invention is to provide an engine ignition timing control device suitable for controlling the ignition timing to accelerate engine warm-up operation and activation of the exhaust catalyst.

[0002]

2. Description of the Related Art An engine ignition timing control device of this type is disclosed, for example, in Japanese Patent Laid-Open Nos. 4-136483 and 5-10238. The former ignition timing control device retards the ignition timing over a predetermined period after starting the idle operation of the engine, that is, retards the latter, and the latter ignition timing control device has the engine in the idle operation, and Its cooling water temperature and intake air temperature,
Regarding the state of the exhaust sensor, the ignition timing is retarded when all predetermined conditions are satisfied.

[0003]

In the case of the former ignition timing control device, the ignition timing retard control is forcibly carried out for a predetermined period, and during that period, the driver operates the vehicle. Even if the vehicle is started, the ignition timing is retarded, which adversely affects the drivability of the vehicle.

Further, even in the latter ignition timing control device, if the above conditions are satisfied due to traffic congestion, signal waiting, etc., the ignition timing is retarded when the vehicle is subsequently started,
Even in this case, the drivability is adversely affected. The present invention has been made based on the above-mentioned circumstances, and an object of the present invention is not to adversely affect drivability of a vehicle, and
An object of the present invention is to provide an engine ignition timing control device capable of optimally controlling ignition timing.

[0005]

The above object is achieved by an ignition timing control device according to the present invention. According to a first aspect of the invention, when the engine is in an idle operation state, the ignition timing is dependent on the temperature of the engine. Ignition timing retarding means for setting retard ignition timing on the retard side, idle state detecting means for detecting an idle state of the engine and outputting a detection signal thereof, and within a first period from the start of the engine. When the detection signal is output, the retard ignition timing is set to the retard ignition timing by the ignition timing retarding means, and when the detection signal is not output, the ignition timing is set to the basic ignition timing.

In the apparatus of claim 2, the switching means includes a prohibiting means, and the prohibiting means delays the ignition timing when it is in the second period immediately after the start within the first period. The retard ignition timing is prohibited from being set by the corner means, and the ignition timing is set to the basic ignition timing. In the case of the device of claim 3, the switching means instantaneously switches the setting of the ignition timing based on the presence or absence of the output of the detection signal. On the other hand, in the device of claims 4 and 5,
The setting change of the ignition timing based on the elapse of the second period or the first period is gradually changed toward the basic ignition timing or the retard ignition timing.

[0007]

According to the ignition timing control device of the present invention, the ignition timing is switched from the basic ignition timing to the retard ignition timing when the engine is in the idle operation state within the first period from the start of the engine. As a result, the exhaust temperature of the engine rapidly rises. However, even if the ignition timing is set to the retard ignition timing, when the idle operation state is released by depressing the accelerator pedal, the ignition timing is returned to the normal basic ignition timing.

According to the second aspect of the present invention, the ignition timing is unconditionally set to the basic ignition timing even immediately after the engine is started and during the second period even within the first period. Claim 3
According to the device of claim 4, the ignition timing is switched instantaneously based on the presence or absence of the idle operation state.
According to the apparatus of No. 5, the switching of the ignition timing with the elapse of the second period or the first period is performed by gradually changing the ignition timing toward the retard ignition timing or the basic ignition timing.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, an ignition control device 4 including an engine 2 is schematically shown, the engine 2 having an intake passage 6 and an exhaust passage 8. The intake passage 6 has a surge tank 10, and the exhaust passage 8 has a warm-up catalytic converter 12 and a main catalytic converter 14 from the upstream side thereof. The main catalytic converter 14 is arranged on the bottom surface of the floor of the vehicle body.

One end of the control passage 16 is connected to the surge tank 10, and the other end is connected to the control valve 18. The control valve 18 is divided by a diaphragm into a control chamber and a valve chamber, and the other end of the control passage 16 is connected to the control chamber. A discharge port of an electric air pump 20 is connected to a valve chamber of the control valve 18, and one end of a secondary air passage 22 is connected to the valve port. Secondary air passage 22
The other end of the engine 2 is guided into the upstream portion of the exhaust passage 8 and
It opens toward the combustion chamber.

An electromagnetic valve 24 is inserted in the control passage 16, while a check valve 26 is inserted in the secondary air passage 22. The check valve 26 allows only the flow toward the exhaust passage 8 and prevents the reverse flow from the exhaust passage 8. The ignition plug 28 of the engine 2 is ignited by receiving an ignition signal from an ignition timing adjuster 30, and the ignition timing adjuster 30 is electrically connected to an output side of an engine control unit (ECU) 32. Further, the electric air pump 20 and the solenoid valve 24 described above are also electrically connected to the output side of the ECU 32.

Further, an ignition switch 34, an idle switch 36, a water temperature sensor 38, a crank angle sensor 40, etc. are electrically connected to the input side of the ECU 32. Here, the idle switch 36 is a contact-type switch that detects whether or not an accelerator pedal (not shown) is operated, and the water temperature sensor 38 is a thermistor that detects the cooling water temperature of the engine 2.

The ECU 32 includes an input / output interface, a microprocessor and a storage device such as a RAM and a ROM. The ROM stores a program for controlling the ignition timing and various ignition timing maps in advance.
Next, an ignition timing control routine executed by the ECU 32 will be described with reference to FIGS. 2 to 4.

Ignition Timing Control Routine: First, it is judged whether or not the signal from the ignition switch (IG SW) 34 is ON (step S1), and the judgment is false.
In the case of (NO), step S1 is repeated. In this case, the ECU 32 is in the standby state. When the determination result of step S1 is true (YES), that is, when the engine 2 is in a startable state, each of the distributed variables a and b is reset to 0 (step S2), and the ignition timing θ of the engine 2 is set to the basic value. The ignition timing θB is set (step S
3). Then, the ECU 32 outputs the basic ignition timing θB to the ignition timing adjuster 30 described above, and as a result, the ignition timing adjuster 30 can ignite the spark plug 28 based on the basic ignition timing θB.

Here, the basic ignition timing θB is read from the basic ignition timing map based on the rotation speed of the engine 2 and its load, and the basic ignition timing map is ECU.
It is stored in advance in 32 ROMs. The ECU 32
Inside, the rotation speed of the engine 2 is detected based on a signal from the crank angle sensor 40, and the engine load is obtained according to the intake air amount.

In the next step S4, it is determined whether or not the engine 2 has been started, that is, whether or not the engine 2 has changed from the cranking state to the complete explosion state. Specifically, the completion of the start is determined by whether or not the rotation speed of the engine 2 has reached the idle rotation speed. Here, the engine 2 has completed the explosion and the signal from the ignition switch 34 is the cranking signal. When the (starting signal) is switched to the ON signal, it is determined that the starting is completed.

If the determination result in step S4 is false,
Steps S3 and S4 are repeatedly performed, and the ignition timing θ is maintained at the basic ignition timing θB during the start of the engine 2. When the start of the engine 2 is completed, it is determined whether or not a predetermined period t1 (about several seconds) has elapsed after the completion of the start (step S5). If the determination here is false, steps S3 to S5 are repeated and step S6 of FIG. 3 is performed when the determination result becomes true.

Therefore, as is apparent from FIG. 5, since the ignition timing θ is maintained at the basic ignition timing θB during the period t1 after the engine 2 is started, the stability of combustion immediately after the engine is started. Is sufficiently secured. In step S6, it is determined whether or not the signal from the idle switch (ID SW) 36 is on. If the determination result here is true, it is determined that the engine 2 is in the idle operation state. In this case, the cooling water temperature TW of the engine 2 is read based on the signal from the water temperature sensor 38 (step S7), and the engine The retard ignition timing θR in the cold idle state of No. 2 is read (step S8).
Specifically, the retard ignition timing map as shown in FIG. 6 is stored in advance in the ROM of the ECU 32, and the retard ignition timing θR is set based on the cooling water temperature TW from the retard ignition timing map.

As is apparent from the retard ignition timing map of FIG. 6, when the cooling water temperature TW is TW1 (eg, -10 ° C.) or less, the retard ignition timing θR takes its maximum value θR1 (eg, + 5 °) to obtain the cooling water temperature. As TW gradually increases from TW1, it gradually decreases from the maximum value θR1, and
When the cooling water temperature TW reaches the warm-up operation completion state of TW2 (for example, 50 ° C.) or more, the retard ignition timing θR takes the minimum value 0.

In the next step S9, it is determined whether or not a predetermined period t2 (for example, about 1 minute) has elapsed since the engine 2 was started. If the determination result here is false, it is determined whether or not the distribution variable a is smaller than 1 (step S10), but immediately after the execution of this ignition timing control routine, at step S2 described above. , The distribution variables a and b are both reset to 0. Therefore, the determination result of step S10 at this point is true, and the next step S1
1 is carried out.

At this step, the timer T (n) is started, and the distribution variable a is set by the following equation based on the value of the timer T (n). a = T (n) / Ta Here, Ta is a constant set to a value sufficiently smaller than t2. After that, in the next step S12,
After the ignition timing θ is calculated based on the following equation and the calculated ignition timing θ is output to the ignition timing adjuster 30, steps S6 and subsequent steps are repeated.

Θ = θR × a + θB × (1-a) After the ignition timing control routine is started, steps S11 and S1 are performed.
When 2 is first implemented, the ignition timing θ remains the basic ignition timing θR because the distribution variable a is still 0. However, when step S11 is repeatedly performed and the value of the distributed variable a increases, the ignition timing θ gradually changes from the basic ignition timing θB toward the retard ignition timing θR.

After that, when the distribution variable a becomes 1 or more and the determination result of step S10 becomes false, the distribution variable a is set to 1 (step S13), and then step S12 is executed. When the distribution variable a is 1, the ignition timing θ becomes the retard ignition timing θR. After the lapse of a predetermined period t1 from the completion of the start of the engine 2, the ignition timing θ is not instantaneously switched from the basic ignition timing θB to the retard ignition timing θR, but the ignition timing θ is changed to the retard ignition timing θR as described above. By gradually changing the ignition timing θ, the ignition timing θ can be retarded during the idle operation of the engine 2 without impairing the stability of combustion.

The retard of the ignition timing θ raises the exhaust temperature of the engine 2 and effectively promotes the warm-up operation of the engine 2 and the activation of the catalysts of the catalytic converters 12 and 14 described above. In addition to the retard of the ignition timing θ described above, when the secondary air is supplied into the exhaust passage 8 during the cold idle operation of the engine 2, this secondary air is used for the combustion of unburned gas in the exhaust gas, The combustion energy further promotes warm-up operation of the engine 2 and activation of the catalyst.

The supply of the secondary air is also controlled by the ECU 32, and the ECU 32 opens the solenoid valve 24 and drives the electric air pump 20 for a predetermined period when the cooling water temperature TW is low. In addition, when the solenoid valve 24 is opened, the negative pressure in the surge tank 10 is transmitted to the control chamber of the control valve 18 through the control passage 16, and as a result, the control valve 18 is opened, whereby the electric air pump 20 is opened. Secondary air can be supplied into the exhaust passage 8 through the secondary air passage 22.

On the other hand, the ignition timing θ is the retard ignition timing θR
When the result of the determination in step S6 is false, that is, when the driver depresses the accelerator pedal and the idle operation state is released, the steps after step S3 in FIG. 2 are performed. The ignition timing .theta. Is instantly returned to the basic ignition timing .theta.B as is clear from FIG. Therefore, even if the vehicle is started after that, the drivability of the vehicle does not deteriorate. When the determination result of step S6 becomes false and the determination returns to true, the ignition timing θ of the engine 2 is instantly returned from the basic ignition timing θB to the retard ignition timing θR.

After that, when the period t2 has elapsed from the start of the engine 2 and the determination result of step S9 becomes true, step S14 of FIG. 4 is executed. In this step, it is judged whether or not the distribution variable b is smaller than 1. At this time, since step S14 is executed for the first time after the execution of the ignition timing control routine, the judgment result is true, and the next step S15 is executed. Is carried out.

In this step, the timer T (m) is started, and the distribution variable b is set by the following equation based on the value of the timer T (m). b = T (m) / Tb Here, Tb is a constant set to the same value as Ta, for example. Then, in the next step S16, the ignition timing θ is set based on the following equation, and the ignition timing θ is output to the ignition timing adjuster 30. Then, steps S6 and subsequent steps are repeated.

.Theta. =. Theta.B.times.b + .theta.R.times. (1-b) Here, when step S16 is first executed, the distribution variable b is still 0, so the ignition timing .theta. Remains the retard ignition timing .theta.R. However, when the value of the distributed variable b increases as the step S15 is repeatedly executed, the ignition timing θ gradually changes from the retard ignition timing θR toward the basic ignition timing θB, as is apparent from FIG.

After that, when the distribution variable b becomes 1 or more and the determination result in step S14 becomes false, the distribution variable b is set to 1 (step S17), and then step S16 is executed. When the distribution variable b is 1, the ignition timing θ becomes the basic ignition timing θB. Even in this case, the ignition timing θ is not instantaneously switched from the retard ignition timing θR to the basic ignition timing θB, so that the combustion stability can be sufficiently ensured.

As described above, the retard of the ignition timing θ is limited only to the predetermined period t2 from the start of the engine 2, so that the retard period of the ignition timing θ becomes unnecessarily long and the fuel efficiency is deteriorated. Absent. With reference to FIG. 7, the solid line and the broken line show the experimental results with and without the control in which the above-described ignition timing control routine is executed, respectively. As is apparent from FIG. 7, when the engine 2 is in the idle operation state,
It can be seen that the exhaust temperature with control rises more quickly than in the case without control, and the bed temperature of the catalytic converters 12 and 14 also rises earlier than without control.

In the above-described embodiment, the ignition timing θ is retarded after the lapse of the period t1 from the completion of the start of the engine 2. However, as shown by the alternate long and short dash line in FIG. The ignition timing θR may be set, or the ignition timing θ may be gradually changed from the completion of the start toward the retard ignition timing θR as shown by the chain double-dashed line. Further, even after the lapse of the period t2, the ignition timing θ may be instantly returned to the basic ignition timing θB as shown by the chain double-dashed line.

Whether or not the engine 2 is in the idle operation state is not limited to the idle switch 36,
For example, it can be determined from the signal of the throttle position sensor. Further, in the above embodiment, the period t1,
Although the starting time of t2 is set to the time when the signal from the ignition switch 34 is switched from the cranking signal to the ON signal, even if the starting time, that is, the completion of the start of the engine 2 is set to the complete explosion time, Good.

[0034]

As described above, according to the ignition timing control apparatus of the first aspect, the ignition timing is retarded according to the temperature of the engine when the engine is in the idle operation state, so the engine warm-up operation is performed. Since the ignition timing is returned to the basic ignition timing when the idle operation state is released, the drivability of the vehicle is not adversely affected. Further, since the retard period of the ignition timing is limited to the first period from the engine start, the fuel consumption does not deteriorate.

According to the second aspect of the present invention, the retard of the ignition timing is prohibited during the second period immediately after the engine is started, so that it is possible to sufficiently secure the combustion stability immediately after the engine is started. According to the apparatus of claim 3, when the ignition timing is switched depending on whether or not the engine is in the idle operation state, the switching is instantaneously performed, so that the drivability of the vehicle can be promptly secured, and the retard of the ignition timing is delayed. It is possible to sufficiently secure the effect of accelerating the warm-up operation.

According to the apparatus of claims 4 and 5, when switching the ignition timing with the passage of time from the start, the ignition timing is gradually changed, so that stable combustion is effectively ensured. be able to.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an ignition timing control device including an engine.

FIG. 2 is a part of a flowchart showing an ignition timing control routine.

FIG. 3 is a part of a flowchart showing an ignition timing control routine.

FIG. 4 is a part of a flowchart showing an ignition timing control routine.

FIG. 5 is a timing chart showing switching of ignition timing.

FIG. 6 is a graph showing a retard ignition timing map.

FIG. 7 is a graph showing experimental results obtained by executing an ignition timing control routine.

[Explanation of symbols]

 2 engine 18 control valve 20 electric air pump 30 ignition timing adjuster 32 engine control unit (ECU) 34 ignition switch 36 idle switch 38 water temperature sensor 40 crank angle sensor

Claims (5)

[Claims] 1. When the engine is in an idle operation state, the ignition timing is set to a retard ignition timing on the retard side in accordance with the temperature of the engine with respect to a basic ignition timing set at least according to the load of the engine. Timing retarding means, idle state detecting means for detecting an idle operation state of the engine and outputting a detection signal thereof, and ignition timing when the detection signal is output within the first period from the start of the engine. Is set to the retard ignition timing by the ignition timing retarding means, and switching means for setting the ignition timing to the basic ignition timing when the detection signal is not output. apparatus. 2. The switching means prohibits the retard ignition timing from being set by the ignition timing retarding means during the second period immediately after the start within the first period, and sets the ignition timing to the basic ignition timing. The ignition timing control device for an engine according to claim 1, further comprising prohibiting means for setting. 3. The ignition timing control device for an engine according to claim 1, wherein the switching means instantaneously switches the ignition timing setting based on whether or not the detection signal is output. 4. When the ignition timing is set to the basic ignition timing based on the lapse of the first period, the switching means gradually changes the ignition timing toward the basic ignition timing. 4. An engine ignition timing control device according to any one of items 1 to 3. 5. The switching means gradually changes the ignition timing toward the retard ignition timing when the ignition timing is set to the retard ignition timing based on the lapse of the second period. Item 5. An engine ignition timing control device according to any one of items 2 to 4.