JPS6291659A - Ignition timing control method for internal combustion engine - Google Patents

Abstract

PURPOSE:To eliminate a timing control by a lag angle greater than that required so as to improve an engine performance by allowing an advance rate in an ignition timing to be increased to meet an increase in engine load and the like in a device where the ignition timing is delayed in angle to meet a condition, in which engine temperature is decreased and then the timing is gradually advanced. CONSTITUTION:When an ignition timing of ignition plugs 7 is controlled in an engine which is provided with catalyst (not shown) for purification of exhaust gas in an exhaust system including an exhaust pipe 15, a lag angle dx corresponding to a decrease in engine temperature detected by a water temperature sensor 22, is computed first by an ECU 50, and the ignition is effected by a spark retard control based on the computed lag angle dx. Subsequently, an advance rate in the timing control which is corresponding to an engine (1) load obtained from output signals detected by an air flow meter 19 and a rotation angle sensor 24 and/or to an engine speed, is computed so as to make a correction in reduction to the lag angle dx by the computed advance rate. After this, the ignition timing is gradually advanced by repeating the above said procedure.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to an ignition timing control method for an internal combustion engine, and particularly relates to an ignition timing control method for an internal combustion engine equipped with a catalyst for purifying exhaust gas.
Concerning methods of crime control.

[Prior Art] Conventionally, in internal combustion engines, the basic ignition advance angle is calculated based on, for example, the load of the internal combustion engine (intake pipe pressure or the amount of intake air per revolution of the internal combustion engine) and the rotational speed, and the basic ignition advance angle is Find the ignition advance angle by correcting the basic ignition advance angle according to the water temperature, etc.
An ignition timing control method is used in which the igniter is controlled using this ignition advance angle as the ignition timing. In addition, in order to purify exhaust gas, such internal combustion engines use an oxidation catalyst that oxidizes carbon monoxide and hydrocarbons in the exhaust gas to purify them into harmless carbon dioxide and water vapor. Several catalytic converters have been proposed that are filled with a three-way catalyst that simultaneously oxidizes nitrogen oxides and reduces nitrogen oxides to harmless carbon dioxide, water vapor, and nitrogen. In order to improve the purification rate of this catalytic converter, it is necessary to maintain the temperature of the catalyst above the temperature at which the catalyst is activated.

However, when the engine is restarted after being left in a stopped state, the exhaust gas purification rate deteriorates because the catalyst temperature is low. Therefore, when starting a cold engine, it is necessary to raise the catalyst temperature quickly.
There is a method of retarding the ignition timing as shown in Japanese Patent No. 7 '2257. That is, when the ignition timing is retarded, the thermal efficiency of the internal combustion engine decreases, the energy in the exhaust gas increases and the exhaust gas temperature increases, and the output of the internal combustion engine decreases, causing the driver to press the accelerator pedal more. Since the exhaust gas level increases, the catalyst temperature increases.

Furthermore, the method for retarding the ignition timing includes cooling at the time of starting the internal combustion engine so that the cooling water temperature does not reach a predetermined value and the retard control stops before the catalyst temperature reaches a sufficient activation temperature. A system has been proposed in which the retard value is determined according to the water temperature, and the retard value is attenuated (advanced) according to the passage of time or the cumulative value of the rotational speed of the internal combustion engine.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional ignition timing control method, by continuing to retard the retard value by attenuating the retard value by a fixed value in accordance with the passage of time or the cumulative value of the rotation speed. Although the catalyst is made to reach its activation temperature, this is not necessarily a suitable method of retardation under high load and high rotation conditions. I mean,
As the load and/or rotational speed increases, the number of exhaust gas stars increases, which acts to raise the catalyst temperature.
There is no need to make the retard value that large. That is, in the conventional example, the angle is retarded more than necessary, resulting in problems such as deterioration of fuel efficiency and reduction in engine output. Furthermore, due to the decrease in output, the amount of depression of the accelerator pedal increased, resulting in an increase in exhaust gas and a problem of worsening of emissions.

The present invention has been made in view of the above-mentioned problems, and even if the load and/or rotational speed of the internal combustion engine increases, the ignition timing can be suitably controlled without unnecessarily retarding the ignition timing too much. It is an object of the present invention to provide an ignition timing control method for an internal combustion engine that can improve fuel efficiency, engine output, and emissions while increasing the temperature of a catalyst.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the means configured in the present invention is as follows: When starting an internal combustion engine having a catalyst for purifying exhaust gas, the ignition is activated in response to a decrease in the temperature of the internal combustion engine. In an ignition timing control method for an internal combustion engine configured to retard the ignition timing and gradually advance the ignition timing in accordance with the passage of time or the cumulative value of the rotational speed of the internal combustion engine, the ignition timing is gradually advanced. The gist of this invention is a method for controlling the ignition timing of an internal combustion engine, in which the ignition timing ratio increases as the load and/or rotational speed of the internal combustion engine increases.

The internal combustion engine in the present invention is one that has a catalytic converter that purifies exhaust gas, and in order to improve the purification rate of this catalytic converter, it is necessary to maintain the temperature of the catalyst above the temperature at which the catalyst is activated. It is something.

At the time of starting the internal combustion engine, for example, the starter signal of the internal combustion engine is received and it is determined whether the starter is currently being driven, or the rotational speed at that time is below a predetermined rotational speed that is significantly lower than idling (for example, 400 rl). Detection is made by determining whether or not it is less than or equal to m.

Retarding the ignition timing according to the decrease in internal combustion engine temperature means:
For example, the ignition timing is retarded from the basic advance value by adding a correction retard value according to the state of decrease in internal combustion engine temperature at the time of startup to the basic advance value determined by engine speed N, intake air amount Q, etc. I have something to do.

The above-mentioned internal combustion engine temperature is the temperature of the internal combustion engine main body, but it may also be determined indirectly based on the cooling water temperature or the like.

The load of an internal combustion engine is, for example, the amount of intake air per revolution of the internal combustion engine, and the amount of air flowing in by an air flow meter or the like is used to detect the amount of intake air.
There are those that detect the intake pipe pressure PM using a pressure sensor or the like.

[Operation] The operation of the present invention will be explained by illustrating the basic procedure diagram in FIG.

When starting an internal combustion engine that has a catalyst that purifies exhaust gas (Pl
), first, the retard value dX is determined according to the decreasing state of the internal combustion engine temperature.
@Calculate P2>, retard the ignition timing using the retard value dX P3), and this routine can be used once. Subsequently, the processing of this routine is started again, and since it is after the start, it branches at the above step P1, and calculates the advance angle ratio dy according to the load Q/N and/or rotational speed N of the internal combustion engine (P4). The retard value dx calculated in the above step P2 is corrected by the above dy, and the ignition timing is retarded (P5).
3). Thereafter, this routine is repeated, and the ignition timing is gradually advanced until the retard angle fidx becomes zero.

[Example] Next, a preferred example of the present invention will be described in detail based on the drawings. 2 to 13 illustrate a first embodiment of the present invention, and FIG. 2 is a system configuration diagram of a six-cylinder engine to which the method of controlling ignition timing for an internal combustion engine of this embodiment is applied.

In the figure, a six-cylinder engine 1 includes a first combustion chamber 6 formed by a first cylinder 2, a piston 3, a cylinder block 4, and a cylinder head 5, and second to sixth cylinders (not shown) having a similar configuration. It is composed of each combustion point. A spark plug 7 and a spark plug (not shown) are disposed at each of the combustion stations.

In the intake system of the first cylinder of the six-cylinder engine 1, an intake boat 9 is connected to the intake pipe 1 via the intake valve 8 of the first cylinder 2.
Connected to 0. A surge tank 11 is provided upstream of the intake pipe 10 to absorb pulsation of intake air.
A throttle valve 12 is disposed upstream of the surge tank 11.

On the other hand, the exhaust system of the first cylinder of the six-cylinder engine 1 is
Exhaust port 14 via exhaust valve 13 of cylinder 2
is in communication with the exhaust pipe 15.

The fuel system includes a fuel supply source consisting of a fuel tank and a fuel pump (not shown), a fuel supply pipe, a fuel injection valve 16 disposed near the intake port 9 of the first cylinder, and other fuel injection valves (not shown). ing.

The ignition system also includes an igniter 17 that outputs high voltage necessary for ignition, and distributes and supplies the high voltage generated by the igniter 17 to each spark plug of each cylinder in conjunction with a crankshaft (not shown). distributor 18
It is composed of

The sensor system includes an air flow meter 19 installed upstream of the throttle valve 12 in the intake pipe 11 to measure the amount of intake air, and an intake temperature sensor installed inside the air flow meter 19 to measure the intake air temperature. 20, Throttle position sensor 1)'12, which detects the opening degree of the throttle valve 12 in conjunction with the throttle valve 12, Water temperature sensor 22, which is installed in the cooling system of the cylinder block 4 and detects the cooling water temperature, Inside the exhaust pipe 15 iJl
An oxygen temperature sensor 23 is provided to detect the residual oxygen concentration in the gas as an analog signal.

Further, inside the disc 1 to the reviewer 18, there is a rotation angle signal that outputs a rotation angle signal every 1/24 rotation of the camshaft of the disc 1 to the reviewer DB, that is, every integer multiple of the crank angle 00 to 30°. A rotation angle sensor 24 that also serves as a speed sensor, and a cylinder discrimination sensor 25 that outputs a reference signal once for each revolution of the camshaft of the distributor 18, that is, for every two revolutions of the crankshaft (not shown) are provided. There is.

In addition, each signal from each of the above-mentioned sensors is input to an electronic control unit (hereinafter referred to as ECU), 50, and is also input to the ECU.
CU3O controls the six-cylinder engine 1 mentioned above.

Next, the configuration of the ECLI 50 will be explained based on FIG. 3.

The ECU 3O is a central processing unit (hereinafter simply referred to as CPU) that inputs and calculates each data detected by the above-mentioned sensors according to a control program, and performs processing to control the various devices mentioned above.
51. Read-only memory (hereinafter simply referred to as ROM) in which the above control program and initial data are stored in advance 52. Random access in which various data input to the ECU 3O and data required for control are temporarily stored. Memory (hereinafter simply referred to as RAM) 53. A battery that is capable of storing and retaining various data necessary for controlling the 6-cylinder engine 1 from now on even if the key switch of the 6-cylinder engine 1 is turned off by the driver. A backup random access memory (hereinafter simply referred to as backup RAM) 54 is provided.

In addition, the ECU 3O includes the above-mentioned air flow meter 19,
Intake temperature sensor 20. Buffers 55 and 56 for output signals from the water temperature sensor 22 and throttle position sensor 21
, 57, 58 are provided, and a multiplexer 59 selectively outputs the output signals of the respective sensors to the CPU 51.
, and A/A converting analog signals into digital signals.
A D converter 60 is also provided.

The C-length signals are then sent to the CPU 51 via the buffers 55, 56, 57, 58, multiplexer 59, and A/D converter 60, and from the CPU 51 to the multiplexer 59 and A/D converter 60. An input/output capo 1-61 for outputting control signals is also provided.

In general, the ECU 3O has the oxygen concentration sensor 2 mentioned above.
A buffer 762 for the output signal of No. 3, and a comparator 63 that compares the output voltage of the oxygen concentration sensor 23 with a predetermined voltage and outputs a signal when the output voltage is equal to or higher than the predetermined voltage are provided. Angle sensor 2
A waveform shaping circuit 64 is provided to shape the waveform of each output signal.

An input capo 1-65 is also provided for transmitting each of the sensor signals to the CPU 51 via a comparator 63 or a waveform shaping circuit 64.

Further, the ECU 3O includes drive circuits 66.67 that supply drive current to the igniter 17 and the fuel injection valve 16, respectively, and each of the drive circuits 66.6.
7 has an output port 8 that outputs a control signal. The output port B is provided with a conveyor A register and a conveyor B register that generate an interrupt at a set predetermined time.

A path line 69 serves as a path for control signals and data between the above-mentioned elements, and a ROM 52 including the CPU 51.
, RAM 53, etc., at predetermined intervals.

Next, ECU3O of the 6-cylinder engine configured in this way
The processing contents of the CPU 51 will be explained with reference to FIGS. 4 to 13.

When the ignition switch (not shown) is turned on, the C
The PU 51 starts executing the main routine shown in the flowchart of FIG. 4 according to a control program stored in the ROM 52 in advance. This main routine is a main control process for the 6-cylinder engine 1. First, in step 100, initial settings are made, such as input/output capotro 1. Input Portro 5. Initial reset of the output port 8 and the like is performed. In the following step 101, the RAM 53 is cleared and predetermined values are set in each register. Continued step 102
The intake air ff1Q and engine rotational speed N per unit time are determined, and from these values, the engine load expressed as Q/N is determined.

In the following step 103, the ignition timing for igniting the air-fuel mixture in the cylinder 6 by the spark plug 7 is calculated. In addition,
This ignition timing control executes the subroutine shown below, and the details will be explained later. Next step 10'
4, the fuel injection time (injector valve opening time) τ is extracted. Then, when the process of step 104 is finished, the process returns to step 102, and from then on, step 102. Step 103. Step 104 is executed repeatedly.

Next, the interrupt routine for the main routine of the CPU 51 mentioned above will be explained.

FIG. 5 is a flowchart showing the A/D conversion interrupt routine. As shown in FIG. 3 mentioned above, the A/D converter 6
0 via the multiplexer 59 to the air flow meter 19
．． Intake temperature sensor 20. Four types of analog signals are input: a water temperature sensor 21, a water temperature sensor 21, and a water temperature sensor 22. Therefore, when the A/D conversion end signal is sent to the CPU 51 from the A/D converter 60, it is first checked in step 110 whether or not the A/D converted value of the signal from the water temperature sensor 22 is being output. to decide. This can be determined, for example, from the detection period of each sensor. Step 11
If it is determined that the A/D converted value is the A/D converted value of the output of the water temperature sensor 22, the process moves to step 111 at t8, and the A/D converted value is stored in a predetermined address for water temperature. In the subsequent step 112, 1 is assigned to the variable Fthw, and the equation moves to the subsequent step 113. 43, Fthw has been cleared in advance in the main routine. On the other hand, if it is determined in step 110 that a sensor output other than the water temperature sensor 22 has been read from the A/D converter 60, the process moves to step 114, and the water temperature sensor 2
The A/D conversion fiQ of the output sensors other than 2 is stored in respective predetermined addresses in the RAM 51, and the process moves to step 113. Then, in step 113, the current RAM5
The sensor signal to be read next is determined based on the type of A/D converted value that has been stored in 1, and a control signal is output to the A/D converter 51 and multiplexer 59, and the water interrupt routine is completed.

The water interrupt routine allows the A/D converted values of each sensor to be used as necessary in the main routine and various interrupt processes described above, thereby always providing the latest sensor output.

Next, the interrupt routine executed every 4m5ec will be explained.

FIG. 6 is a flowchart showing the 4m5ec interrupt routine, and when the process is started, a counter process is executed in step 115. This counter! 2! ! The process increments a variable Cd used in interrupt processing, which will be described later, and 1 is added to it.

Next, step 103 of the main routine shown in FIG.
The ignition timing calculation routine that is called as a subroutine will be explained below.

FIG. 7 is a flowchart showing details of the ignition timing 81 calculation process. When the process is started, it is determined in step 120 whether the variable Fthw is 1.

This Fthw is a constant that is set to 1 when the water temperature sensor signal is received in the A/D conversion interrupt routine described above, and Ft
If it is determined that hW is 1, the process proceeds to step 12.
Move to 1. In step 121, it is determined whether the variable Fd is 1, but this variable Fd is initialized to zero if this process has never been executed.
If it is determined that d is not 1, subsequent steps 122 to 127 are executed. That is, only when this ignition timing measurement routine is executed for the first time, steps 122 to 127 are executed;
From the second time onward, perform steps 122 to 127 above.
Skip the process.

The following step 122 is to transfer 1 to d, and the bit is set so that the process is skipped at step 131 in the second and subsequent ignition timing calculation routines.In the following step 123, the above-mentioned A/D conversion interrupt It is determined whether the stored water temperature T is below 0°C in step 111 of the routine, and if it is greater than O'C, the water temperature is set to 70°C in step 124.
Determine whether it is smaller than. That is, when the water temperature T is below O'C, the process moves to step 125, and the ignition timing is changed to d.
Set the angle value θd to 7° CAB. If the water temperature T is equal to or higher than 0°C but lower than 70°C, the process moves to step 126, and the retard value θd is calculated using the following equation.

θd=7−(King/10) (T: water temperature) When the water temperature T is 70°C or more, the process moves to step 127, and the retard value θd is set to O'CA@.

On the other hand, if it is determined in step 120 that Fthwh) is not 1, the process moves to step 127 described above, and θd
Set O°CA to .

That is, the ignition timing retard value θd has a relationship with the water temperature T shown in the graph of FIG.
A constant value of Δ is taken, and the retard value decreases by 1°C every time the water temperature T rises by 10°C from 0°C.

Subsequently, the process moves to step 128, and a process of attenuation of θd is executed. Note that the leave routine shown after this θd deceleration processing is executed, and will be explained in detail later. The following step 129 calculates the basic ignition advance angle θb, which uses the engine load Q/N and engine rotation speed N calculated in step 102 of the main routine to calculate the basic ignition advance according to a predetermined map as shown in FIG. The corner is like Shinode Tsuru. Note that the blank portions in FIG. 9 are where values are omitted and preferred values are panned. The following step 130 calculates the ignition timing θig, which can be obtained by subtracting the retard value θd from the basic ignition advance angle θb. Then, the obtained ignition timing O1g is stored at a predetermined address.

When the process of step 13a is completed, the process of this routine ends and the process returns to the main routine.

Next, details of the attenuation process of θd, which is subroutine called from step 128 of the ignition timing needle routine in FIG. 7, will be described in detail.

FIG. 10 is a flowchart showing the attenuation routine of θd. When the process starts, in step 140, the variable c
It is determined whether d is 250 or more. Note that this Cd is the variable Cd that was incremented in step 115 of the above-mentioned 4rrl S80 interrupt routine, and when Cd is 250 or more, the process moves to the next step 141, and when Cd is smaller than 250, the main process is started. The process ends and returns to the ignition timing calculation routine. That is, Cd
is a value that is incremented every 4m5ec, and Cd is 2
50 represents l sec, and the processing from step 141 onwards is performed every 1 sec. Step 141 is to clear Cd to zero, followed by step 142 where it is determined whether the engine speed N is 200 Orpm or less, and step 143 where it is determined whether the engine speed N is 300 Orpm or less. If the engine rotation speed N is 2000 rotations or less, the process moves to step 144, where the attenuation ratio of the retard value is set to 0.1, and the engine rotation speed N is 2000 rotations or less.
If the engine rotation speed is greater than 0 rotations and 3000 rotations or less, the process moves to step 145, and Δθ is set to 0°15, and if the engine rotation speed N is greater than 3000 rotations, the process moves to step 146, and 80 is set to 0.2. When the above settings are completed, the process moves to step 147, where a process is executed to calculate θd by subtracting 80 from θd calculated in the ignition timing calculation routine.

In the following step 148, it is determined whether the above-calculated θd is a negative value. If it is a negative value, the process moves to step 149, θd is cleared to zero, and this routine ends. On the other hand, if θd is a positive value in step 148, the process in step 149 is skipped and this routine ends.

Next, a fuel injection valve and igniter control routine for actually opening the fuel injection valve 16 and controlling the igniter 17 using the calculated ignition timing 01g and fuel injection time τ will be described based on the flowchart of FIG. 11.

This process is executed by the ECU 3O in response to a pulse signal output from the rotation angle sensor 1/24 every time the crankshaft rotates 30 degrees, interrupting the main routine.

First, in step 150, in order to calculate the engine rotational speed N, the time required for rotation from the previous interruption at a crank angle of 30° to the current interruption at a crank angle of 30' is calculated. In the following step 151, the crank angle at the time when the current interruption occurs is calculated based on the reference signal output from the cylinder discrimination sensor 25. Next step 15
In step 2, it is determined whether or not there is a cylinder in which the piston of either the first cylinder or the sixth cylinder has reached the top dead center and has entered the intake stroke at the time when the current interruption occurs.

If the conditions in step 152 above are met, the process moves to step 153. Here, for example, if the cylinder that has reached the intake stroke is the first cylinder, the fuel injection valves 16 of the first, fifth, and third cylinders will be injected, and if the cylinder that has reached the intake stroke is the sixth cylinder, the fuel injection valves 16 will be injected. For example, the fuel injection valves 16 of the sixth, second, and fourth cylinders are each opened to start fuel injection. In the following step 154, based on the fuel injection time T calculated in step 104 of the main routine, a time t1 after a time T has elapsed from the current time is set.

The time t1 is the time when each fuel injection valve 16 opened in step 153 is closed. Then, the above-mentioned time t1 is set in the register for the conveyor of the output port 8. On the other hand, if the condition is not met in step 152, step 153 and step 154 are skipped and step 15
Proceed to step 5 for processing.

Next, in step 155, it is determined whether or not the crank angle is 90 degrees before top dead center. If this condition is met, the process moves to step 156. Here, the time t2 at which the igniter 17 is turned on is calculated based on the ignition timing calculated in step 103 of the main routine, and the time t2 is stored in the compare B registers of the output capos 1 to 68.
Set 2. On the other hand, if the condition does not apply in step 155, step 156 is skipped and the process moves to step 157.

Next, in step 157, the crank angle before top dead center is 60
' interrupt is determined.

If this condition does not apply, this process ends.

On the other hand, if the conditions of step 157 above are met,
Processing moves to step 158. Here, the time t3 at which the igniter 17 is turned off is calculated based on the ignition timing calculated in step 103 of the main routine, and the time t3 is set in the conveyor B register of the output port 8. Then, this process ends and the process returns to the main routine.

Thereafter, other first vj entry routines are executed by interrupting the main routine as appropriate.

Next, details of the fuel injection valve closing control routine will be explained based on 71 coaches 1 to 71 in FIG. 12.

This process is performed in step 154 of the fuel injection valve and igniter control routine, and the CPU 51
When the time of the free running timer provided in the ECU 30 matches, an interrupt is generated and executed by the ECU 3O.

When this process is started, in step 160, the fuel injection valve 16 that was opened in the other first interrupt process step 153 is closed. Then, return to the main routine. Thereafter, this process is executed with appropriate interruptions.

Next, the details of the igniter control routine will be explained based on the flowchart of FIG. 13.

This process is based on the time t2 or time t3 set in the conveyor B register in the output port 8 and the free running timer installed in the CPU 51 in steps 156 and 158 of the fuel injection valve and igniter control routine. If the time matches, generate an interrupt and
Executed by CU3O.

When this process is started, it is determined in step 170 whether or not the interrupt is based on the time ↑2 set in the conveyor B register in step 156 of the fuel injection valve and igniter control routine. If this condition is met, the process proceeds to step 171, where the igniter 17 is turned on to end this process and return to the main routine. On the other hand, if the conditions at step 170 are not met, that is, if the mowing is based on time C3, the process proceeds to step 72, where the igniter 17 is turned off, this process is ended, and the process returns to the main routine.

Thereafter, water burying will be executed with appropriate interruptions.

That is, in this embodiment, when the six-cylinder engine 1 is started, the retard value θd is determined according to the A/D conversion value of the signal from the first water temperature sensor 9-22 (the retard value θd is retarded from the basic advance value θb). Further, the retard value is configured to gradually advance by 0 to a damping ratio that changes every second depending on the magnitude of the engine rotational speed at the time. It is possible to suppress the retard value at high rotational speeds, and to obtain an appropriate ignition timing according to the engine rotational speed, which quickly raises the temperature of the catalyst while improving fuel efficiency, engine output, and emissions. It has the advantage of being able to achieve

Next, a second embodiment of the present invention will be described.

The configuration of a six-cylinder engine and the configuration of an ECU using the ignition timing control method for an internal combustion engine of this embodiment are the same as those of the first embodiment. Furthermore, the CPU in the EC and U3O of this embodiment
Regarding the processing content of 51, the attenuation routine of θd is the first
The main routine A is different from the example.
/D conversion interrupt routine, 4m5ec interrupt routine,
The ignition timing calculation routine, fuel injection valve and igniter control routine, fuel injection valve closing control routine, and igniter control routine are exactly the same as those in the first embodiment.

FIG. 14 is a flowchart showing the attenuation routine of θd in this embodiment. When the process starts in the same figure, the judgment in step 200 is executed. Steps 200, 201
, 207, 208, and 209 are the same as steps 140, 141, 147, 148, and 149 in the first embodiment, respectively, and a description thereof will be omitted. In step 202, it is determined whether the engine rotational speed N is 250Orpm or less, and
If the rpm is below, the attenuation rate of the retard value is 0.80.
If 1 is larger than 250 rpm, set 0.15 to 〇. In the following step 205, the engine load Q is
/N is 0.8 (L/rev) or more,
If Δθ is 0.8 or more, it is calculated by adding 0.1 to the above-determined Δθ. Thereafter, from step 207 onward, the lead angle value θd is set to 80 (the lead angle is advanced).

That is, in the second embodiment, the attenuation rate Δθ of the advance angle value Od is configured to change depending on the engine rotation speed and the magnitude of the load. It is possible to suppress the retardation value even under high load conditions, and it is possible to obtain a suitable ignition timing according to the engine speed and load, and while quickly raising the temperature of the catalyst, it improves fuel efficiency, engine output, and emissions. -L can be achieved.

Next, a third embodiment of the present invention will be described. This embodiment also differs from the first embodiment in the attenuation routine for θd, and the processing shown in the flowchart of FIG. 15 is executed. In the figure, when the process is started, the determination in step 300 is executed. Steps 300, 301, 307, 308, 309 are steps 140, 141, 147 of the first embodiment, respectively.
, 148, and 149, and the explanation will be omitted. In step 302, it is determined whether the engine rotation speed N is 1500 rpm or less, and when it is determined that the engine rotation speed N is 1500 rpm or less, 0.1 is set to Δθ required for the attenuation ratio of the retard value θd,
On the other hand, if it is determined that the engine rotation speed N is greater than 1500 rpm, the process moves to step 303, and the engine rotation speed N is 350 rpm.
Determine whether or not it is equal to or higher than Orpm. N is 3500 rpm
If it is determined that Δ0 is equal to or higher than
is smaller than 3500rl)m, i.e. 1500rpm<
If it is determined that N<350 rpm, 80 is calculated using the following formula.

△θ=0.1+ ((N-1500)/2000)Xo
, 1 80 set as above is configured to advance the retard value θd from step 207 onwards.

That is, in the present third embodiment, the attenuation rate Δθ of the retard value θd has a relationship with the engine rotation speed as shown in FIG. Therefore, it is possible to set an appropriate damping ratio Δθ according to the rotational speed N, and it is possible to adjust the ignition timing to 1q according to the engine rotational speed. This has the advantage that engine output and emissions can be improved.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments in any way, and it goes without saying that it can be implemented in various forms without departing from the gist of the present invention. be.

[Effects of the Invention] The ignition timing control method for an internal combustion engine of the present invention retards the ignition timing according to the state of decrease in internal combustion engine temperature at the time of starting an internal combustion engine having a catalyst for purifying exhaust gas, and controls the ignition timing as time passes. Alternatively, in an ignition timing control method for an internal combustion engine configured to gradually advance the ignition timing in accordance with the cumulative value of the rotational speed of the internal combustion engine, the rate at which the ignition timing is gradually advanced is determined by the load on the internal combustion engine. and/b, the ignition timing is configured to increase as the rotational speed increases, and therefore, even if the load and/or rotational speed of the internal combustion engine increases, the ignition timing may be unnecessarily retarded too much. It is possible to appropriately control the ignition timing, quickly raise the temperature of the catalyst, and improve fuel efficiency, engine output, and emissions.

[Brief explanation of drawings]

Fig. 1 is a basic procedure diagram showing the basic concept of the present invention, Figs. 2 to 13 do not show the first embodiment of the invention, and Fig. 2 is a system configuration diagram of a 6-cylinder engine. Figure 3 is EC
A block diagram showing the configuration of the U, FIG. 4 is a flowchart 1 showing the main routine executed by the ECU.
Fig. 5 is a flowchart 1 to 1 showing the A/D conversion interrupt routine executed by the ECU, Fig. 6 is a flowchart showing the 4, m S e C interrupt routine executed by the ECU, and Fig. 7 is a flowchart showing the A/D conversion interrupt routine executed by the ECU. A flowchart showing the details of the ignition timing line shown in Fig. 8 shows the retard value θ.
A graph showing the relationship between d and water temperature, Fig. 9 is a map diagram showing the basic ignition advance angle, and Fig. 10 is a flowchart showing the attenuation routine of θd executed by the ECU.
Figure 1 is a flowchart showing the fuel injection valve and igniter control routine executed by the ECU, and Figure 12 is a flowchart showing the fuel injection valve and igniter control routine executed by the ECU.
FIG. 13 is a flowchart showing the igniter control routine executed by ECtJ;
The figure shows a second embodiment of the present invention, and FIGS. 15 and 16 show a flowchart showing a θd damping routine executed by the ECU. 16 is a flowchart showing a routine for damping θd executed by the ECU, and FIG. 16 is a graph showing the relationship between the damping value of the retard value and the engine rotational speed N. 1...6-cylinder engine 19...F flow meter 20...Intake temperature sensor 21...Throttle position sensor 22...Water temperature sensor 23...M element concentration sensor 24...Rotation angle sensor 25... ...Cylinder discrimination sensor 50...Electronic control unit (ECU) 51...CPU 52...ROM 53...RAM

Claims (1)

[Claims] When starting an internal combustion engine equipped with a catalyst that purifies exhaust gas, the ignition timing is retarded according to the state of the internal combustion engine's temperature drop, and the ignition timing is gradually adjusted over time or according to the cumulative value of the internal combustion engine's rotation speed. In an internal combustion engine ignition timing control method configured to advance the ignition timing, the internal combustion engine is configured such that the rate at which the ignition timing is gradually advanced increases as the load and/or rotational speed of the internal combustion engine increases. Engine ignition timing control method.