JP2967588B2 - Engine ignition timing control device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition timing control device for an engine that corrects an ignition timing in order to prevent a decrease in engine speed due to an external load.

[Prior art] Conventionally, in an air-fuel ratio control system for an engine, when an external load on the engine suddenly increases due to the operation of an air conditioner (air conditioner) or the like, the air-fuel ratio is enriched to prevent a decrease in engine speed. I am trying to do it.

On the other hand, the ignition timing is set by a map search or the like using the engine speed and the basic fuel injection amount or the engine speed and the intake pipe pressure as parameters as before the external load is applied to the engine. −
Japanese Patent Publication No. 115467 discloses a technique for advancing the ignition timing in accordance with an increase in load such as a basic fuel injection amount. There is a response delay from the time when the force acts to the time when this is reflected in the engine load such as the basic fuel injection amount. For this reason,
Even if the ignition timing is advanced according to the engine load such as the basic fuel injection amount, there is a time delay from the external load acting on the engine until the ignition timing is actually advanced, and the engine speed In some cases, it is not possible to sufficiently prevent the drop of the image.

In view of the above circumstances, the present invention uses a simple control process to immediately correct the ignition timing when an external load is applied to the engine, and to reduce the decrease in the engine speed immediately after the external load is applied to the engine. It is another object of the present invention to provide an ignition timing control device for an engine that can appropriately prevent the ignition timing regardless of the engine operating state at that time.

Means for Solving the Problems In order to achieve the above object, the present invention sets an ignition timing based on an engine speed and an engine load, and advances the ignition timing when an external load acts on the engine. In the ignition timing control device for the engine for correcting the angle, as shown in FIG. 1, it is determined whether or not an external load is applied to the engine, and when the external load is applied to the engine, the ignition timing is advanced. Initially, a correction advance amount for angle correction is initially set based on the engine speed, water temperature, and vehicle speed at the start of the operation of the external load, and after the initial setting, the advance correction amount is gradually reduced uniformly. Advancing correction amount setting means for setting, and ignition timing setting means for setting the ignition timing by correcting the basic ignition timing set based on the engine speed and the engine load with the advancing correction amount. Feature And

[Action] In the present invention, it is determined whether or not an external load is applied to the engine, and when the action of the external load is started on the engine, the correction advance amount for advanced correction of the ignition timing is set to an external amount. Initial settings are made based on the engine speed, water temperature, and vehicle speed at the start of the load operation, and after the initial settings, the advance correction amount is gradually and uniformly reduced. Then, the ignition timing is set by correcting the basic ignition timing set based on the engine speed and the engine load by the advance correction amount.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Fig. 2 and subsequent figures show an embodiment of the present invention, Fig. 2 is a schematic diagram of an engine control system, Fig. 3 is a front view of a crank rotor and a crank angle sensor, and Fig. 4 is a front view of a cam rotor and a cam angle sensor. FIG. 5, FIG. 5 is a flowchart showing an ignition timing setting procedure, FIG. 6 is an explanatory diagram of an air conditioner water temperature correction advance amount map, FIG. 7 is an explanatory diagram of an air conditioner / engine speed correction advance amount map, FIG. FIG. 9 is an explanatory diagram of an air conditioner / vehicle speed correction advance angle amount map, FIG. 9 is a flowchart showing an ignition number counting procedure, FIGS. 10 (a) and 10 (b) are flowcharts showing an ignition control procedure, and FIG. FIG. 12 is a time chart of the ignition timing, and FIG. 12 is a time chart showing the on / off state of the air conditioner switch, the air conditioner correction advance amount, and changes in the engine speed.

(Configuration of Engine Control System) Reference numeral 1 in FIG. 2 denotes an engine body, and in the drawing, a horizontally opposed four-cylinder engine is shown. The engine body 1 is divided into two banks on both sides of the cylinder block 1a. An intake manifold 3 is communicated with an intake port 2a formed in a cylinder head 2 of each bank, and an air is supplied upstream of the intake manifold 3. A throttle chamber 5 is communicated through the chamber 4, and an air cleaner 7 is mounted on an upstream side of the throttle chamber 5 via an intake pipe 6.

An intake air amount sensor (hot wire type air flow meter in the figure) 8 is interposed immediately downstream of the air cleaner 7 in the intake pipe 6, and a throttle vibrator 5 a provided in the throttle chamber 5 has a throttle vibrator 5 a. An opening sensor 9a and an idle switch 9b for detecting the full closing of the throttle vibrator are connected to each other.

An idle speed control valve (ISCV) 5c is interposed in a bypass passage 5b communicating the upstream side and the downstream side of the throttle vibrator 5a, and is located immediately upstream of each intake port 2a of each cylinder of the intake manifold 3. An injector 10 is provided, and a spark plug 11 whose tip is exposed to a combustion chamber is attached to each cylinder of the cylinder head 2.

The injector 10 includes a fuel filter 12, a fuel pump
It is connected to a fuel tank 14 via 13 and further to a pressure regulator 15. The downstream side of the pressure regulator 15 is communicated with the fuel tank 14, and the return fuel is returned.

A crank rotor 16 is mounted on a crank shaft 1b supported by a cylinder block 1a of the engine body 1. A crank angle sensor 17 such as an electromagnetic pickup for detecting a crank angle is mounted on the outer periphery of the crank rotor 16. Are opposed to each other.

Further, a cam rotor 18 is axially mounted on a camshaft 1c which makes a half rotation with respect to the crankshaft 1b, and a cam angle sensor 19 for cylinder discrimination is provided on the outer periphery of the cam rotor 18.

As shown in FIG. 3, the crank rotor 16 has projections 16a, 16b, and 16c formed on the outer periphery thereof.
a, 16b and 16c are, for example, cylinders (# 1, # 2 and # 3, # 4)
Position before compression top dead center (BTDC) θ1, θ2, θ3 (for example,
θ1 = 97 °, θ2 = 65 °, θ3 = 10 °).

That is, the protrusion 16a indicates the reference crank angle at the time of setting the ignition timing, and the rotation period f of the engine is calculated from the passage time between the protrusions 16a and 16b. Further, the projection 16c becomes the reference crank angle indicating the fixed ignition timing.

As shown in FIG. 4, projections 18a, 18b, and 18c for discriminating cylinders are formed on the outer periphery of the cam rotor 18. For example, the projections 18a are located after the compression top dead center of the # 3 and # 4 (ATDC). The projection 18b is formed of three projections, and the first projection is formed at the ATDC θ5 position of the # 1 cylinder (eg, θ5 = 5 °). further,
The projection 18c is formed by two projections, and the first projection is formed at the position of ATDC θ6 of the # 2 cylinder (for example, θ6 = 20 °).

As shown in FIG. 11, when three cylinder discrimination pulses (projections 18b) are output from the ATDC 5 ° by the cam angle sensor 19, for example, the crank pulse output from the crank angle sensor 17 is # It can be determined that the signal is a signal indicating the crank angle of three cylinders. If one cylinder determination pulse (projection 18a) of ATDC 20 ° is detected after three cylinder determination pulses from ATDC 5 °, then the crank is determined. It can be determined that the crank pulse output from the angle sensor 17 indicates the crank angle of the # 2 cylinder.

Similarly, two cylinder discrimination pulses (projection 18
The crank pulse after the output of c) indicates the crank angle of the # 4 cylinder.
If one cylinder discrimination pulse (projection 18a) is output to the ATDC 20 ° after each cylinder discrimination pulse, it can be determined that the subsequent crank pulse indicates the crank angle of the # 1 cylinder.

Further, after the cylinder angle determination pulse is output from the cam angle sensor 19, it can be determined that the crank pulse output from the crank angle sensor 17 indicates the reference crank angle of the cylinder.

The crank rotor 16 or the cam rotor 18
A slit may be provided in place of the protrusion on the outer periphery of
Further, the crank angle sensor 17 and the cam angle sensor 19 are used.
Is not limited to a magnetic sensor such as an electromagnetic pickup, but may be an optical sensor or the like.

A knock sensor 20 is attached to the cylinder block 1a, and a cooling water temperature sensor is provided in a cooling water passage (not shown) forming a riser formed in the intake manifold 3.
21 is facing.

An exhaust manifold 22 communicates with an exhaust port 2b of the cylinder head 2, and an O2 sensor 24 faces an exhaust pipe 23 that communicates with the exhaust manifold 22. Reference numeral 25 denotes a catalytic converter.

(Circuit Configuration of Control Device) On the other hand, reference numeral 30 denotes a control device (ECU) composed of a microcomputer, and the CPU 31, the ROM 32, the RAM 33, the backup RAM 34, and the I / 0 interface 35 of the ECU 30 They are connected to each other, and a predetermined stabilized voltage is supplied from the constant voltage circuit 37.

Then, the ECU 30 realizes other functions such as an ignition timing control function such as an advance correction amount setting means and an ignition timing setting means according to the present invention, and an air-fuel ratio control.

The constant voltage circuit 37 is connected to a battery via a control relay 38.
When the key switch 40 is turned on and the relay contact of the control relay 38 is closed, control power is supplied to each part, and the key switch 40 is directly connected to the battery 39 and the key switch 40 is turned off. Even when the relay contact of the control relay 38 is opened, the backup power is supplied to the backup RAM 34 to retain the data.

The input ports of the I / 0 interface 35 are connected to the sensors 8, 9a, 17, 19, 20, 21, and 24, and the idle switch 9b.
A positive terminal 39 is connected to monitor the terminal voltage VB, and a vehicle speed sensor 26 and an air conditioner switch 27 are connected.

On the other hand, to the output port of the I / 0 interface 35, the ignition plug 11 is connected via an igniter 28, and the ISCV 5c, the injector 10, and the fuel pump 13 are connected via a drive circuit 41.

The ROM 32 includes a control program, a basic ignition timing map MPθ described later, and an air-conditioner / water temperature correction advance amount map.
MP ACTW, air conditioner / engine speed correction advance angle map M
Fixed data for control such as P ACN, air conditioner / vehicle speed correction advance angle map MP ACV are stored, and the output value from each sensor after data processing and the
The data processed by the CPU 31 is stored. Also,
The backup RAM 34 stores learning value data and the like, and the stored data is retained even when the key switch 40 is off.

The CPU 31 calculates the intake air amount from the output signal of the intake air amount sensor 8 according to a control program stored in the ROM 32, and calculates the RAM 33 and the backup RAM.
Based on the various data stored in 34, the fuel injection amount corresponding to the intake air amount is calculated, the ignition timing is calculated, and the duty ratio of the drive signal for the ISCV 5c is calculated.

Then, a drive pulse width signal corresponding to the fuel injection amount is output to the injector 10 of the corresponding cylinder at a predetermined timing via the drive circuit 41 to inject fuel, and is applied at a predetermined timing via the igniter 28. An ignition signal is output to the ignition plug 11 of the cylinder. When the air conditioner switch 27 is turned on during the idling operation, the ISCV 5c is driven to control the amount of air in the bypass passage 5b, and idle-up is performed.

(Operation) Next, the operation of the embodiment having the above configuration will be described according to the program of the ignition timing setting procedure shown in the flowchart of FIG.

This program is a routine that is executed at predetermined time intervals or at predetermined intervals. Prior to the first execution, each flag and each data are initialized. And
In step S101, the elapsed time t between the θ1 crank pulse (for example, a BTDC 97 ° crank pulse) from the crank angle sensor 17 and the next θ2 crank pulse (for example, BTDC 65 ° crank pulse) is measured. The period f is calculated based on the crank angle θ (for example, θ = 32 °) corresponding to the crank pulse and the elapsed time t (f = dt / d).
θ).

Next, in step S102, the engine speed N is calculated from the cycle f calculated in step S101 (N = 60 / (2
πf)), and proceeds to step S103.

In step S103, the engine speed N calculated in step S102 and a predetermined complete explosion speed NSET are set.
(For example, 500 rpm) to determine whether or not the engine has completely exploded.

If N ≦ NSET in step S103, it is determined that the engine has not completely exploded, and the flow advances to step S104 to set the complete explosion determination flag FLAG1 (FLAG ← 1) and exit from the routine. If N> NSET It is determined that the engine is completely exploded, and the process proceeds from step S103 to step S105.

In step S105, the intake air amount Q from the intake air amount sensor 8 is read, and the intake air amount Q and the engine speed N
Then, the basic fuel injection amount Tp is calculated (Tp ← K × Q / N; K is a constant), and the routine proceeds to step S106, and the basic ignition timing map MP using the engine speed N and the basic fuel injection amount Tp as parameters.
Search for θ and set the basic ignition timing (angle) θBASE.

Then, the process proceeds to step S107, in which a coolant temperature correction advance amount (angle) θTW is set using the coolant temperature Tw as a parameter, and step S1 is performed.
At 08, a knock control value (angle) θNK based on a signal from knock sensor 20 is set, and the routine proceeds to step S109.

In step S109, it is determined whether or not the air conditioner switch 27 is ON. When the air conditioner switch 27 is OFF, the process proceeds to step S110, in which the air conditioner operation determination flag FLAG2 for determining the operation state of the air conditioner is cleared (FLAG2 ← 0). Then, in step S111, the air conditioner correction advance angle θACON described later is cleared (θACON ← 0), and in step S112, the ignition count flag FLAG3 is cleared (FLAG3 ← 0), and the routine proceeds to step S113.

In step S113, the basic ignition timing θBASE set in step S106, the water temperature correction advance amount θTW set in step S107, the knock control value θNK set in step S108, and the air conditioner correction advance amount θ described below.
ACON is added and corrected.
The ignition time ADV is set by multiplying the cycle f calculated in step (ADV).
← (θBASE + θTW + θNK + θACON) × f), Step S1
At 14, the complete explosion discrimination flag FLAG1 is cleared and the routine exits.

On the other hand, if the air conditioner switch 27 is ON in step S109, the process proceeds from step S109 to step S115,
It is determined whether or not the air conditioner operation determination flag FLAG2 is set. FLAG2 = 0, that is, the air conditioner switch 27 is determined to be OFF in step S109 in the previous routine, and the air conditioner operation determination flag FLAG2 is cleared in step S110. If so, it is determined that the air conditioner switch 27 has been turned on for the first time from OFF and the process proceeds to step S116.

In step S116, the air conditioner operation determination flag FLAG2 is set (FLAG2 ← 1), and then the process proceeds to step S117, in which the air conditioner / water temperature correction advance amount map MP ACTW is searched using the cooling water temperature TW as a parameter, and the air conditioner / water temperature correction advance angle is retrieved. Set the amount AC TW (angle).

As shown in FIG. 6, the air conditioner / water temperature correction advance amount map MP ACTW is for setting the advance amount of the ignition timing in accordance with the cooling water temperature TW. The advance amount is increased on the low temperature side, and the advance amount is decreased on the high temperature side to cope with a decrease in the rotation speed when an external load is applied to an engine such as an air conditioner.

When the process proceeds from step S117 to step S118, the air conditioner / engine speed corrected advance amount map MP ACN is searched using the engine speed N as a parameter, and the air conditioner / engine speed corrected advance amount ACN (angle) is set. To step S119.

This air conditioner / engine speed correction advance angle map MP A
As shown in FIG. 7, CN sets the advance amount for correcting the ignition timing in accordance with the external load from the air conditioner when the engine speed is low. When the engine speed is higher than 1000 rpm, the vehicle is not in an idle state, so that no advance is made.

Further, when the process proceeds from step S118 to step S119, it is determined whether or not the air conditioner / engine rotation speed correction advance amount ACN is “0”. When ACN = 0, the process branches from step S119 to step S111 described above, and ACN If ≠ 0, the process proceeds from step S119 to step S120 to search the air conditioner / vehicle speed correction advance amount map MP ACV using the vehicle speed V as a parameter, set the air conditioner / vehicle speed correction advance amount ACV (angle), and then proceed to step S121. .

The air conditioner / vehicle speed correction advance angle map MP ACV is
As shown in the figure, this is for setting the ignition timing advance amount in the low-speed range lower than 15 km / h. In the high-speed range, the effect of the external load can be ignored, so the advance amount is set to “0”. Has become.

Next, in step S121, it is determined whether or not the air conditioner / vehicle speed correction advance amount ACV is "0". If ACV = 0, the process branches from step S121 to step S111, and if ACv ≠ 0, the process proceeds to step S111. Proceeding from S121 to step S122, the air conditioner / water temperature correction advance amount AC T set in step S117 is set.
W, the air conditioner / engine speed correction advance amount ACN set in step S118, and the air conditioner / vehicle speed correction advance amount ACV set in step S120 are added to obtain the air conditioner correction advance amount θACON (angle). Set (θACON ← AC TW = A
CN = ACV).

Then, the process proceeds to step S123, where the air conditioner correction advance amount θACON set in step S122 is compared with a preset air conditioner correction advance amount upper limit θACONH (for example, 5 CA). When θACON ≧ θACONH, step S124 is performed. The air conditioner correction advance angle θACON with the air conditioner correction advance angle upper limit θACONH
(ΘACON ← θACONH) to prevent the occurrence of knocking due to the over-advance angle, and proceed to step S125. If θACON <θACONH, the process jumps from step S123 to step S125.

In step S125, when the ignition count value ACCUT is cleared (ACCUT ← 0), the ignition count flag FLAG3 is set in step S126 (FLAG3 ← 1), and the process branches to step S113.

On the other hand, when the air conditioner operation determination flag FLAG2 is 1 in step S115, the air conditioner switch 27 has already been turned on, and the air conditioner operation determination flag FLAG2 has been set in the previous routine.
Proceeding from step S115 to step S127, the ignition count value ACCUT is set to the ignition count set value ACCUT SET (for example, 25).
It is determined whether or not the above has been achieved.

If ACCUT <ACCUT SET in step S127, the process jumps to step S130. If ACCUT ≧ ACCUT SET, the process proceeds to step S128 to subtract a set value θACONSET (for example, 1 ゜ CA) from the air conditioner correction advance angle θACON to obtain a new value. Set the air conditioner correction advance angle θACON (θACON ← θACON−θAC
ONSET), the ignition count value ACCT is cleared in step S129 (ACCUT ← 0), and the flow proceeds to step S130.

Then, in step S130, it is determined whether or not the air conditioner correction advance angle θACON has become 0 or less. When θACON ≦ 0, the process branches to step S111. On the other hand, when θACON> 0, the process branches to step S113.

That is, as shown in FIG. 12, with the operation of the air conditioner, the air conditioner correction advance amount θACON is initialized according to the conditions of the cooling water temperature TW, the engine speed N, and the vehicle speed V to advance the ignition timing, After that, the air-conditioner correction advance angle θACON is uniformly and gradually reduced according to the number of ignitions to reduce the advance correction amount with respect to the ignition timing, thereby preventing a decrease in the engine speed.

As a result, as shown by a dashed line in FIG.
When the engine is advanced, such as at idle, immediately after the air conditioner is turned on, the higher the engine temperature, the higher the engine speed N
Is high, and depending on the engine condition such as when the engine temperature is low, the engine speed N
However, in the present invention, the engine condition is accurately grasped, an appropriate advance angle is set, and the engine speed N is reliably prevented from lowering. be able to.

Ignition rotation count value AC in the above ignition timing setting procedure
The CUT is counted by the interrupt routine for each ignition shown in the flowchart of FIG. 9. First, in step S201, it is determined whether or not the ignition number count flag FLAG3 is set.

When FLAG3 = 1 in step S201, the process proceeds to step S202, in which the ignition count value ACCUT is counted up, and the routine exits (ACCUT ← ACCUT + 1). On the other hand, when FLAG3 = 0 in step S201, the routine is continued. Exit.

On the other hand, the actual ignition signal for each cylinder is output according to the following program which is started by interruption by a crank pulse.

The program shown in FIG. 10 (a) is a program that is started by interruption by a θ3 crank pulse (for example, a BTDC10 ° crank pulse). First, in step S301, it is determined whether or not the complete explosion determination flag FLAG1 is set. When FLAG1 = 0, that is, after the engine complete explosion, the routine exits. When FLAG1 = 1, that is, at the time of starting before the engine complete explosion, the process proceeds to step S302, and the cylinder data of the cylinder determined from the predetermined address in the RAM 33 is determined. #I is read, and the routine proceeds to step S303, where an ignition signal is output to the #i cylinder.

After the complete explosion of the engine, the program shown in the flowchart of FIG.
In step S401, it is determined whether or not the complete explosion determination flag FLAG1 is set. If FLAG1 = 1, the routine is exited. If FLAG1 = 0, step S402 is performed. To the ignition time AD set by the above-described ignition timing setting procedure.
V is set in the ignition timer, and the flow advances to step S403.

Then, in step S403, the ignition timer is driven, and in step S404, the cylinder data #i of the cylinder determined from the predetermined address in the RAM 33 is read, and the flow advances to step S405.
After the lapse of ADV, an ignition signal is output to the #i cylinder.

In this embodiment, an example in which the present invention is applied to an ignition timing control device based on time control is shown. However, it is needless to say that the present invention can also be applied to an ignition timing control device using angle control.

[Effects of the Invention] As described above, according to the present invention, it is determined whether or not an external load is applied to the engine, and when the external load is applied to the engine, the ignition timing is advanced. Initially, the correction amount for correction is initially set based on the engine speed, water temperature, and vehicle speed at the start of the operation of the external load, and after the initial setting, the correction amount is set to gradually decrease uniformly. The basic ignition timing set based on the engine speed and the engine load is corrected by the advance correction amount to set the ignition timing. Therefore, when an external load is applied to the engine by a simple control process, a response is obtained. Thus, the ignition timing can be immediately advanced by an appropriate amount, and a decrease in the engine speed immediately after the start of the operation of the external load can be reliably prevented.

Further, when an external load is applied to the engine, the correction advance amount for correcting the ignition timing when an external load is applied to the engine is set to an engine speed at the time when the external load starts to operate, Initial setting is performed based on the water temperature and the vehicle speed, and after the initial setting, the advance correction amount is uniformly and gradually reduced, so that the engine speed is prevented from lowering due to the effect of the external load on the engine. It is possible to optimally set the advance correction amount according to the engine operating state at the start of the operation of the external load, and to reduce the decrease in the engine speed immediately after the start of the operation of the external load on the engine to the engine operating state at that time. Regardless, it is possible to prevent the occurrence of an error accurately, and the driving feeling can be improved.

[Brief description of the drawings]

FIG. 1 is a claim correspondence diagram showing a basic configuration of the present invention, and FIG.
1 shows an embodiment of the present invention, FIG. 2 is a schematic diagram of an engine control system, FIG. 3 is a front view of a crank rotor and a crank angle sensor, FIG. 4 is a front view of a cam rotor and a cam angle sensor, FIG. 5 is a flowchart showing an ignition timing setting procedure, FIG. 6 is an explanatory diagram of an air conditioner water temperature correction advance amount map,
FIG. 7 is an explanatory diagram of an air conditioner / engine speed correction advanced angle map, FIG. 8 is an explanatory diagram of an air conditioner / vehicle speed corrected advanced angle map, FIG. 9 is a flowchart showing a procedure for counting the number of ignitions, FIG. a) and FIG. 10 (b) are flow charts showing an ignition control procedure, FIG. 11 is a time chart of ignition timing, and FIG. 12 shows changes in the on / off state of the air conditioner switch, the air conditioner correction advance amount, and the engine speed. It is a time chart. 1 Engine body 11 Spark plug 17 Crank angle sensor 21 Cooling water temperature sensor 26 Vehicle speed sensor 27 Air conditioner switch 30 Control device (advance angle correction amount setting means, ignition timing setting means)

Claims (1)

(57) [Claims] An ignition timing control device for an engine, which sets an ignition timing based on an engine speed and an engine load and, when an external load acts on the engine, advancing the ignition timing. Is determined whether or not the external load has been applied to the engine, and when the external load is applied to the engine, the correction advance amount for correcting the ignition timing to be advanced is determined by the engine speed and water temperature at the start of the external load operation. And initial setting based on the vehicle speed, and after the initial setting, an advanced angle correction amount setting means for uniformly and gradually decreasing the advanced angle correction amount, and a basic setting based on the engine speed and the engine load. An ignition timing control device for an engine, comprising: ignition timing setting means for setting the ignition timing by correcting the ignition timing with the advance correction amount.