JPH0318666A - Ignition timing control unit for engine - Google Patents

Abstract

PURPOSE:To improve engine power and to reduce a difference in temperatures of exhaust gases between right and left bank rows by detecting difference value of ignition timings generated between right and left bank rows, and correcting ignition timing by means of addition or subtraction of he difference value to or from the optimal ignition timing value. CONSTITUTION:An optimal ignition timing deciding means 103 decides the optimal ignition timing based on detected values of an engine load and a crank angle detected by detecting means 101, 102, and operation-controls an ignition device 107 for right and left banks via an igniting means 106. Here, when the ignition timing of one bank row side cylinders to which the crank angle detecting means 102 is attached is shifted from the ignition timing of the other bank row side cylinders, the difference value is detected by a correcting means 105 based on a signal from a cylinder judging means 104 performing judgement on cylinders between right and left bank rows, the difference value is added to or subtracted from the optimal ignition timing value, and the ignition timing is corrected. In this way, it is possible to suppress dispersion of ignition timings between right and left bank rows, to improve engine power and to reduce a difference in temperatures of exhaust gases between right and left bank rows.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an improvement in an ignition timing control device for electronically controlling the ignition timing of a V-type engine.

2. Description of the Related Art Various types of conventional electronic ignition timing control devices for automobile engines have been provided, one example of which is the one described in Japanese Patent Application Laid-open No. 112861/1983. ing.

Briefly, in this ignition timing control device, a control unit equipped with a microcomputer determines the engine speed N output from a crank angle sensor, and the engine speed N and intake air ffiQ from an air flow meter. It has an ignition timing map assigned with the basic injection amount TP, and looks up the optimal ignition timing corresponding to the operating condition from the ignition timing map based on the current engine speed N and the basic injection amount TP signals. When the set ignition timing is reached, an ignition signal is output to the ignition system.

By the way, in general, in a twin-cam type ■type engine, a pair of camshafts for intake valves and exhaust valves are provided in each cylinder head of the left and right bank rows, respectively.
Rotational force is transmitted to each camshaft from the crankshaft via a timing chain, a cam chain, or the like. The crank angle sensor is provided on one side (for example, the right side) of the exhaust valve camshaft of each bank row, and detects the rotation speed of the right exhaust valve camshaft as the engine rotation speed. A crank angle signal of 1° is detected, and the above-mentioned ignition timing is determined based on these signals.

Problems to be Solved by the Invention However, there is a problem with the conventional ignition timing control device, since the engine speed, etc., is detected from the camshaft rotation speed using a crank angle sensor, it is possible to achieve highly accurate ignition timing. Lack of control. In other words, although the engine's crankshaft always rotates at a constant speed, the camshaft may rotate due to timing chain tension, variations in its own cam profile, or the reaction force of the valve springs of each intake and exhaust valve. Non-uniform speed rotation, that is, rotation fluctuation is occurring. In particular, in the case of a type 6 six-cylinder engine, the lift timings of the intake and exhaust valves are continuous without significantly overlapping within the crank angle range of 2400, as shown in FIG. In other words, if we take the exhaust side of the second, fourth, and sixth cylinders in the left bank row as an example, the exhaust stroke of the fourth cylinder starts at the same time as the exhaust stroke of the second cylinder ends.
Further, the exhaust stroke of the sixth cylinder is started simultaneously with the end of the exhaust stroke of the fourth cylinder, so that the valve lift has a continuous waveform characteristic. On the other hand, the first, third, and fifth cylinders in the right bank row have similar continuous waveform characteristics, and the same is true for each intake side.

As a result, rotational fluctuations occur in the camshaft, and these rotational fluctuations are directly detected by the crank angle sensor and input to the control unit. Therefore, variations occur in the ignition timing between the left and right bank rows, and generally the ignition timing is delayed more on the bank row side where the crank angle sensor is provided than on the bank row side where the crank angle sensor is not provided.

As a result, the control accuracy of the ignition timing decreases, which not only causes a decrease in engine output and a large difference in exhaust temperature between the left and right bank rows, but also deteriorates the controllability of knock control. Note that the normal ignition timing is set at around 25 degrees of crank angle before the piston top dead center during the explosion stroke.

Means for Solving the Problems The present invention has been devised in view of the above-mentioned conventional problems, and as shown in FIG. Crank angle detection means 10 is provided on the camshaft side of at least one of the rotating left and right bank rows and detects the rotation speed of the engine.
2, means 103 for determining the optimum ignition timing based on the engine load value and rotational speed value, cylinder discriminating means 104 for discriminating cylinders between left and right bank rows by the crank angle detecting means 102; Detects the difference in ignition timing between the left and right bank rows based on the signal from the discrimination means,
A correction means 105 for correcting the ignition timing by adding or subtracting the difference value from the optimum ignition timing value, and an ignition means 106 for outputting an ignition signal to the ignition device 107 based on the output signal from the correction means 105. It is characterized by

According to the above-mentioned structure, for example, if the ignition timing of the cylinder on one bank row to which the crank angle detection means 102 is attached is delayed than that of the cylinder on the other bank row, the ignition timing between the two bank rows is delayed. Correction means 1 using the difference value of ignition timing values as a correction value
The correction value is added to the optimum ignition value to advance the ignition timing on the bank side, and this advanced ignition timing signal is sent to the ignition device 107 via the ignition means 106. Output. Therefore, the ignition timing on one bank row can be advanced in accordance with the ignition timing on the other bank row.

Example Hereinafter, the present invention will be explained based on the drawings.

FIGS. 2 and 3 are diagrams showing one embodiment of the present invention.

First, to explain the configuration, in Fig. 2, 1 is a twin cam type ■ type engine, and the right bank row la side is the first,
3rd and 5th cylinders, left bank row lb side is 2nd, 4th and 6th cylinders
It is a cylinder. Intake air is supplied from the air cleaner 2 through the intake manifold 4 through the intake passage 3 as shown by arrows in the figure, and fuel is supplied to the injectors 5 provided at each location based on the injection signal Si.
is injected by. Then, the exhaust gas combusted in the cylinder is introduced into the catalytic converter 7 through the exhaust pipe 6, where the harmful substances in the exhaust gas are purified, and the exhaust gas is discharged to the outside through the muffler 8.

An ignition plug 9 is attached to each engine, and a high voltage pulse Pi is supplied to the ignition plug 9 from an ignition coil 1l via a power controller unit IO. The spark plug 9, the powertrain unit IO, and the ignition coil 1l constitute an ignition device l2 that ignites the air-fuel mixture.
The ignition device 12 generates a high voltage pulse Pi based on the ignition signal Sp.
is generated and discharged. Then, the air-fuel mixture in the cylinder is ignited and exploded by the discharge of the high-pressure pulse Pi, and is exhausted.

The intake air flow ffiQ is detected by a hot wire type air flow meter 13 and controlled by a throttle valve 15 included in a throttle chamber 14 of the intake passage 3. The opening TVO of the throttle valve 15 is detected by the throttle valve opening sensor 16, and the air flow rate bypassing the throttle valve l5 is detected by the AAC valve l.
7, and thereby the idle rotation speed is feedback-controlled to a predetermined value. AAC valve 17 is driven based on auxiliary air amount control signal SA. Separation passage 3
A variable intake control valve 19 is provided in the communication path l8 between a and 3b, and a variable intake control valve 19 is connected to the variable intake control valve SI1.
Based on this, the valve is switched between opening and closing in the low speed range and high speed range. When the engine 1 is running at low speed, the variable intake control valve 19 is closed and the left and right separation passages 3
a, 3b are not electrically connected, and the intake passages for the left and right punctures lb, la in the figure are independent, and the intake port is connected from the throttle valve l5 to the intake valve 2.
Since it reaches 0 and is sucked in from a long boat, the suction efficiency is increased due to the intake inertia effect and low speed torque is improved.

Furthermore, when the operating condition is high speed, the variable intake control valve 19 is opened and the separation passages 3a and 3b are electrically connected, causing intake interference with each other, so that the intake is actually drawn from the thick and short boat of the intake manifold 4. This reduces intake resistance and increases output. In addition, the closing time of the intake valve 20a is controlled by variable control of the cam phase difference through hydraulic control by the variable valve timing control valve 2l, and at low to medium speeds with high loads, the closing time of the intake valve 20 is advanced to improve suction efficiency. high, idol,
At high speeds and high loads, the closing timing is delayed to reduce the intake/exhaust overlap, thereby improving stability and output.

The variable valve timing control valve 2l receives a variable valve timing control signal S. The cam phase difference is changed by hydraulic pressure based on the duty value of , and the valve timing is adjusted. Further, the engine 1 has intake valves 20a.
20a and a pair of camshafts 22a, 22b, which open and close the exhaust valves 20b, 20b, respectively. 23a, 23b are supported, and these camshafts 2 2 a, 2 2 b
．． 2 3 a. Rotational force is transmitted to 23b from a crankshaft (not shown) via a timing chain and a cam chain. Also, bank 1b on the left side in the figure
A crank angle sensor 24 serving as crank angle detection means is attached near the exhaust valve camshaft 23b.

This crank angle sensor 24 is set at a predetermined position before the compression top dead center (TDC) of each cylinder at every explosion interval (120° for a 6-cylinder engine, 180' for a 4-cylinder engine), for example, at a BT
Reference signal Ca that becomes a [H] level pulse at DC70°
In addition to outputting the unit angle of crank angle (for example, 2°
) outputs a unit signal CI that becomes a [H] level pulse. Note that the engine rotation speed N can be determined by counting the pulses of the reference signal Ca. The temperature TW of the cooling water flowing through the water jacket is detected by a water temperature sensor (water temperature detection means) 25, and the vibration V of the engine 1 body is detected by a water temperature sensor (water temperature detection means) 25.
e is detected by the knock sensor 26. Further, the oxygen concentration Vs in the exhaust gas is detected by an oxygen sensor 27, and the temperature of the exhaust gas is detected by an exhaust gas temperature sensor 28.

The exhaust temperature sensor 28 is connected to a switching module 29, and the switching module 29 turns on the exhaust temperature warning light 30 based on the detection output of the exhaust temperature sensor 28. Further, the neutral position Nc of the transmission 3l is detected by the neutral switch 32, and the vehicle speed SP is detected by the vehicle speed sensor 33. The idle state of engine I is detected by idle switch 34. Note that 35 is a canister and 36 is a fuel pump.

Air flow meter 13. Throttle valve opening sensor 16, crank angle sensor 24, water temperature sensor 25, knock sensor 2
6. Each signal from the oxygen sensor 27, neutral switch 32, vehicle speed sensor 33, idle switch 34, key switch (not shown), and battery is sent to the control unit 4.
1 is man-powered. The control unit 4l has functions as a correction means, an ignition timing determination means, etc., and is constituted by a microcomputer or the like. Then, the control unit 41 calculates processing values necessary for combustion control such as ignition timing control based on the sensor information according to a program stored in the internal memory, and according to the calculation results, the injector 5, the exhaust unit 10, - AAC valve l
7. Signals S+, Sp, SA, and SR that drive the variable intake control solenoid valve 19, the variable valve timing control valve 21, and the fuel pump 36
, S and SP to optimally control the operating state of the engine I. Note that 42 and 43 are monitor check lamps, which issue a warning to the driver and maintenance personnel based on a failure detection signal from the control unit 41.

Next, the effect will be explained.

FIG. 3 is a flowchart showing an ignition timing control program in the control unit 41, and this program is executed once every predetermined period (for example, 10+s).

First, in section 1, the engine speed N signal from the crank angle sensor 24 and the intake air ffiQ signal from the air flow meter 13 are manually input. In section 2, the engine speed N and intake air ffiQ are calculated, and then in section 3, the basic combustion injection pulse width Tp (corresponding to load data) is calculated from the engine speed N and intake air ffiQ. Next, in Section 4, the optimum ignition timing T is determined from a predetermined ignition timing table MASOB using the basic fuel injection pulse width Tp and the engine speed N as parameters. Look up. Furthermore, in section 5, a simple determination is made based on the crank angle signal from the crank angle sensor 24, that is, the cylinders to be ignited are the 1st, 3rd, and 5th cylinders of the right bank 1a that do not have the crank angle sensor 24. Determine whether or not.

If it is determined that the cylinder is the first, third, or fifth cylinder, the process moves to section 6, where an optimal ignition timing T1 signal corresponding to the normal operating condition is output to the ignition device 12. On the other hand, if it is determined in Sekunyong 5 that it is No, that is, it is the 2nd, 4th, or 6th cylinder, the process moves to section 7, where the engine speed N and ignition advance angle correction are determined as shown in Figure 4. The lead angle correction value T is looked up from the supplementary table map set using if_ADV as a parameter. In the correction table map, for example, the advance angle correction value is set to l0 when the engine speed N is around 800 rpm when the engine is idling, and is set to 200 rpm during steady operation.
- For p1 to 4400r-p1, set the advance angle to about 2° to 3°, and for about 600Or-p at high rotation, set the advance angle to about 5°.
It is set to an advance angle of °. And in section 8,
A signal obtained by adding the advance angle correction value T, to the optimum ignition timing value T, is output to the ignition device 12.

In this way, in this embodiment, the advance angle correction value control is performed to match the ignition timing of one bank lb side, which is delayed from the optimum ignition timing due to the rotational fluctuation of the camshaft 23a, to the optimum ignition timing of the other bank la side. The ignition timing of the second, fourth and sixth cylinders was adjusted to 2000rpm as shown in Fig. 5A and H.
Since the advance angle control is performed by approximately 2 degrees in the case of 6000'' and approximately 5 degrees in the case of 6000'', the advance angle is controlled by approximately 5 degrees in the case of 6000''.

As a result, the engine output can be improved and the difference in exhaust gas temperature between the two banks can be made as small as possible, and the knock control performance can also be improved.

The ignition timing control also includes water temperature advance correction control based on the cooling water temperature Tw.

Further, in the above embodiment, the crank angle sensor 24 is provided on the left bank lb side, but it is also possible to provide it only on the right bank la side, or on both the left and right sides, and if it is provided on both sides, the ignition timing Control accuracy is further improved. Furthermore, the present invention is not limited to V-type engines, but can also be applied to horizontally opposed engines. Further, the advance angle correction value can be set by calculation in addition to the correction table map.

Effects of the Invention As is clear from the above explanation, according to the present invention, it is possible to sufficiently suppress variations in ignition timing between the left and right bank rows caused by rotational fluctuations of the camshaft, and achieve highly accurate ignition timing control. can be realized. As a result, the output of the engine can be improved, the difference in exhaust gas temperature between the left and right bank rows can be made as small as possible, and the controllability of knock control can be improved.

[Brief explanation of drawings]

FIG. 1 is a diagram corresponding to the claims of the present invention, FIG. 2 is an overall configuration diagram showing an embodiment of the present invention, and FIG. 3 is a flowchart diagram showing ignition timing control of the control unit of the present embodiment.
Figure 4 is the Kakinamasa table map used in this example;
Figure A. B is an explanatory diagram showing the ignition timing advance control in this embodiment, and FIG. 6 is a characteristic diagram showing the lift timing of the intake and exhaust valves in the V-type six engine. 101...Load detection means, 102...Crank angle detection means, 103...Optimum ignition timing determining means, 104.
...Easy discrimination means, 105...Capture means, 106...
- Ignition means, 107...Ignition device. Figure 3

Claims (1)

[Claims] (1) A means for detecting the load of an engine having left and right bank rows, and a crank angle detector provided on the camshaft side of at least one of the left and right bank rows that rotates in synchronization with the crankshaft to detect the rotational speed of the engine. means for determining the optimum ignition timing based on the load value and rotational speed of the engine; cylinder discriminating means for discriminating cylinders between left and right bank rows by the crank angle detecting means; a correction means for detecting a difference value of ignition timing occurring between the left and right bank rows based on the optimum ignition timing value, and correcting the ignition timing by adding or subtracting the difference value from the optimum ignition timing value; and an ignition device based on an output signal from the correction means. An ignition timing control device for an engine, comprising: means for outputting an ignition signal.