JPH01294941A - Control device for engine - Google Patents

Abstract

PURPOSE:To improve startability, by a method wherein, in a device which counts a cylinder discriminating signal, discriminates a cylinder based on the counting result, and performs control classified by a cylinder, during the starting of an engine, control made based on information of discrimination of cylinder in a first cylinder discriminating section is suspended. CONSTITUTION:During running of an engine, a cylinder intended to be ignited is discriminated such that a cam pulse signal from a cam angle sensor 6 is counted in a cylinder discriminating section by a counter 30 and a cylinder is decided by a cylinder discriminating means 31. Namely, the cylinder discriminating means 31 reads count of the counter 30 when a crank pulse signal A is discriminated by a crank pulse discriminating means 20, and clears the counter 30 after a cylinder is discriminated. In this case, a cylinder discrimination starting command means 33 suspends discrimination of a cylinder in a first cylinder discriminating section, and starts discrimination of a cylinder by means of a cam pulse signal in a next cylinder discriminating section.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a control device that performs control for each cylinder, such as ignition timing control and air-fuel ratio control in an engine.

[Conventional technology]

As a control device of this type, Japanese Patent Application Laid-Open No. 57-124208
As described in the above publication, there is a known system in which cylinder discrimination pulses are counted by a counter within a cylinder discrimination interval specified by crank pulses, cylinders are discriminated based on the results, and cylinder-specific control is performed. . Here, at the same time as the engine is started, the counter counts the cylinder discrimination pulses, immediately discriminates the cylinder, and performs individual control for that cylinder.

[Problem to be solved by the invention]

However, in this case, a problem arises in that depending on the stop position of the engine, the cylinder discrimination pulses may be counted incorrectly when the engine is started. That is, for example, in a 4-cylinder engine, when the engine is stopped, the rotation angle of the crankshaft at the stop position is about TDC70'' as it enters the compression stroke, and if this is within the cylinder discrimination area, When starting, there is a risk that the cylinder discrimination pulse will be counted halfway and the count will be lower than the number that actually needs to be counted.This will impair the engine's startability and may cause a backfire. The invention was made based on the above circumstances, and by not performing control based on cylinder discrimination information at least in the first cylinder discrimination section when starting the engine, the cylinder discrimination is performed correctly at the next point in time, and this correct information is performed. The object of the present invention is to provide an engine control device that can perform cylinder-specific control based on the following.

[Means to solve the problem]

Therefore, in the present invention, a pulse cylinder discrimination signal for cylinder discrimination is counted on a rotating body that rotates in synchronization with the rotation of the engine, and the cylinder is discriminated based on the result to perform cylinder-specific control. , stopping cylinder discrimination based on at least one first cylinder discrimination signal when starting the engine;
cylinder discrimination start command means for instructing to start cylinder discrimination from the next cylinder discrimination signal; and cylinder discrimination for cylinders based on counts by a counter after receiving an air volume discrimination start command from the cylinder discrimination start command means. The cylinder discrimination means includes a discrimination means, and a cylinder-specific control means for performing predetermined control for the cylinder designated by the cylinder discrimination means.

[For production]

Therefore, when the engine is started, cylinder discrimination is not performed at least in the first cylinder discrimination section, which prevents erroneous counting of cylinder discrimination pulses. This ensures good engine startability and prevents backfires, etc. The occurrence can be avoided.

【Example】

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a crankshaft of an engine, and the crankshaft 1 is provided with a disc-shaped crank plate 2 for detecting the angular position of the crank. The periphery is marked with a predetermined angular position of the crank angle, for example, in this embodiment, for a four-cylinder engine, the T of each cylinder is
Four protrusions 2a, 2b, 2c, and 2d are provided as pulse detection means that generate pulse signals as reference position signals at 10° and 100° from DC, and detect these protrusions to generate pulse signals. A crank angle sensor 3 that generates the angle is disposed opposite to the crank angle sensor 3. On the other hand, the camshaft 4, which rotates once for every two revolutions of the crankshaft 1, is provided with a disc-shaped cam plate 5 for cylinder discrimination. and,
At this periphery, there is a cylinder discrimination section (from BTDC100' to B
TDC up to 10°), four groups of protrusions 5a, 5b, 5c are formed as pulse detection means so that the number of protrusions corresponding to the cylinder number is grouped. 5d, and a cam angle sensor 6 that detects this protrusion and generates a pulse signal as a cylinder discrimination signal is disposed facing the cylinder. The pulse signals from both the sensors 3 and 6 are together with the signal from the suction pipe pressure sensor 7 that detects the pressure inside the suction pipe.
The signal is input to a control unit 8 for ignition timing control consisting of a microcomputer. This control unit 8 has an input/output interface 8a, a CPU 8
b. ROM8C in which control programs etc. are stored;
Consists of RAM 8d, which temporarily stores data, etc.
According to a predetermined program, the ignition timing is calculated, an ignition signal is given to the drive circuit 9 consisting of a power transistor, etc., and the drive circuit 9 is turned from on to off, thereby igniting the predetermined cylinder via the ignition coil 10 and the distributor 11. A spark voltage is applied to the plug 12. The control unit 8, as shown in FIG.
From the outputs of the crank angle sensor 3 and the cam angle sensor 6, the crank pulse identifying means 20 identifies the protrusions 2a, 2c and the protrusions 2b, 2d.As is clear in FIG. After detecting the crank pulse signal as the reference position signal, the projection 2
The crank pulse signal is identified by whether or not a cam pulse signal as a cylinder discrimination signal is detected at the projections 5a, 5b, 5c, and 5d before the crank pulse signal is detected at points b and 2d. That is, if a cam pulse signal is input between the above-mentioned crank pulse signals, the crank pulse signal following this cam pulse signal is designated as A (corresponding to the protrusions 2a and 2c), and the next crank pulse signal in which no cam pulse signal is input is designated as B ( 2b and 2d). Then, the period calculating means 21 calculates the time when the crank pulse signal A is detected and the crank pulse signal B immediately after that.
The period TAB, that is, the angular velocity of the crankshaft 1, is obtained from the difference from the time when TAB is detected. The period TAB is determined by the engine rotation speed N in the engine rotation speed calculation means 22.
It is calculated as e. On the other hand, the suction pipe pressure calculation means 23 calculates the suction pipe pressure P corresponding to the engine load. Based on this suction pipe pressure P and engine speed Ne, the basic ignition angle search means 24 calculates the basic ignition angle ANGSP by map search etc., and the ignition timing calculation means 2
Output to 5. Then, the ignition timing calculation means 25 calculates the ignition timing TSP by using the input basic ignition angle A N G SPK as the time from the time when the crank pulse signal B indicating the reference position is detected using the period TAB. demand. TSPK = (ANGSP/(B-A)' xT
AB This is set in the timer means 26. The timer means 26 starts measuring time based on the crank pulse signal B identified by the crank pulse identifying means 20, and when the set ignition timing TSP is reached, outputs an ignition timing signal to the drive circuit 9, and the power transistor is activated. Turn off. As a result, a spark voltage is applied to the spark plug 12 of the corresponding cylinder, as described above. On the other hand, to determine which cylinder is to be ignited, the cam pulse signal from the cam angle sensor 6 is detected by the counter 30 in the cylinder determination period (that is, between the previous crank pulse signal B and A).
This is performed by counting the number of cylinders and determining the number using the cylinder determining means 31. Therefore, when the crank pulse signal A is identified by the crank pulse identifying means 20, the counter 30 is given a signal to read the count of the counter 30 and discriminate the cylinder, and then clear the counter 30. Also,
Here, cylinder discrimination start command means 33 is equipped to stop cylinder discrimination in at least the first cylinder discrimination section when starting the engine, and start cylinder discrimination from a cam pulse signal for cylinder discrimination in the next cylinder discrimination section. has been done. Therefore, the cylinder discrimination start command means 3
3, a signal is output so that cylinder discrimination is not executed until the first crank pulse signal is input from the crank angle sensor 3 after the first cam pulse signal is input from the cam angle sensor 6. After the cam pulse signal of the cam angle sensor 3 in the first cylinder discrimination section has passed, the cylinder discrimination start command means 33 gives a signal to start cylinder discrimination to the cylinder discrimination means 31, and based on the cylinder discrimination, will be carried out. A flag is set to start control in the cylinder-specific control means. In the above embodiment, the crank pulse identification means 20 to the ignition timing calculation means 25 are used as control means for each cylinder.
Although the description has been made with reference to an ignition timing control device such as the timer means 26, it goes without saying that the present invention can also be applied to an air-fuel ratio control device. Next, the process of cylinder discrimination in the control unit 8 will be specifically explained with reference to the flowchart shown in FIG. This is because the timing lag of the crank pulse signal A that is first detected after the cam pulse signal for cylinder discrimination is detected has an initial value of 0 when the engine is started. Then, as a result of the determination, if the cylinder discrimination flag is 0, the cylinder discrimination flag is set to 1 in step 5102. Moreover, since the cylinder discrimination flag is 1 after passing step 5102, from the second time onwards, when the above routine is entered, the cylinder discrimination flag is determined to be 1 in step 5101, and step 5103 Then, a control flag for performing cylinder-specific control is set. And step 5104
At step 5105, the cylinder information is saved, and at step 5106, the counter 30 is cleared. Note that after setting the cylinder discrimination flag in step 5102, the process goes to step 8106 and ends. Further, the set cylinder discrimination flag is cleared when the engine speed Ne becomes zero. In this way, after the control unit 8 saves the information for cylinder discrimination, the cylinder-specific control means
Ignition timing control as described above or air-fuel ratio control is performed for the designated cylinder. In this embodiment, the reference position signal used for detecting the engine speed Ne and the cylinder discrimination signal for cylinder discrimination are detected from the crankshaft and the camshaft, respectively, but the present invention is not limited to this. It goes without saying that the detection may be performed anywhere as long as it is a rotating body that rotates in synchronization with the rotation of the engine.

【Effect of the invention】

The present invention has been described in detail above, and by not performing control based on cylinder discrimination information at least in the first cylinder discrimination section when starting the engine, cylinder discrimination can be performed correctly at the next point in time. Since cylinder-specific control can be performed based on correct information, good startability can be maintained when starting the engine, and problems such as backfire can be avoided.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram showing an embodiment of the present invention, Fig. 2 is a configuration diagram of a control unit, Fig. 3 is a time chart of crank pulses and cam pulses, and Fig. 4 is a flow chart of cylinder discrimination in the control unit. It is. 3...Crank angle sensor 6...Cam angle sensor 8...Control unit 30...Counter 31...Cylinder discrimination means 33...Cylinder-specific control start command means Third factor TDC-

Claims (1)

[Claims] A rotating body that rotates in synchronization with the rotation of the engine is provided with a pulse detection means for cylinder discrimination, and a detection means for detecting the pulse detection means and generating a cylinder discrimination signal, and a counter is provided. In a system that counts cylinder discrimination signals and discriminates cylinders based on the results to perform cylinder-specific control, the cylinder discrimination based on at least the first cylinder discrimination signal at the time of engine startup is stopped, and from the next cylinder discrimination signal. cylinder discrimination start command means for instructing to start cylinder discrimination; cylinder discrimination means for performing cylinder discrimination based on a count by a counter after receiving a cylinder discrimination start command from the cylinder discrimination start command means; 1. A control device for an engine, comprising cylinder-specific control means for performing predetermined control on a cylinder designated by the means.