JPH0689735B2 - Ignition timing control device for internal combustion engine - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ignition timing control device for an internal combustion engine (hereinafter referred to as KCS) having a function of detecting knock of an internal combustion engine (engine) and correcting and controlling the ignition timing. It is a thing.

[Conventional technology]

The knock sensor detects knocks that occur in the engine,
KCS for advancing / retarding ignition timing is well known.

When control is performed for each cylinder with this KCS, it is possible to control the ignition limit of each cylinder in the vicinity of the knock limit ignition timing, and to maximize fuel efficiency, output, and performance of the engine.

[Problems to be solved by the invention] However, since the knock limit ignition timing changes every moment depending on the engine state, in the conventional control in which the ignition timing is constantly retarded according to the knock state, the engine state change, etc. If the knock limit ignition timing changes due to the factor, and it suddenly changes to a state where it is very easy to knock, the larger the difference from the current ignition timing, the longer it takes to reach the knock limit ignition timing. There was a problem that the size became large.

Further, in Japanese Patent Laid-Open No. 59-74372, it is considered that the knock occurrence frequency is discriminated (however, only the maximum knock-occurring cylinder is used) and the advance amount is changed as in the present invention. Every time a predetermined number of all knocks occur, that is, because the response is poor, optimal control cannot be performed in an engine state that changes momentarily, such as during a transition.

Therefore, the present invention makes it possible to perform optimum control even in an engine state that changes momentarily such as during a transition.

[Means for solving problems]

Therefore, according to the present invention, as shown in FIG. 1, a knock sensor for detecting knock of an internal combustion engine, a cylinder-specific knock strength determination means for determining the knock strength for each cylinder based on the output from the knock sensor, and a knock strength determination means are provided. Cylinder ignition timing control means for controlling the ignition timing for each cylinder according to the determined knock intensity, cylinder-specific knock number determination means for determining the number of knocks for each cylinder based on the output from the knock sensor, and the knock sensor All-cylinder knock count determination means for determining the knock count of all cylinders based on the output,
A ratio-dependent variable retard angle amount for each cylinder that increases the retard amount for a cylinder having a larger ratio according to the ratio of the knock determination number for each cylinder of the cylinder-specific knock number determination unit to the all-cylinder knock determination number for the all-cylinder knock number determination unit. And an ignition timing control device for an internal combustion engine.

[Action]

Thus, the knock count for each cylinder is determined by the knock count determination means for each cylinder, and the knock count for all cylinders is determined by the knock count determination means for all cylinders. Then, according to the ratio of the number of knock determinations for each cylinder to the number of knock determinations for all the cylinders, the retard angle amount is increased by the ratio-responsive cylinder-by-cylinder retard angle amount varying means.

〔Example〕

 The present invention will be described below with reference to the embodiments shown in the drawings.

FIG. 2 shows the overall configuration of the engine control device. In the figure, 1 is a 4-cycle 4-cylinder engine, 2
Is an air cleaner, 3 is an air flow meter that outputs an intake air amount as an electric signal, and 4 is a throttle valve. Reference numeral 5 denotes a distributor having a reference angle sensor 5A for detecting a reference crank angle position (for example, top dead center) of the engine 1 and a crank angle sensor 5B for generating an output signal at every constant crank angle of the engine. 6 is a knock sensor for detecting the vibration of the engine block corresponding to the knock phenomenon of the engine by a piezoelectric element type (piezo element type), an electromagnetic type (magnet, coil), etc., 7 is an engine that receives the output of the knock sensor. A knock detection circuit for detecting the occurrence of knock. 9 is a water temperature sensor that outputs an electric signal according to the cooling water temperature of the engine 1, 12 is a throttle position sensor that detects the position (open / closed state) of the throttle valve 4 and outputs an electric signal, and 13 is an air-fuel ratio of the exhaust gas (A /
This is an O ₂ sensor that outputs an electrical signal depending on whether F) is richer or leaner than the stoichiometric air-fuel ratio.

Reference numeral 8 denotes a control circuit including a microcomputer for controlling the ignition timing and the fuel injection amount of the engine 1 according to the input signal states from the respective sensors, and 10 the ignition timing control output from the control circuit 8. An igniter and an ignition coil that receive a signal to cut off energization to the ignition coil. The high voltage generated in the ignition coil is applied to the ignition plug of a predetermined cylinder at an appropriate time through the high voltage distribution section of the distributor 5.
Reference numeral 11 is an injector for injecting fuel into the intake manifold based on the fuel injection time determined by the control circuit 8.

Next, the content of the ignition timing control of the present invention performed by the control circuit 8 will be described with reference to the flowchart of FIG.

When an ignition timing calculation interruption occurs in the figure, in step 101, the cylinder ignited immediately before is discriminated from the output signals of the reference angle sensor 5A and the crank angle sensor 5B, and the cylinder number is set to i. Next, at step 102, it is judged from the input signal from the knock sensor 6 whether or not knocking has occurred in the cylinder ignited immediately before. If knocking occurs, the knock intensity (for example, small knock, knocking, large knock) is determined in step 103, and the retard angle amount Δθ _R corresponding to the knock intensity (for example, 0.2 for small knock).
5 ° CA, 0.5 ° CA when knocking, 0.75 ° CA when knocking large)
Is set for each cylinder in which knock has occurred. Then step 104
Then, in order to measure how many knocks are detected in which cylinder, 1 is added to the knock occurrence count KNOCK (i), and the number of knock occurrences is counted for each cylinder. Next, at step 105, the number of knock occurrences in each cylinder is added to count the total number of knock occurrences (S) in all cylinders. Next, at step 106, the ratio of the knock occurrence frequency of that cylinder to the total knock occurrence frequency (S) of all cylinders is calculated (KNOC
K (i) / S), and a knock occurrence frequency coefficient k for each cylinder according to the ratio (eg, k = 4 × KNOCK (i) / S) is determined.

That is, the higher the knock detection frequency, the larger the value of k and the larger the amount of retardation. (See FIG. 4).

Next, at step 107, the retard amount Δθ _R of the cylinder concerned is multiplied by the knock detection frequency coefficient k to correct the retard amount by weighting, and the total retard amount from the basic ignition timing, that is, the corrected ignition timing θ _ci
Ask for. Therefore, the correction ignition timing θ _ci also increases as the knock frequency increases, and control is performed on the more retarded side.

On the other hand, if knocking is not determined in step 102, the process proceeds to step 109, and if knocking does not occur for a predetermined time in steps 110 to 112, the correction ignition timing θ _{ci is changed} to a predetermined angle Δθ _A (for example, if knocking does not occur for 0.4 seconds, 0 .
5 ° CA). Therefore, the ignition timing is advanced by Δθ _A.

Next, at step 108 for the next ignition, the final execution ignition timing θ _i obtained by subtracting the corrected ignition timing θ _ci from the basic ignition timing θ _B determined by the engine speed and the engine load.
To decide.

As can be seen from the above contents, when the knock is detected, the more the knock detection frequency of the cylinder is, the larger the ignition timing retard amount and the more the ignition timing is retarded. (Knock sound) can be quickly controlled.

In the above-mentioned embodiment, the ignition timing retard amount is weighted with a coefficient according to the ratio.
The advance time constant may be changed in the same manner as in JP-A-59-51162 so that the retard amount is changed as a result.

〔The invention's effect〕

As described above, in the present invention, every time the number of knock occurrences of each cylinder is determined, the ignition timing retard of the corresponding cylinder is retarded according to the ratio of the number of knock occurrences of the relevant cylinder to the number of knock occurrences of all the cylinders at that time. Since the amount is variably controlled, it is possible to control the optimum ignition timing for each cylinder with good responsiveness, and it is possible to perform the optimum ignition timing control even in an engine state that changes momentarily, such as during transition. It has an excellent effect.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to the scope of claims of the present invention, FIG. 2 is a partial cross-sectional configuration diagram showing an embodiment of an engine control device to which the device of the present invention is applied, and FIG. 3 is a control circuit in the device shown in FIG. FIG. 4 is a characteristic diagram of the weighting coefficient in the apparatus shown in FIG. 2 for explaining the operation of FIG. DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 5A ... Reference angle sensor, 5B ... Crank angle sensor, 6 ... Knock sensor, 7 ... Knock detection circuit, 8 ... Control circuit.

Claims (2)

[Claims] 1. A knock sensor for detecting knock of an internal combustion engine, a cylinder-specific knock strength determination means for determining knock strength for each cylinder based on an output from the knock sensor, and a knock strength determined by the knock strength determination means. Cylinder ignition timing control means for controlling the ignition timing for each cylinder according to
Cylinder knock number determination means for determining the knock number for each cylinder based on the output from the knock sensor, all cylinder knock number determination means for determining the knock number for all cylinders based on the output from the knock sensor, and this all cylinder knock number An internal combustion engine including ratio-dependent cylinder retarding amount varying means for increasing the retarding amount for a cylinder having a larger ratio according to the ratio of the knocking determining number for each cylinder to the knocking determining number for each cylinder of the determining unit Ignition timing control device for engines. 2. The ratio-responsive cylinder-by-cylinder retard angle amount varying means weights a coefficient according to the ratio to the ignition timing retard amount of the cylinder-by-cylinder ignition timing control means. An ignition timing control device for an internal combustion engine according to the above item.