JPS62255576A - Engine ignition timing control device - Google Patents

Abstract

PURPOSE:To minimize a variation in torque caused by a knocking control, by making a feedback control amount smaller as a spark-retard amount from an optimum igniting timing is larger. CONSTITUTION:A controller 22 is such that an ignition timing is controlled to approach to an optimum ignition timing and when knocking is caused in an engine 1, the knocking is effectively restricted by making a prescribed spark- retard control to the ignition timing based on the data sensed by a knocking sensor 20. Wherein an arrangement is such that an offset amount from the optimum ignition timing is increased, a control amount of the ignition timing is decreased. As a result, since a change in the ignition timing in the vicinity of the optimum ignition timing does not effect torque performance, a feedback control amount of the ignition timing can be set at a relatively large value for restricting knocking with an excellent responsiveness.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine ignition timing control device that detects engine knocking and controls ignition timing so as to suppress knocking.

(Prior Art) Engines are known that include a knock sensor for detecting a knocking state of the engine, and control the ignition timing of the engine based on a signal from the knock sensor to suppress knocking.

For example, Japanese Unexamined Patent Publication No. 58-28597 discloses a control device that suppresses knocking by controlling such ignition timing. In this disclosed device, the engine is equipped with a vibration detection element that detects vibration, and the average value of the amplitude value of the electric signal from the vibration detection element over a plurality of ignition cycles is calculated separately for each cylinder. The occurrence of knocking is detected for each cylinder, and the ignition timing is controlled to be retarded for each cylinder.

(Problem to be Solved) In the engine disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 58-28597, knocking is detected for each cylinder and ignition timing control is performed in accordance with each cylinder. , it is possible to perform knocking control with higher accuracy than a method in which knocking control is performed uniformly on each cylinder.

However, if the ignition timing is controlled to be delayed in order to suppress knocking, there is a problem in that the engine torque decreases. Therefore, from the standpoint of torque performance, it is desirable to minimize the amount of retardation from the optimum ignition timing.

Therefore, in this type of knock control device, when knocking occurs, the ignition timing is retarded by a predetermined amount, and when knocking does not occur, the ignition timing is advanced so as to approach the optimum ignition timing. It is designed to do this. However, the influence that ignition timing has on torque performance is not uniform, and the larger the amount of retardation, the greater the torque drop. If the feed batter control amount of the ignition timing is reduced in order to reduce torque fluctuations, the responsiveness of knocking control deteriorates, resulting in a problem that knocking cannot be effectively suppressed.

(Means for Solving the Problems) The present invention was constructed in view of the above circumstances, and is capable of effectively suppressing knocking with good responsiveness, and
It is an object of the present invention to provide an ignition timing control device for an engine that can minimize torque fluctuations caused by ignition timing control for suppressing knocking.

The ignition timing control device of the present invention includes a knocking detection means for detecting knocking, and based on a signal from the knocking detection means, retards the ignition timing when knocking occurs, and in an operating state where knocking does not occur. In an engine ignition timing control device that performs feedback control of ignition timing to advance the ignition timing, the amount of feedback control of the ignition timing is decreased in response to an increase in the amount of retardation of the ignition timing due to the knocking. It is characterized by being configured as follows.

According to the present invention, when performing feedback control of the ignition timing to suppress knocking, the feedback control amount is set in consideration of the influence of the amount of retardation of the ignition timing on torque performance. In other words, the feed/< ivy control amount is set relatively large near the optimal ignition timing, where changes in ignition timing have relatively little effect on torque performance, and as the retardation amount from the optimal ignition timing increases, the control amount is increased. Control to make it smaller.

(Effects of the Invention) According to the present invention, since the feedback control amount of the ignition timing is set to be relatively large near the optimum ignition timing, knocking can be suppressed with good responsiveness. In this region, changes in ignition timing do not have a significant effect on torque performance, so there is no risk of large torque fluctuations occurring. As the amount of retardation from the optimum ignition timing increases,
Since the feedback control amount is controlled to be small, torque fluctuations caused by knocking control in a state where the retardation amount is large can also be reduced. Therefore, according to the present invention, knocking can be effectively suppressed, and torque fluctuations caused by ignition timing control for suppressing knocking can be suppressed as much as possible.

(Description of Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Referring to FIG. 1, the engine 1 of this example is a four-cylinder reciprocating engine, and each cylinder is provided with a piston 3 that slides inside a cylinder block 2. As shown in FIG. The space above the piston 3 constitutes a combustion chamber 4, and an intake boat 5 and an exhaust port 6 are open to the combustion chamber 4. The intake port 5 and exhaust port 6 are combined with an intake valve 7 and an exhaust valve 8, respectively. In the intake boat 5,
An intake passage 9 is connected to the intake passage 9, and an air cleaner 10 is attached to the upstream end of the intake passage 9.

An air flow sensor 11 for detecting the amount of intake air is arranged downstream of the air cleaner IO, and a throttle valve 12 is arranged further downstream. Air flow sensor 11
An intake air temperature sensor lla is attached to detect the intake air temperature. Further, a surge tank 13 is formed downstream of the throttle valve 12, and an injector 14 for injecting and supplying fuel is arranged further downstream to form an intake system. Further, an exhaust passage 15 communicates with the exhaust port 6 to constitute an exhaust system.

Further, an ignition plug 16 faces the combustion chamber 4, and an ignition coil unit 17 is provided to control the ignition timing of the ignition plug 16.

Further, a water temperature sensor 19 for detecting the temperature of cooling water is attached to the water jacket 18 formed in the cylinder block 2, and a knock sensor 20 for detecting knocking by detecting engine vibration is attached. Further, the cylinder head of the engine I of this example is provided with a crank angle sensor 21 that detects a crankshaft rotation angle from the rotation of a camshaft (not shown).

In the engine 1 of this example, a signal for identifying the cylinder can be obtained from the signal from the crank angle sensor 22.

Further, the engine 1 of this example includes a controller 22 preferably including a microcomputer in order to control fuel injection and ignition timing. Referring also to FIG. 2, the controller 22 receives signals representing the intake air amount and intake air temperature from the air flow sensor 11 and the intake air temperature sensor lla, respectively.

The controller 22 also includes a throttle opening sensor 12a1 that detects the opening of the throttle valve 12, and a water temperature sensor 1.
9, the crank angle signal and cylinder identification signal from the crank angle sensor 21, and the starter signal are manually input.

The signal from the knock sensor 20 is passed through a bandpass filter 2.
4, only signals within a predetermined range of frequencies are selected.

In the controller 22, the signal that has passed through the bandpass filter 24 is directly input to a comparator 25, and on the other hand, the signal is input manually to a circuit 23 that creates a reference level for knocking determination. Ru. The signal from the comparator 25 is input to a knocking determination circuit 26 to determine knocking. Then, the knock determination circuit 26
The signal from the engine is inputted manually to the cylinder determination circuit 27, and the circuit in which the knocking signal is generated is identified.

The controller 22 is provided with means for calculating the ignition timing retard amount e for each cylinder, and in this case, the cylinder discrimination circuit 2
The knocking signal for each cylinder from 7 is input to the average retard amount calculation circuit 28 provided for each cylinder, and the average value of the knocking signal in a predetermined time range 7.7, 2, and F is calculated. It is now calculated. The signal from the average retard amount calculation circuit 28 is input to the retard amount calculation circuit 29 which calculates the ignition timing retard amounts e□, θ, 2, θ82, and eK4 provided for each cylinder. Ru.

Further, a signal from the water temperature sensor 19 is input to a circuit 30 that calculates a correction value θ, for the amount of retardation according to the water temperature. Further, the signal from the intake air temperature sensor tta is input to a circuit 31 that calculates a correction value eAT according to the intake air temperature. Also,
Air flow sensor 11 or throttle valve opening sensor 1
The signals from the crank angle sensor 2a and the crank angle sensor 21 are manually input to a memory 32, and a basic retard amount eBAS2 is calculated from the map stored in the memory 32.

The controller 22 performs predetermined calculations based on these calculated retard amounts to determine the final ignition timing e1. Calculate,
This value is manually input to the ignition signal generation circuit 33. Then, when the ignition timing for the cylinder comes, an ignition signal is output to the igniter 34.

The control of this example will be explained below.

FIG. 3 shows a flowchart of the ignition timing control routine.

Referring to FIG. 3, the controller 22 first initializes the system and determines whether or not the engine l is in the starting state based on various data read, and if the engine is in the starting state, the ignition timing is set to a predetermined value. Hard ignition is performed by setting the value to a certain value. Furthermore, when the engine is not starting, the ignition timing is switched to soft ignition, which is determined based on a calculated value. Next, the controller 22 determines whether the engine is in an idle state, and if the engine is in an idle state, calculates an idle advance angle θIDL and sets it as the ignition advance angle θ1. In addition, in an operating state that is neither starting nor idling, that is, in a normal operating state, the controller 22 determines the basic advance angle eRA,2 using a map based on the engine speed N and the intake IQ. do.

Based on the signal from the water temperature sensor 19, the controller 22 further controls the water temperature correction advance angle θ1 of the ignition timing. The intake temperature correction advance angle eA is determined by the signal from the intake temperature sensor lla.
Calculate each T.

Next, the controller 22 executes the subroutine shown in the flowchart of FIG. 4 to calculate the knock correction advance angle θ□.

Referring to FIG. 4, the controller 22 determines the cylinder N and reads the knocking intensity IIl.

Next, the controller 22 determines the operating state to determine whether or not it is in the knocking control region, and if it is not in the knocking control region, the knocking control based on the ignition timing of this example is not performed. If knocking occurs, the knocking strength IK
Then, the retard angle 'It eR is calculated. next,
The controller 22 calculates a correction value according to the value of the retard angle meR. In this case, the correction flIK4 is stored in a predetermined memory as a map of a function of the retard amount e, and is set to become smaller as the retard amount θ becomes larger.

Next, the controller 22 determines the current knock correction advance angle e.
A new knock correction advance angle eXn is calculated only when K, , is less than or equal to a preset maximum knock correction advance angle θi,. That is, in the control of this example, the knock correction advance angle θ,
This is to limit the negative effect on torque performance as much as possible.

Then, the controller 22 controls the current knock correction advance angle eM
, , is corrected to create a new knock correction advance angle e = θ. +e
Calculate iXKi.

In addition, when knocking is not occurring, the controller 22 determines the current value of the knock correction advance angle eK, and, if the value of the correction advance angle e1 is positive, reduces the retard amount. Read the correction value KA from the map. The correction value KA is given as a function of the average knock correction advance angle, and is set to decrease as the knock correction advance angle increases.

Next, the controller 22 determines the current knock correction advance angle e.
By correcting the value of X, , a new knock correction advance angle θh=θ
, -θAXKA are calculated. In this case, the advance angle amount θ is the ignition timing correction amount when knocking does not occur.

As described above, in the control of this example, when knocking does not occur, the retard amount is gradually decreased to control the ignition timing so that it approaches the optimal ignition timing, and the control amount is retarded. As the angle amount increases, it is made smaller to prevent large torque fluctuations from occurring.

Through the above processing, the calculation of the knocking control subroutine is completed, and the controller 22 again continues the processing of the routine of FIG. 3.

Next, in FIG. 3, the controller 22 calculates the various advance angle correction values obtained in the above procedure and calculates the ignition advance angle θ19 to be output as the final ignition advance value as e19=ell.
Asl: 10 θ, 〒 + θw d − θ, given as .

Then, the controller 22 outputs this finally obtained ignition advance value θ1. is stored in an internal predetermined counter until the ignition timing of the relevant cylinder.

According to the above control in this example, the ignition timing is controlled to be as close to the optimum ignition timing as possible, and when knocking occurs, the ignition timing is controlled to a predetermined retardation. , which effectively suppresses knocking. The relationship between this meshing, ignition timing, and torque fluctuation is
As shown in Figure 5, the amount of retardation from the optimum ignition timing or
As the amount of advance increases, the tendency for the torque to decrease becomes more pronounced. Therefore, if control is simply performed using the same retard control amount θ in response to the occurrence of knocking, in an operating state where the retard amount is large, the torque change ΔT2 will be smaller than the torque change ΔT2 as shown in the figure. This is larger than the torque change ΔT+ at , which increases the discomfort of the occupants and is also unfavorable in terms of output performance. In view of this point, in the control of this example,
As described above, the control amount of the ignition timing is configured to decrease as the amount of offset from the optimum ignition timing increases. This makes it possible to minimize torque fluctuations and effectively suppress knocking.

[Brief explanation of drawings]

FIG. 1 is an overall schematic diagram of an engine according to an embodiment of the present invention, FIG. 2 is a block diagram of a controller, FIG. 3 is a flowchart of an ignition timing control routine, FIG. 4 is a flowchart of a knocking control subroutine, and FIG. The figure is a graph showing the relationship between ignition timing and torque change. ■... Engine, 2... Cylinder block, 3... Piston, 4... Combustion chamber, 5... Intake port, 6... ...Exhaust boat, 7...Intake valve, Death...Exhaust valve, 9.
...Intake passage, 1O...Air cleaner, ll...Air flow meter, 12...
...Throttle valve, 13 surge tank, 14...
・Injector, 15... Exhaust passage, 16.
... Spark plug, 20 ... Knock sensor, 21 ... Crank angle sensor, 22 ...
- Controller, 24...Band pass filter, 25...Comparator, 34...Igniter. Figure 1 Figure 4 C Officer D

Claims (1)

[Claims] A knocking detection means for detecting knocking and a signal from the knocking detection means are used to retard the ignition timing when knocking occurs, and advance the ignition timing under operating conditions in which knocking does not occur. An ignition timing control device for an engine that performs feedback control of ignition timing, characterized in that the amount of feedback control of the ignition timing is reduced in response to an increase in the amount of retardation of the ignition timing due to the knocking. Engine ignition timing control device.