JPS59221434A - Correcting and control system for unequality of intercylinder fuel injection amount - Google Patents

Abstract

PURPOSE:To control unpleasant vibration of engine by correcting the amount of feul injected in such a way that the deviation between average values for the operation periods of each cylinder and the operation periods of all the cylinders becomes less than a given value during the idling period. CONSTITUTION:A cylinder-discriminating pulse sensor 8 and an upper dead point angle sensor 9 are provided to a control unit 1, by which whether engine is in idling state or not is judged. When idling state is judged, the average period of all the cylinders is obtained and then the variation rate of each cylinder is obtained. The deviation between the average period and the period of all the cylinder is obtained, and the fuel injection amount of each cylinder is corrected in such a way as to lower the deviation to less than a reference value. The unpleasant vibration of the engine can thus be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inter-cylinder fuel injection amount disparity correction control method for determining and correcting the disproportionality when the fuel injection amount differs slightly between cylinders in an engine. It is.

Now, in the fuel injection system of an engine, there is a slight difference in the amount of injection from cylinder to cylinder due to dimensional tolerances of the nozzle and delivery valve (the degree of this difference is expressed by the non-uniformity factor), and this causes the engine speed to change. The speed fluctuates with each explosion cycle, producing unpleasant vibrations. This vibration does not cause much of a problem when the car is running at high speed, but it becomes a particular problem when the car is idling, as it can be felt as an unpleasant vibration.

This vibration increases as the non-uniformity ratio increases, and in the case of Al1 vehicles in particular, the inertial mass of the flywheel is small, so it is more sensitive and often causes problems. Particularly in the case of distribution type injection pumps, it is difficult to adjust the disproportionality, and there are limits to reducing the dimensional tolerance of parts, which is a serious problem.

Therefore, we proposed a fuel injection pump that corrects the unevenness of the injection amount for each cylinder and injects the same amount of fuel into each cylinder (see Japanese Patent Application Laid-Open No. 141026/1983).
However, since the existing proposal by Gagaru was not based on the premise of an electronic engine control device, it required an extra high-precision electric rupture valve to realize it, resulting in high costs. It had the disadvantage of becoming a thing.

The present invention has been made in view of the above-mentioned conventional technical circumstances, and therefore, an object of the present invention is to provide a low-cost means without requiring high additional costs, based on the premise of an electronic engine control device. It is an object of the present invention to provide a control method for correcting fuel injection poison non-uniformity between cylinders, which can be realized in the following manner.

In order to achieve the second object, the present invention provides a cylinder-to-cylinder engine.
1. The injection amount imbalance correction control method consists of a step of detecting that the engine is in an idling state, a step of measuring and storing the operating cycle of each cylinder included in the engine when the engine is in an idling state, and a step of detecting that the engine is in an idling state. a step of calculating the average value of the operating cycles of all the cylinders being affected; a step of calculating and storing the variation rate of the operating cycle of each cylinder with respect to the average value; The step of changing the injection amount target value of the cylinder concerned by a certain amount, the fluctuation rate of n for all cylinders being within a certain limit deviation range from the standard value. It is characterized in that each of the steps described above is repeatedly executed until the amount falls within the range.

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an outline of an electronic engine control device on which the present invention is based. Refer to the same figure. Accelerator position, fuel injection amount, engine rotation, fuel temperature, coolant temperature, vehicle speed, etc. are input to the control unit 1 from sensors 2 to 7, and main switch 10.
Set switch 11, resume switch 12, brake/clutch switch 13, air/fun switch 14,
Each switch output is input from the start switch 15.

The control unit 1 takes in these input signals, performs predetermined calculations, etc., and then controls the actuator 2o.
The system instructs the fuel injection amount and controls its timing. In addition, 21 is a cruise indicator lamp,
22 is a self-inspection indicator lamp.

FIG. 2 shows the first step to realize the control method according to the present invention.
0 is a block diagram showing the sensors to be added to the control device shown in FIG. In addition, assuming a four-cylinder engine, the cylinder discrimination pulse sensor 8 generates one pulse every two revolutions of the engine, such as #ICyA! of the injection pump. Installed to output a pulse before pumping (generous). In addition, the top dead center angle sensor 9 sends a pulse (
Install it to output the Top Dead Ccnter pulse (TDC pulse for short).

In the control unit 1, after the cylinder discrimination pulse is input from the sensor 8, the TD that is first input from the sensor 9
C pulse: tf:1. It is determined that the pulse belongs to CyIl, and thereafter, 13t14. #2
The 'f' DC pulse is determined in this order.

FIG. 3 is a chart showing the timing relationship of each signal when measuring the operating period of each cylinder from the cylinder discrimination pulse and i' DC pulse obtained as described above.

As shown in the figure, the period from the TDC pulse of each cylinder to the TDC pulse of the next cylinder is measured using a clock pulse, and this is sequentially repeated to obtain and record each period among the four cylinders (for example, , the period of #1 → #3 = # I
(Memorized at address CyA) 0 This is measured for 31 cycles, for example, and averaged. As a result, for example #1 → #
If the period of 3 is longer than the period of 02-)01, (#l→
Since the average angular velocity of #3 is slower than #2 → #1) #2
The explosive force of #1 is smaller than the explosive force of #1. That is, it is determined that the injection amount is small. This is because the inertial masses are equal, so the output and angular velocity are proportional. Similarly, adjacent cylinders in the order of explosion are sequentially compared in °C to identify the cylinder with the smallest injection amount and the cylinder with the largest injection amount.

FIG. 4 shows the relationship between each period and the gray angular velocity during that period. In addition, in the instantaneous angular velocity graph, the ↑ mark indicates an increase in rotation due to heating of each cylinder.

Returning to FIG. 2, the control unit 1 increases the target value of the injection amount by a certain percentage (for example, 1 inch) before starting injection in the cylinder with the smaller injection amount identified as described above, and increases the target value of the injection amount in the cylinder with the larger injection amount. In some cases, control is performed to reduce the amount.

Then, by repeating the measurement of the operating cycle and the control of the injection amount for each cylinder, the difference in the operating cycle (and therefore the difference in the fuel injection amount) for each cylinder is kept below the standard value. If the correction factor of the injection amount for each cylinder finally obtained in this way is stored in the memory, the inter-cylinder fuel injection amount average rate correction control can be performed immediately during idling according to this correction factor. Unpleasant vibrations can be prevented.

FIG. 5 is a flowchart showing the flow of operations executed by the control Q unit according to the present invention. In FIG.

There is no need to explain each step of (1) to (2) again.

FIG. 6 is a characteristic diagram showing the control characteristics of the kapana when controlling the increase/decrease of the injection amount, corresponding to FIG. 4. In the same figure, the injection amount target value before correction is #1 t#3##4
While it was constant across each TDC of ##2,
The injection amount target value after correction of the unrestricted rate is shown by a dotted line, whereas the actual response characteristic of the cabana is shown by a solid line. At each injection timing, the amount of fuel indicated by the mark is injected.According to the present invention, the measurement and control as described above are performed every time the engine is in an idling state. If the correction factor of the unrestrained factor changes from the previous one for some reason, learning control is executed to correct it again, so there is an advantage that unpleasant vibrations caused by the engine can be constantly suppressed.

In the above-mentioned implementation side, a method of measuring the period of (crank angle 1 go') for each TDC was shown as a method of detecting angular velocity fluctuations, but there are other ways to measure the frequency input of the rotation sensor at high speed F-V
How to convert and compare the maximum and minimum of analog voltage (Part 4)
(Measure the arrow in the figure below) is also considered.

In the first embodiment, the cylinder difference in angular velocity fluctuation is measured during idling, but it is also possible under other conditions by adding logic to determine whether the engine is in a steady state. In addition, control of the non-retention rate is mainly necessary only during idling, so
It is also practical to perform the unrestrained rate correction only when idling (in the above example, the idling correction rate is memorized and corrected under all driving conditions, but in reality, when driving at high speed, the cabana It seems that the response of

It goes without saying that the present invention is applicable not only to distribution type pumps but also to all electronically controlled injection systems such as line pumps, unit injectors, and gasoline injection systems.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an overview of the electronic engine control device on which the present invention is based, and FIG. 2 shows sensors that should be added to the control device in FIG. 1 in order to realize the control method according to the present invention. Block diagram, Figure 3 shows cylinder discrimination pulse and TDC
A chart showing the timing relationship of each signal when measuring the operating period of each cylinder from pulses, FIG. 4 is a graph showing the relationship between the operating period of each cylinder and the instantaneous angular velocity during that period, and FIG. FIG. 6 is a flowchart showing the flow of operations executed by the unit, and FIG. 6 is a characteristic diagram showing the control characteristics of the cabana when controlling the increase/decrease of the injection amount, corresponding to FIG. 4. Code explanation 8... Cylinder discrimination pulse sensor, 9...
Top dead center angle sensor agent Patent attorney Akio Namiki Agent Patent attorney Kiyoimo Matsuzaki I3 Sho4 η2
IITDC Figure 6 111-Crank angle (B odd P score)

Claims (1)

[Claims] 1) a step of detecting that the engine is in an idling state; and a step of measuring and recording the operating cycle of each cylinder included in the engine when the engine is in an idling state;
A step of calculating the average value of the operating cycles of the cylinders included in the engine, a step of calculating and storing the fluctuation rate with respect to the average value of the operating cycle of each cylinder, and a step of calculating and storing the fluctuation rate with respect to the average value, and a step in which the fluctuation rate is within a certain limit with respect to the standard value. For cylinders that differ by more than 100 yen, the method includes at least the step of changing the injection amount target value of the cylinder by a certain amount, so that the fluctuation rate of each of all cylinders is within a certain limit deviation range from the standard value. 1. A control method for correcting inter-cylinder fuel injection amount disobedience, characterized in that each step is repeatedly executed until the amount of fuel injection between cylinders is corrected.