JP3818081B2 - Control device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an internal combustion engine control device, and more particularly to an engine control device that controls the amount of fuel supplied to an internal combustion engine (hereinafter referred to as an “internal combustion engine”).
[0002]
[Prior art]
Generally, in this type of engine control device, the basic injection amount is calculated using the intake air amount and the engine speed as parameters, and the fuel injection amount is determined by correcting the basic injection amount with various correction terms such as temperature. Things are known. The intake air amount is estimated from the throttle opening and the engine rotation speed. This method can simplify the structure, is excellent in cost, and has few failures. It has been adopted.
[0003]
Further, in the above-described engine control device, a predetermined value called a so-called smoothing value of the A / D conversion value of the throttle opening sensor is set in consideration of noise or the like with respect to an electric signal to determine acceleration or deceleration. Therefore, a method of determining acceleration or deceleration when the amount of change in the smoothing value exceeds a predetermined value is employed.
[0004]
[Problems to be solved by the invention]
Since the conventional engine control device needs to maintain the exhaust air / fuel ratio at the time of acceleration / deceleration at the stoichiometric air / fuel ratio, it is necessary to accurately determine the acceleration / deceleration, and the acceleration / deceleration is determined from the A / D conversion value of the throttle opening sensor. A smoothing value for determination is calculated, and in acceleration correction, a change in the throttle opening is obtained from the difference between the smoothing values to detect acceleration, and acceleration correction is performed in accordance with the change in the opening.
[0005]
However, if the throttle opening difference is calculated so that the noise of the A / D conversion value of the throttle opening sensor does not appear, for example, as shown in FIG. As a result, acceleration cannot be detected, and fuel cannot be smoothly injected by only changing the basic injection amount, so that drivability deteriorates.
[0006]
For example, as shown in FIG. 5, even during normal acceleration, acceleration cannot be detected at the initial stage of acceleration due to changes in the throttle opening, as in the case of slow acceleration, so acceleration correction is not performed and smooth acceleration is obtained. As a result, there was a problem that drivability deteriorated.
[0007]
The present invention has been made to solve such a problem, and an object of the present invention is to provide an engine control device that reliably detects acceleration due to a change in throttle opening during slow acceleration and at the initial stage of acceleration.
Another object of the present invention is to provide an engine control device that can achieve smooth acceleration and improve drivability.
Still another object of the present invention is to provide an engine control device that increases the accuracy of the slow acceleration determination as to whether or not the slow acceleration is started and controls the injection amount appropriate for the amount of change in the throttle opening. There is to do.
[0008]
[Means for Solving the Problems]
According to the engine control apparatus of the first aspect of the present invention, the value of the second signal output from the throttle opening sensor and the value of the second signal output from the past throttle opening sensor by the throttle opening value holding means. When the difference between the two signals is within a predetermined first range, the second signal value output from the past throttle opening sensor is held, and the held value is Set. Further, the second signal value output from the throttle opening sensor and the throttle opening after a predetermined first period has elapsed since the fuel injection amount determining means has set the holding value by the throttle opening value holding means. The fuel injection amount is corrected by comparing the holding value set by the value holding unit and correcting the basic injection amount calculated by the basic injection amount calculating unit when the difference between the two values is within a predetermined second range. To decide.
[0009]
For this reason, the value of the second signal output from the throttle opening sensor is calculated, the fluctuation due to noise is removed, and then the slow acceleration start determination logic that detects the minute opening change of the throttle is used, The acceleration correction logic was unable to detect acceleration, and at the time of slow acceleration that opens the throttle very slowly and at the initial stage of acceleration, the acceleration due to changes in the throttle opening is reliably detected, and the basic injection amount is corrected to adjust the fuel injection amount. By deciding, smooth acceleration can be obtained and drivability can be improved.
[0010]
According to the engine control apparatus of the second aspect of the present invention, the value of the second signal output from the throttle opening sensor within the predetermined first period is obtained by the throttle opening value holding means during the past throttle opening. When the value is smaller than the value of the second signal output from the degree sensor, the setting of the hold value is canceled, so that the accuracy of the slow acceleration determination as to whether or not the slow acceleration is started is increased and the amount of change in the throttle opening is increased. On the other hand, an appropriate injection amount can be controlled.
[0011]
According to the engine control apparatus of the third aspect of the present invention, the value of the second signal output from the throttle opening sensor and the throttle opening after the predetermined first period by the throttle opening value holding means. The holding value set by the value holding means is compared, and when the difference between the two is not within the predetermined second range set in advance, the setting of the holding value is canceled, so that whether or not slow acceleration is started It is possible to increase the accuracy of the acceleration determination and control the injection amount appropriate for the change amount of the throttle opening.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, examples showing embodiments of the present invention will be described with reference to the drawings.
FIG. 3 shows an electrical configuration of an engine control apparatus according to an embodiment of the present invention. The control device of this embodiment is mounted on a vehicle, and is an example in which the present invention is applied to a control device for a two-cylinder four-stroke engine.
[0013]
As shown in FIG. 3, the control device of this embodiment includes a sensor provided in an engine (not shown), a control circuit 10 that inputs a signal from the sensor and performs fuel injection, and is output from the control circuit 10. And an actuator controlled by a control signal.
The sensor includes a crank angle sensor 20 that detects a crank angle, and a throttle opening sensor 31 that detects a throttle opening corresponding to the intake air amount.
[0014]
The crank angle sensor 20 is a sensor that detects the rotation of a crankshaft (not shown) of the engine through the rotation of the signal rotor 21, and obtains information such as the ignition timing at every crank angle 360 ° CA indicating the rotation angle. A plurality of pulse signals as one signal are output. The signal rotor 21 is provided with first and second protrusions 21a and 21b so as to be integrally attached to the outer periphery of the signal rotor 21, and the pickup sensor 22 is fixed in proximity to the passing position of the protrusions 21a and 21b. Installed. From the pickup sensor 22, when the projections 21a and 21b pass along with the rotation of the signal rotor 21, positive pulse signals are generated corresponding to the tips of the projections 21a and 21b, and the projections 21a and 21b A negative pulse signal is generated corresponding to each rear end. These pulse signals are input to a waveform shaping circuit 11 described later of the control circuit 10.
[0015]
The throttle opening sensor 31 detects the opening of a throttle valve (not shown) that opens and closes an intake path for introducing air into the engine in conjunction with an accelerator (not shown) to control the amount of intake air. The throttle opening signal is input to an A / D converter 12 (to be described later) of the control circuit 10. Here, the signal output from the throttle opening sensor 31 is input to the control circuit 10 in synchronization with the pulse signal output from the crank angle sensor 20.
[0016]
The control circuit 10 includes a waveform shaping circuit 11 that shapes the pulse signal input from the crank angle sensor 20, an A / D converter 12 that changes an analog signal input from the throttle opening sensor 31 to a digital signal, A microcomputer (hereinafter referred to as a microcomputer) 13 that outputs a calculation and a drive signal for operating the actuator to an optimum value from each signal information, and an injection that outputs a control signal to the actuator based on the drive signal input from the microcomputer 13 Circuits 14 and 15 are provided.
[0017]
The microcomputer 13 has a CPU (Central Processing Unit), ROM, RAM and the like not shown. The ROM stores a control program, fixed data, and the like. The fixed data includes a basic injection time map for calculating the basic fuel injection amount based on the target air-fuel ratio. The RAM stores data after processing output signals from the waveform shaping circuit 11 and the A / D converter 12, data processed by the CPU, and the like. The CPU calculates a fuel injection amount and the like based on various data stored in the RAM according to a control program stored in the ROM. Here, the microcomputer 13 constitutes basic injection amount calculation means, throttle opening value holding means, and fuel injection amount determination means.
[0018]
The actuator includes injectors 40 and 50 as fuel injection valves that inject an optimal amount of fuel at an optimal injection position based on fuel injection signals input from the injection circuits 14 and 15.
Next, the operation of the engine control apparatus of the present embodiment having the above-described configuration will be described with reference to FIGS. Here, in the time chart shown in FIG. 1, the analog signal input from the throttle opening sensor 31 is changed to a digital signal by the A / D converter 12 in synchronization with the pulse signal output from the crank angle sensor 20, The moving average value of the predetermined value (annealed value) is shown. Each moving average value is calculated and counted, for example, every 5 ms (milliseconds). Moreover, the flowchart shown in FIG. 2 has shown the flow of the slow acceleration start determination.
[0019]
For example, when the following equation (1) is satisfied at point A in FIG.
(Moving average value of previous calculation) + (adapted value 1) ≤ (moving average value of current calculation) ≤ (moving average value of previous calculation) + (adapted value 2) (1)
That is, when the difference between (moving average value of current calculation) and (previous moving average value) falls within a predetermined first range (step S11 in FIG. 2), (moving average value of previous calculation) Is set as (moving average holding value), and the point A in FIG. 1 is set in a standby state and (moving average holding value) is held (step S12 in FIG. 2). In other words, (adapted value 1) is a value set to fit as the lower limit value of the first range, and (adapted value 2) is a value set to fit as the upper limit value of the first range. In FIG. 1, (adapted value 1) and (adapted value 2) are 1LSB (1LSB indicates 1-bit movement). Counting is started with the calculation cycle at this time being the first time (step S13 in FIG. 2), and (moving average holding value) is not updated during counting.
[0020]
And, for example, when the following expression (2) is satisfied at the count (conformity value 3) shown at point B in FIG.
(Moving average holding value) <(moving average value of current calculation) ≦ (moving average holding value) + (conformity value 4) (2)
That is, when the difference between the (moving average value calculated this time) and the (moving average holding value) after the lapse of the predetermined first period is within a predetermined second range (step S14 in FIG. 2), Assume that the acceleration start determination condition is satisfied (step S15 in FIG. 2). That is, (adapted value 3) is a count value set to fit as a predetermined first period, and (adapted value 4) is a value set to fit as the upper limit value of the first range. In FIG. 1, (adapted value 3) is 5, and (adapted value 4) is 2LSB. However, during the counting, (moving average value of current calculation) becomes smaller than (moving average value of previous calculation), or (moving average value of current calculation) and (moving average) after a predetermined first period elapses. When the difference from the (holding value) is outside the predetermined second range set in advance, the count is reset and the slow acceleration start determination condition is not satisfied.
[0021]
When the slow acceleration start determination condition is satisfied in the above equation (2), the fuel is obtained by correcting the basic injection amount based on the basic injection time map stored in the ROM of the microcomputer 13 by various correction terms such as temperature by the CPU. Determine the injection amount. Then, a fuel injection signal in the first cylinder is output. Further, a fuel injection signal in the second cylinder is sequentially output based on the determined fuel injection amount. In the present embodiment, the detection of acceleration at the time of slow acceleration has been described as an example. However, the acceleration can be detected at the initial stage of acceleration at the time of normal acceleration other than the above-described slow acceleration.
[0022]
In the embodiment of the present invention described above, the moving average value of the smoothed value of the A / D conversion value of the throttle opening signal output from the throttle opening sensor 31 is calculated, and the fluctuation due to noise is removed. Later, with the slow acceleration start determination logic that detects a slight change in the throttle opening, the acceleration could not be detected with the conventional acceleration correction logic. Smooth acceleration can be obtained and drivability can be improved by reliably detecting the acceleration due to the change in the opening and determining the fuel injection amount by correcting the basic injection amount.
[0023]
Furthermore, in this embodiment, by providing a condition for canceling the standby state that holds the moving average holding value, the accuracy of the slow acceleration determination as to whether or not the slow acceleration is started is improved, and the amount of change in the throttle opening is reduced. Therefore, it is possible to control the injection amount appropriately.
In the embodiment of the present invention described above, the present invention is applied to the control device for a two-cylinder four-stroke engine. However, the present invention is not limited to the number of cylinders of the engine. Needless to say, the present invention can be applied to a control device.
[Brief description of the drawings]
FIG. 1 is a time chart for explaining the operation of an engine control apparatus according to an embodiment of the present invention.
FIG. 2 is a flowchart for explaining the operation of the engine control apparatus according to the embodiment of the present invention.
FIG. 3 is an electrical configuration diagram illustrating an engine control apparatus according to an embodiment of the present invention.
FIG. 4 is a graph for explaining changes in throttle opening with respect to time during normal acceleration and slow acceleration.
FIG. 5 is a graph for explaining a change in the throttle opening with respect to the initial acceleration time during normal acceleration.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Control circuit 11 Waveform shaping circuit 12 A / D converter 13 Microcomputer (basic injection amount calculation means, throttle opening value holding means, fuel injection amount determination means)
14, 15 Injection circuit 20 Crank angle sensor 31 Throttle opening sensor 40, 50 Injector

Claims (3)

A crank angle sensor that outputs a first signal at a predetermined crank angle in synchronization with rotation of the crankshaft of the internal combustion engine;
A throttle opening sensor that detects the throttle opening of the internal combustion engine and outputs a second signal;
A basic injection amount calculating means for calculating a basic injection amount of fuel from a first signal output from the crank angle sensor and a second signal output from the throttle opening sensor; A control device for an internal combustion engine for controlling a fuel amount,
The value of the second signal output from the throttle opening sensor and the value of the second signal output from the throttle opening sensor in the past are compared, and a difference between the two is set to a predetermined first value. A throttle opening value holding means for holding a value of the second signal output from the throttle opening sensor in the past and setting a holding value when in the range;
The second signal value output from the throttle opening sensor and the throttle opening value holding means are set after a predetermined first period has elapsed since the holding value was set by the throttle opening value holding means. The fuel injection amount for determining the fuel injection amount by correcting the basic injection amount calculated by the basic injection amount calculation means when the difference between the two values is within a predetermined second range set in advance A determination means;
A control apparatus for an internal combustion engine comprising: In the predetermined first period, the throttle opening value holding means has a second signal value output from the throttle opening sensor that has been output from the throttle opening sensor in the past. 2. The control device for an internal combustion engine according to claim 1, wherein the setting of the hold value is canceled when the value is smaller than the value. The throttle opening value holding means compares the value of the second signal output from the throttle opening sensor after the predetermined first period and the holding value set by the throttle opening value holding means. 2. The control device for an internal combustion engine according to claim 1, wherein when the difference between the two is not within a predetermined second range set in advance, the setting of the hold value is canceled.

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