JP3932016B2 - Fuel injection amount control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel injection amount control device for an internal combustion engine (hereinafter referred to as an “internal combustion engine”).
[0002]
[Prior art]
The engine fuel injection amount control device calculates a basic injection amount during steady operation based on engine operating conditions such as intake air amount, water temperature, throttle opening, and engine speed. The fuel injection amount at the time of acceleration and deceleration of the vehicle is obtained by correcting the basic injection amount based on the basic injection amount. By detecting the rate of change of the throttle opening that changes in conjunction with the driver's accelerator operation, the fuel injection amount control device determines the driver's operation request, that is, steady operation, acceleration operation, deceleration operation, and fuel injection amount To control. The acceleration operation includes a slow acceleration operation that requires a gentle acceleration by gradually increasing the throttle opening.
[0003]
[Problems to be solved by the invention]
In the conventional slow acceleration correction in which the fuel injection amount is corrected when it is determined that the operation is the slow acceleration operation, if it is determined that the operation is the slow acceleration operation as shown in FIG. The correction period for correction is started, and during the predetermined correction period from the start of the count, the fuel injection amount is corrected and the vehicle is gradually accelerated.
[0004]
However, since the timing for determining the slow acceleration operation may be different for each determination, when the correction period is counted from the timing at which it is determined that the operation is the slow acceleration operation, the slow acceleration correction is performed at the slow acceleration determination timing. The number of fuel injections injected during the period may be different. Since the slow acceleration is a gentle acceleration, if the number of fuel injections during the slow acceleration is different, the drivability felt by the driver is different even if the accelerator opening is opened in the same engine operating state.
[0005]
An object of the present invention is to provide a fuel injection amount control device that prevents fluctuations in the number of fuel injections during slow acceleration correction.
Another object of the present invention is to provide a fuel injection amount control device that smoothly returns to steady operation after completion of slow acceleration correction.
[0006]
[Means for Solving the Problems]
In the fuel injection amount control device according to claim 1, 2 or 3, when it is determined that the operation is the slow acceleration operation, the fuel injection amount is corrected from the next fuel injection timing determined to be the slow acceleration operation. The correction period starts counting. Therefore, if the correction period is the same, the number of fuel injections to be injected within the correction period is equal regardless of the slow acceleration determination timing with respect to the fuel injection timing. That is, the same drivability can be felt if the driver performs a gentle accelerator operation with the same engine operating state and the same degree.
Depending on the engine operating condition, the slow acceleration correction may increase the basic injection amount or decrease the basic injection amount.
According to the fuel injection amount control apparatus of the fourth aspect of the present invention, the fuel injection amount is gradually returned to the basic injection amount after completion of the slow acceleration correction, so that the smooth transition from the slow acceleration operation to the steady operation is performed.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, examples showing embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an electrical block configuration of a fuel injection amount control apparatus according to an embodiment of the present invention. The fuel injection amount control device of this embodiment is mounted on a vehicle and is an example applied to a two-cylinder four-stroke engine.
As shown in FIG. 1, the fuel injection amount control device of this embodiment includes a pickup sensor 10 as a crank angle sensor that detects a crank angle, and a throttle opening sensor 20 that detects a throttle opening corresponding to the intake air amount. And a control means 30.
[0008]
The pickup sensor 10 is a sensor that detects the rotation of a crankshaft (not shown) of the engine through the rotation of the signal rotor 1, and in order to obtain information such as ignition timing, a plurality of pickup sensors 10 are provided for each crank angle 360 ° CA indicating the rotation angle. Outputs a pulse signal. The signal rotor 1 is provided with protrusions 2 and 3 so as to be integrally attached to the outer periphery of the signal rotor 1, and a pickup sensor 10 is fixedly installed in the vicinity of a passing position of the protrusions 2 and 3. The pick-up sensor 10 generates a positive pulse signal corresponding to the tip of each of the protrusions 2 and 3 when the protrusions 2 and 3 pass along with the rotation of the signal rotor 1, and each of the protrusions 2 and 3. A negative pulse signal is generated corresponding to the rear end. These pulse signals output from the pickup sensor 10 are input to a waveform shaping circuit 31 described later of the control means 30.
[0009]
The throttle opening sensor 20 detects the opening of a throttle valve member (not shown) that controls the intake air amount by opening and closing an intake passage for introducing air into the engine in conjunction with an accelerator (not shown). The throttle opening sensor 20 outputs a throttle opening signal to the A / D converter 32.
[0010]
The control means 30 includes a waveform shaping circuit 31 that shapes a pulse signal input from the pickup sensor 10, an A / D converter 32 that changes an analog signal input from the throttle opening sensor 20 to a digital signal, an engine From a microcomputer 33 (hereinafter referred to as “microcomputer”) that outputs a drive signal for controlling the fuel injection amount of the injectors 40 and 41, which are fuel injection devices, based on various signal information indicating the operation state; There are provided injection circuits 34 and 35 for outputting a control signal to the injectors 40 and 41 based on the input drive signal.
[0011]
The microcomputer 33 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 period map for calculating the basic injection amount based on the target air-fuel ratio. The RAM stores data after processing the output signals from the waveform shaping circuit 31 and the A / D converter 32, 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.
[0012]
Next, the operation of the fuel injection amount control apparatus of the present embodiment having the above-described configuration will be described with reference to FIG. The throttle opening in the time chart shown in FIG. 2 is obtained by changing the analog signal input from the throttle opening sensor 20 into a digital signal by the A / D converter 32, and taking into account noise or the like with respect to the electric signal. An average value of so-called annealing values obtained by converting 20 A / D conversion values is shown. The average value of each throttle opening is calculated and counted, for example, every 5 ms.
[0013]
For example, at point A in FIG. 2, the engine is running, the throttle opening sensor 20 is normal, the gear position is other than neutral, the slow acceleration correction is not prohibited, and the following expression (1) is satisfied. When (however, constant 1 ≦ constant 2),
(Previous throttle opening) + (constant 1) ≤ (current throttle opening) ≤ (previous throttle opening) + (constant 2) (1)
That is, when the rate of change of (current throttle opening) with respect to (previous throttle opening) is within a preset first range, (previous throttle opening) is set to (throttle opening holding value). The above-mentioned slow acceleration correction prohibited means that the slow acceleration correction is prohibited if the acceleration is still in progress after the completion of the slow acceleration correction. In equation (1), the previous throttle opening is compared with the current throttle opening. As the past throttle opening, the previous throttle opening is compared with the current throttle opening more than twice. Also good.
[0014]
When the following equation (2) is satisfied at a predetermined number of times from point A in FIG.
(Throttle opening hold value) <(Current throttle opening) ≤ (Throttle opening hold value) + (Constant 3) (2)
That is, it is assumed that the slow acceleration condition is satisfied when the rate of change of (current throttle opening) with respect to (throttle opening holding value) is within a preset second range when a predetermined count number has elapsed. However, if (throttle opening hold value)> (current throttle opening) is satisfied during counting from point A to point B, the counting is stopped and the slow acceleration condition is not satisfied.
[0015]
When the slow acceleration condition is satisfied, as shown in FIG. 3, the system waits until the next fuel injection timing after the slow acceleration condition is satisfied. From the next fuel injection timing, the slow acceleration is performed for a predetermined correction period. Make corrections. The slow acceleration correction is performed by increasing or decreasing the basic injection amount obtained from the basic injection amount map stored in the ROM of the microcomputer 33 according to the engine operating state. The fuel injection amount control signal thus determined is sequentially output from the control means 30 to the injectors 40 and 41.
[0016]
When the slow acceleration condition is satisfied, for example, a normal acceleration condition may also be satisfied. Thus, when both the slow acceleration condition and the normal acceleration condition are satisfied, it is desirable not to increase the fuel injection amount by the slow acceleration correction and to decrease the fuel injection amount depending on the engine operating state such as the engine load and the water temperature. Sometimes. In this case, the fuel injection amount control signal sent to the injectors 40 and 41 is a control signal for reducing the fuel injection amount from the basic injection amount.
[0017]
When the slow acceleration correction period for increasing or decreasing the basic injection amount ends, as shown in FIG. 4, a fuel injection amount control signal is sent to the injectors 40 and 41 so that the fuel injection amount gradually returns to the basic injection amount. Thereby, it is possible to prevent an impact caused by a sudden change in the fuel injection amount and smoothly return from the slow acceleration operation to the steady operation.
[0018]
In the fuel injection amount control apparatus of the present embodiment described above, the start of the correction period counting by the slow acceleration is waited until the next fuel injection timing after the slow acceleration condition is satisfied, and the correction period is started from the next fuel injection timing. Start counting. Therefore, in the same correction period, the number of fuel injections injected in the correction period is equal even if the timing at which the slow acceleration condition is satisfied, and the same drivability can be obtained.
[0019]
In the above embodiment of the present invention, the present invention is applied to the fuel injection amount 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 is applicable to a fuel injection amount control device for a two-stroke engine.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a fuel injection amount control device according to an embodiment of the present invention.
FIG. 2 is a time chart showing a change in throttle opening when a slow acceleration condition is established in the present embodiment.
FIG. 3 is a time chart showing a relationship between a slow acceleration condition establishment timing and a fuel injection timing in the present embodiment.
FIG. 4 is a time chart showing a change in fuel injection amount after completion of the slow acceleration correction.
FIG. 5 is a time chart showing a relationship between a slow acceleration condition establishment timing and a fuel injection timing in a conventional example.
[Explanation of symbols]
10 crank angle sensor 20 throttle opening sensor 30 control means 31 waveform shaping circuit (control means)
32 A / D converter (control means)
33 Microcomputer (control means)
34, 35 Injection circuit (control means)
40, 41 Injector (fuel injection device)

Claims (4)

A crank angle sensor that outputs a crank angle signal at a predetermined crank angle in synchronization with the rotation of the crankshaft of the internal combustion engine;
A throttle opening sensor that detects the throttle opening and outputs a throttle opening signal;
Control means for controlling the fuel injection amount of the fuel injection device, and when the rate of change of the throttle opening obtained from the throttle opening signal is within a predetermined lower limit value and upper limit value, it is a slow acceleration operation The fuel injection amount correction period starts counting from the next fuel injection timing determined to be the slow acceleration operation, and the basic injection amount is increased or decreased during the predetermined correction period . Control means for correcting the fuel injection amount ;
A fuel injection amount control apparatus comprising: The control means compares the value of the throttle opening signal detected this time with the value of the previous throttle opening signal, and when the change rate of the throttle opening is in a predetermined first range, the past The value of the throttle opening signal is held as a holding value, and the value of the throttle opening signal detected after the lapse of a predetermined first period from the setting of the holding value is compared with the holding value, 2. The fuel injection amount control device according to claim 1, wherein when the rate of change is in a predetermined second range set in advance, it is determined that the operation is a slow acceleration operation. 3. The fuel injection amount control device according to claim 1, wherein the control unit increases the fuel injection amount of the fuel injection device from a basic injection amount during the correction period. 4. 4. The fuel injection amount control device according to claim 1, wherein the control means gently returns the fuel injection amount of the fuel injection device to a basic injection amount after the correction period ends.

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