JP2003065120A - Method and device for controlling fuel injection amount - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the supply of an unexpected amount of fuel to an engine until learning compensation operation for an accelerator signal ends. SOLUTION: When controlling a fuel injection amount for the diesel engine 10 based on demand injection amount data QD computed by corresponding to the accelerator signal A, a compensation amount for the accelerator signal A is obtained by learning after starting the start operation of the diesel engine 10, demand injection amount data QD is computed by corresponding to a compensation accelerator signal A' obtained by compensating the accelerator signal A in accordance with the compensation amount, and predetermined limit processing is applied to the demand injection amount data QD until the compensation accelerator signal A' after start of the diesel engine 10 is obtained to control a fuel injection amount for the diesel engine 10 based on limit injection amount data LD on which limit processing is applied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection amount control method and device.

[0002]

2. Description of the Related Art For example, in a conventional system for electronically controlling a fuel injection amount to an internal combustion engine for a vehicle, in addition to an accelerator sensor that outputs an electric signal indicating an operation amount of an accelerator pedal, an engine speed And various sensors for detecting other operating conditions are provided, and the output signals from these sensors are processed by an electronic control unit composed of a microcomputer, and the fuel injection valve is controlled to open and close according to the processing result. It is configured to obtain an appropriate fuel injection amount that matches the operating conditions of the engine.

In such a conventional fuel injection amount control system, the mounting position of the accelerator sensor connected to the accelerator pedal for detecting the operation amount of the accelerator pedal deviates from a predetermined position or changes with time. It is expected that a deviation will occur between the actual operation amount of the accelerator pedal and the detected accelerator operation amount indicated by the output of the accelerator sensor. If such a deviation occurs, it is not possible to appropriately perform the fuel injection supply to the internal combustion engine. Therefore,
Conventionally, when the accelerator pedal is not depressed after the engine is started, learning is performed by assuming that the level of the output signal obtained from the accelerator sensor at that time indicates zero accelerator operation amount. The output signal from the accelerator sensor is corrected according to the above, and the corrected output signal is used in the subsequent control.

[0004]

However, according to the above-mentioned conventional method, until the learning operation is started in which the depression amount of the accelerator pedal is set to zero in order to correct the level of the output signal from the accelerator sensor, The control process by the electronic control unit is performed using a predetermined initial value. Therefore, there is a possibility that a fuel injection amount required by the driver, that is, a fuel injection amount different from the correct fuel injection amount according to the operation amount of the accelerator pedal, is calculated and output in a certain period immediately after the start of the engine. There is.

Therefore, for example, when the driver starts the engine by keying on with the accelerator pedal still depressed, an amount of fuel corresponding to a larger depression amount than that at that time is injected, which causes In the light load state, there is a risk that the engine may immediately fall into an overrun state, causing abnormal engine upswing.

An object of the present invention is to provide a fuel injection amount control method and apparatus which can solve the above-mentioned problems in the prior art.

[0007]

In order to solve the above-mentioned problems, according to the present invention, a required injection amount is calculated in response to an accelerator signal from an accelerator sensor, and an internal combustion engine based on the required injection amount is calculated. In a fuel injection amount control method for controlling a fuel injection amount, a correction amount for the accelerator signal from the accelerator sensor is learned by learning after the start operation of the internal combustion engine, and then the accelerator signal is corrected according to the correction amount. While calculating the required injection amount in response to the corrected accelerator signal obtained by, until the corrected accelerator signal is obtained after the start of the internal combustion engine, a predetermined limiting process is performed on the required injection amount, A fuel injection amount control method is proposed in which the fuel injection amount to the internal combustion engine is controlled based on the required injection amount subjected to the limiting process.

The accelerator signal before correction by learning is
The actual accelerator pedal operation amount at that time may not be shown correctly, but for the required injection amount obtained based on such an incorrect accelerator signal, the required injection amount obtained by the limiting process is It is possible to effectively prevent the fuel that is greatly different from the actual required injection amount from being supplied to the internal combustion engine by applying certain restrictions such as not exceeding the specified upper and lower limits. can do.

According to the present invention, an accelerator sensor for outputting an accelerator signal indicating the operation amount of the accelerator pedal is provided, and the fuel injection amount to the internal combustion engine is controlled in response to the accelerator signal. In the fuel injection amount control device, the accelerator signal is input, the correction amount for the accelerator signal is obtained by learning after the start operation of the internal combustion engine, and the accelerator signal is output as it is until the correction amount is obtained. Then, after the correction amount is obtained, learning correction means for correcting the accelerator signal according to the correction amount and outputting a corrected accelerator signal obtained, and the internal combustion engine in response to the output from the learning correction means A required injection amount calculation means for calculating a required injection amount indicating a fuel injection amount to be supplied, a limiting means for limiting the value of the required injection amount within a predetermined range, and The learning correction unit has a determination unit that determines whether or not the correction by learning is performed, and the output from the limiting unit is provided until the learning correction unit corrects the accelerator signal by the correction amount. A fuel injection amount control device is proposed, which is characterized in that the fuel injection amount is controlled based on the above.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a configuration diagram showing an example of an embodiment of a fuel injection amount control device according to the present invention. The fuel injection amount control device 1 is a fuel injection device for an internal combustion engine of a pressure accumulation type for injecting and supplying fuel to an internal combustion engine of an internal combustion engine vehicle, and includes a common rail 2 and a high pressure pump for supplying high pressure fuel to the common rail 2. A plurality of fuel injection valves 4-1 to 4-N for injecting the high-pressure fuel accumulated in the assembly 3 and the common rail 2 into the combustion chambers of the cylinders 11-1 to 11-N of the N-cylinder diesel engine 10. It has and. These fuel injection valves 4-1 to 4-N are provided with electromagnetic valves V1 to VN for controlling fuel injection, respectively.
1 to VN are controlled to be opened and closed independently by the fuel injection valve drive circuit 13, and the high pressure fuel is injected into the corresponding cylinder at a required timing and in a required amount. And the output shaft 1 of the diesel engine 10
The rotation output from 2 is transmitted to a wheel driving device (not shown) including a transmission.

The high-pressure pump assembly 3 is constructed by integrally assembling a high-pressure pump body 31 driven by the diesel engine 10, a fuel metering unit 32, and an inlet / outlet valve 33. The fuel from the fuel tank 5 is supplied to the fuel metering unit 32 by the feed pump 6, and the fuel metering unit 32 adjusts the fuel supplied from the feed pump 6 to the fuel pressure required by the diesel engine 10. Adjust the pressure and
Send to the outlet valve 33. The inlet / outlet valve 33 uses the fuel sent from the fuel metering unit 32 for the high pressure pump assembly 3
Fuel to the plunger chamber (not shown) of the fuel metering unit 32, which is pressurized to a high pressure in the plunger chamber.
It is supplied to the common rail 2 so that it does not flow back into the common rail 2. Here, the fuel pressure in the fuel metering unit 32 is adjusted by adjusting the fuel metering unit 3
This is performed by controlling the opening / closing of the solenoid valve 34 provided in the No. 2.

As will be described later, the solenoid valve 34 is controlled to be opened / closed by a drive control signal SV from the control unit 7 so that the fuel pressure in the common rail 2 becomes a pressure according to the required injection amount of the internal combustion engine at that time. Has become.
An actual pressure signal PA from a pressure sensor 8 which detects the actual fuel pressure in the common rail 2 is input to the control unit 7 as an input signal.

Reference numeral 9A denotes an accelerator sensor for outputting an accelerator signal A which is a voltage signal indicating the operation amount of the accelerator pedal AP. In the present embodiment, the accelerator pedal AP is used.
And a potentiometer PM connected to the. 9B is a rotation speed sensor that outputs a rotation speed signal N that indicates the rotation speed of the diesel engine 10, and 9C is a cooling water temperature sensor that outputs a water temperature signal T that indicates the cooling water temperature of the diesel engine 10. The accelerator signal A, the rotation speed The signal N and the water temperature signal T are input to the control unit 7.

The control unit 7 calculates the required fuel injection amount according to the operating conditions of the diesel engine 10 at that time based on these input signals, and the fuel required to inject this required fuel injection amount. Energization period of injection valve (valve opening period)
The injection energization period data M indicating is output.

The drive control signal SV output from the control unit 7 for controlling the opening / closing of the solenoid valve 34 is a pulse signal, and its duty ratio is determined as an output value for controlling the solenoid valve 34 in the control unit 7. To be As a result, the high pressure pump body 31 to the common rail 2
It is possible to adjust the flow rate of the high-pressure fuel flowing into the common rail 2, and the pressure of the high-pressure fuel in the common rail 2 can be controlled to a predetermined pressure. Since the structure itself of the high-pressure pump assembly 3 which opens and closes the solenoid valve 34 by controlling the duty ratio in this way to adjust the flow rate of fuel is known, a detailed description of the high-pressure pump assembly 3 will be omitted. .

Next, the configuration of the control unit 7 will be described with reference to FIG. FIG. 2 is a functional block diagram for explaining data processing in the control unit 7, in which the accelerator signal A is input to the learning correction unit 21, where the voltage level of the accelerator signal A and the actual accelerator pedal AP. Correction is performed by learning so that the relationship with the operation amount becomes a predetermined relationship.

FIG. 3 shows the voltage level (V) of the accelerator signal A and the accelerator operation amount θ (%) of the accelerator pedal AP.
A graph showing the relationship between and is shown. Here, the characteristic (X) indicated by the dotted line is a characteristic predetermined at the time of design, and the voltage of the accelerator signal A when the accelerator operation amount θ is zero (%), that is, when the accelerator pedal AP is released. The level is set to 1.4 (V), and the voltage level of the accelerator signal A linearly increases with a predetermined inclination as the accelerator operation amount θ increases.

On the other hand, the characteristic (Y) shown by the solid line in FIG. 3 shows the actual input / output characteristic of the accelerator sensor 9A. In this example, the accelerator pedal AP is released and the accelerator operation amount θ is zero ( %) In case of accelerator signal A
Has a voltage level of 1.25 (V), which is 0.15 (V) lower than the predetermined value.

The learning correction unit 21 is provided when the condition that the accelerator pedal AP is released is satisfied after the start operation (key switch on) of the diesel engine 10 is started.
This difference voltage value −0.15 (V) is acquired by learning,
According to the characteristic (Y) shown in FIG. 3, 0.15 (V) is added to the value of the accelerator signal A obtained from the accelerator sensor 9A, and the addition result is output as a corrected accelerator signal A '. This learning is the accelerator pedal AP
Has a known configuration that is executed under a predetermined condition such as a limit switch (not shown) that is installed near the vehicle is closed when the accelerator pedal is released. Note that the learning correction unit 21 is configured to output the accelerator signal A as it is as the corrected accelerator signal A ′ until the difference voltage value that is the correction amount is obtained.

The corrected accelerator signal A ', which is the output of the learning correction unit 21, is input to the required injection amount map calculation unit 22 to which the rotation speed signal N and the water temperature signal T are input.
Based on these input signals, the fuel injection amount to be supplied to the diesel engine 10 at that time is map-calculated as the required injection amount Q. Then, the required injection amount data QD indicating the required injection amount Q is converted into the required injection amount map calculation unit 22.
Is output from.

The required injection amount data QD is input to the limit calculation unit 23 which performs a limit calculation process for limiting the value of the required injection amount Q between the lower limit value QMI and the upper limit value QMX. The lower limit value QMI indicates the minimum fuel injection amount required to keep the diesel engine 10 in the idle operation state, and the upper limit value QMX indicates the diesel engine 10.
Shows the maximum allowable value of the fuel injection amount required for normal operation without being in an abnormally high rotation state.

The required injection amount data QD is stored in the limit calculation unit 2
Due to the limitation calculation processing in 3, the input / output characteristics of the accelerator sensor 9A deviate largely from the characteristic (X) for some reason, and the learning correction unit 21 does not perform the learning correction, and the accelerator signal A is corrected as it is. Even in the case where the accelerator signal A ′ is input to the required injection amount map calculation unit 22, the diesel engine 10
Is stalled, or diesel engine 1
It is possible to prevent problems such as an abnormally high rotation speed of 0 rpm.

The limited injection amount data LD obtained by the limiting calculation unit 23 performing the limiting calculation process as described above is input to the lamp control calculating unit 24, and is supplied to the diesel engine 10 here. A ramp control process for preventing a sudden change in the fuel injection amount is executed, whereby the target injection amount data Q indicating the target fuel injection amount QT is executed.
TD is output. The target injection amount data QTD is sent to the selection unit 25 to which the required injection amount data QD is input,
Either the target injection amount data QTD or the required injection amount data QD is selectively output by the selection unit 25 as described later, and the data selected by the selection unit 25 is sent to the injection energization period calculation unit 26.

The above-mentioned data selection of the selection unit 25 is performed in response to the output from the comparison unit 27 which compares the voltage value of the accelerator signal A with the voltage value of the learning inrush voltage VG. The learning inrush voltage VG is a voltage signal indicating the voltage value of the accelerator signal A at which the learning correction of the accelerator signal A in the learning correction unit 21 is performed, and the voltage value of the accelerator signal A is the voltage of the learning inrush voltage VG. If it is less than the value,
The output voltage of the comparison unit 27 becomes "H", and the accelerator signal A
When the voltage value of is larger than the voltage value of the learning inrush voltage VG, the output voltage of the comparison unit 27 becomes “L”.

The selection unit 25 selects the target injection amount data QTD when the output voltage of the comparison unit 27 becomes "H" and sends it to the injection energization period calculation unit 26, and the output voltage of the selection unit 25 becomes "L". , The required injection amount data QD is selected and sent to the injection energization period calculation unit 26.

That is, after the start operation of the diesel engine 10 is started, the correction amount is learned by the learning correction unit 21 and the target injection amount data QTD is maintained until a predetermined learning correction for the accelerator signal A based on the correction amount is performed. After being sent to the injection energization period calculation unit 26 and after the learning correction unit 21 has performed the predetermined learning correction on the accelerator signal A, the required injection amount data QD is sent to the injection energization period calculation unit 26.

In the injection energization period calculation unit 26, the selection unit 25
Based on the content of the data sent from the diesel engine 10 the required injection amount indicated by the input data
The energization period (valve opening period) of the fuel injection valve required for injecting into the combustion chamber is calculated, and the injection energization period data M indicating the calculation result is output.

The injection energization period data M is sent to the fuel injection valve drive circuit 13, and the fuel injection valve drive circuit 13 controls the operation of the fuel injection valves 4-1 to 4-N based on this (FIG. 1).
reference).

As described above, the fuel injection amount control device 1
When the learning correction unit 21 does not complete the learning correction for the accelerator signal A after the diesel engine 10 is started, the selection unit 25 selects the target injection amount data QTD, and the fuel injection is performed based on the target injection amount data QTD. Since the amount is limited, the accelerator signal A is not learned and corrected by the learning correction unit 21 for some reason, and the accelerator signal A
Is input as the corrected accelerator signal A ′ to the required injection amount map calculation unit 22 as it is, the diesel engine 10 falls into an stalled state, or the rotational speed of the diesel engine 10 becomes an abnormally high rotational speed state. Problems can be prevented.

The input / output characteristic of the accelerator sensor 9A is not largely deviated from the characteristic (X) shown in FIG. 3, and even if the accelerator signal A is used as it is, there is no problem. The required injection amount map calculation unit 22 always performs a limiting process, but in this case,
The required injection amount data QD will not be practically limited.

In any case, the target injection amount data QTD is always selected by the selector 25 at least during the period from the start of the starting operation of the diesel engine 10 to the end of the learning correction for the accelerator signal A. The maximum value of the target injection amount data QTD is limited to the upper limit value QMX even if the key switch is turned on while the pedal is depressed to start the diesel engine 10.
Can surely be prevented from entering the overrun state.

The configuration of the control unit 7 has been described above with reference to FIG.
Although it has been described with reference to the functional block diagram shown in FIG. 1, each of the above-described functions of the control unit 7 can be realized by causing the microcomputer 7A of the control unit 7 to execute a predetermined control program. That is, the embodiment of the method and apparatus according to the present invention is not limited to the embodiment having the configuration shown in FIG. 2, and each function shown in FIG. 2 can be obtained by causing the microcomputer 7A to execute a predetermined program. It goes without saying that the embodiment may be configured to satisfy the above.

[0034]

As described above, according to the present invention, at least during the period from the start of the internal combustion engine start operation to the end of the learning correction for the accelerator signal, the fuel injection amount is always based on the output from the limiting means. Since the control of
For example, even if the engine is started by turning on the key switch while depressing the accelerator pedal, the maximum value of the required injection amount is limited to the upper limit value, so it is possible to reliably prevent the internal combustion engine from overrunning. can do. Also,
It is possible to prevent the fuel injection amount from becoming too small when the accelerator pedal is released to prevent the internal combustion engine from maintaining the idle operation, and the engine cannot be started or the engine stalls. As described above, even if the input / output characteristics of the accelerator sensor deviate from a predetermined state due to a poor mounting of the accelerator sensor, a change with time, or the like, it is possible to effectively prevent the injection of excessive or insufficient fuel that the driver does not expect. it can.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of an embodiment of a fuel injection amount control device according to the present invention.

FIG. 2 is a functional block diagram showing a configuration of a control unit shown in FIG.

FIG. 3 is an input / output characteristic diagram of the accelerator sensor shown in FIG.

[Explanation of symbols]

1 Fuel injection amount control device 7 control unit 9A accelerator sensor 9B speed sensor 9C Cooling water temperature sensor 10 diesel engine 21 Learning correction unit 22 Required injection amount map calculator 23 Limit calculation unit 24 Lamp control calculator 25 Selector 26 Injection energization period calculation unit 27 Comparison Department A accelerator signal A'correction accelerator signal AP accelerator pedal LD limited injection amount data M injection energization period data N speed signal T water temperature signal Q Required injection amount QD required injection amount data QT target fuel injection amount QTD target injection amount data

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3G084 BA13 CA01 CA02 DA04 EB20                       EC01 EC03 FA10 FA20 FA33                 3G301 JA11 KA01 KA05 MA11 ND25                       NE01 NE16 PE01Z PE08Z                       PF03Z

Claims (2)

[Claims] 1. A fuel injection amount control method for calculating a required injection amount in response to an accelerator signal from an accelerator sensor and controlling a fuel injection amount to an internal combustion engine based on the required injection amount, After starting the operation of starting the internal combustion engine, a correction amount for the accelerator signal from the accelerator sensor is obtained by learning,
Thereafter, the requested injection amount is calculated in response to the corrected accelerator signal obtained by correcting the accelerator signal in accordance with the corrected amount, and the request is maintained until the corrected accelerator signal is obtained after the internal combustion engine is started. A method for controlling a fuel injection amount, wherein a predetermined limiting process is performed on the injection amount, and the fuel injection amount to the internal combustion engine is controlled based on the required injection amount subjected to the limiting process. 2. A fuel injection amount control device comprising an accelerator sensor that outputs an accelerator signal indicating an operation amount of an accelerator pedal, and is configured to control the fuel injection amount to an internal combustion engine in response to the accelerator signal. , The accelerator signal is input, the correction amount for the accelerator signal is obtained by learning after the start operation of the internal combustion engine, and the accelerator signal is output as it is until the correction amount is obtained. After being obtained, learning correction means for outputting the corrected accelerator signal obtained by correcting the accelerator signal according to the correction amount, and the fuel injection amount to be supplied to the internal combustion engine in response to the output from the learning correction means The required injection amount calculation means for calculating the required injection amount, the limiting means for limiting the value of the required injection amount within a predetermined range, and the learning correction means. Determining means for determining whether or not the correction by learning has been performed, and the fuel based on the output from the limiting means until the learning correction means corrects the accelerator signal by the correction amount. A fuel injection amount control device characterized in that the injection amount is controlled.