KR100405735B1 - Method of controlling injection time for fuel injection pump in a diesel engine - Google Patents

Abstract

To provide a method of controlling the fuel injection pump injection timing of a diesel engine that prevents a sudden change in the injection timing due to a change in the cooling water temperature and improves the engine performance by stabilizing the operating state of the engine:

The output voltage value for controlling the timing is mapped according to the detected engine speed and the output voltage value according to the opening angle of the accelerator pedal, and this mapping output voltage is output according to the reference temperature of the cooling water temperature to control the injection timing.

In the temperature range of this band value region, the map switching determination temperature is designated as a constant band value at the following temperature to the reference temperature of the cooling water temperature, and after the constant filtering process is performed based on the output values of the room temperature map and the low temperature map, injection control is performed. Provided is a fuel injection pump injection timing control method for a diesel engine.

Description

Fuel injection pump injection timing control method of diesel engine {METHOD OF CONTROLLING INJECTION TIME FOR FUEL INJECTION PUMP IN A DIESEL ENGINE}

The present invention relates to a method for controlling the injection timing of an electronically controlled fuel injection pump of a diesel engine, and more particularly, to improve the engine performance by stabilizing the operating state of the engine by preventing a sudden change in the injection timing due to a change in cooling water temperature. It relates to a fuel injection pump injection timing control method of a diesel engine.

For example, diesel engines, which are self-ignition engines, require high-precision fuel injectors for injecting high-pressure fuel into the combustion chamber instead of the ignition system, which is essential for gasoline engines. Since a reduction of the number is required, an electronically controlled injection method for electronically controlling the fuel injection device has been adopted.

In the case of the electronically controlled fuel injection device, a physical signal is detected as an electrical signal by each sensor, a switch, and the like, and the engine control unit compares and processes the injection signal and the injection amount control according to the processing result.

In the fuel injection timing control method of the electronically controlled fuel injection device, an output voltage value for controlling timing is usually mapped according to the engine speed detected by the electronic control unit and the output voltage value according to the opening angle of the accelerator pedal. The injection timing is controlled according to the operating conditions of the engine according to the output voltage.

More specifically, as shown in Figs. 6 and 7, first, the engine speed and the accelerator pedal voltage are detected by the electronic control unit, and the coolant temperature is detected (S200).

Then, it is determined whether the detected cooling water temperature is equal to or higher than the reference temperature (S210), and when the condition is satisfied, the output voltage is output as a normal temperature mapping value (S220), the injection timing is controlled (S230), and the S120 If the condition is not satisfied at the step, the output value of the low temperature mapping is output (S240) to control the injection timing (S230).

That is, the logic is configured to operate each mapping according to the cooling water temperature of the engine by configuring a separate mapping in the ROM of the electronic control unit. Usually, a low ohmic map operated at low temperature and a normal temperature operated at room temperature It consists of a map.

The low temperature map is a value in which the injection timing is advanced in order to suppress the occurrence of wall smoke when the operation is performed at low temperature, and the normal temperature map is a map operated in a normal operation state in which the engine is completely warmed up. It is mapped based on the results of performance development taking into account the emission level and output characteristics.

However, when the separate timing map is operated as described above, the ROM data mapping can be made easier by operating a separate map according to each driving state of the engine. When the engine coolant temperature is the reference temperature as shown in FIG. 6, the mode is changed so that the mapped value is changed drastically, thereby causing fluctuations in the engine speed due to the injection amount variation.

For example, if the output value of 2,8V in the low temperature map is 2.3V in the room temperature map, the injection timing of the engine suddenly changes when the map is switched, thereby changing the engine speed according to the injection amount change.

Accordingly, there is a problem in that the driving state of the engine is unstable and the riding comfort is adversely affected.

Therefore, the present invention has been invented to solve the above problems, the object of the present invention is to prevent the sudden fluctuation of the injection timing due to the change in the cooling water temperature to improve the engine performance by stabilizing the operating state of the engine A fuel injection pump injection timing control method of a diesel engine is provided.

1 is a block diagram showing a configuration for operating the present invention.

2 is a control pattern diagram of the present invention.

3 is a view for explaining a filtering method according to the present invention.

4 is an operational control flow chart according to the present invention.

Figure 5 is a graph showing the comparison with the prior art to visually show the effect of the present invention.

6 is a pattern diagram of a conventional injection timing control.

7 is a flowchart of a conventional operation control.

In order to realize this, in the present invention, an output voltage value for controlling timing is mapped according to the detected engine speed and the output voltage value according to the opening angle of the accelerator pedal, and the mapping output voltage is output according to the reference temperature of the cooling water temperature. In controlling the injection timing,

In the temperature range of this band value region, the map switching determination temperature is designated as a constant band value at the following temperature to the reference temperature of the cooling water temperature, and after the constant filtering process is performed based on the output values of the room temperature map and the low temperature map, injection control is performed. Provided is a fuel injection pump injection timing control method for a diesel engine.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention that can specifically realize the above object will be described in detail.

1 is a block diagram of a configuration for operating the present invention, the engine RPM sensor (2) for detecting the engine speed as a sensing means for injection timing control, and the Excel pedal sensor for outputting the operating angle of the accelerator pedal as a voltage (4) and the water temperature sensor 6 which detects cooling water temperature.

The electrical signal input from the sensing means is compared with the engine control unit ECU to control the injection timing control means 8 with the output value processed thereon.

The injection timing control means 8 is composed of an electronic governor, a timing control valve, or the like, referred to as a GE actuator.

2 is a control pattern diagram of the present invention, by designating a map switching determination temperature as a constant band value and performing a constant filtering process based on the output values of the room temperature map and the low temperature map in the temperature section of the band value region, This is to prevent sudden fluctuations in the output value.

The filtering equation is calculated as Vt = 1/256 * {(256-K) Vt1 + KVt2}, where Vt1 is a timing control voltage according to the engine speed and the accelerator pedal voltage in the room temperature map, and Vt2 is a low temperature. The timing control voltage according to the engine speed in the map and the voltage according to the accelerator pedal voltage, K is a filtering constant (arbitrary value), and Vt is a timing control output voltage.

The Petering equation as described above uses a liner interpolation relationship, and the liner interpolation is performed at an arbitrary position (herein, a constant) by varying the output values Vt1 and Vt2.

That is, the meaning of triangle base 256 in FIG. 3 means that when the data calculated by the ECU is 8 bits, the data that the ECU can recognize is at least 00000000 to 11111111, which is 255 in decimal. ) Is equal to 256.

Considering the proportional relationship of triangle, (Vt2-Vt1): 256 = (Vt-Vt1): K is established, and the proportional relationship of this expression can be written as 256 (Vt-Vt1) = K (Vt2-Vt1). If you sum up Vt1 and Vt2 for the output value of Vt, then Vt = K / 256 (Vt2-Vt1) + V1, and if you put it back to Vt1 and Vt2, then Vt = 1/256 * {(256- K) Vt1 + KVt2}.

However, in the above, the constant K can be set to any value, which is set differently according to the characteristics of the operating system.

4 is summarized as the operation flowchart of FIG. 4, the engine speed, the accelerator pedal voltage, and the coolant temperature are detected by the electronic control unit ECU (S100).

After reading the map Vt1 at room temperature and the map Vt2 at low temperature (S110), it is determined whether the cooling water temperature Tw is equal to or greater than the reference temperature (S120).

If it is determined in step S120 that the cooling water temperature is equal to or greater than the reference temperature, the normal temperature map Vt1 is output (S130), the injection timing is controlled (S150), and if the cooling water temperature is smaller than the reference temperature in step S120, the cooling water is determined. It is determined whether ON (Tw) is equal to or less than the determination temperature (S160).

If it is determined in step S160 that the cooling water temperature Tw is equal to or smaller than the determination temperature, the low temperature map Vt2 is output (S170), the injection timing is controlled (S150), and in step S160, the cooling water temperature Tw is the determination temperature. If it is determined to be larger than the timing control output voltage (Vt) to calculate the value of the low temperature map (Vt2) (S180) to control the injection timing (S150).

In the case of controlling the injection timing as described above, looking at the variation in the output value when the calculation time at the time of fluctuation from the output voltage of 2.8V of the low temperature map to 2.3V of the output voltage of the normal temperature map is 50 mSEC, as shown in FIG. Although the fluctuation changes abruptly like the display of the hidden line, it can be seen that the present invention gradually changes as the display of the solid line.

As described above, according to the present invention, it is an invention that can improve the performance by stabilizing the operation state of the engine by preventing the sudden change of the injection timing according to the change in the cooling water temperature by the improvement of the control logic without any additional device.

Claims (4)

The output voltage value for controlling the timing is mapped according to the detected engine speed and the output voltage value according to the opening angle of the accelerator pedal, and this mapping output voltage is output according to the reference temperature of the cooling water temperature to control the injection timing. In the temperature range of this band value region, the map switching determination temperature is designated as a constant band value at the following temperature to the reference temperature of the cooling water temperature, and after the constant filtering process is performed based on the output values of the room temperature map and the low temperature map, injection control is performed. Fuel injection pump injection timing control method of the diesel engine, characterized in that made. The method according to claim 1, wherein in the filtering process, Vt1 is the timing control voltage according to the engine speed and accelerator pedal voltage in the room temperature map, Vt2 is the timing control voltage according to the engine speed in the low temperature map and the voltage according to the accelerator pedal voltage. When K is a filtering integer (arbitrary value), A timing control output voltage Vt is calculated as 1/256 * {(256-K) Vt1 + KVt2}. Detecting the engine speed, the accelerator pedal voltage, and the coolant temperature; When the first step is completed, reading a map at room temperature and a map at low temperature that are already mapped, and then determining whether the cooling water temperature is equal to or greater than the reference temperature; A third step of controlling the injection timing by outputting a room temperature map when it is determined that the cooling water temperature is equal to or greater than the reference temperature in the second step; A fourth step of determining whether the cooling water temperature is less than or equal to the determination temperature if it is determined that the cooling water temperature is lower than the reference temperature in the second step; If it is determined in the fourth step that the cooling water temperature is equal to or smaller than the determination temperature, a low temperature map is output to control the injection timing, and if it is determined in the fourth step that the cooling water temperature is larger than the determination temperature, the timing control output voltage is calculated to be determined. A fuel injection pump injection timing control method for a diesel engine, characterized in that the fifth step of controlling the injection timing by a calculated value. The timing control output voltage Vt of claim 5, wherein Vt1 is the timing control voltage according to the engine speed and the accelerator pedal voltage in the room temperature map, Vt2 is the timing control voltage according to the voltage according to the engine speed and the accelerator pedal voltage in the low temperature map, and K is a filtering constant (arbitrary value). ), 1/256 * A fuel injection pump injection timing control method of a diesel engine, characterized in that calculated by {(256-K) Vt1 + KVt2}.