KR20030089328A - a device and the method for full pressure controling at cold start of diesel engine - Google Patents

Abstract

PURPOSE: A device and a method are provided to achieve improved starting ability during the cold start of diesel engine. CONSTITUTION: A device comprises a vehicle operating state detection unit(100); an engine control unit(200) for receiving the information relating to the coolant temperature, intake air temperature, fuel pressure and operation of ignition switch, setting a fuel amount in accordance with the coolant temperature and intake air temperature, setting a fuel correction amount in accordance with the difference of fuel pressure, determining the final fuel injection amount, and outputting a fuel injection control signal during the cold start of engine; and a driving unit(300) for controlling the amount of fuel being injected to the engine by being synchronized with the fuel injection control signal output from the engine control unit.

Description

Fuel level control device and method for cold start of diesel engine {a device and the method for full pressure controling at cold start of diesel engine}

The present invention relates to a diesel engine, and more particularly, to an apparatus and a method for controlling a fuel amount at low temperature start-up of a diesel engine capable of improving startability according to cooling water temperature, intake temperature and fuel pressure at low temperature start-up.

In the case of a diesel engine employing an electronically controlled fuel injection system, the viscosity of the fuel decreases due to the freezing of the fuel due to the characteristics of the diesel fuel at low temperature outside the temperature of minus -25 ° C.

At this time, since the pressure of the frozen fuel while the fuel is being supplied to the engine drops significantly compared to the room temperature condition, since the fuel characteristic is lowered at the start due to the low fuel pressure condition and the engine's own resistance when the engine is cold when cold, There is a problem that the startup does not take place or the startup time is long.

Therefore, conventionally, the engine is started by determining the fuel injection amount relative to the cooling water temperature in the memory map according to the engine cooling water temperature at low temperature cold and outputting a corresponding fuel injection control signal.

However, in the conventional method described above, the fuel injection amount is determined according to the engine cooling water temperature during cold operation. However, since there is no intake air temperature and fuel pressure measurement and control function, there is a limit in determining the amount of fuel required for actual starting in the engine in case of cold start. This problem is impaired.

Accordingly, an object of the present invention is to solve the above-mentioned problems, by calculating the amount of fuel set according to the fuel pressure to increase the amount of fuel set according to the intake air temperature and the cooling water temperature at low temperature start-up in a diesel engine to startability at low temperature cold start It is an object of the present invention to provide a fuel amount control device and a method thereof for low temperature start-up of a diesel engine.

1 is a block diagram showing the configuration of the fuel amount control device at low temperature start-up of a diesel engine applied to the present invention,

2 is a flowchart illustrating a method for controlling fuel amount at low temperature start of a diesel engine according to the present invention.

<Description of Symbols for Main Parts of Drawings>

100: vehicle operating state detection means 110: cooling water temperature detection unit

120: intake air temperature detector 130: fuel pressure detector

140: ignition detection unit 200: engine control means

300: driving means

The present invention for achieving the above object,

Vehicle operating state detection means for detecting a vehicle operating state that varies with the vehicle operating state change;

Sets the fuel amount according to the cooling water temperature and the intake temperature at low temperature cold start by receiving the cooling water temperature, the intake temperature, the fuel pressure and the ignition switch state detected and applied by the vehicle operation state detecting means, and sets the fuel correction amount according to the fuel pressure difference. Engine control means for determining a final fuel injection amount based on the set fuel amount and outputting a fuel injection control signal at low temperature cold start;

It characterized in that the drive means for controlling the amount of fuel injected into the engine in synchronization with the fuel injection control signal during the low-temperature cold start output from the engine control means.

The present invention for achieving the above object,

When the diesel engine is started, determining whether to cool the engine by receiving the coolant temperature, the intake air temperature, and the fuel pressure;

When the low temperature cold start is determined in the step, setting an input fuel amount for each cooling water temperature and setting an fuel amount for each intake temperature;

Comparing the fuel pressure and the set fuel pressure difference input in the step with a predetermined set pressure;

Setting a fuel amount by correcting the fuel pressure when the difference between the fuel pressure and the set fuel pressure input in the step is higher than a predetermined set pressure;

In this step, the amount of fuel set for each of the cooling water temperature, the intake temperature, and the corrected fuel pressure may be calculated to determine a final fuel injection amount, and output a predetermined fuel injection control signal.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram illustrating a configuration of a fuel amount control device at low temperature start of a diesel engine applied to the present invention, and FIG. 2 is a flowchart illustrating a method of controlling a fuel amount at low temperature start of a diesel engine applied to the present invention.

As shown in FIG. 1, the apparatus 100 for detecting a vehicle operating state detects a vehicle operating state such as a coolant temperature, an intake air temperature, a fuel pressure, an ignition switch state, and the like, which vary according to a change in the vehicle operating state.

The engine control device 200 receives the coolant temperature, the intake air temperature, the fuel pressure, and the ignition switch state detected and applied by the vehicle operation state detection device 100 to set the fuel amount according to the coolant water temperature and the intake temperature during cold start. The fuel correction amount is set according to the fuel pressure difference, and the final fuel injection amount is determined based on the set fuel amount, and the fuel injection control signal is output during cold start.

The driving device 300 adjusts the amount of fuel injected into the engine in synchronization with the fuel injection control signal during the low temperature cold start output from the engine control device 200.

The vehicle operating state detection apparatus 100 includes a coolant temperature detection unit 110 for detecting a change in the coolant temperature that varies according to a change in the vehicle operating state;

An intake air temperature detector 120 detecting a intake air temperature drawn into the engine according to a change in a vehicle operating state;

A fuel pressure detector 130 for detecting a variable fuel pressure state supplied to the engine according to a change in a vehicle operating state;

The ignition switch detector 140 detects a change in the engine starting state according to the change in the vehicle operating state.

A fuel injection control method at low temperature cold start of the diesel engine having the above configuration will be described with reference to FIG. 2.

When the diesel engine is started to drive the vehicle, the engine control apparatus 200 initializes all variables used and drives a fuel pump (not shown) to supply fuel to the engine (S100).

The vehicle operating state detecting apparatus 100 detects a coolant temperature, an intake air temperature, a fuel pressure, and an ignition switch state that vary according to a change in the vehicle operating state.

Thus, the engine control apparatus 200 outputs a predetermined control signal to receive the coolant temperature, the intake air temperature, the fuel pressure, and the ignition switch state detected by the vehicle operation state detection device 100. ) Outputs the detected coolant temperature, intake air temperature, fuel pressure and ignition switch status.

The engine control apparatus 200 receives a coolant temperature, an intake air temperature, a fuel pressure, an ignition switch state, and the like applied from the vehicle operating state detection device 100 to determine a low temperature cold start state (S110).

In the above-described low temperature cold start state determination, when the condition of cooling water temperature <first set value (−25 ° C.) and intake air temperature <second set value (−30 ° C.) is satisfied, it is determined as a low temperature cold start state.

Therefore, when the low temperature cold start state is determined in the above, the fuel amount A according to the cooling water temperature is set in the fuel amount map table set in the memory for each cooling water temperature, and the fuel amount map table set in the memory for each intake temperature is applied to the intake temperature. The fuel amount B is set (S120).

Subsequently, the engine control apparatus 200 receives the fuel pressure applied from the fuel pressure detecting sensor provided in the fuel distribution pipe, subtracts the base fuel pressure stored in the memory, and then calculates a predetermined value C by a predetermined third. It is determined whether it is higher than the set value (15 bar) (S130).

If it is determined that the value calculated above (measured fuel pressure-base fuel pressure) is higher than the third set value (15 bar), the engine control apparatus 200 calculates and corrects the fuel amount increase by the amount of the fuel pressure decrease (D). (S140).

Subsequently, the engine control apparatus 200 determines the final fuel injection amount by calculating the fuel amounts A and B set for each cooling water temperature and intake temperature in the memory map to the fuel amount increase value corrected in step S140, and then A predetermined fuel injection control signal is output (S150).

However, when it is determined that the value (measured fuel pressure-base fuel pressure) calculated in S130 is lower than or equal to the third set value 15bar, the engine control apparatus 200 corrects the fuel amount increase by the amount of the fuel pressure decrease. The final fuel injection amount is determined using only fuel amounts A and B set for each cooling water temperature and intake temperature in the memory map, and then a corresponding fuel injection control signal is output.

Thus, when the fuel pressure is lowered at the low temperature cold start as described above, by controlling the fuel amount to achieve a suitable air-fuel ratio through the increase in the fuel amount, it may be possible to make a good start.

As described above, the present invention, in order to ensure that the engine starts well at low temperature start in the diesel engine, by calculating the amount of fuel set according to the fuel pressure to the amount of fuel set according to the intake air temperature and cooling water temperature, by increasing the amount of correction, Simultaneous start up can be improved.

Claims (4)

Vehicle operating state detection means for detecting a vehicle operating state that varies with the vehicle operating state change; Sets the fuel amount according to the cooling water temperature and the intake temperature at low temperature cold start by receiving the cooling water temperature, the intake temperature, the fuel pressure and the ignition switch state detected and applied by the vehicle operation state detecting means, and sets the fuel correction amount according to the fuel pressure difference. Engine control means for determining a final fuel injection amount based on the set fuel amount and outputting a fuel injection control signal at low temperature cold start; And a driving means for controlling the amount of fuel injected into the engine in synchronization with the fuel injection control signal during the low temperature cold start output from the engine control means. The vehicle operating state detecting unit according to claim 1, further comprising: a cooling water temperature detecting unit for detecting a change in cooling water temperature which is varied according to a change in the vehicle operating state; An intake air temperature detector for detecting intake air temperature drawn into the engine according to a change in the vehicle operation state; A fuel pressure detector for detecting a variable fuel pressure state supplied to the engine according to a change in a vehicle operating state; A fuel amount control device for low temperature start-up of a diesel engine, comprising: an ignition switch detection unit for detecting a change in an engine starting state according to a change in a vehicle operating state. When the diesel engine is started, determining whether to cool the engine by receiving the coolant temperature, the intake air temperature, and the fuel pressure; When the low temperature cold start is determined in the step, setting an input fuel amount for each cooling water temperature and setting an fuel amount for each intake temperature; Comparing the fuel pressure and the set fuel pressure difference input in the step with a predetermined set pressure; Setting a fuel amount by correcting the fuel pressure when the difference between the fuel pressure and the set fuel pressure input in the step is higher than a predetermined set pressure; The fuel amount control at low temperature start-up of the diesel engine, characterized in that for calculating the final fuel injection amount by calculating the amount of fuel set by the cooling water temperature, the intake temperature and the correction fuel pressure by outputting a predetermined fuel injection control signal Way. The fuel injection control signal of claim 3, wherein when the difference between the input fuel pressure and the set fuel pressure is lower than the predetermined set pressure, the final fuel injection amount is determined by the fuel amount set for each of the cooling water temperature, the intake temperature, and the corrected fuel pressure. A fuel amount control method at low temperature start-up of a diesel engine comprising the step of outputting.