KR100240400B1 - Fuel injection ending point retarding method for vehicle using variable valve timing device - Google Patents

Abstract

The present invention relates to a fuel injection end timing delay method for a vehicle employing a variable valve timing apparatus. In the related art, even when the valve opening and closing timing and the valve lift are variable, the fuel injection end timing is not variable, so combustion performance and fuel economy are good. There was a problem that did not, and thus the increase of HC.

2 to 3, the present invention is particularly useful in a vehicle having a variable valve timing device 12 capable of changing the intake valve timing, in particular in an apparatus for varying the fuel injection timing corresponding to the opening angle of the intake valve. If the intake valve has a large open angle, the fuel injection end time (T _inj ) can be delayed to reduce the amount of fuel adhering to the cylinder wall in the transient state, thereby making the distribution of the mixer in the combustion chamber uniform. By improving HC to reduce the fuel efficiency and the exhaust gas is reduced.

Description

How to delay the end of fuel injection of diesel vehicles with variable valve timing device

The present invention relates to a method for delaying the end of fuel injection of a diesel vehicle employing a variable valve timing device. More particularly, the fuel injection timing is controlled in response to the open advance value of an intake valve. Method for delaying the fuel injection end time of a diesel vehicle employing a variable variable valve timing device which improves combustion performance, reduces HC, and improves fuel efficiency by reducing the attachment of the gas mixture in the combustion chamber. .

Since valve timing is a very important factor, the valve mechanism is designed in consideration of the valve mechanism, and this valve timing refers to a valve opening and closing timing for each stroke of the piston. The opening and closing of the valve does not open and close at the top dead center or bottom dead center of the piston but operates as follows.

The intake valve opens in front of the piston's suction stroke, i.e., before top dead center, and after a suction stroke, i.e. after bottom dead center, is briefly wiped. This is to fill the cylinder as many cylinders as possible using the inertia of suction.

The valve is also opened before the exhaust stroke of the piston, i.e., before the bottom dead center, so that the combustion gas is quickly discharged from the combustion chamber and immediately closed at the top dead center after the exhaust stroke has been passed to the intake stroke. It is to perfect as much as possible.

Figure 1 shows a valve timing diaphragm, in which there is a time when the intake valve and the exhaust valve are open together from the end of the exhaust stroke to the beginning of the intake stroke. It is for.

In general, the opening degree of the intake valve is required to be increased in order to increase the intake and exhaust efficiency of a high speed diesel engine.

Also can be reduced in terms of purification of the exhaust gas exhaust valve to the open state when the zoom by mixing a part of the combustion gas into the intake mixing slowly the burning rate becomes low NO _X is highest combustion temperatures (NOx) in the.

However, under low load conditions, HC (hydrocarbon) increases and blows down due to the blow-by of the mixer, so that an optimum overlap is created for each diesel engine.

Recently, for high power in a wide range of rotation from low speed to high speed, the variable valve timing device of the valve opening and closing time and the valve lift has been adopted depending on the operating conditions.

Among them, the variable valve timing control system (NVCS) converts the opening / closing timing of the intake side by parallelizing the relative angle between the camplier and the camshaft, and the variable valve timing lift mechanism (VTEC) uses both the low speed cam and the high speed. It adopts the method of switching the valve opening / closing timing with two types of cams and the valve lift at the same time.

However, in the related art, even when the valve opening and closing time and the valve lift are variable, the fuel injection end time is not variable, there is a problem of poor combustion performance, poor fuel economy, and an increase in HC.

Accordingly, the present invention has been made to solve the above-mentioned conventional problem, and controls the fuel injection timing in response to the open advance value of the intake valve, and reduces the amount of fuel attached to the cylinder wall in the transient state in the combustion chamber An object of the present invention is to provide a method for delaying the fuel injection end time of a diesel vehicle employing a variable valve timing device that improves combustion performance, reduces HC, and improves fuel efficiency by uniformly distributing the mixer.

The present invention for realizing the above object is based on the intake air amount detected by the air flow meter and the diesel engine speed signal detected by the diesel engine speed sensor. Opening and closing of the valve is controlled, and the fuel injection timing is the opening angle (opening angle) of the intake valve ( The larger) increases the fuel injection end time.

Therefore, in the present invention, a diesel vehicle equipped with a variable valve timing device capable of changing the intake valve timing, particularly when the intake valve has a large open angle, the fuel is attached to the cylinder wall surface in a transient state to delay the end of the fuel injection. It is possible to reduce the amount to be made, thereby making the distribution of the mixer in the combustion chamber uniform, thereby improving the combustion state and reducing the HC, thereby improving fuel economy and reducing the exhaust gas.

1 is a diagram for explaining a valve timing diaphragm.

2 is a schematic view showing a configuration according to the present invention.

3 is a flowchart for implementing a method according to the invention.

* Explanation of symbols for main parts of the drawings

10: intake camshaft 12: variable valve timing device

14 air flow meter 16 engine speed sensor

18 ECU 20 Solenoid valve

Referring to the configuration and operation of the present invention in detail based on the accompanying drawings as follows.

The present invention is the open angle of intake valve ( Calculating the fuel injection end time (T _inj ), and whether the acceleration state Determining whether TA is greater than the set value A, and the amount of change in the throttle valve opening amount ( If TA) is larger than the set value (A), it is a fuel injection end time delay method of a diesel vehicle employing a variable valve timing device, which is configured to add an acceleration delay time (TA _CC ) to a previously calculated end time (T _inj ). .

2 is a schematic view showing a configuration according to the present invention, Figure 3 is a flow chart for implementing another method in the present invention.

Here, in the present invention, the variable valve timing device 12 mounted on the intake camshaft 10 receives the intake air amount detected by the air flow meter 14 and the diesel engine speed signal detected by the diesel engine speed sensor 16. When the amount of advance determined by the predetermined map is based on the control, the opening and closing of the solenoid valve 20 is controlled from the ECU 18, and the fuel injection unit opens the amount of open advance of the intake valve ( The larger) increases the fuel injection end time.

Therefore, the present invention is the open angle of intake valve ( Calculate fuel injection end time (T _inj ), and change the throttle valve opening amount ( TA) will be delayed as the fuel injection end time (T _inj) deohaejun to the set value (A) is greater than the end time of the previously calculated acceleration delay (TACC) (T _inj).

In order to control the amount of fuel injected into the cylinder wall surface, it is preferable to delay the fuel injection timing. However, even if the injection timing is delayed, if the atomization of the injected fuel is not sufficient, the distribution of the mixer entering the combustion chamber is uneven and the combustion efficiency is reduced.

Therefore, the present invention improves the atomization of the fuel according to the internal EGR effect even if the valve open angle is large.

Therefore, the present invention is set so as to delay the fuel injection end timing (T _inj ) when the valve opening advance amount becomes large, so that the control of fuel adhered to the cylinder wall surface and the improvement of fuel atomization can be satisfied.

As described above, the present invention is particularly useful in diesel vehicles having a variable valve timing device capable of changing the intake valve timing, particularly in a device for varying the fuel injection timing corresponding to the open advance angle of the intake valve. By delaying the fuel injection end time (T _inj ), it is possible to reduce the amount of fuel adhering to the cylinder wall in the transient state, and to improve the combustion state by reducing the HC by making the distribution of the mixer in the combustion chamber uniform. It is effective in improving fuel economy and reducing exhaust gas.

Claims (1)

Open angle of intake valve ( Calculating the fuel injection end time (T _inj ), and whether the acceleration state Determining whether TA is greater than the set value A, and the amount of change in the throttle valve opening amount ( If the TA is greater than the set value A, diesel with a variable valve timing device configured to delay the fuel injection time by adding the delay time TA _CC calculated at the time of acceleration to the end time T _inj previously calculated. A method for delaying the end of fuel injection of a vehicle.