KR19980068825A - Target shaft for camshaft sensor with 90 degree split recognition and fuel injection control method at initial start-up - Google Patents

Abstract

According to the present invention, after a cranking decision using a target wheel capable of 90 degree division recognition, a cam position can be immediately determined, that is, cylinder discrimination is possible at the time of 1 TDC (90 degree). Target wheel for camshaft sensor and initial start-up that enables 90-degree split recognition to prevent wetting of injected fuel by sequential injection and sequential injection only during TDC period. The present invention relates to a fuel injection control method.

According to the present invention, a camshaft sensor target wheel includes four quadrants whose radius is changed every 90 degrees, and the radius of each quadrant (Ra, Rb, Rc, Rd) is small, medium, large, and medium. It is characterized in that the two quadrants having the intermediate lengths Rb and Rd facing each other have similar areas.

In the present invention, since the target wheel is capable of 90 degrees of segmentation recognition, cylinder discrimination is possible immediately after 1 TDC (90 degrees) has elapsed after cranking is determined. It is possible to prevent the injected fuel from wetting and thereby reduce the emission gas.

Description

Target shaft for camshaft sensor with 90 degree split recognition and fuel injection control method at initial start-up

The present invention relates to a camshaft sensor target wheel capable of 90-degree split recognition and a fuel injection control method at initial start-up, in particular, after a cranking determination using a target wheel capable of 90-degree split recognition. Cam position can be determined immediately after 1 TDC (90 degrees) elapsed, that is, cylinder discrimination can be performed. Simultaneous injection for 1 TDC period during initial start-up and sequential injection prevents wetting of injected fuel. Accordingly, the present invention relates to a camshaft sensor target wheel capable of 90-degree split recognition, and a fuel injection control method at initial startup.

The fuel injection of the vehicle gasoline engine employs an electronically controlled system, and a type of injection into the intake manifold is mainly used. The basic principle of the fuel injection is to always apply a constant pressure to the fuel system and open the solenoid valve (ie, the injector) to eject the fuel into the intake manifold.

The control of the electronic fuel injection is to realize the engine's output performance, fuel economy and pollution gas reduction under various driving conditions.For this purpose, the engine's coolant temperature, intake air temperature, intake manifold pressure and atmospheric pressure The air conditioner relay, fuel pump relay, injector, ignition coil, ISC valve, etc. are controlled by the microcomputer based on the detection of the vehicle speed, the throttle opening amount, the crank angle signal, and the like using various sensors.

The control by the computer is largely divided into injection timing control and injection amount control. First, the injection timing control uses the ignition signal of the ignition coil, and the injection amount control creates the basic injection time by the ignition signal and the intake air amount signal of the ignition coil, and simultaneously maintains the injection time by the detection signal from each sensor. Final injection time is set to operate.

If the above-mentioned fuel injection is performed once per engine revolution, the timing of injection is made in synchronism with ignition, so 1 time for 2 ignitions for 4 cylinders and 1 for 3 ignitions for 6 cylinders. Participating at the meeting rate.

On the other hand, the injection amount control generates a signal of the rotation speed based on the signal of the ignition coil, and generates a basic injection signal by using this signal and the intake air amount signal. The computer then changes the weight according to the start / warm, the intake temperature correction, the change in the throttle opening amount by the throttle position sensor (TPS), that is, the weight according to the increase in output, the voltage correction according to the battery voltage level, the suction detected by the MAP sensor. The final injection time for driving the injector is obtained by performing correction such as correction in accordance with the change in air volume.

On the other hand, during the initial start-up, the ECU processes the output signal of the camshaft sensor installed in the camshaft to determine the first cylinder, and sequentially performs the fuel injection control for each cylinder.

Conventionally, a pin type or a hole type has been used as a target wheel in order to obtain an output signal for performing cylinder No. 1 determination in a camshaft sensor.

However, in the conventional target wheel, only one point of 360 degrees is displayed, and therefore, it takes up to one stroke to receive the first cylinder discrimination signal at initial startup. As a result, all the cylinders have to be injected at the same time, so that the fuel injected into each cylinder is wetted.

In order to improve the above-mentioned problem, an improved target wheel capable of recognizing two parts by 180 degrees has been used, but a target wheel capable of identifying the first cylinder more quickly is required.

Accordingly, the present invention has been made in view of the problems of the prior art, and its object is to determine the cam position immediately after the cranking determination by 1 TDC (90 degrees) using a target wheel capable of 90 degree division recognition, that is, a cylinder. Camshaft sensor with 90-degree split recognition that can be discriminated to prevent jetting of injected fuel by simultaneously spraying and sequential injection for only 1 TDC period at initial start-up and thus reducing emissions. To provide a target wheel and a fuel injection control method at initial startup.

1 is a front view showing the shape of the target wheel for camshaft sensor 90 degrees divided recognition according to the present invention,

2 is an output waveform diagram of a sensor detected when the target wheel of FIG. 1 is used;

FIG. 3 is a timing diagram illustrating a cylinder discrimination when 1 TDC has elapsed after the cranking determination using the output waveform of the sensor shown in FIG. 2, and a sequential injection process of each cylinder.

* Description of the symbols for the main parts of the drawings *

41: target wheel 13: camshaft sensor

In order to achieve the above object, the present invention is a camshaft sensor target wheel, the radius consists of four quadrants each of which is changed every 90 degrees, the radius of each quadrant (Ra, Rb, Rc, Rd) is small The two quadrants having the middle, large, and middle lengths, and having opposite radiuses Rb and Rd, have a similar area to each other, and provide a target wheel for a camshaft sensor.

In addition, according to another feature of the present invention, the fuel injection system having a camshaft sensor and a target wheel having a radius of each of the four quadrants each of which the radius is changed every 90 degrees, the radius of each of the quadrants small, medium, large, middle A method of controlling fuel injection at initial startup of a fuel cell, the method comprising: performing simultaneous injection on all cylinders until a first TDC is detected, and before a difference in voltage level and a level change are made between adjacent sections when the TDC is detected; Determining a corresponding cylinder according to the voltage level. According to the determination of the cylinder, the simultaneous injection is stopped, and the individual injection for the cylinder is provided, characterized in that it provides a fuel injection control method during the initial startup.

As described above, in the present invention, since the target wheel can be divided into 90 degrees, the cylinder can be discriminated immediately after 1 TDC (90 degrees) has elapsed after the cranking determination. The injection can be prevented from wetting the injected fuel and the emission gas can be reduced accordingly.

(Example)

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

1 is a front view showing a shape of a camshaft sensor target wheel capable of 90 degree segment recognition according to the present invention, FIG. 2 is an output waveform diagram of a sensor detected when the target wheel of FIG. 1 is used, and FIG. FIG. 2 is a timing diagram illustrating a cylinder discrimination when 1 TDC has elapsed after the cranking determination using the output waveform of the sensor illustrated in FIG. 2, and a sequential injection process of each cylinder.

Referring first to Figure 1, the camshaft sensor target wheel 11 of the present invention is the radius of each change by 90 degrees, the quadrant radius (Ra, Rb, Rc, Rd) of small, medium, large, medium The two quadrants having a length and having opposite lengths of radius Rb and Rd have the same area and shape.

In addition, the camshaft sensor 13 including a light emitting diode and a pair of photodiodes is disposed adjacent to one side of the target wheel 11.

Therefore, the light emitted from the light emitting diode of the sensor 13 is reflected from the target wheel 11 rotating together with the camshaft, and the reflected light proportional to the area of the target wheel is detected through the photodiode, and as shown in FIG. A camshaft position signal having a voltage waveform of the shape is periodically generated.

In addition, since the magnitude of the voltage of the camshaft position signal is changed every 90 degrees, one TDC pulse signal as shown in FIG. 3 (A) can be periodically obtained every time the magnitude is changed by processing the signal. have.

On the other hand, the voltage waveform for the camshaft position signal shown in FIG. 3 (B) has two portions where the voltage magnitude increases and decreases, respectively, so that the first TDC occurs when switching from the intermediate voltage to the lowest voltage. When the transition from the lowest voltage to the intermediate voltage, three times of TDC is generated, when the transition from the middle voltage to the highest voltage, four times of TDC is generated, and when the transition from the highest voltage to the middle voltage, TDC is generated. Can be set.

Therefore, for example, in the case of a four-cylinder engine, the fuel injection and the intake valve of the first cylinder (CYL # 1) are opened in the lowest voltage section (D4-D1) as shown in Figs. Open the fuel injection and intake valve of cylinder 3 (CYL # 3) in (D1-D2), and the fuel injection and intake valve of cylinder 4 (CYL # 4) in the highest voltage section (D2-D3). The fuel injection and the intake valve of the second cylinder (CYL # 2) may be opened in the intermediate voltage section (D3-D4) detected after the highest voltage section (D2-D3).

As a result, when using the camshaft position signal of the present invention, for example, when voltage waveforms are detected in the order shown in Fig. 3 (B), if one TDC pulse signal is generated after the cranking determination is made, Discrimination is possible. That is, since the voltage level is switched from the intermediate voltage section (D3-D4) to the lowest voltage section (D4-D1), it is recognized that the first TDC has been generated. The fuel injection is sequentially controlled by opening the fuel injection and opening the intake valve of the second cylinder in response to the TDC # 2.

In addition, after each fuel injection and intake valve open stroke is completed for each cylinder, the ignition is performed when 1 TDC pulse signal is generated, and the stroke is repeated when the next TDC pulse signal is generated.

Therefore, in the present invention, since the co-injection only needs to be performed during the period of 1 TDC after the cranking determination, the wet phenomenon due to the co-injection of a large amount of fuel does not occur.

As described above, in the present invention, since the target wheel can be divided into 90 degrees, the cylinder can be discriminated immediately after 1 TDC (90 degrees) has elapsed after the cranking determination. The injection can be prevented from wetting the injected fuel and the emission gas can be reduced accordingly.

While specific embodiments of the present invention have been illustrated and described by way of example, the present invention is not limited to the above-described embodiments, and the present invention belongs to those skilled in the art without departing from the spirit of the present invention. Various changes and modifications can be made by those who have

Claims (2)

In the target wheel for camshaft sensors, the radius is composed of four quadrants each of which is changed every 90 degrees, and the radius (Ra, Rb, Rc, Rd) of each of the quadrants has a length of small, medium, large, and medium, A target wheel for a camshaft sensor, characterized in that the two quadrants having opposite lengths Rb and Rd have similar areas. It is composed of four quadrants whose radius is changed every 90 degrees, and the radius of each quadrant is small, medium, large and medium. The method may include: performing co-injection for all cylinders until the first TDC is detected, and determining the cylinders according to the difference between the voltage levels of adjacent sections and the voltage level before the level change is made when the TDC is detected. And stopping the simultaneous injection in accordance with the determination of the corresponding cylinder, and executing individual injection of the corresponding cylinder.