KR100188772B1 - The injection timing adjusting device and method of diesel engine - Google Patents

Abstract

A communication path connecting the high pressure chamber and the low pressure chamber of the control chamber to each other in order to precisely and variably control the fuel injection timing by correcting an error between the target injection timing and the actual injection timing programmed in the electronic control unit (ECU); A timing control valve for opening and closing a communication path, a roller holder rotation angle sensor installed in a roller holder interlocked with the timer piston, and a comparator for calculating a correction value by comparing the signal with a target injection timing of an electronic controller. And an injection timing adjusting device for a diesel engine comprising a controller for turning on / off the timing control valve as a signal of the comparator; According to the injection timing adjusting device, the roller holder rotation angle sensor detects the shift signal of the roller holder, feeds this signal back to the comparator, and compares the target injection timing input from the electronic control device to calculate a correction value. By adjusting the current supplied from the controller to the valve coil as a duty ratio according to the correction value, the timing control valve is turned on / off, thereby adjusting the injection timing of the diesel engine, which enables to control the progress of fuel injection timing repeatedly and precisely. Suggest.

Description

Apparatus and method for adjusting the injection timing of diesel engine

1 is a schematic diagram showing an injection pump of a typical diesel engine.

2 is an enlarged side sectional view of a conventional injection timing adjusting device.

3 is an enlarged view showing the injection timing adjusting device according to the present invention.

* Explanation of symbols for main parts of the drawings

26: roller holder 48A: timer piston

51A: control chamber 52: spring

56: high pressure chamber 57: low pressure chamber

58: communication path 59: timing control valve

60: roller holder rotation angle sensor

[Industrial use]

The present invention relates to an apparatus and a method for adjusting the injection timing of a diesel engine, and more particularly, to compare and analyze the error between the target injection timing programmed in the electronic control unit (ECU) and the actual injection timing fed back, and spraying as the information. The present invention relates to a fuel injection timing adjusting device and a method for accurately changing the timing.

[Prior art]

The fuel device of the diesel engine has a function of injecting fuel at high pressure into high pressure and high temperature air in a combustion chamber.

The torque generated by the engine is determined by the amount of fuel burned, so it is necessary to accurately control the amount of fuel injected into the combustion chamber in order to obtain the desired rotational speed and power.

In addition, the spraying time, the spraying period, the spraying rate and the spraying condition are the time conditions for spraying.

The fuel device of the diesel engine includes a fuel supply pump for pumping fuel in a fuel tank, a governor for adjusting the amount of injected fuel in accordance with the rotational speed of the engine, and an injection timing adjusting means for adjusting the fuel injection timing in accordance with the rotational speed of the engine. It is made of an injection pump comprising a.

FIG. 1 is a schematic diagram of a diesel engine injection pump generally used. A drive shaft 46 is rotatably installed in a housing 22 through which an intake passage 21 is opened, and a drive gear 24 is provided in the drive shaft 46. ) Is coupled to the driven gear 25 on the governor side to transmit rotational force.

One side surface of the drive gear 24 is in contact with the cam plate 29 of the plunger 28 positioned coaxially with the drive shaft 23.

A governor shaft 30 is provided on the driven gear 25 of the governing gear, and a sleeve 31 is installed on the shaft to move in the axial direction, and the sleeve 31 has a flange. 32 is formed, and the flange 32 has a conical weight 33, which is pushed by the sleeve 31 while being opened by centrifugal force.

The end of the sleeve 31 is to be in contact with the start lever 34, the start lever 34 is coupled to the tension lever 35 at one support point.

The pin 36 is coupled to the upper lever of the tension lever 34, which is connected to the control lever 37 and the spring 38 to be pulled.

A finger is coupled to the lower end of the starting lever 34, and the finger is connected to a control spool 39 slidably coupled to the outer circumference of the plunger 28.

The pump chamber in the housing 2 in which these components are installed has a discharge passage 40, in which a fuel cut solenoid valve 41 which controls the supply of fuel is located. The fuel is made to flow into the distribution passage 43 drilled through the plunger 28 through the pressure chamber 42 formed at the end of the plunger 28.

The bypass passage 44 is opened in the distribution passage 43 so that the fuel can be returned to the pump chamber according to the position of the control spool 39, and each nozzle (not shown) is provided through the distribution valve 45. It is configured to adjust the injection amount of the number through).

The timer piston 48 of the injection timing control means 47, which is installed in a direction orthogonal to the drive shaft 46 provided with the drive gear 24, has an inner diameter ring 50 of the roller holder 26 through the pin 49. ) In a radial direction.

2 is a view showing the injection timing control means 47 shown in FIG. 1 in a direction orthogonal to the drive shaft 46. The control chamber 51 is formed integrally with the housing 22, and the control chamber 51 ) Includes a timer piston 48 which is supported by a spring 52 and is urged in one direction.

The control chamber 51 is provided with a first passage 53 so that the timer piston 48 can resist the spring 52 so that the high-pressure side fuel of the pump chamber can be operated, where the spring 52 is located at a low pressure. A second passage 54 on which side fuel acts is established.

The spring 52 is installed between the timer piston 48 via a shim 55 and is installed with another shim 56 between the control chamber 51. do.

The injection timing control means 47 formed in this way has a state of FIG. 2 due to the elastic force of the spring 52 because the fuel pressure has a weak force pushing the timer piston 48 from right to left when the speed of the pump is low. .

However, the higher the speed of the pump, the higher the fuel pressure, so that the piston 48 will move to the left, beating the spring 52 force.

When the timer piston 48 moves to the left and the right as described above, the pin 49 moves together to slightly rotate the roller holder 26 clockwise or counterclockwise.

As the roller holder 26 rotates in the forward and reverse directions as described above, the longitudinal movement of the PAM plate 29 is changed to adjust the injection timing of the fuel.

[Problem trying to solve the invention]

On the other hand, in a vehicle equipped with an electronic control device, as is well known, the fuel injection time is automatically controlled by the target injection time programmed in the electronic control device according to the rotational speed (RPM) of the vehicle.

That is, the fuel injection timing control means by the automatic control method is provided with a passage for communicating the right high pressure chamber and the left low pressure chamber of FIG. 2 described above with a valve means interposed therebetween to open and close the valve means. By controlling the duty ratio of the current supplied to the valve coil according to the target injection timing of the electronic controller, the fuel injection timing is controlled by adjusting the left and right movement of the timer piston 48 and the rotation of the roller holder 26 accordingly. I'm in control.

However, the target injection timing of the above electronic control apparatus has a considerable error between the actual injection timing. For example, a considerable error occurs between the point of top dead center TDC of the cylinder which is the target injection timing and the point of time when the needle valve of the nozzle which is the actual injection timing is opened.

As a result, the error of the fuel injection timing acts to lower the output of the vehicle. In the conventional electric vehicle, a needle lift sensor is installed in the nozzle to overcome this problem, thereby feeding back the variation of the needle valve. The fuel injection timing is variably controlled by comparing and analyzing the target injection timing of the electronic control apparatus and adjusting the valve means of the injection timing control means as the signal analyzed as described above.

However, such a nozzle has to be equipped with a sensor for measuring the displacement of the needle valve, which not only complicates the structure but also requires high technology in manufacturing. In addition, since the sensor of the nozzle is manufactured separately from the injection pump, there is a problem that the reliability is lowered between the injection timing control means installed in the injection pump.

In addition, in order to feed back the signal detected by the needle lift sensor described above and apply it as correction information, a separate external circuit is required.

Accordingly, an object of the present invention is achieved in view of the above-described problems of the prior art, and overcomes the technical difficulties in manufacturing a nozzle having a needle lift sensor, and also detects the actual injection timing in the injection pump. It is to provide the injection timing adjustment device of diesel engine to install and improve the reliability.

In addition, another object of the present invention is to feed back the signal of the actual injection timing of the diesel engine for comparing and analyzing the error with the target injection timing of the electronic control device, and precisely and variably control the injection timing as the information It is to provide a method for adjusting the injection timing.

[Means to solve the problem]

In order to achieve the above object, the present invention comprises the following means.

That is, the present invention provides a roller holder rotation angle sensor on the inner circumferential surface of the roller holder having a roller contacting the cam plate surface interlocked with the plunger to reciprocate the plunger, thereby detecting the actual injection timing. We propose an injection timing adjustment device.

Here, the injection timing adjustment device of the present invention is a comparator for comparing the actual injection timing fed back by the roller holder rotation angle sensor and the target injection timing of the electronic control device to calculate a correction value, according to the signal of the comparator And a controller for controlling the duty ratio of the current supplied to the coil of the valve, and a timing control valve for opening and closing a fuel passage communicating with the high pressure chamber and the low pressure chamber of the control chamber according to the control signal of the controller.

In addition, the present invention feeds back the variation of the roller holder detected by the roller holder rotation angle sensor, that is, the actual injection timing to the comparator, and compare and correct the target injection timing determined by the electronic control device through the comparator After calculating the value, the controller controls the duty ratio of the current supplied from the controller to the valve coil according to the information, and turns on / off the timing control valve so that the high pressure chamber and the low pressure chamber of the control chamber integrally formed in the pump housing communicate with each other. The fuel passage of the diesel engine which variably opens and closes the fuel passage to adjust the timer piston and the rotation of the roller holder interlocked with the timer piston, thereby repeatedly and precisely controlling the fuel injection timing. Suggest a method.

EXAMPLE

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, non-limiting preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 shows a fuel injection timing adjusting device according to the present invention, and reference numeral 22 denotes a pump housing.

51A of control chambers are integrally formed in the said pump housing 22, The timer piston 48A is supported by the spring 52 at one side inside. A sealed cup 55 is provided between the spring 52 and the timer piston 48A.

In addition, the first passage 53A communicates with the control chamber 51A such that the timer piston 48A resists the spring 52 so that the high pressure side fuel of the pump chamber can act on the high pressure chamber 56.

The high pressure chamber 56 is connected to each other via a communication path 58 between the low pressure chamber 57 where the spring 52 is disposed, and the communication path 58 is a timing control valve ( 59) is configured to be openable and closeable.

Here, the timing control valve 59 generally employs a solenoid valve, and the coil of the solenoid valve is supplied with a control current from an electronic controller to control the valve on / off, that is, opening and closing.

That is, when current flows in the valve coil, the solenoid valve 59 is turned on (moved to the lower side of the drawing) to open the communication path 58, and the high pressure fuel supplied from the pump chamber passes through the low pressure chamber 57. By discharging to the inlet side of the pump chamber through the second passage 54A, the timer piston 48A is moved from left to right by the elastic force of the spring 52, and the roller holder 26 interlocking with it is rotated counterclockwise. Let's go.

On the other hand, when the solenoid valve 59 is turned off, the communication path 58 is closed to increase the fuel pressure of the high pressure chamber 56, and the timer piston 48 moves to the left side after winning the spring 52 force. As a result, the roller holder 26 is rotated clockwise.

On the other hand, a roller holder rotation angle sensor 60 is installed in the roller holder 26 interlocked through the timer piston 48A and the pin 49, which means that the amount of rotation of the roller holder 26 is changed. It is provided for detecting the actual injection timing.

The roller holder rotation angle sensor 60 feeds back a signal detected by an electrically connected comparator. In the comparator, the actual injection timing and the electronic control unit (ECU) detected by the roller holder rotation angle sensor 60 are detected. The correction value is calculated by analyzing the error with the target injection timing input from the.

Subsequently, the comparator transmits the correction value to the controller. The controller controls the intermittent pulse wave current flowing through the coil of the solenoid valve 59 as a duty ratio and quickly adjusts the response speed of the valve. It is provided for.

The solenoid valve 59 controlled by the controller in this way controls the timer piston (by precisely controlling the communication path 58 communicating the right high pressure chamber 56 and the left low pressure chamber 57 of the control chamber 51A with each other). The roller holder 26 interlocked with the reciprocating movement of 48A is rotated in the rotational direction or the opposite direction of the drive shaft 46 to advance the injection timing of the fuel.

The fuel injection timing adjusting apparatus of the present invention having such a configuration not only adjusts the timer freely as described above, but also repeatedly adjusts the injection timing, that is, correcting the actual injection timing and the target injection timing. It is possible to precisely control the injection timing.

[Effects of the Invention]

As described above, the present invention provides a roller holder rotation angle sensor on the inner circumferential surface of the roller holder having a roller in contact with the cam plate, detects the actual injection timing and feeds it back to the comparator to the target injection timing By adjusting the timing control valve for controlling the reciprocating movement of the timer piston with a correction value, precise fuel injection timing can be adjusted.

Here, the present invention comprises a roller holder rotation angle sensor integrally mounted in the pump bar, unlike the conventional needle lift sensor is integrated in the pump, it is possible to improve the reliability of the product. .

In addition, according to the present invention, unlike the conventional nozzle is equipped with a needle lift sensor, the structure is complicated and difficult to manufacture, it is easy to manufacture the nozzle by removing the sensor requiring a high technology.

On the other hand, the present invention is not limited to the distribution type fuel injection pump described through the above-described embodiment, it is also applicable to a stand-alone and cavity injection pump.

Claims (2)

An injection timing adjusting device of a diesel engine having an injection timing control means for progressively controlling the timing of injection of fuel when the pumping pressure is increased due to the speed of the engine being increased, the timer piston being supported by a spring in the control chamber. A communication path connecting the high pressure chamber and the low pressure chamber to be disconnected from each other, and the timing of advancing the injection timing by blocking the high pressure fuel supplied from the pump chamber and pushing the timer piston against the spring as it is installed and turned off on the communication path. And a roller holder rotation angle sensor installed on an inner circumferential surface of the roller holder interlocked with the timer piston to detect the actual injection timing, and a signal fed back from the roller holder rotation angle sensor to the target injection of the electronic controller. A comparator for comparing the timing and calculating a correction value, and transmitting a signal of the comparator. Of the injection timing adjustment device of the diesel engine, characterized by yirueojim a controller for turning on / off the timing control valve to control a duty ratio. The roller holder rotation angle sensor detects the shift signal of the roller holder, feeds this signal back to the comparator and compares and analyzes the target injection timing input from the electronic control device to calculate a correction value. By controlling the current supplied to the coil as a duty ratio, the timing control valve is turned on / off, thereby rotating the reciprocating movement of the timer piston and the roller holder interlocked with the timer piston, thereby repeatedly and precisely advancing the fuel injection timing. A method for adjusting the injection timing of a diesel engine, characterized in that the control is made possible.