KR20030054502A - A Cold Start Control System for Common Rail-Direct Injection- Diesel Engine - Google Patents

Abstract

PURPOSE: A cold start control system is provided to achieve improved starting ability of engine by detecting the cold start state and heating the fuel being supplied to the common rail during the cold start. CONSTITUTION: A cold start control system comprises a heating bar(12) serving as an output unit, and which is accommodated in a common rail(7) of a diesel engine; a coolant temperature sensor(4) for sensing the temperature of the coolant and a key switch(14) for sensing the start state, wherein the coolant temperature sensor and the key switch serve as an input unit; and a control unit(10) including a cold zone, and which duty-controls supply of power to the heating bar in accordance with the signal input from the coolant temperature sensor. The control unit includes a power supply controller(20) constituted by a power transistor or a rheostat for controlling power supply to the heating bar.

Description

Cold Start Control System for Common Rail Direct Injection Diesel Engine

The present invention relates to a cold start control system for a common rail direct injection diesel engine. More specifically, in a common rail direct injection diesel engine in which a high-pressure fuel is rapidly injected, the fuel is heated and supplied to improve startability. The present invention relates to a cold start control system of a common rail direct injection diesel engine.

In general, unlike the gasoline engine, the exhaust gas characteristics of diesel engines generate dust emissions, that is, soot during incomplete combustion, and the common rail direct injection diesel engines have drastically improved these particulate emissions.

In other words, by directly injecting high-pressure fuel into the cylinder, the combustion efficiency is significantly improved. For this purpose, the high-pressure fuel supply system is used to control the injection state in accordance with the engine driving conditions. Common rails are essential for maintaining fuel.

Exemplary drawing FIG. 1 is a conceptual diagram of a common rail direct injection diesel engine, and includes an engine speed sensor 2, an intake air temperature sensor 3, a coolant temperature sensor 4, and an accelerator pedal position sensor at an input of a control unit 1. (5) Each sensor is connected to monitor the running state of the engine, and the injector 6, which is a high-speed solenoid, is connected to the output stage so that the appropriate fuel injection according to the engine running state is carried out by the common rail 7. .

However, since the engine and fuel are not preheated at low temperature, it is difficult to expect normal combustion efficiency and start-up is stable. Therefore, there is a possibility of excessive emission of pollutants. It was not enough.

In particular, the common rail direct injection diesel engine described above was more severe when the cooled high-pressure fuel was injected directly because it is a high-pressure fuel injection.

Accordingly, an object of the present invention is to provide a cold start control system for a diesel engine that detects a cold start state and heats and supplies fuel in a common rail to improve engine startability.

1 is a conceptual diagram of a common rail direct injection diesel engine,

2 is a block diagram of a cold start control system according to the present invention;

3 is a flowchart of a cold start control system according to the present invention.

-Explanation of symbols for the main parts of the drawings-

4-coolant temperature sensor, 6-injector,

7-common rail, 10-control unit,

12-heated bar, 14-keyswitch,

16-ignition switch, 18-start switch,

20-power supply control means, 22-cold zones,

24-indicator light, 26-instrument panel,

DETAILED DESCRIPTION Hereinafter, the most preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. . Other objects, features, and operational advantages, including the purpose, working effects, and the like of the present invention will become more apparent from the description of the preferred embodiment.

For reference, the embodiments disclosed herein are only presented by selecting the most preferred examples to help those skilled in the art from the various possible examples, the technical spirit of the present invention is not necessarily limited or limited only by this embodiment, Various changes and modifications are possible within the scope without departing from the technical spirit of the present invention, as well as other equivalent embodiments will be found.

1 is a block diagram showing a cold start control system of a diesel engine according to the present invention and Figure 2 is a flow chart of a diesel engine cold start control system according to the present invention, the present invention is a diesel engine common rail as an output means (7) Heated heating bar (12) inserted into the installation: the coolant temperature sensor (4) for detecting the coolant temperature as an input means and the key switch for detecting the starting state (14): a cold set according to the cold state as a control means The heating bar 12 to the start switch 18 contact point after the ignition switch 16 contact of the key switch 14 according to the cooling water temperature inputted from the cooling water temperature sensor 4 compared to this cold zone including the zone. Control unit 10 including a power supply control means 20 so that the heating temperature of the heating bar 12 can be duty-controlled according to the transmission signal of the cooling water temperature sensor 4 and the cold zone until the engine warm-up after the start and the engine warm up. To this Eojin a cold start control system of the common rail direct injection diesel engine.

As described above, the present invention provides a cold start control system that improves startability by heating and supplying fuel during cold start of a common rail direct injection diesel engine.

The present invention for this purpose is a heating bar 12 is built into the common rail (7) as a heating means of the feed fuel.

Considering that the common rail 7 is a fuel distribution site to the injector 6, the position of the common rail 7 is close to the injector 6, and the common rail 7 is a high pressure of about 1350 bar. When the rod-type electric resistance type heating bar 12 is most preferably embedded.

Naturally, the heating bar 12 is connected to a power source through a power supply line, and the control unit 10 controls the power supply line.

The control unit 10 controls the power supply by an input signal from the input means, and the input means are the key switch 14 and the coolant temperature sensor 4.

The key switch 14 is a means for detecting the starting state of the diesel engine, the coolant temperature sensor 4 is a means for detecting the warm-up state of the engine while detecting the cold state from the coolant temperature.

That is, the ignition switch 16 is contacted and at the same time detects the cold state according to the coolant temperature input from the coolant temperature sensor 4, in the cold state, the heating bar 12 is rapidly moved until the start switch 18 is contacted. It is heated.

On the other hand, it is preferable to provide a separate indicator 24 on the instrument panel 26 to indicate to the user that the heating bar is operating in the cold state, which is suitable for interlocking with the indicator of the existing preheating device.

Next, when the start switch 18 is contacted after completion of preheating and the start is completed, the warm-up of the engine is monitored by the signal of the cooling water temperature sensor 4, and the control unit 10 then monitors the temperature of the heating bar 12. It will be controlled.

To this end, the control unit 10, which is a control means, is set to a cold zone to control the power supply to the heating bar 12 in comparison with the input signal of the cooling water temperature sensor 4, and to control the power supply amount to the heating bar. To this end, power supply control means 20 such as a power transistor or a variable resistor is included in the control unit 20.

Therefore, the fuel heating according to the present invention is divided into two, one is the fuel heating in the initial cold state before starting, the other is the fuel heating up to the engine warm-up after starting.

3, the ignition switch 16 is contacted with the key switch 14, and the cooling water temperature sensor 4 transmits a signal for a cold state to the control unit 10. .

The control unit 10 detects the cold state therefrom, and determines the cold state when the coolant temperature is lower than the set value.

When it is determined that the cold state is determined, the control unit 10 heats the heating bar 12 to rapidly heat the fuel filled in the common rail 7, and at the same time, notifies the user of the fuel preheating to the instrument panel 26.

At this time, the fuel preheating may be linked with the existing preheating device, and it is also preferable to set the calorific value of the heating bar such that the fuel of the common rail is heated after the intake air of the existing preheating device is completed.

When the fuel preheating is completed, the user contacts the start switch 18 to complete the start of the engine, and the control unit 10 monitors the warm-up state of the engine from the coolant temperature sensor 4.

That is, duty control is performed through the power supply adjusting means as the engine warms up, and when the engine warm up is completed, the power supply is interrupted to stop the operation of the heating bar.

As described above, according to the present invention, since the heating bar is mounted on the common rail, the control unit rapidly heats the fuel supplied to the common rail during cold startup, thereby improving initial starting performance and reducing the emission of pollutants.

Claims (1)

An electric heating bar 12 inserted into the diesel engine common rail 7 as an output means: a coolant temperature sensor 4 for detecting a coolant temperature as an input means and a key switch 14 for detecting a starting state: a control means The start switch 18 after contact with the ignition switch 16 of the key switch 14 according to the coolant temperature input from the coolant temperature sensor 4 including the cold zone set according to the cold state. Power supply control means 20 so that the heating temperature of the heating bar 12 can be duty-controlled according to the output signal of the cooling water temperature sensor 4 and the cold zone until the contact of the heating bar 12 and the engine warm-up after starting up. Cold start control system of a common rail direct injection diesel engine consisting of a control unit (10) included.