KR100384140B1 - Pilot injection control device of common rail type diesel engine and control method thereof - Google Patents

Abstract

The present invention relates to a pilot injection technology of a diesel engine common rail system (CRS).

The present invention measures the actual feedback data of the pilot injection timing map of each cylinder through the vibration signal generated for each cylinder explosion measured by the acceleration sensor, while maintaining the vibration signal increased by the explosion. By obtaining the duration of the start (duration) to find the actual feedback data, when the optimum pilot injection is not made by changing the characteristics of the injector, it compensates for the noise and exhaust characteristics of the vehicle in the initial state of the vehicle It provides a diesel engine common rail type pilot injection compensation control device and its control method to maintain the same and to improve the noise and regulation as well as the vehicle exhaust gas.

Description

Pilot injection control device of diesel engine common rail type and its control method {Pilot injection control device of common rail type diesel engine and control method}

The present invention relates to a pilot injection technology of a common rail system (CRS) of the diesel engine, and in particular, the optimum pilot injection is not made when the characteristics of the injector are changed, thereby compensating the vehicle. The present invention relates to a pilot injection system of a diesel engine common rail-type pilot injection system and a control device thereof and a method for controlling the noise and exhaust gas characteristics to be the same as the initial state of shipment of the vehicle.

As is well known, in diesel engines, combustion noise is a large vector that influences engine noise, and as the high pressure fuel injection is inevitably adopted in accordance with the tightening of the doubling gas regulations, a large increase in the combustion noise increases the high pressure fuel injection system. It has emerged as the biggest challenge to be solved.

At this time, a diesel engine common rail type has been developed. The diesel engine common rail type has been developed to improve noise as well as exhaust gas regulation and performance in the future. It was developed to meet the two goals of the trade off relationship of mitigation.

That is, as shown in Figure 4, the 500Hz to 2.5kHz band that affects the noise is significantly reduced due to the pilot injection can be seen that the noise is reduced to about 8.0dBA in the same rpm region,

The configuration includes a high pressure pump (HPP) required to form a high pressure fuel, a rail for maintaining and forming a required fuel pressure, an injector 10 for injecting fuel as shown in FIG. 3, and a high pressure pump and a rail and an injector ( 10) consists of a pipe for connecting and a sensor for control and the electronic control unit 20 as shown in FIG.

In addition, the operation of the system is such that the fuel is forced to the rail side by a high pressure pump connected to the crank part of the engine, and in the rail, the high pressure is generated by the collected fuel, so that the fuel is discharged at a specific pressure according to the high pressure collected on the rail. Is sent to the injector side.

At this time, the fuel is injected into the engine by the solenoid device inside the injector.

In addition, the pilot injection is performed before the main injection of the fuel, the pilot injection is to inject a small amount of fuel before the main injection in advance to create the atmosphere conditions necessary for the fuel ignition so that a smooth explosion of the engine Therefore, the noise caused by this can be reduced (the noise of the pilot injection is normally reduced by about 2-4 dBA).

That is, the electronic control unit 20 obtains information such as an excel pedal, an engine rpm, an AFS, a vehicle speed, a vehicle stage, a cam angle, a fuel temperature, a rail pressure, a coolant temperature, and the like. By controlling the fuel amount of the pilot injection, it is possible to control the timing of the pilot injection.

Looking at this in more detail as follows.

As shown in FIG. 2, the electronic control unit 20 controls the fuel amount of the pilot according to the measured engine rpm and the position of the accelerator pedal, the rail pressure and the coolant temperature, while the fuel amount, the engine rpm, the cam angle and the coolant are controlled. The timing of pilot injection is controlled according to the temperature of the bar. First, the rail pressure and engine rpm information are read.

After reading the position of the pedal and the temperature of the coolant through the engine rpm information, the fuel amount is determined from the fuel amount map according to the rpm and the pedal of the engine (A), and the fuel amount map according to the engine rpm and the temperature of the coolant. Determine the fuel amount in (B).

Then, after selecting a smaller one from the determined fuel amount of A or B (C), the smaller one selected from the comparison result, comparing the fuel amount (D) determined from the fuel amount map according to the rail pressure obtained from the rail pressure again (E) is determined as the amount of fuel applied for pilot injection.

Therefore, the pilot injection as described above is very important, and the control is also difficult, if the injection is made only a little out of the optimum point, rather than a deterioration of noise as well as a large problem occurs.

Here, the difficulty in pilot injection as described above is that a very small amount of fuel must be injected at an appropriate timing, which is very important for the response and reliability of the injector.

However, this is a problem in the injector, which is not a problem that is a problem for a large amount of fuel injection such as main injection due to the injection characteristic change due to a small amount of fuel leakage (LEAK) and the return spring tension, but a very small amount such as pilot injection The fuel injection has a considerable effect, and the problem that the timing of the pilot injection as well as the characteristics of the fuel amount differ from the map of the electronic control unit 20 has arisen.

The cause of the problem is that if the fuel injection in the injector outputs a specific signal from the electronic control unit 20 to the injector according to the characteristics of the purely on the map of the electronic control unit 20, the injector has a solenoid therein. The fuel is injected by moving the needle NEEDLE according to the voltage input, since there is no conventional method of compensating for the characteristic change of the injector without feedback of the result of the command.

That is, the method of determining the fuel amount and timing of the pilot made in the conventional electronic control unit 20 only selects data on the map determined by the test and determines only by the logic (minimum value selection). As a result, there is a problem of generating a result that is different from the intended characteristic due to the change in the characteristics of the hardware, in particular, the injector.

Accordingly, an object of the present invention is to solve the conventional problems as described above, and an object of the present invention is to provide a pilot injection timing map for each cylinder through a vibration signal generated for each explosion of each cylinder measured from an acceleration sensor. While measuring the actual feedback data, it is possible to obtain the duration of the vibration signal maintained by the explosion and then to obtain the actual feedback data by obtaining the duration when the vibration starts to decrease, thereby making the optimum pilot injection while changing the characteristics of the injector. Compensation for the failure of a diesel engine common rail-type pilot injection compensation control to compensate for this problem and maintain the noise and exhaust characteristics of the vehicle at the same state as the initial vehicle. It is to provide an apparatus and a control method.

1 is a configuration diagram of a conventional diesel engine common rail pilot injection control system.

Figure 2 is a flow chart showing a conventional diesel engine common rail type pilot injection control method.

3 is a configuration diagram of an injector applied to a diesel engine common rail type.

Figure 4 is a graph showing the combustion pressure change when the pilot injection on / off.

5 is a configuration diagram of a diesel injection common rail type pilot injection control system according to an embodiment of the present invention.

6 is a flowchart illustrating a pilot injection control method of a diesel engine common rail type according to an embodiment of the present invention.

FIG. 7 is a graph illustrating a result of reducing noise in the same rpm region as compensating for the pilot injection fuel amount and the injection timing of an injector according to an embodiment of the present invention. FIG.

※ Explanation of symbols for main parts of drawing

10: injector 20: electronic control unit

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

5 is a configuration diagram showing a diesel injection common rail pilot injection system as an embodiment of the present invention.

According to this drawing,

After obtaining information such as an accelerator pedal, engine rpm, AFS, vehicle speed, vehicle number, cam angle, fuel temperature, rail pressure, coolant temperature, and the like, the amount of fuel for pilot injection is controlled through the obtained information. In the configuration comprising an electronic control unit 20 for controlling the timing of the pilot injection,

In addition, an acceleration sensor 21 for recognizing the combustion explosion during engine operation is additionally formed on the top deck of the cylinder.

The electronic control unit 20 measures the feedback data (F) of the current fuel amount for the injector pilot injection timing map of each cylinder through the vibration signal generated for each explosion of the cylinder measured by the acceleration sensor 21, Then, the feedback data (G) of the learning fuel amount for the pilot injection timing of the injector is measured through the persistence when the vibration signal increased due to the explosion is maintained and then begins to decrease, and then the actual feedback data (when F = G) is measured. As a result of measuring the characteristics of the injector, it is characterized in that the pilot injection timing of each cylinder is compared with the feedback data and initial value of the fuel amount, and then the pilot injection timing and the fuel injection amount are adjusted and compensated by the difference value.

And, the pilot injection compensation control method of the diesel engine common rail type through the electronic control unit 20, as shown in Figure 6,

The pilot injection control method controls the pilot fuel amount according to the measured engine rpm, the position of the accelerator pedal, the rail pressure and the coolant temperature, and controls the pilot injection timing according to the fuel amount, the engine rpm, the cam angle and the coolant temperature. In

Measuring feedback data (F) of the current fuel amount for the injector pilot injection timing map of each cylinder through the vibration signal generated for each cylinder explosion measured by the acceleration sensor;

Measuring the feedback data (G) of the learning fuel amount for the pilot injection timing of the injector and then measuring the actual feedback data (when F = G) through the persistence when the vibration signal increased due to the explosion is maintained and begins to decrease. ;

Comparing the injector pilot injection timing of each cylinder with feedback data and an initial value when the characteristic of the injector is changed from the above step, and adjusting and compensating the pilot injection timing and fuel injection amount by the difference value; It is characterized in that the further including.

Referring to Figures 5 and 6 attached to the operation of one embodiment of the present invention configured as described above are as follows.

First, the electronic control unit 20 obtains information such as an accelerator pedal, an engine rpm, an AFS, a vehicle speed, a vehicle stage, a cam angle, a fuel temperature, a rail pressure, a coolant temperature, and the like through the obtained information. While controlling the fuel amount of the pilot injection, it is possible to control the timing of the pilot injection.

That is, the electronic control unit 20 controls the pilot fuel amount according to the measured engine rpm and the position of the accelerator pedal, the rail pressure and the coolant temperature, while the pilot control is performed according to the fuel amount, the engine rpm, the cam angle and the coolant temperature. The timing of injection is controlled. First, the rail pressure and engine rpm information are read.

After reading the position of the pedal and the temperature of the coolant through the engine rpm information, the fuel amount is determined from the fuel amount map according to the rpm and the pedal of the engine (A), and the fuel amount is determined from the fuel amount map according to the engine rpm and the temperature of the coolant. Determine (B).

Then, after selecting a smaller one from the determined fuel amount of A or B (C), the smaller one selected from the comparison result, comparing the fuel amount (D) determined from the fuel amount map according to the rail pressure obtained from the rail pressure again (E) is finally determined as the amount of fuel applied for pilot injection.

In this case, when the characteristic of the hardware changes, that is, the characteristic of the injector changes while traveling over a certain distance (about 20,000 km) after the vehicle is released,

The electronic control unit 20 measures the feedback data F of the current fuel amount for the pilot injection timing map of each cylinder through the vibration signal generated for each explosion of the cylinder measured by the acceleration sensor 21.

That is, the acceleration sensor 21 added to the upper deck portion of the cylinder recognizes the combustion explosion when the engine is operating. This is when the timing of the pilot injection is one cylinder. The cam position sensor and engine rpm signal are used to determine the explosion timing of the cylinder.

Then, the injection timing of the injector can be determined through the explosion timing of the corresponding cylinder.

In this way, the actual feedback data (F) of the pilot injection timing map of each cylinder can be measured. In the case of fuel volume, the sustained vibration signal maintained by the explosion is maintained, and the persistence when it begins to decrease can be measured. The feedback data G of the learning fuel amount is measured.

Then, when the characteristics of the injector are changed, the injector pilot injection timing of each cylinder is compared with the feedback data and the initial value of the fuel amount, and then the pilot injection timing and fuel injection amount are compensated by the difference value as the initial (vehicle shipment point). The noise level of the diesel engine vehicle and the state of exhaust gas can be secured stably.

Here, FIG. 7 is a graph showing the result of reducing the noise in the same rpm region by compensating for the pilot injection fuel amount and the injection timing of the injector through the same method as described above.

As described above, the present invention measures actual feedback data on the pilot injection timing map of each cylinder through vibration signals generated for each cylinder explosion measured by the acceleration sensor, while maintaining the vibration signal increased by the explosion. By obtaining the duration of the start and decrease of the feedback, the actual feedback data can be obtained, so that the optimum pilot injection is not made by changing the characteristics of the injector, thereby compensating for the noise and exhaust characteristics of the vehicle. By maintaining the same condition as the vehicle shipped state, there is an effect to improve the noise and regulation and performance of the vehicle's exhaust gas.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes will fall within the scope of the claims.

Claims (2)

After obtaining information on the accelerator pedal, engine rpm, AFS, vehicle speed, vehicle number, cam angle, fuel temperature, rail pressure, coolant temperature, and controlling the fuel amount of the pilot injection through the obtained information, In the configuration comprising an electronic control unit 20 for controlling the timing of the pilot injection, In addition, an acceleration sensor 21 for recognizing the combustion explosion during engine operation is additionally formed on the top deck of the cylinder. The electronic control unit 20 measures the feedback data (F) of the current fuel amount for the injector pilot injection timing map of each cylinder through the vibration signal generated for each explosion of the cylinder measured by the acceleration sensor 21, Then, the feedback data (G) of the learning fuel amount for the pilot injection timing of the injector is measured through the persistence when the vibration signal increased due to the explosion is maintained and then begins to decrease, and then the actual feedback data (when F = G) is measured. When the characteristics of the injector are changed, the diesel engine common rail is characterized by comparing the pilot injection timing of each cylinder with feedback data and initial values for the fuel amount, and adjusting and compensating the pilot injection timing and fuel injection amount by the difference value. Pilot Injection Compensation Control. The pilot injection control method controls the pilot fuel amount according to the measured engine rpm, the position of the accelerator pedal, the rail pressure and the coolant temperature, and controls the pilot injection timing according to the fuel amount, the engine rpm, the cam angle and the coolant temperature. In Measuring feedback data of a current fuel amount on an injector pilot injection timing map of each cylinder through vibration signals generated for each cylinder explosion measured by the acceleration sensor; Measuring actual feedback data after measuring feedback data of the learning fuel amount with respect to the pilot injection timing of the injector through the persistence when the vibration signal increased by the explosion starts to decrease; Comparing the injector pilot injection timing of each cylinder with feedback data and an initial value when the characteristic of the injector is changed from the above step, and adjusting and compensating the pilot injection timing and fuel injection amount by the difference value; Pilot injection compensation control method of the diesel engine common rail type, characterized in that further comprising.