KR20190073175A - Noise reduction system of engine - Google Patents

Abstract

According to an embodiment of the present invention, a noise reduction system of an engine comprises: the engine including at least two cylinders, injectors injecting fuel into a combustion chamber, and a crankshaft outputting rotation torque; a speed sensor for sensing a rotational speed of the crankshaft; and a controller including a control logic, which detects the rotational speed of the crankshaft in an explosion stroke section for each of the cylinders in which fuel injected from the injector is combusted, calculates acceleration using the respective rotational speed, calculates output torque for each of the cylinders by using the calculated acceleration, and corrects injection characteristics of main injection and pilot injection of the injector to reduce the difference in the output torque for each of the cylinder.

Description

TECHNICAL FIELD [0001] The present invention relates to an engine noise reduction system,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a noise reduction system for an engine that reduces noise generated in an engine under a set condition by varying a fuel injection quantity or the like injected from an injector mounted for each cylinder.

An internal combustion engine is an apparatus for converting thermal energy generated by combustion of fuel into mechanical energy, and can be classified into a gas internal combustion engine, a gasoline internal combustion engine, a diesel internal combustion engine, or the like depending on the fuel to be used. Such internal combustion engines are generally used in automobiles, heavy equipment, ships, generators, and the like.

A compression ignition internal combustion engine in which combustion is generated by a compression ignition system among internal combustion engines generates an axial output using high temperature and high pressure generated by combustion. Particularly, in the case of a compression ignition internal combustion engine having a multi-cylinder, precise control is required so that each cylinder can generate the same average effective pressure, which is related to the degree of generation of harmful exhaust emissions generated in the internal combustion engine, Fuel consumption efficiency, vibration, and noise.

On the other hand, in this compression ignition internal combustion engine, an abnormal combustion process, that is, knocking may occur due to spontaneous ignition of an unburned mixture that has not yet reached the flame surface. Long-lasting knocking can damage parts of the combustion chamber due to increased heat load and the generation of pressure waves.

An important parameter affecting the knocking tendency of the internal combustion engine is the ignition timing. When the fuel air mixer in the combustion chamber is ignited too early, knocking combustion occurs. Therefore, after the knocking process is detected in the internal combustion engine, there is a method of delaying the ignition timing as a possible measure to prevent knocking in the subsequent combustion. However, since too late ignition causes efficiency loss, a knocking control device for detecting whether or not knocking combustion has occurred is used in the internal combustion engine.

The knocking control should be carried out at maximum safety to ensure combustion stability and to prevent damage to the internal combustion engine and with high accuracy to obtain maximum efficiency. Therefore, there is an increasing need for combustion phase control in order to secure the stability of combustion and reduce the emission of harmful exhaust gas.

Generally, as a method for controlling the combustion phase, the total heat generation amount is obtained by using the formula for obtaining the pressure and the heat generation amount in the combustion chamber and the specific heat generation amount is used (for example, 50% of total heat generation: MFB50) A method of detecting the combustion phase is used.

In order to perform the above-described method of analyzing the heat generation amount, a combustion pressure sensor for obtaining the pressure in the combustion chamber is mounted on the engine cylinder. However, when the combustion pressure sensor is mounted on one cylinder, the combustion state of the other cylinders may be deteriorated because the combustion phase information on the other cylinders not equipped with the combustion pressure sensor is not known accurately. There is a problem in that the cost increases.

The matters described in the background section are intended to enhance the understanding of the background of the invention and may include matters not previously known to those skilled in the art.

An object of the present invention is to provide an engine noise reduction system capable of effectively reducing noise generated in an engine by correcting a fuel injection quantity injected from an injector mounted for each cylinder.

An engine noise reduction system according to an embodiment of the present invention includes an engine having at least two cylinders and an injector injecting fuel into each of the combustion chambers and having a crankshaft outputting a rotational torque, And a crankshaft rotation speed in an explosion stroke section for each cylinder in which the fuel injected from the injector is combusted, calculates an acceleration using each of the rotation speeds, And a controller having a control logic for calculating an output torque per cylinder and correcting injection characteristics of the main injection and the pilot injection of the injector so that the difference in output torque per cylinder is reduced.

The injection characteristic may include an injection amount.

The controller can correct the injection characteristic in a low speed region in which the rotational speed of the crankshaft is equal to or less than a set value.

The controller can correct the injection characteristic in a low torque region where the output torque of the crankshaft is equal to or lower than a set value.

The injection amount may be corrected according to preset data.

The injection amount of the pilot injection may be corrected in proportion to the correction amount corresponding to the injection amount of the main injection.

The pilot injection may be injected earlier than the main injection at a predetermined time interval.

The injector may inject diesel.

The injection characteristic may include an injection timing, and the controller may perform control logic to advance or retard the timing of the main injection or the pilot injection.

The noise reduction method for an engine according to an embodiment of the present invention includes the steps of sensing a rotation speed of a crankshaft of an engine, calculating a rotation acceleration in a cylinder-by-cylinder expansion stroke using the sensed rotation speed, And correcting the injection amount of the pilot injection and the main injection of the injector so that the difference between the calculated torques of the cylinders is reduced.

The main injection of the injector and the injection amount of the pilot injection can be corrected under the condition that the rotational speed and the output torque of the crankshaft of the engine are respectively equal to or less than the set values.

The injection amount of the pilot injection may be corrected in proportion to the correction amount corresponding to the injection amount of the main injection.

The noise reduction system of the engine according to the embodiment of the present invention can optimize the NVH sound quality performance by correcting the injection amount of the main injection and the pilot injection to effectively reduce the noise generated in the engine.

In particular, the acceleration is calculated at the rotational speed of the engine, the output torque for each cylinder is calculated using the calculated acceleration, the injection amount of the main injection and the pilot injection is corrected so that the difference value of the torque is reduced, .

1 is a configuration diagram of an engine noise reduction system according to an embodiment of the present invention.
2 is a general control flowchart of an engine noise reduction system according to an embodiment of the present invention.
3 is a flowchart illustrating a method of controlling a noise reduction system of an engine according to an embodiment of the present invention.

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

It is to be understood, however, that the present invention is not limited to the illustrated embodiments, and that various changes and modifications may be made without departing from the spirit and scope of the invention. .

In order to clearly illustrate the embodiments of the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the entire specification.

In the following description, the names of the components are denoted by the first, second, etc. in order to distinguish them from each other because the names of the components are the same and are not necessarily limited to the order.

1 is a configuration diagram of an engine noise reduction system according to an embodiment of the present invention.

Referring to FIG. 1, the system includes a controller 100 and an engine 130, which includes an injector 110 and a speed sensor 120.

The injector 110 is provided for each cylinder, and is configured to inject fuel into each cylinder. The speed sensor 120 senses the rotational speed of the crankshaft of the engine 130.

The speed sensor 120 includes a tooth that rotates together with the crankshaft, and a sensing unit that senses the tooth. The parts not described in the present invention refer to known technologies.

The controller 100 controls the injector 110 installed for each cylinder according to the driving information to inject fuel, and can correct the fuel injection amount and timing.

The injector 110 performs main injection and pilot injection, and the pilot injection is injected faster than the main injection.

The controller 100 senses the rotational speed of the output side of the engine 130 sensed by the speed sensor 120, that is, the rotational speed of the crankshaft, and calculates rotational acceleration using the sensed rotational speed. Then, the controller 100 calculates a torque output in the expansion stroke of each cylinder by using the calculated rotation acceleration.

Here, the controller 100 can calculate the torque per cylinder by using the rotational speed of the crankshaft in the region including the expansion stroke for each cylinder to calculate the torque per cylinder.

In the embodiment of the present invention, the controller 100 compares the torques of the cylinders with each other, and corrects the injection amount or the injection timing of the main injection and the pilot injection, which are injected from the injector 110, can do.

For example, when the output torque of the first cylinder is 10, the output torque of the second cylinder is 11, the output torque of the third cylinder is 12, and the output torque of the fourth cylinder is 12, The main injection amount can be controlled so that the overall output torque reaches 12 by increasing the setting ratio.

Here, the controller 100 may correct the injection amount or injection timing of the main injection.

The controller 100 may be implemented by one or more microprocessors operating according to a set program, and the set program may include a series of instructions for performing a method according to an embodiment of the present invention to be described later.

2 is a general control flowchart of an engine noise reduction system according to an embodiment of the present invention.

Referring to FIG. 2, the controller 100 senses the rotational speed of the crankshaft of the engine 130 through the speed sensor 120 in S200.

In S210, the controller 100 calculates the rotational speed of the crankshaft by cylinder, and in S220, the controller 100 calculates the rotational acceleration of the crankshaft in the region corresponding to the cylinder-by-cylinder expansion stroke (explosion stroke).

In S230, the controller 100 calculates the torque generated in the expansion stroke of each cylinder by using the rotation acceleration value. Here, there is a certain equation between the torque and the acceleration, and the description of this relation is physically / chemically obvious, so it is omitted.

In S240, the controller 100 calculates the difference value of the torque corresponding to the cylinder-by-cylinder expansion stroke, and controls the fuel injection amount of each cylinder injector 110 so that the difference value is reduced. Here, the controller 100 may correct the injection amount of the main injection or the pilot injection of the injector 110, respectively, or correct the injection timing.

3 is a flowchart illustrating a method of controlling a noise reduction system of an engine according to an embodiment of the present invention.

Referring to FIG. 3, the controller 100 starts the control at S300.

In S310, the controller 100 detects or receives the driving information. Here, the driving information includes the RPM of the engine 130, the engine output torque, the fuel injection amount of the injector 110, the pilot injection amount and timing, the main injection amount and timing, the cooling water ON, . ≪ / RTI >

In step S320, the controller 100 determines whether the sound quality improvement condition of the engine 130 is satisfied. Here, the sound quality improvement condition can be satisfied with a low load condition in which the RPM is within the set value and the output torque of the engine 130 is within the set value. For example, in the idling state of the engine 130, the sound quality improvement condition can be satisfied.

If the condition of S320 is satisfied, S330 is performed, and if the condition of S320 is not satisfied, S380 is performed.

In S330, the controller 100 senses the rotational speed of the crankshaft of the engine 130 via the speed sensor 120 and calculates the rotational acceleration.

In S340, the controller 100 calculates the torque per cylinder in the expansion stroke of each cylinder. In S350, the controller 100 calculates the difference value between the torque per cylinder and the reference value.

In step S360, the controller 100 determines whether the difference value is larger than the set value. If the condition of S360 is satisfied, the controller 100 performs step S370. If the condition of S360 is not satisfied, the controller 100 performs step S380.

In S370, the controller 100 corrects the fuel injection amount / injection timing of the injector 110 so that the cylinder-by-cylinder difference value is reduced. In S380, the controller 100 determines whether the start-off condition of the engine is satisfied. If the condition of S380 is satisfied, the controller 100 ends the control at S390, and if the condition of S380 is not satisfied, the controller 100 performs S310 again.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, And all changes to the scope that are deemed to be valid.

100: controller 110: injector
120: speed sensor 130: engine

Claims (12)

An engine having at least two cylinders, a crankshaft having injectors injecting fuel into the combustion chamber, respectively, and outputting a rotational torque;
A speed sensor for sensing a rotational speed of the crankshaft; And
A crankshaft rotational speed detecting means for detecting a rotational speed of the crankshaft in an explosion stroke section for each cylinder in which the fuel injected from the injector is burnt, calculating an acceleration using each of the rotational speeds, And a control logic for correcting injection characteristics of the main injection and the pilot injection of the injector so that a difference in the output torque per cylinder is reduced. Wherein the noise reduction system comprises: The method according to claim 1,
Wherein the injection characteristic includes an injection amount. The method according to claim 1,
The controller comprising:
And the injection characteristic is corrected in a low speed region where the rotational speed of the crankshaft is equal to or less than a set value. The method according to claim 1,
The controller comprising:
And the injection characteristic is corrected in a low torque region where the output torque of the crankshaft is equal to or lower than a set value. 3. The method of claim 2,
Wherein the injection amount is corrected in accordance with preset data. 6. The method of claim 5,
Wherein the injection amount of the pilot injection is corrected in proportion to a correction amount corresponding to the injection amount of the main injection. The method according to claim 1,
Wherein the pilot injection is first injected at a predetermined time interval than the main injection. The method according to claim 1,
Wherein the injector injects diesel. The method according to claim 1,
Wherein the injection characteristic includes an injection timing,
Wherein the controller performs control logic to advance or retard the timing of the main injection or the pilot injection. Sensing a rotational speed of the crankshaft of the engine;
Computing rotational acceleration in the expansion stroke of each cylinder using the sensed rotational speed;
Calculating a torque per cylinder using the calculated rotational acceleration; And
Correcting the injection amount of the main injection and the pilot injection of the injector so that the difference between the calculated torques of the cylinders is reduced; The noise reduction method of the engine performing the noise reduction method. 11. The method of claim 10,
Wherein the main injection of the injector and the injection amount of the pilot injection are corrected under the condition that the rotational speed and the output torque of the crankshaft of the engine are respectively equal to or less than the set values. 11. The method of claim 10,
Wherein the injection amount of the pilot injection is corrected in proportion to a correction amount corresponding to the injection amount of the main injection.

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