KR20140117920A - Engine control system for dual fuel engine - Google Patents

Abstract

The present invention relates to an engine control system for a dual fuel engine using an oil fuel and a gas fuel. The engine control system for a dual fuel engine of the present invention comprises: an oil fuel injector (22) for injecting an oil fuel to a combustion chamber; a pilot injector (24) for injecting a pilot fuel; a gas intake valve (26) for injecting a gas fuel to an intake port; a knock sensor (12) installed on each cylinder to sense knock; a combustion pressure sensor (14) installed on each cylinder to sense combustion pressure; an injection control panel (120) which is connected with the pilot injector (24) and the gas introducing valve (26) to control operation; a cylinder monitoring panel (130) which is connected with the knock sensor (12) and the combustion pressure sensor (14) to monitor combustion pressure and the knocking of the cylinder; and a main control panel (100) which controls the operation of a pump and the opening and closing of an oil fuel supplying passage and a gas fuel supplying passage according to an oil fuel or a gas fuel operation mode, determines knock information or cylinder pressure information authenticated by the cylinder monitoring panel (130), and sends a control signal for the pilot injector (24) or/and the gas introducing valve (26) to the injection control panel (120) by a knock removal and cylinder balancing control program.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control system for a dual fuel engine,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a dual fuel large engine using an oil fuel and a gaseous fuel, and more particularly, to an engine control system for a dual fuel engine that monitors internal conditions of the cylinder and effectively performs cylinder balancing.

In a gas carrier such as liquefied natural gas (LNG), gas fuel stored in a storage tank is easily used as fuel, and gas used in the tank is not re-liquefied. And a dual fuel engine that selectively or simultaneously uses gaseous fuel. In the case of large-scale diesel engines used in power generation facilities of offshore structures, marine structures, or plants using gas such as LNG or LPG, dual fuel engines are also introduced that can use gaseous fuels together.

Large diesel engines using dual fuel (diesel engines) are used in a gas fuel operating mode using gaseous fuels, an oil fuel operating mode using oil fuels (eg, Marine Diesel Oil, Heavy Fuel Oil, etc.) And a mixed operation mode in which fuel is simultaneously used.

The oil fuel is injected into the combustion chamber by an oil fuel injector provided in each cylinder head, the gaseous fuel is distributed from the main feed pipe to each cylinder-specific distribution pipe, and the gas amount in the gas admission valve (GAV) assembly Is regulated and injected into the intake port of the cylinder head through the gas injector.

Since the dual fuel engine is based on a diesel engine that self-ignites by compressing the intake air to high temperature and high pressure unlike a gasoline engine that ignites the fuel by spark plug, it induces ignition of the gas fuel And a pilot injector (Micro Pilot Injector) as a small-sized oil fuel injector.

Since gas fuels such as natural gas have a low self-ignition temperature and a high self-ignition temperature of around 550 ° C, just before injecting the main fuel, gaseous fuel in the gas fuel operating mode, A pilot injection process (pilot injection process) by injecting pilot oil (eg, Marine Diesel Oil, Marine Gas Oil, etc.) by injecting a small amount of fuel through the injector can stably ignite the gaseous fuel.

Further, even in the oil fuel operation mode, it is possible to improve the NOx improvement and the combustion performance by improving the combustion environment of the combustion chamber by injecting a small amount of pilot oil through the pilot injector immediately before injecting the diesel fuel as the main fuel.

As described above, in the dual fuel engine, it is necessary to provide a separate supply system for the supply of the two main fuel and the pilot oil, and to operate in two operation modes or more, The control system is also very complicated.

In particular, since the dual fuel engine is based on a diesel engine, precise operation control in the gas fuel mode is a very important factor in determining whether or not it can operate in the gas fuel mode. For example, in the oil fuel operation mode, combustion is caused by compression ignition of the fuel as in a general diesel engine, but in the gas fuel operation mode, pilot injection must be performed in advance to induce ignition of the gaseous fuel. Therefore, even when the ignition timing by the gaseous fuel is set to be the same in the gas fuel operation mode, the advance of the combustion (explosion), the maximum pressure, and the timing of generation of the maximum pressure are different for each cylinder.

Therefore, in the above-described dual fuel engine, balancing control between the cylinders is very important in order to stably maintain the operating characteristics of the engine.

In order to control the balancing between the cylinders, it is an effective method to keep the combustion pressure between the cylinders uniform. That is, the maximum combustion pressure among the cylinders is uniformly maintained, thereby eliminating engine instability such as vibration due to uneven torque, and maximizing the efficiency by uniformly raising the maximum combustion pressure of all the cylinders.

However, in order to uniformly adjust the maximum combustion pressure, it is necessary to detect the combustion pressure and the knocking state for each cylinder. Conventionally, there is no means for measuring and monitoring the internal state of the cylinder (combustion chamber) It is difficult to effectively carry out the present invention.

Published Patent Publication No. 10-2010-0074084 (published on July 1, 2010) Published Patent Publication No. 10-2008-0078504 (Published Aug. 27, 2008) Open Patent Publication No. 10-2004-0095274 (published on November 12, 2004)

Accordingly, the present invention relates to an engine control system for a dual fuel engine that can effectively perform cylinder balancing by measuring and monitoring internal conditions of the cylinder.

In order to achieve the above object, an engine control system of a dual fuel engine according to the present invention is an engine control system of a dual fuel engine using an oil fuel and a gaseous fuel, comprising: an oil fuel injector for injecting an oil fuel into a combustion chamber; A pilot injector for injecting pilot fuel; A gas inflow valve for injecting gaseous fuel into the intake port; A knock sensor installed in each cylinder for sensing a knock; A combustion pressure sensor installed in each cylinder for sensing a combustion pressure; An injection control panel connected to the pilot injector and the gas inlet valve to control the operation; A cylinder monitoring panel, connected to the knock sensor and the combustion pressure sensor, for monitoring the knocking of each cylinder and the combustion pressure; And controls the opening and closing of the oil fuel supply passage and the gas fuel supply passage according to the oil fuel or gas fuel operation mode and determines the knock information or the cylinder pressure information applied from the cylinder monitoring panel and controls knocking and cylinder balancing control program And a main control panel for supplying a control signal for the pilot injector and / or the gas inflow valve to the injection control panel.

In one embodiment, the cylinder monitoring panel receives and monitors a noise signal applied from a knock sensor of each cylinder, and transmits a knock signal acquisition result to a main control panel when a signal related to the knock is captured. ; And the signal of the combustion pressure applied from the combustion pressure sensor of each cylinder is captured and the pressure signal related to the knock is captured and transmitted to the main control panel or the combustion pressure graph for each cylinder is generated, And a combustion monitoring unit for calculating an average combustion maximum pressure of all the cylinders and transmitting them to the main control panel.

In the engine control system of the dual fuel engine according to the present invention, when the main control panel determines that a knock has occurred in a certain cylinder, the main control panel may delay the injection timing of the pilot injection valve and / To reduce the duration of the gaseous fuel injection.

In the engine control system for a dual fuel engine according to the present invention, the main control panel controls a gas fuel injection duration time period for a cylinder in which a pressure deviation exceeding a predetermined value is generated based on combustion pressure information for each cylinder, And to increase or decrease the opening time of the gas inlet valve by bringing it into the gas inlet valve of the cylinder.

According to the engine control system for a dual fuel engine according to the present invention, knock sensors and combustion pressure sensors are provided in cylinders, and information about them is monitored through a cylinder monitoring panel, thereby eliminating knocking, It is possible to effectively perform the control of balancing to make it happen.

It can also improve stability and reliability in a gaseous fuel operation mode of a dual fuel engine based on a diesel engine.

1 is a diagram showing an overall configuration of an engine control system of a dual fuel engine according to the present invention.
2 is a diagram showing a cylinder balancing system of an engine control system of a dual fuel engine according to the present invention.
FIG. 3 is a view for explaining the relationship of monitoring the cylinder knocking state in the cylinder balancing process according to the present invention.
FIG. 4 is a view for explaining the control relationship by monitoring the combustion pressure in the cylinder balancing process according to the present invention.

Hereinafter, an embodiment of an engine control system arrangement structure of a dual fuel engine according to the present invention will be described in detail with reference to the accompanying drawings.

In the present specification and claims, "or / and" are defined to include each and every one or more combinations of the mentioned items.

1 is a diagram showing an overall configuration of an engine control system of a dual fuel engine according to the present invention.

1 shows a large dual fuel engine for a marine or a plant and its control system in which the dual fuel engine 10 is operated in an oil fuel operation mode using oil fuel and a gas fuel operation mode using gas fuel .

The overall control of the dual fuel engine 10 is performed in a main control panel 100 having a central control unit of an engine control system and is controlled by a local operating panel (LOP) Speed and output, air fuel ratio, main fuel supply cutoff, pilot fuel cutoff, fuel mode switching, fuel (fuel injection), fuel injection, and the like are received from the engine 110 and the injection control panel Distribution control, cooling medium temperature, engine operation state calculation, control for engine safety, etc., and performs the cylinder balancing control and the knock control operation according to the present invention.

In order to provide two kinds of fuel, the cylinder head 20 of the dual fuel engine 10 is provided with an oil fuel injector 22 for injecting the oil fuel into the combustion chamber and a pilot injector 24, and a gas inlet valve (GAV) 26 for injecting gaseous fuel into the intake port is provided.

The local operating panel 110 is installed for each individual engine and communicates the respective engine status information and commands with the main control panel 100 while all status values of each engine are displayed and monitored. The local operating panel 110 may also have a touch screen for displaying the measurements of the individual engines and displaying the input or action menu buttons so that the manager can perform monitoring while operating the respective engine have.

The injection control panel 120 is connected with the pilot injector 24 and the high pressure pump for pilot injection as well as with the gas inlet valve 26.

In the present invention, the main control panel 100 controls opening and closing of the oil fuel feed path and the gas fuel feed path and driving of the pump in accordance with the oil fuel or gas fuel operation mode, and controls the overall and individual adjustment signals The injection control panel 120 causes the injection control panel 120 to control the injection timing and the injection duration of the pilot injector 24 and the gas inlet valve 26 (i.e., the injection amount).

In the present invention, each cylinder (i.e., combustion chamber) of the dual fuel engine 10 for the knock control and the cylinder balancing control is provided with a knock sensor 12 for sensing the knock and a combustion pressure sensor 14 for sensing the combustion pressure, Respectively.

The cylinder monitoring panel 130 is connected to the knock sensor 12 and the combustion pressure sensor 14. The cylinder monitoring panel 130 monitors the knock state and the cylinder pressure in real time under the control of the main control panel 100, To the panel (100).

The main control panel 100 performs cylinder balancing control and knock control based on data transmitted from the cylinder monitoring panel 130.

2 is a diagram showing a cylinder balancing system of an engine control system of a dual fuel engine according to the present invention.

Referring to FIG. 2, the cylinder monitoring panel 130 includes a knock monitoring unit 132 for monitoring the knock state (intensity) of each cylinder, and a combustion monitoring unit 134 for monitoring the cylinder-by-cylinder combustion pressure.

The knocking monitoring unit 132 receives a signal for each cylinder knock condition from the knock sensor 12, captures a signal of a level likely to knock in the noise generated in the cylinder, and outputs the acquired result to the main control panel 100 ).

The combustion monitoring unit 134 receives a signal for each cylinder combustion pressure from the combustion pressure sensor 14 to generate a pressure graph and sends the generated information to the main control panel 100, .

In the main control panel 100, a program for knock control and cylinder balancing is set in advance, and knock control and cylinder balancing control are performed based on the knock applied from the cylinder monitoring panel 130 and information on the combustion pressure.

FIG. 3 is a view for explaining the relationship of monitoring the cylinder knocking state in the cylinder balancing process according to the present invention. See FIG. 2 in parallel.

3, the knocking monitoring unit 132 of the cylinder monitoring panel 130 receives and monitors a noise signal applied from the knock sensor 12 of each cylinder, as shown in the right side of FIG. 3, And transmits a knock signal acquisition result to the main control panel 100 when an associated signal is captured.

3, the combustion monitoring unit 134 of the cylinder monitoring panel 130 receives a signal indicative of the combustion pressure applied from the combustion pressure sensor 14 of each cylinder, And transmits the pressure signal acquisition result to the main control panel 100 when the pressure signal related to the knock is captured.

The main control panel 100 performs a control operation for knock canceling by a knock control option (program) when any one of the above-mentioned two knock signals is reached.

For example, when it is judged as knocking, the main control panel 100 slows down the pilot injection timing or decreases the duration of the gas fuel injection until the knock is eliminated.

If the pilot injection timing is delayed, the combustion temperature is lowered and knocking can be eliminated. Thus, when the knocking disappears, the pilot injection timing is advanced to the standard value again.

Reducing the duration of the gas fuel injection reduces the amount of gaseous fuel and makes the mixer lean, thus eliminating knocking. When the knocking disappears, the duration of the gaseous fuel injection is again increased to the standard value.

If it is determined that the knock control is impossible due to the knock intensity being severely set above the set value or knock control is performed but the knocking continues for more than the set time, the gas fuel operation mode is stopped and the diesel mode, Switch to oil fuel operation mode.

4 is a view for explaining a control relationship by monitoring the cylinder combustion pressure in the cylinder balancing process according to the present invention. See FIG. 2 in parallel.

Referring to FIG. 4, as an example of cylinder balancing control by monitoring the combustion pressure, it is assumed that the maximum combustion pressure Pmax between the cylinders is uniform, that is, the maximum combustion pressure of the specific cylinder is equal to the average combustion maximum pressure Pmax-average), so that the difference in the maximum combustion pressure among the cylinders can be controlled.

For this purpose, the combustion monitoring unit 134 receives a signal for each cylinder combustion pressure from the combustion pressure sensors 14 of each cylinder to generate a pressure graph, and based on the generated graph, And the average combustion maximum pressure Pmax-average of all the cylinders, and then transmits the information to the main control panel 100. [

In the main control panel 100, based on the information transmitted from the combustion monitoring unit 134, a signal for increasing or decreasing the duration of the gas fuel injection is generated for a cylinder having a pressure deviation of a predetermined value or more, The combustion maximum pressure of the corresponding cylinder is adjusted by increasing or decreasing the opening time of the gas inlet valve to the gas inlet valve 26 (see FIG. 1).

As described above, according to the present invention, a knock sensor and a combustion pressure sensor are provided in a cylinder, and information on the knock sensor and the combustion pressure sensor is monitored through a cylinder monitoring panel, thereby effectively performing knocking or balancing to uniformize the combustion pressure for each cylinder . It can also improve stability and reliability in a gaseous fuel operation mode of a dual fuel engine based on a diesel engine.

The foregoing is a description of certain preferred embodiments of the present invention. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein, but may be modified and altered without departing from the spirit and scope of the invention as defined in the appended claims.

10: Engine
12: Knock sensor
14: Combustion pressure sensor
20: Cylinder head
22: Oil fuel injector
24: Pilot injector
26: Gas inlet valve (GAV)
100: Main control panel
110: Local operating panel
120: Injection control panel
130: Cylinder monitoring panel
132: Knock monitoring unit
134: Combustion monitoring unit

Claims (4)

An engine control system for a dual fuel engine using oil fuel and gaseous fuel,
An oil fuel injector 22 for injecting the oil fuel into the combustion chamber;
A pilot injector (24) for injecting pilot fuel;
A gas inlet valve (26) for injecting gaseous fuel into the intake port;
A knock sensor 12 installed in each cylinder for sensing a knock;
A combustion pressure sensor 14 installed in each cylinder for sensing the combustion pressure;
An injection control panel 120 connected to the pilot injector 24 and the gas inlet valve 26 to control the operation thereof;
A cylinder monitoring panel (130) connected to the knock sensor (12) and the combustion pressure sensor (14) for monitoring knocking and combustion pressure of each cylinder;
Controls the opening and closing of the oil fuel supply passage and the gas fuel supply passage and the pump driving according to the oil fuel or gas fuel operation mode, judges the knock information or the cylinder pressure information applied from the cylinder monitoring panel 130, And a main control panel (100) for delivering a control signal to the injection control panel (120) by means of a balancing control program to the pilot injector (24) and / or the gas inflow valve (26) Engine control system. The method according to claim 1,
The cylinder monitoring panel (130)
A knock monitoring unit 132 for receiving and monitoring a noise signal applied from the knock sensor 12 of each cylinder and transmitting a knock signal acquisition result to the main control panel 100 when a signal related to the knock is captured; And
A signal about the combustion pressure applied from the combustion pressure sensor 14 of each cylinder is received and a pressure signal related to the knock is captured and transmitted to the main control panel 100 or a combustion pressure graph for each cylinder is generated, And a combustion monitoring unit (134) for obtaining a maximum combustion pressure Pmax of the entire cylinder and an average combustion maximum pressure Pmax-average of the entire cylinder and transmitting the same to the main control panel 100 system. 3. The method according to claim 1 or 2,
The main control panel 100 may be configured to delay the injection timing of the pilot injection valve 24 and / or continue the gas fuel injection continuation of the gas inlet valve 26 until it is determined that a knock has occurred in any cylinder Wherein the controller is configured to perform a control operation to reduce the time. 3. The method according to claim 1 or 2,
The main control panel 100 generates a signal for increasing or decreasing the duration of the gaseous fuel injection for the cylinder in which a pressure deviation of a predetermined value or more is generated based on the combustion pressure information for each cylinder transmitted from the cylinder monitoring panel 130 And to perform a control operation for increasing or decreasing the opening time of the gas inlet valve to the gas inlet valve (26) of the cylinder.

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