KR20090027810A - Diesel lng dual fuel system in common rail diesel engine - Google Patents

Abstract

A diesel LNG dual fuel system in a common rail diesel engine is provided to reduce diesel fuel amount and increase LNG fuel amount when a vehicle is driven at high speed. A diesel LNG dual fuel system in a common rail diesel engine comprises: a diesel feed port(100); and a controller(200) electrically connected to a high pressure pump(130), a pressure sensor(150) and an injector(160) of the diesel feed port. The diesel feed port comprises: the high pressure pump compressing the diesel of a diesel tank(110); the pressure sensor sensing the inner pressure of a common rail; the injector spraying the diesel to a cylinder; and a return line(170) returning the remained diesel in the diesel tank.

Description

DIESEL LNG DUAL FUEL SYSTEM IN COMMON RAIL DIESEL ENGINE}

The present invention relates to a diesel LNG blending system of a common rail diesel engine, and more particularly, a common rail diesel which can rapidly reduce soot compared to a conventional common rail diesel engine by burning a fuel formed by mixing diesel and LNG. A diesel LNG horn system of an engine.

In general, a diesel engine has an advantage of obtaining a larger output than a gasoline engine or a gas engine. However, a diesel engine has a larger amount of exhaust gas than a gasoline engine or a gas engine, and NO _X or SO _X that is mixed with the exhaust gas. There is a problem of environmental pollution due to, etc., and also has the disadvantage of being expensive to the gas (LPG, LNG) economically.

Recently, a common rail system of a diesel engine has been commercialized to complement such a general diesel engine, and a conceptual diagram of a common common rail system is shown in FIG. 1. As shown in FIG. 1, the common rail system includes a diesel tank 1, a fuel filter 2, a high pressure fuel pump 3, a common rail 5, a pressure sensor 4, and a rail pressure regulating valve 7. , The injector 6, the electronic control unit (ECU) 9, and the return line 8, pressurizes the fuel supplied from the diesel tank 1 to the required pressure in the high-pressure fuel pump 3. When the pump is conveyed to the common rail 5, the high-pressure fuel stored in the common rail 5 is injected into the cylinder by operating the injector 6 under the control of the ECU 9.

The common rail system of diesel engines allows the engine ECU to precisely inject the appropriate amount of fuel at the right time according to the speed and load, so that efficient combustion is possible, which reduces emissions and improves engine output. There is this.

However, according to the common rail system of the diesel engine, although the emission gas is slightly reduced, the above-mentioned problems of environmental pollution still exist because a certain amount of diesel fuel must be combusted for the engine output.

The present invention has been made to solve the above-described problems, the diesel LNG of the common rail diesel engine that can be burned fuel formed by mixing the diesel and LNG so that the smoke is rapidly reduced compared to the conventional common rail diesel engine The purpose is to provide a mixed system.

The above object of the present invention,

In a system for mixing diesel and LNG in a cylinder of a common rail diesel engine to be combusted together, a diesel tank, a high pressure pump that sucks diesel from the diesel tank and compresses and delivers the diesel at high pressure, and the diesel tank and the high pressure pump A fuel filter disposed between the fuel filter for filtering impurities of the diesel, a common rail for storing the high pressure diesel connected to the high pressure pump, and a pressure sensor mounted on the common rail to sense pressure in the common rail; And an injector connected to the common rail to inject diesel supplied to the cylinder, and a return line connected to the diesel tank and the common rail and returning the remaining diesel injected into the cylinder by the injector to the diesel tank. A diesel supply unit; and electrically connected to the high pressure pump, the pressure sensor, and the injector. It is connected to the control unit; and an intake unit for sucking the air from the outside to supply to the cylinder; and supply the LNG to the intake unit so that the LNG can be supplied with air to the cylinder, but is electrically connected It is achieved by providing a diesel LNG mixing system of the common rail diesel engine comprising a; gas supply unit controlled by the control unit.

According to a preferred aspect of the present invention, the control unit receives data from the first ECU for controlling the high-pressure pump and the injector of the diesel supply unit, the second ECU for controlling the gas supply unit, and the pressure sensor of the diesel supply unit. And a third ECU that modulates the data and transmits the data to the first ECU so that the first ECU controls the injector to adjust the injection amount of diesel injected into the cylinder.

According to a more preferred feature of the invention, the intake unit is combined with the intake pipe and the gas supply unit and the pipe connected to the intake pipe through which air is introduced from the outside, the air and LNG can be mixed, the mixer and And an intake manifold that is coupled and guides the air and LNG to be uniformly distributed to the cylinder.

According to a further preferred feature of the present invention, the gas supply unit is connected to the LNG tank, the vaporizer and the vaporizer supplied to the gas supplied in a liquid state, and the cooling is provided to provide heat to the vaporizer A gas supply shutoff valve installed between the waterline and the carburetor and the intake unit, the gas supply shutoff valve being electrically connected to the second ECU so that supply and blocking of gasified LNG through the carburetor to the intake unit can be controlled; And a pressure reducer installed between the gas supply shutoff valve and the intake unit so that the pressure of the LNG supplied to the intake unit can be adjusted.

According to a further preferred feature of the present invention, the gas supply unit is installed between the pressure reducer and the intake unit, the proportioner is electrically connected to the second ECU so that it can be controlled that the proportional supply of LNG to the intake unit It further includes a null valve.

According to a further preferred feature of the invention, the control unit is connected to the second ECU selection switch for transmitting data for the diesel combustion mode or diesel LNG mixed mode to the second ECU, and the appropriate voltage is applied to the second ECU It further comprises a transformer connected to be supplied.

According to a further preferred feature of the invention, the controller further comprises a lamp connected to the second ECU and indicating the diesel LNG mixed mode mode status.

According to the diesel LNG blending system of the common rail diesel engine according to the present invention, the smoke formed by mixing the diesel and the LNG is combusted, so that the smoke can be drastically reduced as compared to the conventional common rail diesel engine.

In addition, the diesel fuel amount is reduced and the LNG fuel amount is increased during the high-speed driving of the vehicle, so the effect of the reduction of smoke can be maximized, and a larger output can be obtained due to the combustion of high calorie LNG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, this is only to describe in detail enough to be able to easily carry out the invention by those skilled in the art, which does not mean that the technical spirit and scope of the present invention is limited.

2 is a schematic diagram of a diesel LNG blending system of a common rail diesel engine according to the present invention, Figure 3a is a conceptual diagram of a diesel LNG blending system of a common rail diesel engine according to the present invention, Figure 3b is a common according to the present invention It is a block diagram of the diesel LNG mixing system of rail diesel engine.

As shown in FIG. 2, the diesel LNG mixing system of the common rail diesel engine according to the present invention includes a diesel supply unit 100, a control unit 200, an intake unit 300, and a gas supply unit 400. Here, the diesel supply unit 100 supplies diesel to the engine 500, the intake unit 300 supplies air to the engine, and the gas supply unit 400 supplies LNG to the intake unit 300 to intake unit 300. Serves to ensure that air and LNG are simultaneously supplied to the engine 500. Therefore, diesel and LNG may be supplied together to the cylinder of the engine 500, and the supply amount of diesel and LNG is controlled by the controller 200. More detailed features of the diesel supply unit 100, the control unit 200, the intake unit 300, the gas supply unit 400 will be described with reference to Figures 3a and 3b.

As shown in FIGS. 3A and 3B, the diesel supplier 100 serves to supply diesel to the cylinder 510 of the engine 500, and includes a diesel tank 110, a fuel filter 120, and a high pressure. The pump 130, the common rail 140, a pressure sensor 150, an injector 160, and a return line 170 are included. That is, the diesel supplier 100 corresponds to a common rail diesel engine.

Here, the diesel tank 110 is preferably formed of a heat insulating material having a rigidity to block the heat transmitted from the outside, it is preferable that a suitable valve and a safe valve is mounted to prevent excessive pressure generation.

In addition, the fuel filter 120 is provided between the diesel tank 110 and the high pressure pump 130 to purify the diesel before the diesel is supplied to the high pressure pump and to smoothly operate the high pressure pump to filter out impurities of the diesel. Play a role.

In addition, the high pressure pump 130 serves to suck diesel from the diesel tank 110 and compress and discharge the diesel at high pressure. The high pressure pump 130 is a mechanical rotary pump driven by a camshaft and pressurizes the diesel to a pressure of about 1,350 bar. The diesel is transported to the rail 140. The high pressure pump 130 is controlled by the first ECU 210a of the control unit 200.

In addition, the common rail (Common Rail) 140 is to store the high pressure diesel pumped to the high pressure pump 130, and serves to send fuel by the amount injected every time to the injector 160, for preventing backflow A check valve and high pressure sensor can be attached.

In addition, the pressure sensor 150 is mounted on the common rail 140 and serves to detect the pressure in the common rail 140, and measures the fuel pressure of the common rail 140 and transmits it to the control unit 200. The control unit 200 receives this data and uses it as a signal for adjusting the injection amount and injection timing of diesel. That is, the pressure sensor 150 transmits data on the fuel pressure of the common rail 140 to the third ECU 210c of the controller 200, and the third ECU 210c modulates the data, and then the first ECU 210c modulates the data. The injection amount and injection timing of diesel are controlled by transmitting to the ECU 210a so that the injector 160 is controlled by the first ECU 210a. A more detailed description thereof will be described later.

In addition, the injector 160 is connected to the common rail 140 to inject diesel supplied from the common rail 140 into the combustion chamber of the cylinder 510 of the engine 500 according to a signal transmitted from the control unit 200. It is. The injector 160 is composed of an electric solenoid (not shown), a needle (not shown), and a nozzle (not shown), and injects diesel by the control of the controller 200, After the nozzle is opened and injected, the remaining diesel is returned to the diesel tank 110 through the return line 170. On the other hand, the injection timing and injection amount of diesel by the injector 160 is controlled by the first ECU (210a) of the control unit 200, a detailed description thereof will be described later.

On the other hand, the diesel supply unit 100, as shown in Figure 3b, may further include a pressure control valve 180 that serves to adjust the pressure of the common rail 140, the pressure control valve 180 The valve adjusts the pressure of the common rail 140 to the pressure required by the first ECU 210a. The pressure sensor 150 senses the pressure in the common rail 140 and sends data to the third ECU 210c. When transmitting, the third ECU 210b transmits it to the first ECU 210a, and the first ECU 210a receiving the data analyzes the same to control the pressure regulating valve 180. At this time, correction is made according to cooling water temperature, battery voltage and intake temperature, and when the diesel temperature is high, the pressure may be lowered to a specific operating point level to limit the temperature.

The control unit 200 is a high pressure pump 130, a pressure sensor 150 of the diesel supply unit 100, the gas supply shutoff valve 440 of the injector 160 and the gas supply unit 300, the professional valve 460 As shown in FIGS. 3A and 3B, the first ECU 210a, the second ECU 210b, and the third ECU 210c are electrically connected to each other. For example, the selection switch 230 may further include a transformer 240 and a lamp 250.

Here, the first ECU (210a) controls the high pressure pump 130 of the diesel supply unit 100 so that the diesel is pressurized to a high pressure and the injector 160 to control the injection amount and injection timing of the diesel injected into the cylinder Play a role.

In addition, the second ECU 210b serves to control the gas supply unit 400 so that LNG is supplied to the cylinder, and specifically, the gas supply shutoff valve 440 and the professional valve 480 of the gas supply unit 400. It is electrically connected with and transmits and controls the signal. That is, the second ECU 210b controls the gas supply shutoff valve 440 so that LNG is supplied or blocked from the gas supply part 400 to the intake part 300, and also controls the professional valve 460. LNG is proportionally supplied from the gas supply unit 400 to the intake unit 300. In addition, as described below, the second ECU 210b transmits data on the acceleration state received from the accelerator sensor 520 to the third ECU 210c.

In addition, the third ECU 210c transmits data such that the first ECU 210a controls the injector 160 to adjust the injection amount of diesel injected into the cylinder, and is electrically connected to a pressure sensor ( The data about the pressure in the common rail 140 is received from 150 and transmitted to the first ECU 210a so that the first ECU 210a controls the injector 160. At this time, the third ECU 210c transmits the data received from the pressure sensor 150 to the second ECU 210b and receives the data on the acceleration state from the second ECU 210b. The data about the pressure in the common rail 140 received from 150 is modulated and transmitted to the first ECU 210a. Therefore, since the first ECU 210a receives the modulated data from the third ECU 210b and controls the solenoid valve (not shown) of the injector 160, the injection amount of diesel is adjusted regardless of the acceleration state. .

For reference, an accelerator sensor 520 is installed in the engine 500, and the accelerator sensor 520 serves to transmit data on the state of the accelerator to the second ECU 210b. The second ECU 210b receiving the data from the accelerator sensor 520 transmits the data to the third ECU 210c and controls the gas supply unit 400 to supply LNG according to the acceleration state. When LNG is supplied to the cylinder, it is necessary to be adjusted to reduce the injection amount of the diesel supplied to the cylinder, the third ECU (210c) serves to implement this. That is, when the pressure sensor 150 transmits data on the pressure in the common rail 140 to the third ECU 210c, the third ECU 210c modulates the received data as described above, and then the first first. The first ECU 210a controls the injector 160 so as to reduce the injection amount of diesel injected into the cylinder.

In addition, the selector switch 230 is connected to the second ECU 210b to transmit data on the diesel combustion mode or the diesel LNG mixed mode to the second ECU 210b, and the selector switch 230 is diesel LNG. When in mixed mode, the second ECU 210b receiving the signal transmits data to the gas supply unit 400 so that LNG may be supplied. In addition, the transformer 240 serves to supply an appropriate voltage to the second ECU 210b, and the lamp 250 receives a signal from the second ECU 210b to display a state of the diesel LNG mixed mode of the engine. do.

The intake unit 300 serves to suck air from the outside to supply the cylinder 510 of the engine 500, as shown in FIGS. 3A and 3B, the intake pipe 310 and the mixer 320. Including the intake manifold 330, the air is introduced from the outside through the intake pipe 310 and the air is supplied to the cylinder 510 through the intake manifold (330). At this time, it is preferable that a mixer 320 is provided between the intake pipe 310 and the intake manifold 330, and the air and LNG are mixed in the mixer 320. That is, the mixer 320 is connected to the gas supply unit 400 by a pipe so that LNG is supplied from the gas supply unit 400 to the mixer 320, and air and LNG are mixed in the mixer 320 to intake the manifold 330. It is supplied to the cylinder 510 through). Here, the intake manifold 330 serves to uniformly distribute the air and LNG mixed in the mixer 320 to guide the cylinder 510.

The gas supply unit 400 serves to supply LNG to the intake unit 300 to supply the cylinder 510 in a state where air and LNG are mixed in the intake unit 300, as illustrated in FIGS. 3A and 3B. As shown, the LNG tank 410, vaporizer 420, cooling water line 430, gas supply shutoff valve 440, pressure reducer 450, and a professional valve 460.

Here, the LNG tank 410 is a low temperature tank to store the gas at a temperature condition of approximately -163 ℃. Therefore, in the LNG tank 410, LNG is stored in the liquid state, and the liquid fuel is supplied to the vaporizer 420.

And, the vaporizer (Vaporizer) 420 serves to change the LNG supplied in the liquid state from the LNG tank 410 into a gas state to be easily mixed with air. In the vaporizer 420, in order to gasify the liquid LNG, heat must be provided, and for this, a cooling water line 430 is provided. That is, the cooling water line 430 serves to provide heat to the vaporizer 420 and is installed to circulate the engine 500 and the vaporizer 420. Therefore, the liquid LNG may be vaporized into gas by the vaporizer 420 by the hot water discharged from the engine 500, and the cold water, which is deprived of heat from the vaporizer 420, is returned to the engine 500. The cooling water is circulated.

In addition, the gas supply shutoff valve 440 is installed between the vaporizer 420 and the intake unit 300 and serves to control the blocking of supply of LNG, which is gas, to the intake unit 300 via the vaporizer 420. And, it is controlled by the second ECU (210b) of the control unit 200 is electrically connected, when the selection switch 230 of the control unit 200 is the diesel combustion mode, the gas supply shutoff valve 440 is always closed However, when the selector switch 230 is a diesel LNG mixed mode, the opening and closing of the gas supply shutoff valve 440 is controlled according to a signal transmitted from the second ECU 210b so that LNG is supplied or blocked. will be.

The gas regulator 450 is provided between the gas supply blocking valve 440 and the intake unit 300, and the LNG supplied to the intake unit 300 by opening the gas supply blocking valve 440. It plays a role in regulating pressure. More specifically, the pressure reducer 450 serves to lower the pressure of LNG gasified and supplied through the vaporizer 420 to an appropriate pressure.

In addition, a proportional gas control valve 460 is provided between the pressure reducer 450 and the intake part 300 to be lowered to an appropriate pressure by the pressure reducer 450 to the intake part 300. It serves to supply the LNG supplied proportionally, LNG is supplied to the mixer 320 of the intake unit 300 through the professional valve 460. The professional valve 460 is controlled by the second ECU 210b of the controller 200 which is electrically connected. As described above, the accelerator sensor 520 installed in the engine 500 includes the second ECU ( When the data on the state of the accelerator is transmitted to 210b, the second ECU 210b analyzes the data to control the professional valve 460.

Hereinafter will be described the operation of the diesel LNG mixing system of the common rail diesel engine according to the present invention with reference to Figures 3a and 3b. First, when the engine 500 is started, diesel is supplied to the cylinder 510 by the diesel supply unit 100 so that the vehicle is driven. Specifically, the high pressure pump 130 sucks diesel of the diesel tank 110 and feeds it to the common rail 140, and then the pressure sensor 150 provides data on the pressure in the common rail 140. The third ECU 210c transmits the data to the third ECU 210c, and the third ECU 210c transmits the data to the first ECU 210a. The first ECU 210a analyzes the received data so that the injector 160 injects diesel. By controlling the diesel injection is supplied to the cylinder 510 through the injector 160.

Here, when the selection switch 230 of the control unit 200 is selected as the diesel LNG mixed mode, the accelerator sensor 520 transmits data on the state of the accelerator to the second ECU 210b, and the second ECU 210b opens the gas supply blocking valve 440 of the gas supply unit 400 so that LNG is supplied to the mixer 320 of the intake unit 300. At this time, the third ECU 210c receives the data on the acceleration state from the second ECU 210b and modulates the data on the pressure in the common rail 140 received from the pressure sensor 150 to thereby modulate the first. It transmits to the ECU 210a. In addition, the first ECU 210a analyzes the modulated data transmitted from the third ECU 210c to control the solenoid valve of the injector 160 to reduce the diesel injection amount.

Meanwhile, as described above, LNG exists in a liquid state in the LNG tank 410 maintaining approximately −163 ° C., but is gasified by a cooling water circulated through the cooling water line 430 in the vaporizer 420. After being adjusted to an appropriate pressure at 450, it is proportionally supplied to the mixer 320 by a professional valve 460 controlled by a signal transmitted by the second ECU 210b.

When the gas supply shutoff valve 440 is opened, the LNG is supplied through a supply line connected to the mixer 320. At this time, since the LNG supply line is higher than the pressure of the intake unit 300, the LNG is intake unit 300. Sucked into) and mixed with air in the mixer 320 and then uniformly distributed through the intake manifold 330 and supplied to the cylinder 510.

On the other hand, even when the accelerator pedal becomes high speed, as described above, the first ECU 210a because the third ECU 210c modulates and transmits the data received from the pressure sensor 150 to the first ECU 210a. ) Controls the solenoid valve of the injector 160 so that the injection amount of diesel supplied to the cylinder is not increased.

Accordingly, while the amount of diesel supplied to the cylinder 510 is reduced, the amount of LNG is relatively increased. Thus, as the amount of diesel supplied to the cylinder 510 is reduced, NO _X or SO _X generated during combustion of diesel is reduced. In addition, the generation of soot components can be reduced, so that not only the effect of soot reduction can be obtained, but also a larger output can be obtained due to the combustion of high calorie LNG.

1 is a conceptual diagram of a common common rail system.

Figure 2 is a schematic diagram of a diesel LNG mixing system of a common rail diesel engine according to the present invention.

3a is a conceptual diagram of a diesel LNG mixing system of a common rail diesel engine according to the present invention;

Figure 3b is a block diagram of a diesel LNG mixed system of a common rail diesel engine according to the present invention.

※ Explanation of symbols used in main part of drawing

100: diesel supply unit 110: diesel tank

120: fuel filter 130: high pressure pump

140: common rail 150: pressure sensor

160: injector 170: return line

200: control unit 210a: first ECU

210b: second ECU 210c: third ECU

230: selection switch 240: transformer

250: lamp 300: intake portion

310: intake pipe 320: mixer

330: intake manifold 400: gas supply unit

410: LNG tank 420: carburetor

430: cooling water line 440: gas supply shutoff valve

450: pressure reducer 460: professional valve

500: engine 510: cylinder

520: accelerator sensor

Claims (7)

In the system of the diesel and LNG to be mixed together in the cylinder of the common rail diesel engine, A diesel tank, a high pressure pump that sucks diesel from the diesel tank, compresses it to high pressure, and sends it; a fuel filter disposed between the diesel tank and the high pressure pump to filter impurities from diesel; and supplied with the high pressure pump. A common rail for storing high-pressure diesel, a pressure sensor mounted on the common rail to sense a pressure in the common rail, an injector for injecting diesel supplied and connected to the common rail to the cylinder, and the diesel tank A diesel supply unit connected to a common rail and including a return line which returns the remaining diesel injected into the cylinder by the injector to the diesel tank; A control unit electrically connected to the high pressure pump, the pressure sensor, and the injector of the diesel supply unit; An intake unit for sucking air from the outside and supplying it to the cylinder; And And a gas supply unit supplying LNG to the intake unit so that LNG may be supplied to the cylinder together with air, and controlled by the controller which is electrically connected to the diesel LNG blending system of the common rail diesel engine. The method according to claim 1, The control unit includes a first ECU for controlling the high pressure pump and the injector of the diesel supply unit, a second ECU for controlling the gas supply unit, and after receiving data from the pressure sensor of the diesel supply unit, the first ECU controls the injector. And a third ECU for modulating the data to control the injection amount of the diesel injected into the cylinder and transmitting the modulated data to the first ECU. The method according to claim 1 or 2, The intake unit is coupled to the intake pipe and connected to the gas supply unit and the pipe so that the air and the air inflow from the outside, the air and LNG can be mixed, and the mixer and the air and LNG is coupled to the cylinder Diesel LNG mixing system of the common rail diesel engine comprising an intake manifold for guiding to be uniformly distributed. The method according to claim 2, The gas supply unit is connected to the LNG tank and the LNG tank, a vaporizer for gasifying LNG supplied in a liquid state, a cooling water line provided to provide heat to the vaporizer, the vaporizer and the intake unit A gas supply shutoff valve installed between the second ECU so that the supply and blocking of the gasified LNG through the vaporizer to the intake part can be controlled, and the pressure of the LNG supplied to the intake part is controlled. Diesel LNG mixing system of the common rail diesel engine comprising a pressure reducer is provided between the gas supply shutoff valve and the intake portion so as to be possible. The method according to claim 4, The gas supply unit may further include a professional valve installed between the pressure reducer and the intake unit and electrically connected to the second ECU to control the proportional supply of LNG to the intake unit. Common LNG Diesel Engine's Diesel LNG Mixture System. The method according to claim 2, The control unit may further include a selection switch connected to a second ECU to transmit data regarding a diesel combustion mode or a diesel LNG mixed mode to the second ECU, and a transformer connected to supply a proper voltage to the second ECU. Diesel LNG blending system of the common rail diesel engine, characterized in that. The method according to claim 6, The control unit is connected to the second ECU diesel LNG blending system of the common rail diesel engine, characterized in that it further comprises a lamp for indicating the diesel LNG blending mode status.

Images