KR102335332B1 - Fuel reforming system using a supercharger - Google Patents

Abstract

A fuel reforming system according to an embodiment of the present invention includes an engine generating mechanical power by burning reformed gas, an intake line connected to the engine and supplying reformed gas and air to the engine, and the engine is connected and is provided in an exhaust line for distributing exhaust gas discharged from the engine and an exhaust gas recirculation (EGR) line branching from the exhaust line, mixing the exhaust gas with fuel, and reforming the fuel mixed with the exhaust gas a fuel reformer, branched from the intake line, a first bypass line provided to bypass and supply external air to the engine by a bypass valve, and a first bypass line provided in the first bypass line, the external air a supercharger for supplying the compressed air to the engine, a second bypass line connecting the supercharger and the fuel reformer to communicate compressed air from the supercharger to the fuel reformer, and operating conditions of the engine and an air supply control unit configured to control a path through which external air is supplied to the engine by controlling the bypass valve based on the .

Description

Fuel reforming system using supercharger {FUEL REFORMING SYSTEM USING A SUPERCHARGER}

The present invention relates to a fuel reforming system using a supercharger, and more particularly, to a fuel reforming system capable of controlling a path of compressed air, including a supercharger that compresses external air and supplies it to an engine.

In general, an exhaust gas recirculation (EGR) system is a system mounted on a vehicle to reduce harmful exhaust gases.

This exhaust gas recirculation system functions to circulate a part of exhaust gas discharged from the engine to the intake air to reduce the amount of oxygen in the mixture, reduce the amount of exhaust gas, and reduce harmful substances in the exhaust gas.

In addition, since the exhaust gas discharged from the engine is at a high temperature, the efficiency of the engine can be improved by utilizing its thermal energy.

Meanwhile, a fuel reformer is a device for changing fuel characteristics using a catalyst, and the fuel reformer may be applied to increase combustion efficiency or to activate a post-treatment device.

However, under some engine operating conditions, sufficient hydrogen production may not be achieved due to insufficient oxygen supply required for reforming by the partial oxidation reaction of the reforming catalyst, thereby reducing reforming efficiency.

The present invention was developed to solve this problem, and by providing an electric supercharger in the intake line of the fuel reforming system, the path of intake air is changed according to engine operating conditions, thereby increasing the reforming efficiency of the fuel reforming system. To provide a fuel reforming system that can

A fuel reforming system according to an embodiment of the present invention includes an engine generating mechanical power by burning reformed gas, an intake line connected to the engine and supplying reformed gas and air to the engine, and the engine is connected and is provided in an exhaust line for distributing exhaust gas discharged from the engine and an exhaust gas recirculation (EGR) line branching from the exhaust line, mixing the exhaust gas with fuel, and reforming the fuel mixed with the exhaust gas a fuel reformer, branched from the intake line, a first bypass line provided to bypass and supply external air to the engine by a bypass valve, and a first bypass line provided in the first bypass line, the external air a supercharger for supplying the compressed air to the engine; a second bypass line connecting the supercharger and the fuel reformer to communicate compressed air from the supercharger to the fuel reformer; and operating conditions of the engine and an air supply control unit configured to control a path through which external air is supplied to the engine by controlling the bypass valve based on the .

On the other hand, in the fuel reforming system according to an embodiment of the present invention, a compressor connected to the intake line and compressed to supply the reformed gas and air to the engine, and connected to the exhaust line and installed with the exhaust gas It further includes a turbine that is rotated to generate power.

Meanwhile, the fuel reforming system according to an embodiment of the present invention may further include a catalyst disposed in the exhaust line behind the EGR line and purifying nitrogen oxides contained in the exhaust gas.

The catalyst occludes nitrogen oxides contained in exhaust gas in a lean atmosphere, desorbs nitrogen oxides stored in a rich atmosphere, and reduces nitrogen oxides or desorbed nitrogen oxides contained in exhaust gas. It may include an oxide storage catalyst (Lean NOx Trap; LNT).

The catalyst may include a selective reduction catalyst (Selective Catalytic Reducer; SCR) for reducing nitrogen oxides contained in exhaust gas using a reducing agent.

An EGR cooler for cooling the reformed gas, and an EGR valve provided at a rear end of the EGR cooler to control the flow rate of the reformed gas may be installed in the EGR line.

The fuel reformer may be installed in front of the EGR cooler in the EGR line.

The air supply control unit may control the bypass valve to be opened or closed based on an operating condition of the engine.

The air supply control unit may control the bypass valve to close when the operating condition of the engine is a low load region.

The air supply control unit may control the bypass valve to be opened and external air to be introduced into the supercharger through the first bypass line when the operating condition of the engine is a heavy load or a high load region.

The air supply control unit may control the air compressed in the supercharger to flow into the fuel reformer through the second bypass line when the driving condition of the engine is a heavy load region.

The operating conditions of the engine may be revolutions per minute (RPM) and engine load (torque) of the engine.

According to an embodiment of the present invention, by providing an electric supercharger in the intake line of the fuel reforming system, the reforming efficiency of the fuel reforming system is increased by differently controlling the path of intake air supplied to the engine according to engine operating conditions. can do it

1 is a diagram schematically showing a fuel reforming system according to an embodiment of the present invention.
2 is a graph illustrating an intake air path according to an engine operating condition of a fuel reforming system according to an exemplary embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. The present invention may be embodied in several different forms and is not limited to the embodiments described herein.

In addition, in various embodiments, components having the same configuration are typically described in one embodiment using the same reference numerals, and only configurations different from the one embodiment will be described in other embodiments.

It is noted that the drawings are schematic and not drawn to scale. Relative dimensions and proportions of parts in the drawings are exaggerated or reduced in size for clarity and convenience in the drawings, and any dimensions are illustrative only and not limiting. In addition, the same reference numerals are used to indicate similar features to the same structure, element, or part appearing in two or more drawings. When a part is referred to as being “on” or “on” another part, it may be directly on the other part or the other part may be involved in between.

The embodiment of the present invention specifically represents one embodiment of the present invention. As a result, various modifications of the diagram are expected. Accordingly, the embodiment is not limited to a specific shape of the illustrated area, and includes, for example, a shape modification by manufacturing.

Hereinafter, a fuel reforming system according to an embodiment of the present invention will be described with reference to FIG. 1 .

1 is a diagram schematically showing a fuel reforming system according to an embodiment of the present invention.

Referring to FIG. 1 , the fuel reforming system 100 includes an engine 10 , an intake line 5 , an exhaust line 15 , a fuel reformer 20 , a first bypass line 16 , It includes a supercharger 40, a second bypass line 18, and an air supply control unit (not shown).

The engine 10 converts chemical energy into mechanical energy by burning a mixture of fuel and air. The engine 10 is connected to the intake manifold to receive air into the combustion chamber, and exhaust gas generated in the combustion process is collected in the exhaust manifold and then discharged out of the engine 10 . An injector is installed in the combustion chamber to inject fuel into the combustion chamber.

A diesel engine is exemplified here, but a lean burn gasoline engine may be used. In the case of using a gasoline engine, the mixture is introduced into the combustion chamber through the intake manifold, and a spark plug for ignition is mounted on the upper portion of the combustion chamber. In addition, when a gasoline direct injection (GDI) engine is used, the injector is mounted on the upper part of the combustion chamber like a diesel engine.

Also, various compression ratios, preferably the engine 10 having a compression ratio of 16.5 or less can be used.

The intake line 5 is connected to the inlet of the engine 10 and supplies reformed gas and air to the engine 10 , and the exhaust line 15 is also connected to the outlet of the engine 10 and is discharged from the engine 10 . circulate exhaust gas.

A portion of the exhaust gas discharged from the engine 10 through the EGR line 17 is re-supplied to the engine 10 . In addition, the EGR line 17 is connected to the intake manifold of the engine 10 so that a portion of the exhaust gas is mixed with air to control the combustion temperature. This control of the combustion temperature is performed by adjusting the amount of exhaust gas supplied to the intake manifold. Accordingly, the EGR line 17 may be equipped with an EGR valve 26 for controlling the flow rate of the reformed gas.

The exhaust gas regeneration system implemented by the EGR line 17 supplies a portion of the exhaust gas to the intake system of the engine 10 when it is necessary to reduce the emission amount of nitrogen oxides according to the operating state of the engine 10 . When introduced into the combustion chamber, the exhaust gas, which is an inert gas whose volume does not change, relatively lowers the density of the mixture, thereby lowering the flame propagation speed during fuel combustion. The production of nitrogen oxides is suppressed.

The fuel reformer 20 is provided in the EGR line 17 branched from the exhaust line 15 , mixes the EGR gas introduced through the EGR line 17 with fuel, and reforms the fuel in which the EGR gas is mixed.

The fuel reformer 20 may include an inlet through which the EGR gas is introduced, a mixing unit through which the EGR gas and fuel are mixed, a reforming unit for reforming fuel, and an outlet through which the reformed gas is discharged.

The first bypass line 16 may be branched from the intake line 5 , and may be provided such that external air is bypassed and supplied to the engine 10 by the bypass valve 4 .

The first bypass line 16 includes a supercharger 40 that compresses external air and supplies it to the engine 10 . The supercharger 40 may be an electric supercharger 40 .

The second bypass line 18 connects between the supercharger 40 and the fuel reformer 20 , and communicates air compressed in the supercharger 40 to the fuel reformer 20 .

On the other hand, the fuel reforming system 100 according to an embodiment of the present invention is installed connected to the intake line 5 and compressed to supply reformed gas and air to the engine 10 by means of a compressor 6 , and an exhaust line ( 15) may further include a turbine 7 that is installed to be rotated by exhaust gas to generate power.

In addition, it may include an intercooler 8 that is connected to the compressor 6 and re-cools the air and reformed gas flowing into the intake line 5 of the engine 10 and a throttle valve 9 that adjusts the flow rate.

In addition, the fuel reforming system 100 according to an embodiment of the present invention is disposed in the exhaust line 15 behind the EGR line 17 and further adds a catalyst 30 for purifying nitrogen oxides contained in the exhaust gas. may include

The catalyst 30 occludes nitrogen oxides contained in exhaust gas in a lean atmosphere, desorbs nitrogen oxides occluded in a rich atmosphere, and reduces nitrogen oxides or desorbed nitrogen oxides contained in exhaust gas. It may include a nitrogen oxide storage catalyst (Lean NOx Trap; LNT). The nitrogen oxide storage catalyst may oxidize carbon monoxide (CO) and hydrocarbons (HC) contained in exhaust gas. Here, it should be understood that the hydrocarbon refers to both a compound composed of carbon and hydrogen contained in exhaust gas and fuel.

In addition, the catalyst 30 may include a selective reduction catalyst (Selective Catalytic Reducer; SCR) for reducing nitrogen oxide contained in the exhaust gas by using a reducing agent. The reducing agent may be urea (urea) injected from the injection module.

An exhaust pressure control valve 32 for controlling the flow rate of exhaust gas may be provided in the exhaust line 15 at the rear end of the catalyst 30 .

Meanwhile, the EGR line 17 may be provided with an EGR cooler 25 for cooling the reformed gas, and an EGR valve 26 provided at a rear end of the EGR cooler 25 to control the flow rate of the reformed gas.

In this case, the fuel reformer 20 may be installed in front of the EGR cooler 25 of the EGR line 17 .

Meanwhile, the air supply control unit controls a path through which external air is supplied to the engine 10 by controlling the bypass valve 4 based on the operating conditions of the engine 10 . At this time, the operating conditions of the engine are

The air supply control unit may control the bypass valve 4 to be opened or closed based on the operating conditions of the engine 10 .

2 is a graph illustrating an intake air path according to an engine operating condition of a fuel reforming system according to an exemplary embodiment of the present invention.

1 and 2 , when the operating region of the engine 10 is a low load region (region A), that is, when the engine torque is low or the engine speed is small, the air supply control unit may control the bypass valve 4 It can be controlled to close. Accordingly, the outside air is supplied to the compressor 6 and the engine 10 along the path A.

When the operating condition of the engine is a heavy load region (region C) or a high load region (region B), the air supply control unit may control the bypass valve 4 to open. Accordingly, external air may be introduced into the supercharger 40 through the first bypass line, and air compressed in the supercharger 40 may flow along the path C or the path B.

When the driving condition of the engine is the heavy load region (region C), air compressed in the supercharger 40 may be introduced into the fuel reformer 20 through the second bypass line 18 .

External air is compressed in the supercharger 40 only when the driving condition of the engine is in the heavy load region, that is, when the engine has an appropriate engine torque and an appropriate engine speed, and the compressed air flows into the fuel reformer 20 to generate fuel It is possible to efficiently use the reformer 20 and to improve fuel reforming efficiency.

As described above, by providing the electric supercharger in the intake line of the fuel reforming system, the reforming efficiency of the fuel reforming system can be increased by differently controlling the path of intake air supplied to the engine according to engine operating conditions.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and it is easily changed by a person skilled in the art from the embodiment of the present invention to equivalent Including all changes to the extent recognized as being

4: Bypass valve 5: Intake line
6: Compressor 7: Turbine
8: intercooler 9: throttle valve
10: engine 15: exhaust line
16: first bypass line 17: EGR line
18: second bypass line 20: fuel reformer
25: EGR cooler 26: EGR valve
30: catalyst 32: exhaust pressure control valve
40: supercharger 100: fuel reforming system

Claims (12)

an engine generating mechanical power by burning reformed gas;
an intake line connected to the engine and supplying reformed gas and air to the engine;
an exhaust line connected to the engine and configured to distribute exhaust gas discharged from the engine;
a fuel reformer provided in an exhaust gas recirculation (EGR) line branched from the exhaust line, mixing the exhaust gas with fuel, and reforming the fuel mixed with the exhaust gas;
a first bypass line branched from the intake line and provided so that external air is bypassed and supplied to the engine by a bypass valve;
a supercharger provided in the first bypass line and supplying the engine by compressing external air;
a second bypass line connecting the supercharger and the fuel reformer and communicating the compressed air from the supercharger to the fuel reformer; and
and an air supply controller configured to control a path through which external air is supplied to the engine by controlling the bypass valve based on an operating condition of the engine. In claim 1,
a compressor connected to the intake line and compressed to supply the reformed gas and air to the engine; and
The fuel reforming system further comprising a turbine connected to the exhaust line and rotated by the exhaust gas to generate power. In claim 1,
The fuel reforming system is disposed in the exhaust line behind the EGR line, the fuel reforming system further comprising a catalyst for purifying nitrogen oxides contained in the exhaust gas. In claim 3,
The catalyst occludes nitrogen oxides contained in exhaust gas in a lean atmosphere, desorbs nitrogen oxides stored in a rich atmosphere, and reduces nitrogen oxides or desorbed nitrogen oxides contained in exhaust gas. A fuel reforming system comprising an oxide storage catalyst (Lean NOx Trap; LNT). In claim 3,
The catalyst is a fuel reforming system comprising a selective reduction catalyst (Selective Catalytic Reducer; SCR) for reducing nitrogen oxides contained in exhaust gas using a reducing agent. In claim 1,
In the EGR line,
An EGR cooler for cooling the reformed gas, and
A fuel reforming system in which an EGR valve is installed at the rear end of the EGR cooler to control the flow rate of the reformed gas. In claim 6,
The fuel reformer is installed in front of the EGR cooler in the EGR line. In claim 1,
The air supply control unit,
A fuel reforming system that controls the bypass valve to be opened or closed based on an operating condition of the engine. In claim 8,
The air supply control unit,
A fuel reforming system for controlling the bypass valve to close when the driving condition of the engine is a low load region. In claim 8,
The air supply control unit,
When the driving condition of the engine is a heavy load or a high load region, the bypass valve is opened, and the fuel reforming system controls so that external air flows into the supercharger through the first bypass line. 10. In claim 9,
The air supply control unit,
When the operating condition of the engine is a heavy load region, the fuel reforming system controls the air compressed by the supercharger to flow into the fuel reformer through the second bypass line. In claim 1,
The operating conditions of the engine are the engine revolutions per minute (RPM) and the engine load (torque) of the fuel reforming system.

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