KR100505295B1 - Fuel heating system for an LPG engine - Google Patents

Abstract

In the present invention, by adding a heating means in the carburetor to preheat the fuel until the fuel temperature reaches a predetermined temperature, deterioration and incomplete starting performance generated by supplying the engine to a sieve in which the fuel is not properly vaporized at the time of cold start or in the excessive operation state The present invention relates to a fuel preheating system for an LPG engine that can suppress combustion and minimize combustion emissions.

In the present invention, the liquid fuel introduced into the gas inlet at one end of the vaporizer housing to which the cooling water is supplied is vaporized by flowing into the preheating chamber and the primary chamber, and the vaporized fuel is opened and closed by supplying the gas supply passage to the secondary chamber by the valve assembly. In the carburetor of the vehicle, the preheater is disposed in contact with the liquid fuel in the preheating chamber, operating at start-up to heat the liquid fuel in the preheating chamber to provide a heat source for evaporation to the liquid fuel supplied to the primary chamber. ; A power supply unit supplying power to the preheater; And temperature control means for sensing the fuel temperature to control the operation of the preheat heater by intermittently controlling the power supplied from the power supply unit to the preheat heater in accordance with the fuel temperature.

Description

Fuel heating system for an LPG engine

The present invention relates to a device for smoothly supplying fuel to an LPG (Liquefied petroleum gas) engine, and more particularly, by adding a heating means in a vaporizer to preheat the fuel until the fuel temperature reaches a certain temperature. The present invention relates to a fuel preheating system for an LPG engine capable of suppressing incomplete combustion and minimizing combustion emissions.

In recent years, the demand for low pollution and high efficiency technology of engines has been greatly expanded due to increased regulations on automobile exhaust gas and increased interest in environmental pollution. For the research of low pollution engines, the development of low pollution engines using LPG and CNG, which have higher hydrogen and carbon ratio than gasoline, is being actively conducted.

In particular, with rising oil prices, LPG vehicles are increasing day by day, and domestic LPG vehicles are spreading more than 600,000 units. At this point, the problems of environmentally friendly and economical LPG vehicle improvement and system security have emerged as important issues.

The ignition engine (engine) above emits about 80% of unburned hydrocarbon (UHC) emissions during the first five minutes of startup. In particular, during the cold start of the transient state, most of the harmful substances are emitted until the uneven mixing of air and fuel and the conversion efficiency of the three-way catalyst reach a steady state. This is because the fuel is supplied to the engine without complete vaporization of the fuel in the vaporizer during cold start. This will be described in more detail with reference to FIGS. 1 and 2.

1 is a graph showing the temperature and pressure behavior of the preheating chamber and the primary chamber of the carburetor when the engine is used when the conventional carburetor is used. In addition, Figure 2a is a cross-sectional view showing a schematic structure of a conventional vaporizer, Figure 2b is a perspective view showing the configuration of the preheat chamber inlet portion in Figure 2a.

As can be seen in the figure, the LPG fuel introduced through the fuel inlet 12 installed at the inlet of the preheating chamber 11 is filtered by the filter 13 and introduced into the preheating chamber 11. LPG fuel introduced into the preheating chamber 11 of the vaporizer 10 is preheated by the cooling water of the cooling water chamber 14 in contact with the preheating chamber 11. As a result, the temperature of the LPG fuel is maintained at approximately 15 ° C. in the preheating chamber 11. However, while the fuel moves from the preheating chamber 11 to the primary chamber 16, the fuel is rapidly dropped from 15 ° C to maintain about 5 ° C. The reason why the temperature drops sharply is because the fuel moves from the preheating chamber 11 to the primary chamber 16 and takes the latent heat of vaporization from the surroundings. Therefore, in view of the above results, if the temperature of the fuel supplied to the vaporizer 10 is lower, the fuel temperature in the primary chamber 16 will be lowered below 5 ° C. A typical one of such cases is cold start (initial start). At this time, since the cooling water is not heated, the LPG temperature is low, so that vaporization does not occur well. This phenomenon is more severe in winter.

In order to overcome this problem, the conventional carburetor requires the operator to shut off the liquid solenoid valve before turning off the engine after the normal operation, or supply only the fuel in the full gas state to the engine when the coolant temperature of the engine is lower than a certain temperature immediately before the engine control logic. It was made. However, in the former case, even if the driver cuts off the solenoid valve, the liquid fuel is filled in the preheating chamber after the blocking, and thus, the liquid fuel filled in the preheating chamber is consumed to obtain an effect. However, in this case, not only the consumption of fuel is large, but also there is a cumbersome operation. In addition, even if the solenoid valve is not shut off, the latter method does not show any difference in starting performance due to the liquid fuel filled in the preheating chamber.

In the LPG vaporizer using the conventional cooling water as described above, when the temperature of the engine coolant is below a certain temperature, the LPG vaporization performance is deteriorated, and it does not satisfy the mixing ratio of air and fuel required at the start-up, and it takes a long time to start the engine. There was a problem of releasing emissions into the atmosphere.

Therefore, an object of the present invention is to devise to solve the above-mentioned drawbacks, by adding a heating means in the carburetor to preheat the fuel until the fuel temperature reaches a certain temperature, the fuel is not evaporated properly during cold start engine The present invention provides a fuel preheating system for an LLP engine that can suppress the deterioration of starting performance and incomplete combustion generated by supplying to the engine and minimize combustion emissions.

Fuel preheating system for the LLP engine according to the present invention for achieving the above object is to vaporize the liquid fuel introduced into the gas inlet at one end of the vaporizer housing to which the cooling water is supplied to the preheating chamber and the primary chamber, the vaporized fuel is valve assembly An LPG vehicle vaporizer that opens and closes a furnace gas supply path and supplies it to the secondary chamber, wherein the vaporizer is disposed in contact with the liquid fuel in the preheating chamber, and is operated at startup to heat the liquid fuel in the preheating chamber to supply the primary chamber. Preheat heater to provide a heat source for evaporation to the liquid fuel to be; A power supply unit supplying power to the preheater; And temperature control means for sensing the fuel temperature to control the operation of the preheat heater by intermittently controlling the power supplied from the power supply unit to the preheat heater according to the fuel temperature.

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

Figure 3 is a view showing the configuration of the fuel preheating system for the LPG engine according to the present invention, Figure 4 is a view showing the structure of the inlet portion of the preheating heater is installed in the present invention. In addition, Figure 5 is a cross-sectional view showing the overall structure of the vaporizer is equipped with a fuel preheating system for the LPG engine according to the present invention.

The present invention is provided at the inlet of the preheating chamber (11), the preheating heater (30) for preheating the fuel charged in the initial start-up supply to the primary chamber (16), and a power supply unit for supplying power to the preheating heater (30) (Battery 40) and temperature control means for detecting the fuel temperature and controlling the ON / OFF of the preheat heater (30).

As shown in FIG. 3, the temperature control means arranges the temperature sensor 52 at the outlet side of the preheating chamber 11 to measure the fuel temperature output from the preheating chamber 11, and detects the temperature by the temperature sensor 52. The preheated heater 30 is operated and controlled until the fuel reaches the set temperature by comparing the set temperature value to the control unit 54. The control unit 54 is composed of a logic circuit input to an electronic control unit (ECU) of a vehicle which supplies or cuts power to the preheating heater 30 to operate the preheating heater 30. In addition, the control unit 54 may be configured as a separate unit of a simple ON / OFF logic circuit, and may be simply mounted and applied to an existing LPG vehicle.

In addition, the temperature control means is a thermosensitive switch composed of bimetal or the like, and is installed on the power supply line supplied from the power supply unit 40 to the preheating heater 30, so that the preheating heater 30 is within a predetermined temperature range. You can also configure the power supply intermittently to work.

When the LPG vehicle is a light vehicle or a supplemental vehicle, it is preferable to configure the temperature control means by a thermo switch such as a bimetal to immediately control the preheat heater 30. However, it is preferable to configure the temperature control means by the combination of the temperature sensor 52 and the control unit 54 for the fine temperature adjustment and the convenience of further installation and change. At this time, it is effective to install at least one or more temperature sensors 52 in the vaporizer 10 housing.

At least one of the above preheat heaters 30 is effectively disposed in the LPG fuel flow space in the preheating chamber 11, and furthermore, the preheat heater 30 is directly contacted with the LPG, so that the preheat heater 30 is inserted into an external body such as a crystal tube to maintain airtightness. It must consist of intrusive heater. This intrusion heater can be used with a glow-plug that can carry more than 11A of current from a 12V to 15V supply. The preheating heater 30 is supplied with power according to the ON signal of the start switch, and when the temperature sensor 52 detects that the fuel temperature has risen to a set temperature, the preheating heater 30 is cut off and the operation is stopped. In addition, since the fuel temperature is low at the time of cold start, the operation of the preheating heater 30 may be detected by the temperature sensor 54 to control the fuel temperature by comparing it with the set temperature value in the controller 54. For example, when the set temperature is set to 20 ° C., when the fuel temperature detected by the temperature sensor 52 is 20 ° C. or less, the preheat heater 30 is supplied with power and operated. The power to the furnace is cut off to vaporize the LPG fuel at higher fuel temperatures due to vaporization due to pressure differentials and elevated cooling water temperature. This will be described in more detail later in the description of the operation.

Now, the operation of the present invention will be described in detail with reference to the above-mentioned drawings.

When the LPG vehicle is started, power is supplied from the power supply unit 40 to the preheating heater 30 while the start switch is turned on. Therefore, the liquid fuel filled in the preheating chamber 11 of the vaporizer 10 is heated by the preheating heater 30 which is in contact with it, and the temperature rises. When the heated fuel is sent from the preheating chamber 11 to the primary chamber 16, the fuel is decompressed and vaporized. At this time, the liquid fuel easily vaporizes while covering the latent heat of evaporation at the temperature of the fuel.

In addition to the method of interlocking with the start switch during cold start, the fuel temperature is detected by the temperature sensor 52 from the start, and the control unit 52 compares the detected value with the set value, and if the current detection value is lower than the set value, the preheat heater There is a method of operating 30. This will be described in detail with reference to the flowcharts of FIGS. 3 and 6 as described above.

When the vehicle is started, the temperature sensor 52 detects the fuel temperature in the preheating chamber 11 and sends it to the control unit 54 (steps 100 and 110). The control unit 54 compares the detected temperature value with the set value. (Step 120) If the detected temperature value is smaller than the set value in comparison, the control unit 54 operates by supplying power to the preheating heater 30 from the power supply unit 40 (step 122). Can be changed, and it is preferable to set it at about 15 ~ 20 ℃. Since the fuel temperature is smaller than the set value at the start, the preheating heater 30 is operated to heat the fuel through the above process. (Step 124) Therefore, the fuel temperature is changed at an instant and the temperature sensor 52 ) Continuously detects the temperature and sends it to the control unit 54. The controller 54 compares the set value and the detected value, and when the detected value is larger than the set value, stops the power supply from the power supply unit 40 to the preheat heater 30 to stop the operation of the preheat heater 30. 120,126) Of course, at this time, since the engine has been operated to some extent, the temperature of the cooling water rises to approximately 80 to 90 ° C, and vaporization of the liquid fuel is possible even at this temperature alone. As described above, when the temperature of the liquid fuel is low, it is detected and heated by the preheating heater 30, which is a forced heat source, more easily and sufficient vaporization is possible. This can be clearly seen in the graph of measuring the fuel temperature while the preheat heater 30 of FIG. 6 is operated.

7 shows the fuel temperature in the vaporizer preheating chamber and the primary chamber after the preheating heater is operated. As shown in the graph, the fuel temperature in the preheating chamber 11 is a constant temperature when the preheating heater 30 is operated. The temperature rises to about 18 deg. C and the state is maintained, but the fuel temperature in the primary chamber 16 continues to rise. As such, since a heat source for LPG fuel evaporates from the preheating heater 30 which starts according to the operation of the start switch or the temperature sensor during cold start, the vaporization of the liquid fuel into gas can be carried out more quickly and easily. do. Therefore, complete vaporization of the fuel in the primary chamber 16 is possible, so that the state of the fuel supplied to the engine can also be supplied to the LPG in a complete gas state. Of course, since the engine is supplied with the combustion of such a gaseous fuel, a good combustion state can be obtained. Therefore, not only the amount of the pollutant discharged from the engine can be significantly reduced, but also the starting performance is improved.

The embodiments disclosed herein are only presented by selecting the most preferred examples to assist those skilled in the art from the various possible examples, the technical spirit of the present invention is not necessarily limited or limited only by this embodiment, the present invention Various changes and modifications are possible within the scope without departing from the spirit of the invention, as well as other equivalent embodiments.

As described above, the fuel preheating system for the LLP engine according to the present invention adds heating means to the carburetor to preheat the fuel for a predetermined time according to the temperature of the engine coolant so that the fuel is supplied to the engine without the fuel being vaporized properly during cold start. It is possible to suppress the deterioration and incomplete combustion of the starting performance generated and to minimize the combustion emissions. Furthermore, the present invention has a simple structure in which the fuel is supplied to the engine by assisting the complete vaporization of the liquid fuel during cold start or in the transient operation state (for example, rapid acceleration), thereby improving the combustion performance and thus the initial startability and low temperature startability of the LPG vehicle. There is an advantage to increase. Therefore, there is an effect that the fuel economy of the vehicle is improved and the output is kept stable.

Detailed description of the embodiments of the present invention will be made with reference to the accompanying drawings, in which numerals designate corresponding parts in the drawings.

1 is a graph showing the temperature and pressure behavior of the preheating chamber and the primary chamber of the carburetor when the engine is started using a conventional carburetor.

Figure 2a is a cross-sectional view showing a schematic structure of a conventional vaporizer,

Figure 2b is a perspective view showing the configuration of the preheating chamber inlet portion in Figure 2a,

3 is a view showing the configuration of the fuel preheating system for the LLP engine according to the present invention,

4 is a view showing the structure of the preheating chamber inlet portion in which the preheater is installed in the present invention,

5 is a cross-sectional view showing the overall structure of a carburetor equipped with a fuel preheating system for an LLP engine according to the present invention;

6 is a flowchart sequentially showing an operation process of the present fuel preheating system shown in FIG.

7 is a graph showing fuel temperatures in the vaporizer preheating chamber and the primary chamber after the preheating heater is operated.

** Explanation of symbols for main parts of drawings **

10: carburetor 11: preheating chamber

14 coolant chamber 16 primary chamber

30: preheat heater 40: power supply

52: temperature sensor 54: control unit

Claims (6)

LPG vehicle vaporizer which vaporizes liquid fuel introduced into the gas inlet at one end of the vaporizer housing to which cooling water is supplied to the preheating chamber and the primary chamber, and supplies the vaporized fuel to the secondary chamber by opening and closing the gas supply passage through the valve assembly. To A preheating heater disposed in the preheating chamber and operating at start-up to heat the liquid fuel in the preheating chamber to provide a heat source for evaporation to the liquid fuel supplied to the primary chamber; A power supply unit supplying power to the preheater; And And a temperature control means for sensing the fuel temperature and controlling the operation of the preheat heater by intermitting the power supplied from the power supply unit to the preheat heater according to the fuel temperature. The preheating heater is a penetration heater disposed in contact with the liquid fuel in the preheating chamber and inserted into an airtight exterior body to maintain airtightness. The temperature control means is disposed at a fuel outlet side of the preheating chamber and compares a temperature sensor detecting the fuel temperature with a current temperature value detected by the temperature sensor with a set temperature value, wherein the current temperature value is less than or equal to the set temperature value. And a control unit for supplying power to the preheating heater and blocking the supply of power to the preheating heater. delete delete delete The fuel preheating system of claim 1, wherein the control unit comprises a logic circuit input to an electronic control unit (ECU) of the vehicle. 2. The fuel preheating system of claim 1, wherein the control unit is configured as a separate unit of a simple ON / OFF logic circuit that can be easily installed and applied to an existing LPG vehicle.