KR20110072701A - Start-up improvement system of LP engine - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for improving startability of an LPG engine, comprising: a coolant temperature sensor 32 for detecting a coolant temperature, an intake temperature sensor 34 for detecting a temperature of air sucked into the intake manifold 44, and a vaporizer; Mounted on an additional fuel supply line 50 branching from the fuel outlet of 20 to the intake manifold 44, the on / off valve 52 for regulating fuel supply, and the detected cooling water temperature and intake It is characterized in that it comprises a control unit 30 for determining whether to correspond to the startability improvement conditions based on the on, and controls the operation of the on / off valve 52.

LPG engine, starter improvement system

Description

Start-up Improvement System for LP Engines {STARTING PERFORMANCE IMPROVING SYSTEM IN LPG ENGINE}

The present invention relates to a system for improving startability of an LPG engine, and more particularly, to a startability improvement system of an LPG engine having a separate fuel supply control device for improving startability.

Liquefied Petroleum Gas (LPG) has a higher octane price than gasoline, so the engine does not knock, so the engine has a long service life, less carbon monoxide in the exhaust gas, and a cheaper price than gasoline. have.

In the case of an engine using such LPG fuel, a DI (Direct Injection) engine that injects fuel directly into the combustion chamber of the engine using an injector, and a MPI (Multi-Point Injection) engine that injects fuel into the intake manifold of the engine and Alternatively, a vaporizer and mixer are used from the LPG fuel tank, which does not have an injector and instead stores LPG fuel, which results in a relatively long fuel line problem and the vapor pressure of the fuel tank at low temperature startup. Due to this insufficient pressure, the pressure itself in the fuel tank is not easy to deliver the liquid fuel to the vaporizer, and the initial startability is not good because the fuel is not vaporized smoothly.

In addition to the problem of initial startability at low temperature, a start delay problem occurs when the engine is restarted after cooling the engine to some extent through soaking after the vehicle is run hot.

In order to improve the low temperature startability of the LPG engine, in the prior art, there is a method of preheating the LPG by using a preheater for preheating the LPG supplied from the fuel tank to a certain degree and the heat of the engine coolant. Since the effect occurs only when the temperature of the cooling water is raised to some extent, the problem of initial startability at low temperature remains.

As another method for low temperature startability, Utility Model Publication No. 193-0005043 uses a method of directly supplying vaporized fuel from a carburetor at low temperature to an intake manifold without going through a mixer. Although it can be improved to some extent, fuel consumption is reduced because additional fuel is supplied throughout the engine running, and a start delay problem that may occur when the engine is restarted after cooling to some extent after the engine is not driven for the first time is still maintained. Remains.

The LPG startability improvement system according to the present invention, in the conventional LPG system having poor startability at low temperature due to the quality of the LPG fuel, by supplying the fuel without the mixer to the intake manifold to make the ignition easier It can improve and solve the start-up delay that may occur when restarting after the engine is running hot. In addition, by supplying additional fuel to the intake manifold only under specific conditions by using the cooling water temperature and intake temperature sensors, and after starting is completed, additional fuel is not supplied from the carburetor to the intake manifold, thereby improving fuel economy. Can be.

In order to achieve the above object, an aspect of the present invention provides a system for improving startability of an LPG engine, including a cooling water temperature sensor detecting a cooling water temperature, an intake temperature sensor detecting a temperature of air sucked into an intake manifold, and a vaporizer. Mounted on an additional fuel supply line branching from the fuel outlet and connected to the intake manifold to determine whether the start-up improvement condition is met based on the on / off valve for regulating fuel supply and the detected coolant and intake temperatures It characterized in that it comprises a control unit for controlling the operation of the on / off valve.

In addition, the startability improvement system of the LPG engine of one aspect of the present invention is characterized in that the controller determines whether the startability improvement condition is determined by using the detected temperature difference between the cooling water temperature and the cooling water temperature and the intake temperature.

Moreover, the startability improvement system of the LPG engine of 1 aspect of this invention is characterized by the control part closing an ON / OFF valve at the time of engine start completion determination.

Still another aspect of the present invention is a method for improving the startability of an LPG engine with an on / off valve mounted on an additional fuel supply line branching from a fuel outlet of a carburetor and connected to an intake manifold. Monitoring the engine condition; Measuring the cooling water temperature and the intake air temperature sucked into the intake manifold; Determining whether the condition corresponds to the startability improvement condition based on the detected cooling water temperature and intake temperature; Opening the on / off valve if the determination result corresponds to a condition for improving startability; If the engine state corresponds to the start-up condition, characterized in that it comprises the step of closing the on / off valve.

In addition, the control unit of the startability improvement system of the present invention is characterized in that the on / off valve is opened when the difference value between the cooling water temperature and the intake temperature is smaller than the preset value.

In addition, the control unit of the startability improvement system of the present invention is characterized in that after the start is completed, the on / off valve is closed.

The LPG startability improvement system according to the present invention, in the conventional LPG system having poor startability at low temperature due to the quality of the LPG fuel, by supplying the fuel without the mixer to the intake manifold to make the ignition easier It can improve and solve the start-up delay problem that may occur when restarting after hot running of the engine. In addition, by supplying additional fuel to the intake manifold only under specific conditions by using the cooling water temperature and intake temperature sensors, and after starting is completed, additional fuel is not supplied from the carburetor to the intake manifold, thereby improving fuel economy. Can be.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention can be specifically realized the object of the present invention. The present embodiments are not intended to be limiting, and in describing the embodiments, the same names and the same reference numerals are used for the same configurations.

1 shows a startability improvement system 1 of an LPG engine according to an embodiment of the present invention. Since LPG is easy to vaporize and expands to about 250 times its volume when in a gaseous state, conventional LPG gas injection systems utilize high pressure fuel in an LPG fuel tank (10) called Bombe. Keep in liquid state. The carburetor 20 is provided with the fuel opening / closing valve 22. The on-off valve 22 is preferably an electronic valve capable of operating on / off by electronic control. The on-off valve 22 is opened by the engine control unit (ECU) 30 when the engine is in an ignition ON state, and LPG fuel is fed to the vaporizer 20 by the vapor pressure of the fuel in the tank 10. Done. In the vaporizer 20, the fuel is depressurized to atmospheric pressure and vaporized. The vaporized fuel then flows to the mixer 40, which is sucked by the negative pressure of the intake air in the venturi tube in the mixer 40 and combusted in the combustion chamber. The ECU 30 controls the mixer 40 so that the sucked air and the vaporized fuel are mixed at a ratio most suitable for combustion and supplied to the combustion chamber according to the engine rotation speed and the throttle opening amount.

However, LPG gas injection system does not have good startability at low temperature because LPG is not easy to vaporize due to low ambient air temperature, and it is difficult to burn since it is mixed with low temperature intake air in the mixer 40. to be. In order to solve this problem, in the present invention, an additional fuel supply line 50 branched from the fuel outlet of the vaporizer 20 and connected to the intake manifold 44, and mounted on the additional fuel supply line 50, A fuel supply regulator 52 is provided for opening and closing the additional fuel supply line 50. In the present embodiment, the fuel supply control device 52 is an electronic on / off valve 52 capable of operating opening and closing by electronic control, but is not limited to this, it is also possible to use another type of control device. The ECU 30 determines the startability improvement condition, and when the condition is satisfied, the on / off valve 52 is opened to allow the vaporized fuel from the vaporizer 20 to the intake manifold 44 without passing through the mixer 40. To be supplied immediately. Conventionally, when the cooling water temperature is measured and the cooling water temperature is lower than a predetermined temperature, fuel is additionally supplied from the vaporizer 20 to the intake manifold 44. However, in the present invention, the cooling water temperature sensor 32 and the intake air temperature sensor 34 are provided. And by monitoring the engine running state, the ECU 30 first determines whether the startability needs to be improved, and supplies additional fuel to the intake manifold 44 when the condition is satisfied, thereby reducing not only the startability of the vehicle but also the low temperature. Even in the case of restart after hot running, startability can be improved. The starting line improvement conditions will be described later.

Next, with reference to FIG. 2, the startability improvement system of this invention is demonstrated. 2 is a flow chart of a fuel in a low temperature startability improvement system according to an embodiment of the present invention. The LPG fuel stored in the liquid phase in the high pressure LPG fuel tank 10 is fed to the vaporizer 20 by the vapor pressure of the fuel when the fuel open / close valve 22 attached to the vaporizer 20 is turned on. The ECU 30 determines whether the start-up improvement control is performed based on the coolant temperature and intake temperature data detected by the coolant temperature sensor 32 and the intake air temperature sensor 34 mounted on the engine. In the present embodiment, it is determined whether the startability improvement control based on the cooling water temperature and the intake temperature data detected from the cooling water temperature sensor 32 and the intake air temperature sensor 34, but is not limited thereto. Instead, the startability improvement control may be performed by combining with an outside temperature sensor. The ECU 30 closes the on / off valve 52, which is a fuel supply control device, when it is determined that startability improvement control is unnecessary, so that all fuel vaporized from the vaporizer 20 is supplied to the mixer, and from the air filter in the mixer. The filtered air is mixed with the filtered air at the most suitable ratio for combustion and fed to the engine combustion chamber. The ECU 30 ignites and combusts the air / fuel mixture at a preset ignition timing according to the load of the engine so as to generate the highest output.

On the other hand, when the ECU 30 determines that startability improvement control is necessary based on the detected cooling water temperature and intake temperature data, the ECU 30 opens the on / off valve 52 to supply air supplied through the mixer. In addition to the / fuel mixture, start-up is better by allowing the vaporized fuel to be fed directly to the intake manifold 44 without passing through the mixer. On the other hand, when the ECU 30 is continuously determined to start the engine smoothly while monitoring the engine condition, by closing the on / off valve 52 again to prevent unnecessary supply of additional fuel.

Next, the operation sequence of the startability improvement system 1 is demonstrated with reference to FIG. 3 is a flow chart showing the operation sequence of the startability improvement system according to an embodiment of the present invention. When the engine is in the ignition ON state by the driver's key operation, the ECU 30 measures the current cooling water temperature and the intake air temperature by using the cooling water temperature sensor 32 and the intake air temperature sensor 34 (100). . When the measured cooling water temperature is less than the first set value T_1, for example, 15 ° C. (110), in order to improve low temperature startability, the ECU 30 opens the on / off valve 52 to intake the vaporized LPG fuel to the intake manifold. An additional supply 120 to 44 facilitates starting. When the measured cooling water temperature is the first set value T_1, for example, 15 ° C. or more, the ECU 30 determines that the low temperature startability improvement is unnecessary and determines whether the restartability improvement is necessary. When the measured cooling water temperature is less than the second set value T_2, for example, 65 ° C. (120), the ECU 30 calculates a difference between the measured cooling water temperature and the intake temperature, and the difference value is the third set value T_3. For example, when the temperature is less than 10 ° C. 130, the ECU 30 opens the on / off valve 52 to additionally supply 120 vaporized LPG fuel to the intake manifold 44 to improve restartability. To facilitate. On the other hand, while the on / off valve 52 is opened and the additional vaporized fuel is supplied, the ECU 30 continuously monitors the engine state and determines that the engine is smoothly started (140), that is, starting completion. If the determination is made, the on / off valve 52 is closed 150 again to prevent unnecessary fuel from being supplied unnecessarily, thereby improving fuel economy.

As described above, the present invention can control the fuel amount so as to have a rich air-fuel ratio by using both the cooling water temperature and the intake air temperature, so that not only can the start-up of the low temperature starter be improved, It can also solve the problem of start-up delay, which is common when restarting to a certain degree. In addition, there is an advantage that can be prevented unnecessary fuel consumption by closing the valve after the normal start is completed.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings. It will be apparent to those skilled in the art that various modifications and changes can be made without departing from the technical spirit of the present invention.

1 is a block diagram of a low temperature startability improvement system according to an embodiment of the present invention.

2 is a flow chart of a fuel in a cold startability improvement system according to an embodiment of the present invention.

3 is an operational flowchart of the startability improvement system.

Description of the Related Art [0002]

10: LPG Fuel Tank

20: Vaporizer

22: fuel opening and closing valve

24: fuel hose

30: ECU

32: coolant temperature sensor

34: Intake air temperature sensor

40: Mixer

42: air filter

44: intake manifold

50: additional fuel supply line

52: on / off valve

Claims (4)

As a starter improvement system of LPG engine, Cooling water temperature sensor 32 for detecting the cooling water temperature, An intake air temperature sensor 34 for detecting a temperature of air sucked into the intake manifold 44; An on / off valve 52 mounted on an additional fuel supply line 50 branching from the fuel outlet of the vaporizer 20 and connected to the intake manifold 44, and regulating the fuel supply, and The controller 30 determines whether the condition corresponds to the startability improvement condition based on the detected cooling water temperature and the intake temperature, and controls the operation of the on / off valve 52. Start up improvement system of the LPG engine comprising a. The system of claim 1, wherein the controller determines whether or not starting conditions are improved by using the detected cooling water temperature and the temperature difference between the cooling water temperature and the intake temperature. The start-up improvement system of the LPG engine according to claim 1 or 2, wherein the control unit closes the on / off valve when the engine is finished starting. Startability of the LPG engine with an on / off valve 52 mounted on an additional fuel supply line 50 branching from the fuel outlet of the vaporizer 20 and connected to the intake manifold 44 to regulate fuel supply. In the improvement method, Monitoring engine status; Measuring the cooling water temperature and the intake air temperature sucked into the intake manifold 44; Determining whether the condition corresponds to a condition for improving startability based on the detected cooling water temperature and intake temperature; Opening the on / off valve (52) when the determination result corresponds to a condition for improving startability; Closing the on / off valve 52 when the engine state corresponds to a start-up condition How to improve the startability of the LPG engine comprising a.

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