JPH07293345A - Water quantity control method in lpg vaporizer hot water circuit - Google Patents

Abstract

PURPOSE:To smoothly start at a cold time by introducing a part of engine cooling water through a valve which controls a rate of passing water according to a temperature condition to a vaporizer, utilizing it for vaporizing LPG, feeding it to a cylinder block, and thereby promoting vaporizing of LPG. CONSTITUTION:Cooling water is fed into a cylinder block 1 of an engine 10 by means of a water pump 6 after cooling an engine. A part of the water is fed to a vaporizer 4 through a cylinder head 2 and a thermo valve 3. Heat is supplied to liquefied LPG for vaporizing, and circulated to an intake side of the water pump 6 through a thermo housing 5. The thermo valve 3 is in an opened condition when the engine is cold. Cooling water is supplied to the vaporizer 4 by the same rate as a discharge rate of the water pump 6. When the engine is hot, thermo valve 3 is closed to reduce the water quantity passing the vaporizer 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water amount control method for an LPG vaporizer hot water circuit in an industrial vehicle such as a forklift truck.

[0002]

2. Description of the Related Art A conventional fuel system for an industrial vehicle that uses LPG (liquefied petroleum gas) is constructed as shown in the system diagram of FIG. 8, in which cooling water for an engine e is guided to a vaporizer b by a hose c. The liquid LPG supplied from the pipe a is vaporized and supplied to the vaporizer d. As shown in FIG. 9, the balance of the flow rate of the cooling water of the conventional engine e is the water amount V passing through the vaporizer b regardless of whether the cooling water is cold or warm.
_{When 1} is constant and the amount of water that circulates through the engine and returns to the thermo housing without passing through the vaporizer is V ₂ , the discharge amount V ₀ of the water pump is V ₀ = V ₁ + V ₂ .

[0003]

However, in the above-described conventional structure, even when the cooling water temperature is cold immediately after the engine is started, or when the cooling water temperature after the engine is warmed up increases,
Even in the case of overheating in the summer, the amount of cooling water passing through the vaporizer was constant, but when the cooling water temperature is cold, the heat of vaporization of LPG is absorbed to prevent the temperature in the vaporization chamber from decreasing, and In order to maintain vaporization, it is necessary to secure a certain amount of water. On the other hand, when the cooling water temperature rises, a large amount of water is not required for the vaporizer, and in the case of overheating, it is essentially preferable to increase the cooling water to the radiator side. That is, there is a problem in effective distribution of the amount of cooling water. This invention makes it the subject to solve such a problem.

[0004]

The present invention has been made in view of the above problems, and when the cooling water is cold immediately after the engine is started, the amount of water to the vaporizer is increased to sufficiently cool the cooling water. When the engine is warm, a valve is installed between the engine cylinder head and the vaporizer to reduce the amount of water and control the increase / decrease in the amount of water passing depending on the water temperature condition, and to let the cooling water pass through. In the vaporizer chamber of the vaporizer, After being used for vaporization, it is returned to the thermo housing and sent to the engine cylinder block by the water pump.

[0005]

By adopting the above configuration, it is possible to control the increase / decrease in the amount of water passing through the vaporizer according to the temperature condition of the cooling water. Therefore, when the cooling water is cold immediately after the engine is started, When the amount of water is increased and the amount of cooling water is sufficiently warm and the cooling water is warm, the amount of water is decreased and the surplus amount of water is sent to the radiator, whereby effective distribution of the cooling water is performed.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a perspective view showing an embodiment, and FIG. 2 is a system diagram. A part of the cooling water sent to a cylinder block 1 of an engine 10 by a water pump 6 passes from a cylinder head 2 to a vaporizer 4 through a thermo valve 3. Sent. Here, the liquid LPG gas is heated by the water temperature of the cooling water, vaporized, and then guided to the thermo housing 5 and circulated by the water pump 6. Another part of the cooling water is sent to the radiator 7 and cooled and then guided to the thermo housing 5.

FIG. 7 is an explanatory diagram showing the flow rate balance of the cooling water. When the cooling water is cold, the valve 3 is in the open state, the amount of water V ₁ passing through the vaporizer 4 and the thermostat from the cylinder head 2 through the bottom bypass 9. The sum of the amount of water V ₂ returned to the housing 5 is substantially equal to the amount of discharge V ₀ of the water pump 6. That is, V ₀ = V ₁ + V ₂ . However, when the cooling water is warm, the valve 3 is closed and the vaporizer 4
The amount of water passing through is reduced to a small amount of water v ₁ , and the difference in water amount (V ₁ −v ₁ ) is increased and sent to the radiator 7, and then returns to the thermo housing 5.

FIG. 3 is a sectional view of the thermovalve, FIG. 4 is a sectional view of the thermovalve in an open state, and FIG. 5 is a sectional view of the thermovalve in a closed state. In FIG. 3, the thermoactuator 1 is attached to the seat surface 11a of the valve case 11.
When 4 is pressed against the seat 13 attached to the valve stem 12 against the force of the spring 15, the cooling water passes through the orifice 12a of the valve stem 12 and the amount of water is reduced. That is, the thermoactuator 14 pulls in the valve stem 12 when it is cold, and is in an open state where cooling water can pass through the groove 11b inside the valve case 11 as shown in FIG. Is pushed out to be in a closed state as shown in FIG. Although FIG. 3 shows the thermo-valve with an orifice as an example, it goes without saying that it is also possible to use electric control by combining a water temperature detection sensor, an actuator, and a flow rate adjusting valve, but at the present time, the implementation of FIG. An example is considered as the cheapest method.

FIG. 6 is a sectional view of the inside of the thermo housing 5, which has an inlet 16 from the radiator 7, an inlet 17 from the bottom bypass 9 and an outlet 18 to the water pump 6.
The inlet 16 and the inlet 17 are switched by the thermostat 19 when the temperature of the cooling water is low and high. When the temperature is low, the inlet 16 is closed and the inlet 17 is opened.
6 is open and the inlet 17 is closed. Others Return from vaporizer 4 and intake manifold 2
The bypass 23 from the governor 22 of 1 is the water pump 6
Is connected to the outlet 18 to.

[0010]

As described in detail above, the present invention increases the amount of water to the vaporizer when the cooling water is cold at the time of starting the engine, promotes vaporization in the vaporizer, and improves cold startability. It becomes smoother than before, and when the cooling water after warming up is warm, the amount of cooling water is reduced and effective distribution of cooling water is performed, so when the vehicle is used in the summer or overheat. The amount of water to the radiator side will increase more than before and the cooling performance of the radiator will be improved, overheating will be reduced and the vaporization of LPG gas can be stably maintained and a rational cooling system can be realized. become.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a system diagram of an embodiment of the present invention.

FIG. 3 is a sectional view of a thermovalve.

FIG. 4 is a cross-sectional view of the thermo valve when opened.

FIG. 5 is a cross-sectional view of the thermovalve when it is closed.

FIG. 6 is a sectional view of the inside of the thermo housing.

FIG. 7 is an explanatory diagram showing flow rate balance.

FIG. 8 is an explanatory diagram of a fuel system of an industrial vehicle that uses LPG.

FIG. 9 is an explanatory diagram showing a conventional flow rate balance.

[Explanation of symbols]

 1 Cylinder Block 2 Cylinder Head 3 Thermo Valve 4 Vaporizer 5 Thermo Housing 6 Water Pump 10 Engine

Claims (2)

[Claims] 1. A cylinder head 2 of an engine 10 is passed through a valve 3 which controls the increase / decrease of the amount of passing water according to the water temperature condition.
A part of the cooling water is guided to the vaporizer 4 and used for vaporizing the LPG, and then returned to the thermo housing 5 and sent to the cylinder block 1 of the engine 10 by the water pump 6, which is a characteristic feature of the LPG vaporizer hot water. Circuit water control method. 2. A water amount control method for an LPG vaporizer hot water circuit according to claim 1, wherein a thermo valve with an orifice is used as the valve 3 for controlling the increase / decrease in the amount of water passing through.