JPH0441968A - Fuel supply device for in-line injection system of diesel engine - Google Patents

Abstract

PURPOSE:To achieve atomization of the droplet of fuel in injecting the fuel from an injection nozzle with the lowered viscosity thereof and hence to aim at improvement in properties of exhaust gas by preheating a high pressure fuel press-fed from an injection pump through a heat exchanger. CONSTITUTION:In a six-cylinder diesel engine including an in-line injection system, high pressure fuel pipings 6a to 6f extending from a fuel injection pump 2 to injection nozzles 3a to 3f is partially made to pass through a hot water tank 8 constituting an exchanging means 7. Meanwhile, water is supplied from a high temperature side piping 13 for cooling water in an engine through an inlet 14 and a piping 15 to a supply port of the hot water tank 8. Also, hot water discharged from a discharge port of the hot water tank 8 is made to pass through a return piping 18 to be joined with high temperature water discharged from a discharge port of the hot water tank 8. The high pressure fuel before fuel injection is heated by the hot tank 8 constituting the heat exchanging means 7, thus lowering the viscosity of fuel injected from respective injection nozzles 3a to 3f.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is intended to improve exhaust gas in a fuel supply system equipped with a fuel injection system equipped with a Bosch Taib size injection pump, for example. Technology] The method that has been explored in the past to improve exhaust gas is to inject fuel at high pressure.In order to realize this method, it is necessary to increase the capacity of the injection pump.
This inevitably leads to larger sizes, which increases the driving torque from the engine, which has a large impact on output performance.In addition, unit injectors have been proposed, but in this case, the engine structure would need to be significantly changed. There is.

[l1u to be solved by the invention] An object of the present invention is to atomize droplets of injected fuel without increasing the capacity of the fuel injection pump or without requiring significant changes to the engine structure. and to provide a device that makes it possible to improve exhaust gas.
l! Means for Solving the Problem] The means for solving the above problem in this invention is as follows.7 In the invention of claim 1, an engine cooling pipe is installed in the middle of the high-pressure fuel pipe from the fuel injection pump to the injection nozzle of the tasel engine. A heat exchange means is provided in which hot water on the high temperature side is circulated, thereby heating the high-pressure fuel just before injection.

In the invention of claim 2, a heat exchange means consisting of a hot water tank heated by a heater is disposed in the middle of the high-pressure fuel pipe line from the fuel injection pump to the injection nozzle of the diesel engine.7. This heats the high-pressure fuel just before injection.

[Effect]

In the apparatus configured as described above, the viscosity of the fuel is lowered by heating the fuel in the high-pressure fuel pipe line leading from the fuel injection pump to the injection nozzle by heat exchange means, and droplets of fuel are injected from the injection nozzle. By atomizing the fuel, combustion efficiency is increased and exhaust gas power is improved.

〔Example〕

Next, the present invention will be explained in detail according to an illustrated embodiment.7 In FIG. 1, l schematically represents a six-cylinder diesel engine equipped with a size-type injection system, and in this figure, 2 represents a fuel injection system. The pumps are shown, 38 to 3f are injection nozzles, 4 is a water pump, and 5 is a radiator. The cooling system of the engine 1 is a cooling system surrounding the combustion chamber.
The water pump 4 cools the parts that require cooling, such as the engine head and cylinder lychee, and then sends the water, which has reached a relatively high temperature (generally 80 to 85 degrees Celsius), to the radiator 5 to cool it and cool the engine again. A circulation system is formed in which the fuel is fed to the necessary parts, but in one embodiment of the present invention shown in FIG. A portion of the heat exchanger 5 passes through the inside of the hot water tank 8 constituting the heat exchange means 7.The structure of the heat exchanger 5 is shown in detail with respect to the high pressure fuel pipe 6f in FIG. In order to improve efficiency, heat absorption fins 9 are provided on the outer periphery of the high pressure fuel pipe 6f formed in a meandering shape,
The high-pressure fuel that enters the hot water tank 8 from the inlet [0] on the side of the fuel injection pump 2 absorbs heat from the hot water [1] flowing through the hot water tank 8 to increase its temperature, and is then pressure-fed to the injection nozzle 3f from the outlet 12. It will be done. These configurations are
The same applies to the other high pressure fuel pipes 68 to 6e.

Returning to FIG. 1, hot water is communicated from the high-temperature side pipe 13 of the engine 1 to the supply port 6 of the hot water tank 8 through the intake port 14 and the pipe 15. The hot water from the engine of the water pump 4 is merged with the high temperature water coming from the engine of the water pump 4 through the return pipe 18 from the outlet 17 of the hot water tank 8. Instead of taking in the hot water taken out from the high-temperature part of the cooling water, the water in the hot water tank 8 may be heated by the heater 19 (shown by the imaginary line in FIG. 2), or both may be used in combination. good.

In the above configuration, by heating the high-pressure fuel before fuel injection by the heat exchange means consisting of the hot water tank 8 described above, the viscosity of the fuel decreases when injected from the injection nozzles 38 to 3f.

The droplets can be atomized and combustion can be improved.7 In other words, as shown in Figure 3, the relationship between fuel temperature and viscosity is such that as the a degree increases, the viscosity decreases2, and the viscosity decreases. When the droplets become atomized during injection due to the decrease in the amount of water, smoke generation decreases as shown in FIG. In other words, the exhaust gas is improved.3 In addition, as in this invention, it is important to heat the fuel on the high-pressure side, and heating on the low-pressure side will prevent cavitation due to bubble generation and fuel injection amount failure. This is inconvenient because stability occurs. [Effects of the Invention] According to the device having the above configuration of the present invention.

By heating the high-pressure fuel pumped from the injection pump by passing it through a heat exchange means, the viscosity is reduced.
When injected from the injection nozzle, droplets are atomized and exhaust gas can be improved.

[Brief explanation of the drawing]

Figure 1 is a layout diagram of a diesel engine equipped with the device of the present invention, Figure 2 is an enlarged sectional view of its main parts, Figure 3 is a graph showing the relationship between fuel temperature and viscosity, and Figure 4 is a graph showing the relationship between fuel temperature and viscosity. This is a graph showing the relationship between the particle size of droplets and the amount of smoke generated. 2 Fuel injection pumps 38-3f Injection nozzles 68-6f High-pressure fuel pipe 7 Heat exchange means 8 @water tank Pipe line 7: Heat exchange means 8: Hot water tank Figure 3 High temperature Figure 4 20 30-40 Particle size μm

Claims (2)

[Claims] (1) A heat exchange means is installed in the middle of the high-pressure fuel pipe line from the diesel engine's fuel injection pump to the injection nozzle, through which hot water on the high-temperature side of the engine cooling water is circulated, and is then transferred to the high-pressure fuel just before injection. A fuel supply device for an in-line injection system for a diesel engine, which is characterized by heating. (2) A heat exchange means consisting of a hot water tank heated by a heater is placed in the middle of the high-pressure fuel pipe line from the fuel injection pump to the injection nozzle of the diesel engine, which heats the high-pressure fuel just before injection. A fuel supply device for an in-line injection system for a diesel engine, characterized by: