JPH02227551A - Method and device for feeding heated liquid fuel by means of fuel injection pump - Google Patents

Abstract

PURPOSE: To improve the combustibility by a simple configuration by transmitting quantity of heat of exhaust gas to fuel through an auxiliary medium in a device supplying heat to maintain pressure and temperature of fuel between a fuel injection pump and a fuel injection valve properly. CONSTITUTION: One end of a heat pipe 4 is supported on a heat exchanger 2 which is attached to an exhaust passage 3 of an internal combustion engine 1 and takes out exhaust gas heat, and the other end of the heat pipe 4 is fixed on an intermediate member 5 surrounding a heating section 6 surrounded by a thermal insulation body 25. A discharge side of a fuel injection pump 9 having a piston 10 and a drive device 11 is connected with the heating section 6, and a fuel injection valve 8 is provided on a fuel flow-out side of the heating section 6. Moreover, a capsule 19 is connected with the heat pipe 4 to control pressure and activation amount of an auxiliary medium through a conduit 16 and is constituted by storing a bellows 18 in a pressure chamber 20, and a capacity of the capsule 19 is enlarged in accordance with a rise of steam pressure to keep boiling temperature and pressure of the auxiliary medium constant.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is a method for supplying heated liquid fuel by a fuel injection pump, in which fuel under high pressure is supplied to a fuel injection valve. , at an optimum pressure level and an optimum temperature level to ensure that the fuel remains in a liquid state until exiting the fuel injector and is then transferred to a vapor state by latent heat. , of the type with heat supply after the fuel injection pump, and a device for carrying out this method.

[Prior art 1] In order to generate a combustible mixture, liquid fuel is prepared by breaking it down into particles as small as possible, but in this case, the ideal state is that the fuel is in a gaseous state. . For this purpose, gas heat must be supplied to the liquid fuel. The supply of heat of vaporization in conventional internal combustion engines takes place when the liquid fuel is more or less finely dispersed in the combustion gas. In this case, the fuel is vaporized at a low temperature and kept open for a suitable length of time. As a result, incomplete combustion occurs at high speeds, resulting in increased fuel consumption and poor exhaust gas emissions.

Methods and devices are known for supplying heat of vaporization to fuel before it enters the combustion gases. In known methods and devices, the fuel is heated before it exits the fuel injection valve until it is vaporized by latent heat as soon as it is injected.

In this case, the fuel vaporization is rapid and complete;
Exhaust gas values and fuel consumption are advantageous even at high speeds.

For fuel to be heated without forming bubbles of steam,
In known methods and devices of this type, in which it is necessary to ensure that the temperature of the fuel does not exceed a predetermined temperature that is dependent on the fuel pressure, the fuel is heated. The desired temperature can be kept constant relatively easily by electrical heating.

However, the power required in this case is extremely large. That is, for an engine output of about 20kW, about 1k
A power of W is required. If the internal combustion engine were to generate such electricity itself, as it must do in automobiles, the weight of the internal combustion engine would increase;
It also costs a lot of money.

Another configuration for heating fuel is DH-O8 No. 32
In this arrangement, known from 43 809, heat from the exhaust gas is supplied to the fuel. In this case, a periodically activated fuel injection pump delivers fuel to a pressure accumulator which is always kept under high pressure. The fuel reaches the fuel injection valve from this pressure accumulator via the exhaust gas heat exchanger.

With such a configuration, it is only possible to heat the fuel without generating steam bubbles, since the fuel is heated under extremely high pressure. The temperature on the fuel side in the heat exchanger can be very high (e.g. 400° C.), so that the fuel is brought to a high pressure, e.g. l 20 bar, so that it remains in a liquid state during heating. . Since these components, such as fuel injection pumps and fuel injection valves, are subject to high pressures, their manufacture is expensive. Furthermore, the pump drive efficiency must be particularly high. Therefore,
Efficiency improvements using exhaust gas heat are rarely implemented due to mechanical losses. If the heat supply is carried out at a relatively low constant temperature, degrees Celsius, the objective is that the fuel is vaporized by latent heat during heating, at a relatively low pressure, e.g. less than 1/4 of the fuel pressure used in the above configuration. This will be achieved at low pressure conditions.

Problem to be Solved by the Invention 1 The problem of the present invention is to improve the fuel supply system of the type mentioned in the introduction, and to apply a relatively low pressure to the fuel from an uncontrolled high-temperature heat source while maintaining a relatively low constant temperature. [Means for Solving the Problem 1] According to the invention, in a method of the type mentioned at the outset, the problem consists in supplying heat by the auxiliary medium released during condensation of the auxiliary medium vapor. It is solved by heating the fuel by latent heat and controlling the temperature level of the fuel by the condensation temperature of the auxiliary medium.

Furthermore, the object according to the invention is to provide an apparatus for carrying out a method of the type mentioned at the outset; in which the heat tube is connected via a conduit to a container in which an auxiliary medium in liquid state is stored, either completely or partially; The solution is that the volume of the container is changed by the arrangement of the piston or the bellows.

[Operations and Effects J] Due to the provision of an interposition for the auxiliary medium, there may be a large temperature difference between the heat source and above the fuel during heat transfer to the fuel. By using the latent heat of the auxiliary medium to heat the fuel, the temperature level of the fuel is maintained within a narrow range. The pressure level is therefore also advantageously selected.

Further advantageous developments of the invention are described in claims 2 to 16.

The change of state of the auxiliary medium can be realized based on the known heat tube principle. In known thermal tubes, steam is condensed only to the extent necessary for the heat demand of the fuel.

Stabilization of the condensing temperature is achieved by stabilization of the vapor pressure by means of a variable volume vessel connected to the heat tube. According to the heat tube, the unstable energy supply of the heat source is solved by partially removing the auxiliary medium.

Therefore, even though the temperature of the engine exhaust gas heat is high and large temperature fluctuations occur in the exhaust gas heat, the fuel can be heated by the engine exhaust gas heat. Heating of fuel using exhaust gas heat through the interposition of an auxiliary medium is as follows:
Based on the heat tube principle, many aspects of efficiency improvement are positive.

[Example 1 The invention will now be explained with reference to the illustrated embodiment.

According to FIG. 1, an internal combustion engine l is provided with a heat exchanger 2 for extracting exhaust gas heat. Heat exchanger 2 is exhaust passage 3
and supports the heat tube 4. heat tube 4
An intermediate member 5 is fixed to the end opposite to the heat exchanger 2 , and the intermediate member 5 surrounds the heating section 6 .

A fuel injection valve 8 is provided on the fuel outflow side of the heating section 6. A thermal insulator 25 surrounds the heat pipe 4 and the heating section 6. A fuel injection pump 9 with a piston IO and a drive 11 is connected to the opening of the heating section 6 on the fuel supply side. A one-way valve 13 is provided at the inlet of the fuel injection pump 9 into the displacement chamber 12, and a one-way valve 14 is provided at the outlet from the displacement chamber 12. A front pump 15 is connected to the one-way valve 13 on the fuel inflow side.

A thermal tube 4 is connected to the capsule 19 via a conduit 16 in order to control the pressure of the auxiliary medium and the active amount of the auxiliary medium. The capacity of the capsule 19 is varied by the bellows 18. In the illustrated embodiment, the bellows 18 is surrounded by a capsule 19 such that a pressure chamber 20 is formed between the bellows 18 and the capsule 19 . The capsule 19 is completely sealed, the conduit 16 is filled mainly with auxiliary medium condensate 21, and the heat tube 4 is filled mainly with steam 22.

The mode of operation of the fuel supply device according to FIG. Inflow. When the piston IO is driven by the drive member 11, a predetermined amount of fuel is supplied to the one-way valve 14.
The fuel exits the fuel injection pump 9 via the fuel injection pump 9 and finally flows under high pressure into the heating section 6. The heating section 6 is the fuel injection valve 8
The temperature is maintained at approximately the same temperature along the fuel passage by supplying heat. Thereby, the fuel receives approximately the same temperature until it reaches the fuel injection valve 8. Due to the high pressure acting on the fuel, the fuel injector 8
is opened and fuel flows into the combustion chamber 7. Due to the relatively low pressure acting in the combustion chamber 7, the heated fuel quickly passes into the vapor state. At the end of the pump stroke, the pressure in the heating section 6 drops to a predetermined value and the fuel injection valve 8 is closed again.

Heat transfer begins when the heat exchanger 2 heats the vaporization zone 23 to the boiling temperature of the auxiliary medium in the heat tube 4. In this case, the vapor 22 liberated in the vaporization zone 23 is diffused in the heat tube 4 under the influence of pressure and thereby reaches the condensation zone 24 . Since the temperature of the condensation zone 24 is lower than the temperature of the vaporization zone 23, the vapor 22 is condensed in this condensation zone 24. In this case, the steam 22 gives off heat, which is conducted from the tube wall of the condensing zone 24 via the intermediate member 5 to the heating section 6 . The heating zone 6 receives the boiling temperature of the auxiliary medium until the temperature difference is small. Similarly to the heating section 6, the fuel that has flowed into the heating section 6 while remaining at a low temperature also receives the boiling temperature of the auxiliary medium until the temperature difference further decreases by the time it reaches the fuel injection valve 8. Condensation area 2
The auxiliary medium which has passed into the liquid state in 4 flows back into the vaporization zone 23 under the action of gravity, whereby heat transfer is started again.

If the fuel flow is small, the heating section 6 is cooled by the fuel very little. As a result, the temperature difference with respect to the boiling temperature is reduced and the amount of steam condensed is also small.

When the fuel injection process is completely stopped, steam condensation is reduced to the extent necessary to compensate for heat losses. Conversely, if the heating section 6 loses a lot of heat due to a large amount of fuel injection, a lot of steam will be condensed.

To avoid the formation of vapor bubbles within the fuel,
Since it is important to keep the boiling temperature and pressure of the auxiliary medium constant, a control system is built into the capsule 19.

As the steam pressure increases, the capacity of the capsule 19 also expands, thereby readjusting the predetermined pressure. A conduit 16 leading to a capsule 19 is attached to the deepest point of the vaporization zone 23. The condensate that has completely filled the capsule 19 is collected at this location before being vaporized. As mentioned above, when the vapor pressure increases, capsule I9
more condensate 21 by expanding the capacity of
becomes received within the capsule 19. the result,
Only a small amount of condensate is boiled and the steam pressure is reduced again. Such a control process is reversible and takes place continuously, so that even after temporary fluctuations the pressure is quickly brought back to a balanced state. Furthermore, since the heating section 6 and the intermediate part 5 are made of heat storage material, the fuel temperature is hardly influenced by fluctuations in the pressure and boiling temperature of the auxiliary medium.

The initial internal pressure within the heat tube 4 is regulated by a gas pad. This gas pad acts on the bellows 18 from the outside within the capsule 19.

Insulators 25 are provided in the intermediate chambers of these elements so that the heat is conducted to the heating section 6 in a controlled manner only by the heat exchanger 2.
is completely filled.

In order to avoid overheating of the vaporization zone 23, the heat exchanger 2 or a part thereof can be made of a material whose thermal conductivity decreases significantly as the temperature increases. For example, semi-steel has a thermal conductivity of 200 to 500°C. Also, a material whose thermal conductivity changes significantly during the transition from solid to liquid may be filled between the vaporization zone 23 of the heat tube 4 and the heat exchanger 2.

As shown in FIG. 2, the capsule 19 is connected via a conduit 16 to the lowest point of the vaporization zone 23 of the heat tube 4 in order to control the pressure of the auxiliary medium.

If a relatively large amount of heat is inadvertently transferred from the internal combustion engine 1 to the heating section 6, the risk of vapor bubbles forming in the fuel has to be taken into account. In FIG. 3, another heat tube 27 is shown which is fixed to the intermediate member 5 by means of a vaporization zone 26, the condensation zone 28 of the heat tube 27 supporting cooling ribs 29. When the temperature of the vaporization zone 26 rises to boiling temperature due to the sudden rise in the temperature of the heating zone 6,
Heat transfer is started from the heating section 6 toward the cooling ribs 29. This prevents the temperature from rising too high in a self-limiting manner.

As shown in FIG. 4, the container 17 is closed by a piston 34. The piston 34 is loaded by a spring 35 and uses the spring force to regulate the pressure of the auxiliary medium.

According to FIG. 5, a heating coil 36 is mounted around the heating section 6 for providing additional heating. If the fuel must be heated immediately upon starting the engine, the heating coil 36 is required. Once the heat exchanger 2 in the exhaust passage 3 reaches the operating temperature, no additional electrical heating is required as described above.

The invention is not limited to the embodiments described above, but many other embodiments are possible. Furthermore, the device according to the invention can be used not only in the two-stroke engines mentioned above but also in four-stroke engines. The fuel may also be supplied into the intake pipe of the engine, and a relatively large number of heat pipes may be associated with each heating section,
Instead of the gravity-actuated heat tubes mentioned above, heat tubes with capillary tubes may also be used.

[Brief explanation of the drawing]

The drawings show several embodiments of the device according to the invention; FIG. 1 is a longitudinal sectional view of the device according to the invention, FIG. 2 is a longitudinal sectional view of an exhaust gas heat exchanger with heat tubes, and FIG. FIG. 4 is a vertical cross-sectional view of a heating section showing another embodiment, FIG. 4 is a vertical cross-sectional view of a container showing another embodiment, and FIG. 5 is a longitudinal cross-sectional view of a heating section showing yet another embodiment. l... Internal combustion engine, 2... Heat exchanger, 3... Exhaust passage 4... Heat pipe, 5... Intermediate member, 6... Heating section, 7... Combustion chamber, 8... ... Fuel injection valve, 9... Fuel injection pump, lO... Piston, 11... Drive device, 12... Displacement chamber, 13.14... One-way valve,
15... Front pump, 16... Conduit, 17... Container, 18... Bellows, 19... Capsule, 20...
・Pressure chamber, 21... Condensate, 22... Steam, 23.
... Vaporization zone, 24... Condensation zone, 25... Heat insulator, 26... Vaporization zone, 27... Heat tube, 28... Condensation zone, 29... Cooling lip, 34... piston, 3
5...Spring, 36...Heating coil procedure amendment (voluntary)

Claims (1)

[Claims] 1. A method for supplying heated liquid fuel by a fuel injection pump, the method comprising supplying fuel under high pressure to a fuel injection valve until the fuel flows out from the fuel injection valve. at an optimum pressure level and an optimum temperature level to ensure that the fuel remains in a liquid state and is transferred to a vapor state by latent heat after exiting the fuel injector.
In a type that supplies heat after the fuel injection pump, the fuel is heated by the latent heat of the auxiliary medium released when the vapor of the auxiliary medium is condensed, and the temperature level of the fuel is controlled by the condensation temperature of the auxiliary medium. A method for supplying heated liquid fuel by means of a fuel injection pump, characterized in that: 2. The method as claimed in claim 1, characterized in that the auxiliary medium is circulated between the vaporization zone (23) and the condensation zone (24) based on the heat tube (4) principle. 3. The method according to claim 1 or 2, wherein the pressure of the auxiliary medium is controlled to control the condensation temperature of the auxiliary medium. 4. The method of claim 1 or 2, wherein the amount of circulating auxiliary medium is varied in order to control the heat transfer efficiency. 5. The method according to claim 1 or 2, wherein the heat for vaporizing the auxiliary medium is extracted from exhaust gas heat. 6. The method according to claim 1, wherein the heat for vaporizing the auxiliary medium is obtained by an electric heating device. 7. A device for carrying out the method according to any one of claims 1 to 4, in which the heat tube (4) is a conduit (16).
via which it is connected with a container (19) which stores completely or partially the auxiliary medium in liquid state, the volume of which can be varied by the arrangement of the piston (34) or the bellows (18). A device for supplying heated liquid fuel by a fuel injection pump, characterized in that: 8. Device according to claim 7, characterized in that the container (19) and the heat pipe (4) are connected by a vaporization section (23) of the heat pipe (4). 9. Device according to claim 7, characterized in that the adjusting force produced by the spring (35) or the enclosed gas pad (20) acts on the piston (34) or the bellows (18). 10. Device according to claim 1 or 2, characterized in that the condensation zone (24) is provided vertically above the vaporization zone (23). 11. The elements (5, 6) for supplying heat to the fuel, depending on their material and configuration, are connected from the condensation zone (24) to the fuel injection valve (8).
11. The device as claimed in claim 1, wherein the device has a high thermal conductivity up to ) and has only a small temperature difference in each case with respect to the condensation temperature of the auxiliary medium. 12. The members (5, 6) supplying heat to the fuel are connected to the condensation zone (
24) to the fuel injection valve (8) are made of a material that has a good heat storage effect, and until the temperature fluctuations caused by the fuel flow are controlled by the auxiliary medium control system, the parts (5, 6) temperature fluctuation is small,
12. Device according to any one of claims 1 to 11. 13. The heated fuel guiding element (6) is connected to the vaporizing zone (26) of the hot tube (27) serving for cooling, and the condensing zone (28) of the hot tube (27) is connected to the cooling medium. The pressure of the auxiliary medium in the heat tube (27) is regulated so that the boiling temperature of the auxiliary medium is only slightly higher than the optimal fuel temperature, and the above-mentioned member (6) is protected from inadvertent engine waste heat. 4. Device according to claim 1, characterized in that the heat tube (27) is activated whenever it becomes too hot. 14. The device according to claim 1, wherein a heat insulator (25) preventing direct heat transfer is provided between the heat source (3) and the element (6). 15. whether the components between the heat source (3) and the heat tube (4) contain or are made of a material with a variable thermal resistance that increases with increasing temperature; 6. The device according to claim 5.