JPH02181027A - Hydrogen-or liquefied natural gas-powered engine - Google Patents

Abstract

PURPOSE:To efficiently cool a suction pump and improve its durability by providing a suction pump between an intake and a take-out port of an oxygen enriched air supply means and also providing an exhaust fan at an exhaust port of the above-mentioned means together with turning the downstream side of the exhaust fan to the suction pump. CONSTITUTION:In an engine 2, to which oxygen enriched air is supplied and to which hydrogen or liquefied natural gas is selectively supplied as fuel, an air cleaner 10 is installed on the air intake (6a) side of a main body 6 of an oxygen enriched air supply mechanism 4, while an engine-driven, suction pump 12 is installed on the air take-out (6b) side of the main body 6. With this, oxygen enriched air, whose oxygen concentration is thickened by using an oxygen enriched film 8, can be exhausted to the air take-out (6b) side. In addition, the main body 6 is provided with an exhaust port 14 which is connected with an exhaust fan 16. The downstream side 14z of this exhaust port 14 is turned to the suction pump 12, so that unnecessary, nitrogen enriched air can be exhausted therefrom and at the same time this nitrogen enriched air can be used as cooling gas for the suction pump 12.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an engine for hydrogen and liquefied natural gas, and in particular, it supplies hydrogen and liquefied natural gas as fuel according to the load operating state of the engine, and This invention relates to a hydrogen/liquefied natural gas engine that improves engine performance by supplying hydrogen and liquefied natural gas.

[Conventional technology] Gasoline, diesel oil, etc. are mainly used as fuel for internal combustion engines, but in view of various problems such as pollution caused by harmful exhaust substances and resource depletion, alternative fuels have recently been used. Hydrogen and liquid natural gas (LNG) are attracting attention. Since hydrogen and liquid natural gas are gaseous fuels, they can mix well with air and produce a homogeneous air-fuel mixture, resulting in good combustion and a reduction in harmful exhaust emissions. It has various advantages such as:

As such an engine, for example, the special public
Some of these are disclosed in Japanese Patent Application Laid-Open No. 808, Japanese Patent Application Laid-Open No. 162226-1980, and Japanese Patent Application Laid-open No. 119928-1987, respectively.

Japanese Patent Publication No. 57-4808 discloses a method for stably supplying hydrogen by adjusting the amount of exhaust gas supplied to heat metal hydride to generate hydrogen according to the pressure of the generated hydrogen. A hydrogen engine is disclosed.

In addition, Japanese Patent Application Laid-Open No. 5Ei-162226 discloses that liquefied natural gas compressed at low pressure is dissolved in a solvent such as kerosene and stored.
A liquefied natural gas engine that uses liquefied natural gas vaporized and retained on this solvent as fuel has been disclosed.

Furthermore, Japanese Patent Application Laid-Open No. 58-119928 discloses that by arranging an exhaust valve and a hydrogen supply valve facing each other on both sides of two intake valves provided in a combustion chamber, hydrogen flows toward the high-temperature exhaust valve. A hydrogen engine has been disclosed in which the occurrence of premature ignition and knocking is prevented by blocking the flow of air.

[Problems to be Solved by the Invention] Incidentally, in conventional hydrogen/liquefied natural gas engines, in order to obtain air with high oxygen concentration from the oxygen enriched membrane of the oxygen enriched air supply means, oxygen is supplied by the intake pump. A predetermined pressure difference is created between the front and rear parts of the enrichment membrane.

If the suction pump increases the pressure difference and the air flow rate, the suction pump will become hot and there is a risk that it will be damaged. In other words, the maximum usable temperature of current suction pumps is approximately 120'C, and in order to satisfy the above-mentioned required oxygen concentration and flow rate, the temperature must rise by approximately 80'C, so There is an inconvenience that the suction pump is damaged more frequently during high-speed driving or when pitching.

[Object of the Invention] Therefore, the object of the present invention is to provide a predetermined gap between the intake side and the outlet side of the oxygen-enriched air supply means of a hydrogen-filled liquefied natural gas engine in order to eliminate the double disadvantage. In addition to providing a suction pump that creates a pressure difference, an exhaust fan is provided at the exhaust port of the oxygen-enriched air supply means, and the downstream side of the exhaust fan is directed toward the suction pump to cool the suction pump. To provide a hydrogen/liquefied natural gas engine that can reliably cool the suction pump by directing exhaust air from a fan toward the suction pump, and can prevent damage to the suction pump.

[Means for Solving the Problem] To achieve this object, the present invention provides a hydrogen O liquefied natural gas fuel supply system that supplies either hydrogen as a fuel or liquefied natural gas depending on the load operating state of the engine. In the engine, a suction pump is provided to create a predetermined pressure difference between the intake side and the outlet side of the oxygen-enriched air supply means, and an exhaust fan is provided at the exhaust port of the oxygen-enriched air supply means, and the In order to cool the suction pump, the downstream side of the exhaust fan is directed toward the suction pump.

[Function] With the above configuration, when the hydrogen/liquefied natural gas engine is driven, the exhaust air from the exhaust fan is directed toward the suction pump, thereby reliably cooling the suction pump and preventing damage to the suction pump. is prevented.

[Examples] Examples of the present invention will be described in detail below based on the drawings.

1 to 3 show embodiments of this invention. 1st
In the figure, 2 is a hydrogen/liquefied natural gas engine (hereinafter referred to as the "engine"), and 4 is an oxygen-enriched air supply mechanism that is an oxygen-enriched air supply means. In this example, the engine 2 is supplied with oxygen-enriched air and
Hydrogen and liquefied natural gas are supplied as fuel.

The oxygen-enriched air supply mechanism 4 supplies oxygen-enriched air to the engine 2. A chemical film 8 is provided. An air cleaner 10 is provided on the air intake port 6a side of the main body 6, and a suction pump 12 driven by, for example, the driving force of the engine 2 is provided on the air intake port 6b side of the main body 6. This suction pump 1
2, the intake port 6a side and the outlet port 6b of the oxygen enrichment membrane 8
A pressure difference is generated between the two sides, and the oxygen concentration in the air is increased by the oxygen-enriching membrane 8 on the outlet 6b side to generate oxygen-enriched air.

In this way, oxygen-enriched air is generated by increasing the oxygen concentration in the air on the intake port 6b side, while nitrogen-enriched air is generated on the intake port 6a side as air with increased nitrogen concentration due to a reduction in oxygen concentration. will be residually generated. If this nitrogen-enriched air stays around the intake hole 6a, the introduced air will become saturated with nitrogen-enriched air, making it difficult to generate oxygen-enriched air.

Therefore, an exhaust port 14 is provided in the main body 6 of the oxygen-enriched air supply mechanism 4, an exhaust fan 16 is provided in the exhaust port 14, and the downstream side 142 of the exhaust port 14 is directed toward the suction pump 12. There is.

Thereby, unnecessary nitrogen-enriched air can be exhausted to the outside and can also be used as cooling air.

The oxygen-enriched air generated on the side of the outlet 6b of the oxygen-enriched membrane 8 flows through a communication path 18 starting downstream of the suction pump 12.
As a result, the oxygen-enriched air is supplied to an oxygen-enriched air introduction chamber 22 provided at the starting end side of the intake passage 20 of the engine 2. Introduction room 22
A vaporizer 66, which will be described later, is provided inside, and cools the oxygen-enriched air using the latent heat of vaporization of liquefied natural gas, which is the fuel.

The oxygen-enriched air cooled in the introduction chamber 22 is mixed with fuel by a mixer 24 to produce an air-fuel mixture, the flow rate is adjusted by an intake throttle valve 26, and the air is supplied to the combustion chamber 30 via an intake valve 28. . Exhaust gas produced by combustion in the combustion chamber 30 is discharged to the exhaust passage 34 via the exhaust valve 32 and exhausted to the outside.

Oxygen enrichment membrane 8 in the main body 6 of the oxygen enriched air supply mechanism 4
consists of a reference oxygen enrichment film 8-0 serving as a reference, and first and second oxygen enrichment films 8-L 8-2 configured similarly to this reference oxygen enrichment film 8-0.

The reference oxygen enrichment membrane 8-0 and the first and second oxygen enrichment membranes 8-1, 8-2 communicate with the intake port 6a, respectively, and communicate with the outlet 6b, respectively. Said first
, on the outlet port 6b side of the second oxygen enrichment membrane 8-1.8-2,
First and second control valves 36-1 and 36-2 are provided, respectively. These first and second control wells 36-1 and 36-2 are connected to a control means (not shown). By this control means, the first
By opening and closing the second control valve 36-1.36-2, the first and second oxygen enrichment membranes 8-1.8-2 are communicated with and cut off from the outlet 6b side.

An inlet side pressure sensor 38 and an outlet side pressure sensor 40 are provided on the intake port 6a side and the outlet port 6b side of the main body 6, and an introduction chamber pressure sensor 42 and an introduction chamber intake temperature sensor are provided in the introduction chamber 22. A sensor 44 is provided. Each of these sensors 3
8 to 44 are connected to the control means (not shown) so that the difference between the pressures respectively detected by the intake side pressure sensor 38 and the outlet side pressure sensor 40 becomes a predetermined pressure. The suction pump 12 is driven and controlled.

Further, the pressure within the introduction chamber 22 is a pressure difference between the amount of oxygen-enriched air required by the engine 2 and the amount of oxygen-enriched air supplied by the oxygen-enriched air supply mechanism 4. Therefore, in accordance with the pressure inside the introduction chamber 22 detected by the introduction chamber pressure sensor 42 while taking into account the introduction chamber intake temperature detected by the introduction chamber intake temperature sensor 44, the control means controls the first and second control valves 36- 1. Generation of oxygen-enriched air in the oxygen-enriched membrane 8 by controlling the opening and closing of 36-2 to selectively connect the first and second oxygen-enriched membranes 8-L 8-2 to the outlet 6b side. Control the increase/decrease in area. As a result, the amount of oxygen-enriched air supplied from the oxygen-enriched air supply mechanism 4 can be increased or decreased according to the amount of oxygen-enriched air required by the engine 2, and the oxygen-enriched air can be supplied appropriately without causing a large change in oxygen concentration. can do.

The oxygen-enriched air from the oxygen-enriched air supply mechanism 4 is supplied to the engine 2 as desired. In other words, it is possible to supply the fuel over the entire range from the low-load operating state to the high-load operating state of the engine 2, or it is also possible to supply only in a specific load operating state. In addition, code 4
Reference numeral 6 represents an intake check valve that sucks the atmosphere into the introduction chamber 22, and 48 represents an exhaust check valve that exhausts air from the introduction chamber 22 to the atmosphere.

A hydrogen tank (not shown) that stores hydrogen, which is the fuel supplied to the engine 2, is made of, for example, metal hydride (METAL).
HYDRIDE), hydrogen is stored by the mixer 24, a hydrogen mixture is generated by the intake throttle valve 26, and the flow rate is adjusted by the intake throttle valve 26 and supplied to the combustion chamber 30.

Further, a hydrogen tank heating mechanism (not shown) is connected to the cooling water passage 50 of the engine 2, and uses the heat of the exhaust gas to raise the temperature of the cooling water flowing toward the heating mechanism.

The liquefied natural gas tank 52 that stores liquefied natural gas as fuel to be supplied to the engine 2 is filled with cryogenic liquefied liquefied natural gas through a liquefied natural gas filling pipe 54 and a liquefied natural gas filling valve 5θ. The liquefied natural gas in the liquefied natural gas tank 52 is taken out by the liquefied natural gas take-off valve 58 and supplied by the liquefied natural gas supply pipe 60.

The liquefied natural gas supply pipe 60 includes a filter 62 and a solenoid valve 6.
4. Vaporizers 66 are sequentially arranged.

The solenoid valve 64 is connected to a control means (not shown). Further, the vaporizer 66 is provided in the introduction chamber 22, and heats and evaporates the liquefied natural gas through heat exchange with the oxygen-enriched air, and cools the oxygen-enriched air.

Liquefied natural gas supply pipe 60 downstream of the vaporizer 66
is connected to a supply pipe 68, and a regulator 70 is provided in the middle of this supply pipe 68.

The supply pipe 68 supplies liquefied natural gas to the mixer 24 , the mixer 24 generates a mixture of liquefied natural gas, the flow rate is adjusted by the intake throttle valve 26 , and the mixture is supplied to the combustion chamber 30 .

The vaporizer 66 also includes a first passage 72 through which oxygen-enriched air passes, and a first passage 72, as shown in FIG. 2.3.
It has radial fins 74 provided in the middle of the passage 72, and a second passage 76 for liquefied natural gas (LNG) passing through the center of the radial fins 74.

A collection recess 78 is provided at the bottom of the first passage 72 to collect water in the oxygen-enriched air condensed by heat exchange, and the first to third passages
As shown in the figure, a water passage 80 is provided that starts at the lower part of the collection recess 78 and terminates on the downstream side 14z of the exhaust port 14.

Next, the effect will be explained.

When the engine 2 is driven, the control means (not shown)
The suction pump 12 is driven and controlled so that the pressure on the intake port 6a side and the pressure on the outlet port 6b side of the main body 6 of the oxygen-enriched air supply mechanism 4 become predetermined pressures.

In addition, the first and second control valves 3
6-1.36-2 is controlled to open and close, and the first and second oxygen enrichment membranes 8-L 8-2 are selectively communicated with the outlet 6b to generate oxygen-enriched air in the oxygen enrichment membrane 8. Control the increase/decrease in area.

As a result, the amount of oxygen-enriched air supplied from the oxygen-enriched air supply mechanism 4 can be increased or decreased according to the amount of oxygen-enriched air required by the engine 2 without causing a significant change in oxygen concentration.
Supply appropriately.

Either hydrogen or liquefied natural gas is supplied depending on the load operating state of the engine 2, for example, a low-load operating state such as an idling operating state or a low-speed operating state, or a high-load operating state such as an accelerating operating state or a high-speed operating state. control to do so.

Further, the exhaust air from the exhaust fan 16 is discharged toward the suction pump 12 from the downstream side 14z of the exhaust port 14.

At this time, water condensed by heat exchange within the vaporizer 66 is collected in the collection section 78 and guided to the downstream side 14z of the exhaust port 14 by the water passage 80,
The suction pump 12 is blown by the above-mentioned exhaust gas.

Thereby, the suction pump 12 can be cooled by the exhaust gas discharged by the exhaust fan 16, and
Water is blown onto the suction pump 12 by this exhaust air and the water from the vaporizer 66, and the suction pump 12 can be further cooled by the heat of evaporation of the water, which is advantageous in practice.

Furthermore, since the suction pump 12 can be reliably cooled, it is possible to prevent the suction pump 12 from being damaged, especially when driving at high speed for a long time in the summer or when riding uphill.

Furthermore, since this can be achieved by simply extending the exhaust port 14 and forming the water passage 80, the structure is not extremely complicated and costs can be kept low, which is economically advantageous.

[Effects of the Invention] As explained in detail above, according to the present invention, a predetermined pressure difference is created between the intake side and the outlet side of the oxygen-enriched air supply means of a hydrogen/liquefied natural gas engine. In addition to providing a suction pump, an exhaust fan was provided at the exhaust port of the oxygen enriched air supply means, and the downstream side of the exhaust fan was directed toward the suction pump in order to cool the suction pump. The suction pump can be reliably cooled by the exhausted air, and damage to the suction pump can be prevented, especially during long hours of high-speed driving or pitching in the summer. Furthermore, since the configuration of the oxygen-enriched air supply means is not extremely complicated, costs can be kept low, which is economically advantageous.

[Brief explanation of the drawing]

1 to 3 show examples of the present invention, and FIG.
FIG. 2 is a schematic enlarged cross-sectional view of a vaporizer, and FIG. 3 is a schematic end view of the vaporizer taken along the line ■-■ in FIG. 2. In the figure, 2 is a hydrogen/liquefied natural gas engine, 4 is an oxygen-enriched air supply mechanism, 6 is the main body, 6a is an intake port, and 6b
is an outlet, 8 is an oxygen enrichment membrane, 10 is an air cleaner, 12
14 is a suction pump, 14 is an exhaust port, 14z is a downstream side, 16 is an exhaust fan, 22 is an introduction chamber, 36-1 is a first control valve, 3
6-2 is a second control valve, 38 is an intake side pressure sensor, 40
is an outlet side pressure sensor, 42 is an inlet chamber pressure sensor, 44
is an inlet room intake temperature sensor, 46 is an intake check valve, 48 is a discharge check valve, 52 is a liquefied natural gas tank, 66 is a vaporizer, 72 is a first passage, 74 is a radial fin, 76 is a second passage, 78 is a collection recess, and 80 is a water passage. Patent Applicant Representative Patent Attorney Yoshimi Saigo Suzuki Automobile Industry Co., Ltd. Figure 3

Claims (1)

[Claims] 1. In a hydrogen/liquefied natural gas engine that supplies either hydrogen or liquefied natural gas as a fuel depending on the load operating state of the engine, the connection between the intake side and the outlet side of the oxygen-enriched air supply means A suction pump that generates a predetermined pressure difference between them is provided, and an exhaust fan is provided at the exhaust port of the oxygen-enriched air supply means, and a downstream side of the exhaust fan is directed toward the suction pump in order to cool the suction pump. A hydrogen/liquefied natural gas engine characterized by being equipped with a