JPH02157464A - Super-low pollution internal combustion engine - Google Patents

Abstract

PURPOSE:To obtain a super low pollution internal combustion engine which can be mounted on a vehicle and which can treat nitrogen oxides in exhaust gas by carrying out the synthesis of ammonia on the vehicle with the hydrogen of fuel and the nitrogen in the air as the raw materials and introducing ammonia into the exhaust gas. CONSTITUTION:A liquid hydrogen in a liquid hydrogen tank 1 is sent into a heat exchanger 4 to be vaporized into a hydrogen gas and, then stored in a high pressure hydrogen gas tank 5. Part of air which is taken into an engine 7 is sent to a nitrogen separating device 10 where it is separated by means of a separating film, etc. to be a high density nitrogen, which, together with the hydrogen from the high pressure hydrogen gas tank 5, is sent to an ammonia synthesizing reactor 12 to synthesize ammonia, which is separated by a solid acid vessel 13 for adsorbing/separating ammonia and stored in an ammonia tank 16. The density of NOX in an engine exhaust gas is detected by a sensor 21, a control valve 17 is feedback controlled based on the judgment of an electronic control device 19, a defined quantity of ammonia from the ammonia tank 16 is mixed with the exhaust gas to decompose NOX by a NOX treating catalyst bed 20 and exhaust same.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is directed to the treatment of nitrogen oxides (hereinafter referred to as
This invention relates to an ultra-low-pollution internal combustion engine that processes wastewater (referred to as N031) on-vehicle.

[Prior art and problems to be solved by the invention] A hydrogen engine is an engine that uses hydrogen, which can be obtained in unlimited amounts from seawater, as fuel. Hydrogen is vaporized from liquid to high-pressure gas and is injected directly into the combustion chamber of the engine. It is attracting attention because it produces clean exhaust and high power by igniting it using electric heat.

In conventional gasoline and diesel engine engines,
Harmful IC, Co, NOx, and particulates exist in the exhaust gas. Furthermore, concerns have been raised regarding CO2, which is likely to worsen the global environment. In this respect, hydrogen engines are attracting attention as clean engines that do not generate HC, Co, or particulates, but the problem of NOx emissions remains.

As a conventional NOx treatment technology in exhaust gas, NO8 is used in the field of stationary boilers and diesel engines.
A method (SCR method) is adopted in which ammonia is introduced from a cylinder together with diesel engine exhaust into the treatment catalyst bed, and NoX is reduced through the following reaction.

2NHZ +2NO+(1/2) O! -2N l
+3LO However, the above treatment method has the problem of having to periodically fill or replace the ammonia cylinder, and is unsuitable for use in vehicles due to weight, maintenance, etc., and is not suitable for practical use. has not yet been reached.

On the other hand, conventional ammonia production methods use large-scale equipment to produce ammonia under high pressure, and also use a freezing method for gas purification, making it difficult to install on vehicles.

The present invention is intended to solve the above problems, and aims to provide an ultra-low-pollution internal combustion engine that can be installed in a vehicle and that can treat nitrogen oxides in engine exhaust. do.

[Means for Solving the Problems] In order to achieve this object, the ultra-low pollution internal combustion engine of the present invention includes a liquid hydrogen tank, a hydrogen gas tank that vaporizes and stores liquid hydrogen in the tank, and a hydrogen gas tank that vaporizes and stores liquid hydrogen in the tank. The engine is equipped with an engine in which hydrogen gas is injected, a nitrogen separation device that separates nitrogen from the intake air of the engine, and an ammonia synthesis reactor that synthesizes ammonia using the nitrogen and the hydrogen gas. The method is characterized in that the ammonia is introduced into a catalyst bed that selectively reduces the ammonia.In short, ammonia is synthesized on the vehicle using hydrogen in the fuel and nitrogen in the air as raw materials, and ammonia is introduced into the exhaust gas. This is a characteristic feature.

[Effect]

In order to synthesize ammonia on a vehicle, ■ there must be nitrogen, ■ there must be hydrogen, ■ there must be a low CO concentration, ■
It is necessary to carry out the reaction at high pressure. In the present invention, ■ Nitrogen uses nitrogen in the air, ■ Hydrogen uses hydrogen fuel, ■ No CO, and ■ High-pressure reaction is achieved by using a pressurizing pump. It is.

〔Example〕

Examples will be described below with reference to the drawings.

1 is a configuration diagram showing one embodiment of the ultra-low pollution internal combustion engine of the present invention.

The present invention is comprised of a hydrogen engine A and a NOx treatment device.

The hydrogen engine A includes a liquid hydrogen tank 1, a pump 2, a motor 3, a heat exchanger 4, a high pressure hydrogen gas tank 5, an injection valve 6,
Consisting of an engine 7, a pump 2 is operated by a motor 3, and liquid hydrogen stored in a liquid hydrogen tank 1 is sent to a heat exchanger 4 to be vaporized into hydrogen gas, and then stored in a high-pressure hydrogen gas tank 5. . The pressure in the tank 5 is always maintained at an appropriate pressure by a controller 8 that controls the speed of the motor 3 based on a signal from a tank pressure sensor 9. Most of the hydrogen gas in the tank 5 is injected into the engine 7 from the injection valve 6 and combusted.

The NOX treatment device FB includes a nitrogen separator jfIO1 pressure pump 11. It is composed of an ammonia synthesis reactor 12, a solid acid layer 13 for adsorption and desorption of ammonia, a circulation pump 15, an ammonia tank 16, a control valve 17, an electronic control device 19, and a catalyst bed 20 for NOX treatment.

A part of the air taken into the engine 7 is transferred to the nitrogen separator 1
Send to 0, minutes here! IIIE! ! , a molecular sieve, etc. to separate it into highly concentrated nitrogen, and send it together with hydrogen from the high-pressure hydrogen gas tank 5 to an ammonia synthesis reactor 12 by a pressurizing pump 11, where ammonia is synthesized. The catalyst used at this time is a ruthenium-based catalyst, such as Ru.
-CsOH/AlsO1 catalyst is used. In the present invention, CO1CO! which is a catalyst poison! Since ammonia is not included in the raw material gas, ammonia can be synthesized relatively easily.

Solid acid tank 1 for ammonia adsorption and desorption of generated ammonia
3 and stored in an ammonia tank 16. Acid-treated silica, alumina or zeolite is suitable as the solid acid. Solid acids have the property of adsorbing ammonia at a relatively low temperature of about 100'C and desorbing ammonia at a high temperature of about 400C. Two layers of this solid acid are provided, and ammonia is adsorbed or separated by repeating heating and cooling alternately, and the separated ammonia is stored in an ammonia tank 16. Unreacted nitrogen and hydrogen are sent to the ammonia synthesizer 12 again by the circulation pump 15.

Then, the sensor 21 detects the NQ, i in the air of the engine U.
4 degrees, and feedback controls the control valve 17 according to the concentration based on the judgment of the electronic control device 19.
A predetermined amount of ammonia is mixed into the exhaust gas from the ammonia tank 16, and NO8 is decomposed in the NO treatment catalyst bed 20 and exhausted.

Note that the control valve 17 may be controlled by detecting the engine speed and load. Additionally, if an excessive amount of ammonia is supplied, the ammonia concentration sensor 22
may be detected and controlled to reduce the ammonia supply amount.

〔Effect of the invention〕

In this way, the present invention makes it possible to apply the NOX treatment system using the SCR method, which was previously only used in stationary boilers and diesel engines, to the treatment of υ gas in hydrogen engines, and to reduce the amount of HC, CO1, and particulate. It is possible to provide an ultra-low pollution internal combustion engine with extremely low emissions.

Furthermore, in the present invention, ammonia can be synthesized relatively easily because C01CO□, which is a catalyst poison, is not contained in the raw material gas.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the ultra-low pollution internal combustion engine of the present invention. A...Hydrogen engine〉〆, B...No, processing device, 1
...Liquid hydrogen tank, 2...Pump, 3...Motor, 4...Heat exchanger, 5...High pressure hydrogen gas tank,
6... Injection valve, 7... Engine, IO... Nitrogen separation device, 11... Pressure pump, 12... Ammonia synthesis reaction L13... Solid acid layer for ammonia adsorption and desorption,
15...Circulation pump, 16...Ammonia tank,
17...la? 11 Balf, 19...Electronic control unit, 20...No, treatment catalyst bed.

Claims (1)

[Claims] (1) A liquid hydrogen tank, a hydrogen gas tank that vaporizes and stores liquid hydrogen in the tank, an engine into which the hydrogen gas is injected, and a nitrogen separation device that separates nitrogen from the intake air of the engine. An ultra-low pollution internal combustion engine comprising an ammonia synthesis reactor for synthesizing ammonia using the nitrogen and hydrogen gas, and introducing the ammonia into a catalyst bed that selectively reduces nitrogen oxides in exhaust gas.