DE102008035271A1 - Method for catalytic processing of exhaust gases from diesel engines in motor vehicle, involves producing contaminated gases with potential and kinetic energy during fuel combustion by interaction of exhaust gases and catalysts - Google Patents

Abstract

The method involves producing contaminated gases e.g. soot, nitrogen oxide, carbon monoxide and hydrocarbon, with potential and kinetic energy during fuel combustion by interaction of exhaust gases and catalysts. A catalytic converter is arranged on blades and at walls of an exhaust gas duct. A cylinder-piston-assembly and a valve of a combustion chamber of a diesel engine are coated with a catalytic active coating. Required amount of oxidant e.g. propane and air, is supplied for removal of the contaminated gases. An independent claim is also included for a device for processing exhaust gases from diesel engines.

Description

The present invention relates to environmental protection and the processing of diesel exhaust.

Aim:

Development of a new technology and a device for the catalytic processing of exhaust gases with the aim of reducing pollutant emissions and increasing the efficiency of the engine.

State of the art:

The reduction of pollutant emissions is achieved through the use of optimum fuel-oxygen / air proportion and optimal temperature conditions within the combustion chamber and the catalyst.

There are known catalytic reactors which use ceramic or metal substrates with required catalyst coating.

Each device has a metal housing (usually stainless steel) containing a one-piece ceramic or stainless steel structure. The structure is coated with a required catalyst.

One catalyst oxidizes CO and CnHm, the other reduces NOx from the exhaust gases of a diesel engine.

Because of its thin walls, the ceramic carrier of the catalyst is brittle and prone to vibration or damage (cracking) when shaken.

Damage that occurs to the catalyst can be caused by vibration or thermal shock when in contact with puddle splashes.

A motor vehicle catalyst fulfills several functions. He not only takes over the dry cleaning, but also noise reduction and formation of a planned backpressure in the exhaust system.

Modern catalytic systems ensure effective contact with the catalyst through the use of high hydraulic resistance devices (nominal Re> 10000).

The existing known types of catalysts have their disadvantages, namely: high aerodynamic resistance at higher loads, especially in the case of a two- or multi-stage cleaning. The flow cross-section of the channels remains unchanged during operation, so vortex formation at lower flow rates is insufficient, at higher flow rates results in excess resistance.

Therefore, a portion of the engine output to overcome the aerodynamic drag of the catalyst design is uselessly spent, bringing with it a substantial reduction in engine performance and economy.

At temperatures below optimal operating temperature, slowing down and losses occur in the catalytic reaction efficiency.

If the reaction temperature is higher than the optimum heat state, the catalyst and its ceramic carrier may be damaged (eg, sintering).

The engine operating in various modes produces combustion gases having different temperatures and chemical compositions.

The temperature of the exhaust gases also changes as it passes through the exhaust system.

At the moment, there is no single catalytic converter that would carry out the purification of diesel exhaust gases from all pollutants, which necessitates the use of multi-stage purification processes (eg: Bluetec for Mercedes-Benz, 3- to 4-stage).

The z. Existing development work (exhaust gas recirculation, alternative fuel types, etc.) can only provide partial solutions to this problem because the fuel still burns badly and the environment is polluted (CO, CnHm, NOX), d. H. the use of a catalyst is necessary, which in turn brings losses in performance and efficiency through hydraulic resistances.

Known patent ( DE 3929297 C2 A catalyst for the purification of exhaust gases, in particular from superstoichiometrically operated internal combustion engines and gas turbines from a one-piece present as a honeycomb body exhaust gas purifying catalyst having a catalyst for the selective reduction of nitrogen oxides by means of ammonia gas and in a downstream portion of an oxidation catalyst in an upstream section and as a coating of a downstream section is applied as a Vollextrudat reduction catalyst.

In a known invention ( DE 103 35 265 A1 The present invention is based on the object of developing a new technology for the catalytic exhaust system and for the combustion chamber, which helps to solve the above problems.

The advantage of this invention is that the exhaust system can function without a separate catalytic converter unit and a separate damper damper; The quality of the catalytic purification is maintained and even improved.

The invention minimizes engine leaning in the modes which require increased and maximum power (uphill, overhaul, etc.) and thus contributes to safety, economy and environmental protection.

Furthermore, this invention ensures a qualitative fuel combustion at the exclusion of extreme temperature units, which leads to the reduction of all pollutant emissions.

description

Parts of the engine and the exhaust system (including turbocharger), which come into contact with exhaust gases are coated with (or composed of) catalytically active substances. This makes it possible to dispense with a separate catalyst unit, which causes the lowering of the engine power, and perform the catalytic purification without loss of power through hydraulic resistances of the catalyst.

This reduces the probability of mechanical and chemical damage to the catalyst.

On the catalytic components of the engine mixing and mutual reaction of fuel and oxidizer occur (for example: diesel fuel and air). Walls, pistons and other parts of the engine are coated with or composed of catalyst.

This makes it possible to improve the combustion process, to make it more complete and economical and to reduce pollutant emissions (CO, CnHm, NOx, soot). The use of coatings of catalysts (eg, oxidizing and other catalysts) avoids the formation of combustion residues and other deposits on the surface of the exhaust system and exhaust gas turbocharger. This makes it possible to increase the life of the catalyst and turbocharger and to contribute to better environmental protection.

For fuel economy and emission reduction, as well as maintaining the operating temperature of the catalyst, electrical energy from the generator driven by the turbocharger is used.

The catalytic exhaust gas turbocharger operates in the temperature range which is optimal for the catalytic reaction (eg is heated up electrically).

The use of differently oriented catalytic converters along the exhaust system makes it possible to remove all pollutants from the exhaust gases.

For example, first, the fuel is oxidized on the oxidation catalyst and then, after adding a reducing agent [NH 3, CO (NH 2) 2, etc.], nitrogen oxides (NO x) are removed in the reduction catalysis section.

Connecting the turbocharger to, for example, a generator or other adjustable resistor allows optimal velocity and resistance of exhaust streams to be achieved. The resistance of a generator or other variable resistors is adapted to the engine operating condition to achieve optimum resistance in the exhaust system.

This makes it possible to use the energy generated by the turbocharger in corresponding processes for improving the engine characteristics.

There is known a method of cooling turbine blades (movable or stationary) with air which is supplied through the incorporated internal channels and out of the specific window openings ( RU 2 294 438 C2 ; FR 04 00289 ).

In this invention, the o. E. Cooling windows, which are located on the movable or fixed blades, a chemical medium / a mixture for reducing the emission of pollutants and for the simultaneous cooling of the blades supplied.

For example: A reagent for reducing emissions (e.g., urea solution) is supplied through the windows on the blades in the catalytic turbine and / or in front of the catalyst, allowing for optimum mixing with minimal resistance. This makes it possible to reduce pollutant emissions.

The use of this invention makes it possible to improve the acceleration characteristics of the engine with its increasing load (starting, overtaking, etc.). This thus contributes to the reduction of the frequency of disturbances, reduction of fuel consumption and, accordingly, to the reduction of pollutant emissions.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 3929297 C2 [0019]
• DE 10335265 A1 [0020]
• RU 2294438 C2 [0034]
• FR 0400289 [0034]

Claims (1)

A method and apparatus for processing exhaust gases (diesel) for diesel engines which produce pollutant gases (soot, NOx, CO, CnHm) with non-zero energy (potential and kinetics) at fuel combustion; consists in the interaction of exhaust gases and catalysts. 1. differs in that the corresponding parts of the diesel engine and its exhaust system (including turbocharger), which come into contact with exhaust gases, are coated with a catalyst or from the catalytically active for the purpose of environmental protection and increasing the specific performance and efficiency Put together substances. The catalyst present on the blades and on the exhaust-gas channel walls causes the pollutants to after-burn and precludes the use of a filter. 2. differs from P.1 in that the relevant parts of the combustion chamber of the diesel engine (eg cylinder-piston group, valves) are coated with a catalytically active substance for the purpose of environmental protection, as well as increasing its specific performance and economy; to be composed of such. 3. differs from P.1 and 2 in that the catalytic converter is designed to have a different chemical composition in different sections of the exhaust gas removal path including the combustion chamber for the purpose of environmental protection and increasing the specific performance and economy of the diesel engine It is conditional that the characteristic values of the gases change in the course of the combustion process in diesel engines and in exhaust gas discharge paths. 4. differs from P.3 in that for the purification of various pollution components in the diesel engine (eg CO, CnHm against NOx) for the purpose of environmental protection as well as the increase in specific performance and economy a multi-stage purification process (oxidation and reduction ), for which various turbocharger stages are coated with different catalysts or - in the case of several turbochargers - different catalysts are applied to different turbochargers. 5. differs from P.1 in that for the purpose of environmental protection and increasing the specific performance and economy to improve the catalytic process within the exhaust duct of the diesel engine, a number of various improvement measures (eg.: Whirling inserts, special form of gas discharge path, optimal Roughness of both the walls, and the turbine wheel of the turbocharger, etc.) is implemented. 6. differs from P.4 in that for the purpose of environmental protection and increasing the specific performance and economy of the diesel engine, the turbocharger has an adjustable hydraulic resistance (eg: by connection to the alternator or to another variable resistor, use of the variable angle Shovels, etc.), which results in optimum speed and resistance of exhaust gas streams. The resistance of the generator etc. is adjusted to the operating condition of the diesel engine for the purpose of achieving optimum resistance of the exhaust system. 7. differs from P.1 to 6. in that for the purpose of environmental protection, increase in specific performance and economy, the parts of the diesel engine and / or the exhaust system are provided with a catalyst with integrated heaters, the temperature of the catalysts in the optimal Hold area. The operation of the heaters is selected by an integrated control and regulation system. 8. differs from P.7 in that the catalyst is warmed up prior to starting the diesel engine, thereby improving catalyst life and operating efficiency over its lifetime. 9. differs from P.7 and 8 in that electrical energy is used to maintain the operating temperature of the diesel engine catalyst, which is generated by a turbocharger-driven generator, allowing it to move away from the over-stoichiometric engine operation and, in the end, fuel economy and downslope to win the emissions. 10. differs from P.9 in that a readily oxidizable fuel and / or oxidant (e.g., propane and air) are necessarily added to maintain the operating temperature of the diesel engine catalyst in the exhaust gases. 11. To remove the soot from the diesel engine exhaust gases required amounts of the oxidant (eg: N2O4, etc.) are supplied. The oxidant is used for afterburning of soot and other contaminants at lower temperatures, which allows to dispense with the soot filter. 12. differs from P.10 and 11 in that the section of the exhaust gas discharge path in the diesel engine in which the additional fuel ( Oxidant) is burned, as a burner or as a similar device is executed. As required, the oxidant and / or fuel is supplied in stages. 13. differs in that a medium / a mixture for reducing the emission of pollutants is fed through the cooling window on the blades of the diesel engine turbocharger, which serves for cooling at the same time. 14. differs from P.12 in that the cooling channels, which supply the cooling medium (gas or liquid) to the diesel engine turbocharger, are made of a catalyst or coated with a catalyst, which converts the cooling medium by endothermic reaction, which provides better cooling.