Internal combustion engine fuel supply system

Abstract

A system to supply hydrogen-rich fuel to an internal combustion engine, whereby a hydrogen-rich gas is produced from a liquid raw fuel by a hydrogen generator. The exhaust line of the internal combustion engine contains an exhaust purification system, such as a DeNOx catalytic converter, which is at least temporarily supplied with hydrogen-rich gas through a bypass line. In addition, the exhaust line is in thermal contact with the hydrogen generator in order to recover thermal energy.

Description

FIELD OF THE INVENTION [0001] The invention concerns a system for supplying fuel to an internal combustion engine. DESCRIPTION OF THE RELATED ART [0002] A goal in the development of motor vehicles with internal combustion engines today is the reduction of fuel consumption and carbon dioxide emissions. It is also desired to reduce other pollutants in the exhaust, in particular nitrogen oxides (NOx). [0003] Motor vehicles with cracking carburetors, in which hydrocarbon fuels are converted by a partial oxidation device prior to entering the internal combustion engine, are well known. However, this conversion process typically requires temperatures over 800° C., resulting in the formation of soot particulates. In addition, the exothermic nature of the reaction leads to an energy loss during the chemical conversion. [0004] DeNOx (nitrogen oxide removal) catalytic converters, which reduce nitrogen oxides in the exhaust by converting the nitrogen oxides to nitrogen with a suitable catalyst...

AI Technical Summary

Benefits of technology

[0006] The present system includes a hydrogen generator to produce a hydrogen-rich fuel for combustion in an internal combustion engine. The hydrogen-rich fuel may also be used in a downstream DeNOx catalytic converter to reduce the NOx content of the engine exhaust. Heat is recovered from the exhaust stream and supplied to the hydrogen generator to support the endothermic conversion of raw fuel to the hydrogen-rich fuel.

[0007] Using endothermic reactions during the production of hydrogen-rich fuel increases the calorific value of the reactants by the amount of energy recovered from the engine exhaust. This leads to a correspondingly higher overall efficiency of the whole system, which goes hand in hand with a reduction in carbon monoxide emissions.

[0008] Hydrogen-rich fuel produced by endothermic steam reforming in addition to being suitable for combustion in the internal combustion engine, is particularly useful as a reducing agent in a DeNOx catalytic converter. The increased nitrogen output, which in the case of methanol—due to the high purity of the fuel—predominantly consists of thermal nitrogen oxides, can be reduced by a DeNOx catalytic converter in combination with the use of the produced hydrogen-rich fuel as a reducing agent. This makes it possible to increase the combustion temperature, and thus the efficiency, of the internal combustion engine.

Problems solved by technology

For conversion of hydrocarbon fuels, similar amounts of energy have to be transferred at significantly higher temperatures, so that the energy content and the temperature level are potentially only sufficient to partially convert the fuel.

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