Patent ID: 6041593
Filing Date: 2000-03-28
Classification: F01N,F02B,Y02A,Y02T

Abstract:
A device for reducing emissions in a catalytic converter exhaust system for a combustion engine, said catalytic converter providing reduced emissions after a light-off time has passed during start-up of the engine, said device comprising:an exhaust pipe connecting the engine with the catalytic converter,an air/fuel mixture forming means for providing a mixture of air and fuel to the engine,a control unit adapted for controlling the air-fuel mixture forming means so that a high concentration of hydrogen and other combustible gasses are generated in the exhaust gas during start-up of the engine, andan air supply means for supplying secondary air downstream of at lease one engine exhaust valve during cold starting of the engine, for forming a gas mixture with the exhaust gas,said engine being provided with a plurality of primary exhaust outlet pipes, wherein said primary exhaust outlet pipes are shaped with a first section and a second section, the second section having a larger cross-sectional area than the first section, said second section positioned downstream of said first section with respect to the direction of flow of the exhaust gas, and whereinsaid control unit is adapted to control said generation of hydrogen and the operation of said air supply means, thereby generating an exhaust oxidation in said gas mixture, so that heat energy generated during the oxidation is supplied to the catalyst, thereby providing a reduction to the light-off time of the catalyst.