Exhaust gas recirculation cooling system
AssigneeCaterpillar Inc.
InventorsBrett M. Bailey, David A. Pierpont
Life of this patent
Estimating the term…
Abstract
A twin-turbocharged internal combustion engine improves compression efficiency and improves response by serial arrangement of a first turbocharger and a second turbocharger. An exhaust gas recirculation (EGR) system using boost cooling reduces emissions of nitrogen oxides (NOx). The EGR system cools recirculated exhaust gas by exchanging heat with compressed, cooled combustion air in an EGR heat exchanger. The second turbocharger has a variable geometry turbine to control flow of recirculated exhaust gas.
Claims14
An internal combustion engine comprising:
- an engine block;
- a cylinder head connected with said engine block;
- an exhaust manifold fluidly connected with said cylinder head;
- an inlet manifold fluidly connected with said cylinder head;
- a first turbocharger having a first turbine and a first compressor, an inlet portion of said first turbine being fluidly connected with said exhaust manifold through a first fluid conduit;
- a second turbocharger having a second turbine and a second compressor, an inlet portion of said second turbine being fluidly connected with said exhaust manifold through a second fluid conduit, an outlet portion of said first compressor being fluidly connected with an inlet portion of said second compressor;
- an outlet portion of said second compressor being connected with said intake manifold through a compressed gas conduit;
- an exhaust gas recirculation conduit fluidly connecting said second fluid conduit with said intake manifold;
- a bypass conduit fluidly connecting said compressed gas conduit with the inlet portion of said first turbine;
- and
- an exhaust gas recirculation heat exchanger being adapted to thermally connect said exhaust gas recirculation conduit with said bypass conduit.
A method of controlling an exhaust gas recirculation system for an internal combustion engine comprising the steps:
- sensing an engine operating parameter;
- reducing restrictions to a flow of exhaust gas through an EGR conduit wherein said engine operating parameter indicates production of NOx;
- reducing restrictions to a flow of combustion air through a bypass conduit wherein said engine operating parameter indicates production of NOx;
- and
- exchanging heat between said flow of combustion air and said flow of exhaust gas.
Dependencies are inferred from the claim text.