Back to results
US 7,302,939 B2Granted
Exhaust gas recirculation methods and apparatus for reducing NOx emissions from internal combustion engines
AssigneeWestport Power Inc.
InventorsPhilip G. Hill, Mark E. Dunn, Sandeep Munshi
Life of this patent
Estimating the term…
Abstract
A method of operating an internal combustion engine employs exhaust gas recirculation (EGR) in combination with directly injected gaseous fuels that are burned within the engine in a stratified combustion mode. An engine that employs EGR includes an injector adapted to provide a high pressure quantity of fuel into a combustion chamber within a given pressure range, at a given angle and through a nozzle hole size to help provide for EGR tolerance and, consequently, reduce emissions.
Claims34
A method of operating a gaseous-fuelled internal combustion engine, said method comprising:
- during a cycle of said engine:
- (a) directing an intake charge from an intake line into a combustion chamber of said internal combustion engine,
- (b) compressing said intake charge within said combustion chamber,
- (c) injecting a directly injected gaseous fuel into said compressed intake charge within said combustion chamber at a pressure above 12 MPa,
- (d) igniting said directly injected gaseous fuel,
- (e) burning said directly injected gaseous fuel,
- (f) directing exhaust gas produced during burning of said directly injected gaseous fuel from said combustion chamber into an exhaust line,
- wherein a quantity of said exhaust gas from said exhaust line is directed through an EGR line to said intake line and, during a subsequent cycle of said engine, a subsequent intake charge comprises said quantity of said exhaust gas;
- and
- wherein said quantity of said exhaust gas is dependent on at least one of:
- (1) a target NOx concentration resulting from burning said directly injected gaseous fuel, and (2) said pressure.
8 more elements
A method of operating a gaseous-fuelled internal combustion engine, said method comprising:
- during a cycle of said engine:
- (a) directing an intake charge from an intake line into a combustion chamber of said internal combustion engine,
- (b) compressing said intake charge within said combustion chamber,
- (c) injecting a directly injected gaseous fuel into said compressed intake charge within said combustion chamber at a pressure above 12 MPa,
- (d) igniting said directly injected gaseous fuel,
- (e) burning said directly injected gaseous fuel,
- (f) directing exhaust gas produced during burning of said directly injected gaseous fuel from said combustion chamber into an exhaust line,
- (g) determining an emissions concentration within said exhaust gas directed from said combustion chamber, said emissions concentration being the concentration of one of:
- (1) carbon monoxide,
- (2) hydrocarbons,
- (3) combined carbon monoxide and hydrocarbons,
- (4) combined carbon monoxide and particulates,
- (5) combined hydrocarbons and particulates, or
- (6) combined carbon monoxide, hydrocarbons and particulates,
- (h) determining an EGR rate set point at which said emissions concentration exceeds a maximum emissions concentration,
- (i) adjusting said quantity of said exhaust gas to provide an EGR level below said set point when said emissions concentration exceeds said maximum emissions concentration,
- wherein a quantity of said exhaust gas from said exhaust line is directed through an EGR line to said intake line and, during a subsequent cycle of said engine, a subsequent intake charge comprises said quantity of said exhaust gas.
14 more elements
A method of operating an internal combustion engine, said method comprising:
- during a cycle of said engine:
- (a) directing an intake charge from an intake line into a combustion chamber of said internal combustion engine,
- (b) compressing said intake charge,
- (c) introducing a fuel into said intake charge within said combustion chamber,
- (d) igniting said fuel,
- (e) burning said fuel,
- (f) directing exhaust gas generated by combustion of said fuel from said combustion chamber into an exhaust line;
- (g) determining an emissions concentration within said exhaust gas, said emissions concentration being the concentration of one of:
- (1) carbon monoxide,
- (2) hydrocarbons,
- (3) combined carbon monoxide and hydrocarbons,
- (4) combined carbon monoxide and particulates,
- (5) combined hydrocarbons and particulates, or
- (6) combined carbon monoxide, hydrocarbons and particulates,
- (h) determining an EGR level set point at which said emissions concentration equals or exceeds a maximum emissions concentration,
- (i) determining a predetermined quantity of said exhaust gas to direct through an EGR line, said quantity of said exhaust gas providing an EGR level below said set point,
- (j) directing a quantity of said exhaust gas based on said predetermined quantity of said exhaust gas to an EGR line to said intake line, wherein during a subsequent cycle of said engine, a subsequent intake charge comprises said quantity of said exhaust gas.
14 more elements
Dependencies are inferred from the claim text.