Back to results
US 8,997,457 B2Granted
Catalyst heating with exhaust back-pressure
AssigneeFord Global Technologies, LLC
InventorsThomas G. Leone, Peter C. Moilanen
Life of this patent
Estimating the term…
Abstract
Embodiments for controlling an exhaust back-pressure valve are provided. In one example, a method for operating an engine comprises closing an exhaust back-pressure valve in response to a component temperature, and adjusting intake and/or exhaust valve operation in response to closing the exhaust back-pressure valve to reduce cylinder internal exhaust gas recirculation (EGR). In this way, combustion stability may be maintained while the exhaust back-pressure valve is closed.
Claims19
A system, comprising:
- an engine including a variable camshaft timing system;
- a catalyst positioned in an exhaust of the engine;
- an exhaust back-pressure valve positioned downstream of the catalyst;
- and
- a controller including instructions to:
- close the exhaust back-pressure valve when a temperature of the catalyst is below a threshold;
- and
- adjust the variable camshaft timing system to reduce intake and exhaust valve overlap responsive to the closing of the exhaust back-pressure valve.
5 more elements
A method for operating an engine, comprising:
- throttling a flow of exhaust gas by closing an exhaust back-pressure valve in response to a component temperature;
- and
- adjusting intake and/or exhaust valve operation in response to closing the exhaust back-pressure valve to reduce valve overlap and thereby reduce cylinder internal exhaust gas recirculation (EGR).
A method for an engine, comprising:
- during a first condition, operating the engine by combusting fuel with a first, higher amount of spark retard and allowing exhaust flow with an open exhaust back-pressure valve;
- and
- during a second condition, advancing spark timing by operating the engine by combusting fuel with a second, lower amount of spark retard and throttling exhaust flow with a closed exhaust back-pressure valve.
Dependencies are inferred from the claim text.