System and method of gas recirculation in an internal combustion engine
View Patent ↗A gas recirculation system is disclosed for improving engine braking in an internal combustion engine having an intake valve, an exhaust valve, and a cylinder. The system includes an exhaust manifold operatively connected to the cylinder through the exhaust valve; an intake manifold operatively connected to the cylinder through the intake valve; and a gas recirculation passage adapted to recirculate gas from the exhaust manifold to the intake manifold during an engine braking event.
1. A gas recirculation system for improving engine braking in an internal combustion engine having an intake valve, an exhaust valve, and a cylinder, said gas recirculation system comprising:
an exhaust manifold operatively connected to the cylinder through the exhaust valve;
an intake manifold operatively connected to the cylinder through the intake valve; and
a gas recirculation passage adapted to recirculate gas from said exhaust manifold to said intake manifold during an engine braking event.
2. The system of claim 1 , further comprising means for controlling the flow of recirculated gas to the engine cylinder, said flow control means operatively connected to said exhaust manifold.
3. The system of claim 2 , wherein said flow control means comprises a turbocharger.
4. The system of claim 2 , wherein said turbocharger is selected from the group consisting of: a variable geometry turbocharger, a wastegated turbocharger, and a fixed geometry turbocharger.
5. The system of claim 3 , wherein said flow control means further comprises a flow control device located downstream of said turbocharger.
6. The system of claim 5 , wherein said flow control device is an exhaust brake operative between a fully open position and a fully closed position.
7. The system of claim 2 , further comprising a gas recirculation valve disposed in said gas recirculation passage.
8. The system of claim 7 , said gas recirculation valve operative between a fully open position and a fully closed position.
9. The system of claim 7 , said valve having a first position for selectively recirculating gas from said exhaust manifold to said intake manifold through said gas recirculation passage during the engine braking event, and a second position for directing gas through said flow control means.
10. A method of improving engine braking using gas recirculation in an internal combustion engine having an intake valve, an exhaust valve, an intake manifold, an exhaust manifold, and a cylinder, said method comprising the steps of:
providing a gas recirculation passage connecting the exhaust manifold to the intake manifold; and
recirculating gas from the exhaust manifold to the intake manifold through the gas recirculation passage during an engine braking event.
11. The method of claim 10 , further comprising the steps of:
providing a valve disposed in the gas recirculation passage; and
selectively operating the valve during the engine braking event.
12. The method of claim 11 , wherein the step of operating the valve comprises the step of opening the valve during the engine braking event.
13. The method of claim 12 , further comprising the step of providing an external gas recirculation event.
14. The method of claim 11 , wherein the step of operating the valve comprises the step of closing the valve during the engine braking event.
15. The method of claim 14 , further comprising the step of providing an internal gas recirculation event.
16. The method of claim 10 , further comprising the step of using the recirculated gas to clean the intake manifold.
17. A method of improving operation of an internal combustion engine based on at least one engine operating parameter, said method comprising the steps of:
measuring the engine operating parameter;
providing gas recirculation during at least two engine processes selected from the group consisting of: engine braking operation, cleaning operation, and positive power exhaust gas recirculation operation; and
controlling the flow of the recirculated gas based on the value of the engine operating parameter.
18. A gas recirculation system for improving engine braking in an internal combustion engine having an intake valve, an exhaust valve, and a cylinder, said gas recirculation system comprising:
an exhaust manifold operatively connected to the cylinder through the exhaust valve;
an intake manifold operatively connected to the cylinder through the intake valve;
a gas recirculation passage adapted to recirculate gas from said exhaust manifold to said intake manifold during an engine braking event;
a turbocharger operatively connected to said exhaust manifold; and
a flow control device located downstream of said turbocharger.
19. The system of claim 18 , wherein said turbocharger is selected from the group consisting of: a variable geometry turbocharger, a wastegated turbocharger, and a fixed geometry turbocharger.
20. The system of claim 18 , wherein said flow control device comprises an exhaust brake operative between a fully open position and a fully closed position.
21. The system of claim 18 , further comprising a gas recirculation valve disposed in said gas recirculation passage.
22. The system of claim 21 , said gas recirculation valve operative between a fully open position and a fully closed position.
23. The system of claim 21 , said gas recirculation valve having a first position for selectively recirculating gas from said exhaust manifold to said intake manifold through said gas recirculation passage during the engine braking event, and a second position for directing gas through said turbocharger.