Engine exhaust temperature control

Patent metadata

Field	Value
Publication number	US-9810122-B2
Application number	US-201514746616-A
Country	US
Kind code	B2
Filing date	Jun 22, 2015
Priority date	Jun 22, 2015
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

Methods and systems for improving operation of an engine at higher speeds and loads are disclosed. In one example, fuel may be injected to an exhaust system of the engine so that temperatures of exhaust system components may be reduced when the engine is operated at higher speeds and loads.

First claim

The invention claimed is:

1. An engine operating method, comprising:
operating a Miller cycle engine with fuel injected in an exhaust system of the Miller cycle engine at a location upstream of a turbine coupled to a crankshaft of the Miller cycle engine; and
passing exhaust gases from the Miller cycle engine through the turbine, where the turbine is coupled to the crankshaft via a transmission and where the turbine is coupled to the crankshaft via a turbine clutch; the method further comprising closing the turbine clutch in response to a temperature of an exhaust component exceeding a threshold.

2. The method of claim 1 , further comprising selectively opening and closing a driveline disconnect clutch to couple the turbine to the Miller cycle engine.

3. The method of claim 1 , where exhaust gases rich of stoichiometric pass through the turbine.

4. The method of claim 3 , further comprising mixing the exhaust gases rich of stoichiometric with air from an intake manifold of the Miller cycle engine.

5. The method of claim 4 , where the mixing the exhaust gases rich of stoichiometric with air from the intake manifold of the Miller cycle engine is at a location in the exhaust system of the Miller cycle engine upstream of a catalyst and downstream of the turbine.

6. The method of claim 1 , further comprising igniting the fuel injected upstream of the turbine via a spark plug.

7. An engine operating method, comprising:
in response to a temperature of exhaust of a Miller cycle engine being greater than an exhaust component degradation threshold temperature, injecting an amount of fuel in an exhaust system of the Miller cycle engine upstream of a turbine while operating the Miller cycle engine, the turbine arranged upstream of a catalyst in the exhaust system;
introducing an amount of air from an intake system of the Miller cycle engine to a location in the exhaust system upstream of the turbine via a second passage;
at the location in the exhaust system upstream of the turbine, mixing the amount of fuel injected in the exhaust system upstream of the turbine with the amount of air introduced from the intake system via the second passage; and
introducing an amount of air from the intake system to a location downstream of the turbine and upstream of the catalyst via a first passage, the amount of air introduced via the first passage based on the amount of fuel injected in the exhaust system upstream of the turbine and the amount of air introduced from the intake system via the second passage.

8. The method of claim 7 , where the turbine is coupled to a crankshaft of the Miller cycle engine via a turbine clutch, the method further comprising closing the turbine clutch in response to the temperature of the exhaust being greater than the exhaust component degradation threshold temperature.

9. The method of claim 7 , wherein the amount of fuel injected in the exhaust system upstream of the turbine is based on turbine speed and driver demand torque.

10. The method of claim 7 , where introducing the amounts of air from the intake system to the exhaust system provides a stoichiometric exhaust gas mixture to the catalyst.

11. The method of claim 7 , where the amount of fuel injected upstream of the turbine is combusted in an expansion chamber in the exhaust system.

12. The method of claim 11 , where the expansion chamber is upstream of the turbine.

13. The method of claim 7 , where the amount of fuel injected upstream of the turbine is ignited via a spark plug.

14. The method of claim 6 , further comprising coupling the turbine to vehicle wheels.

15. An engine system, comprising:
a Miller cycle engine having a compressor, an exhaust passage, a turbine located along the exhaust passage, a catalyst located along the exhaust passage downstream of the turbine, and a fuel injector configured to inject fuel to the exhaust passage upstream of the turbine, the Miller cycle engine further including a first passage from an intake passage to the exhaust passage at a location downstream of the turbine and upstream of the catalyst, and a second passage from the intake passage to the exhaust passage at a location upstream of the turbine; and
a controller including non-transitory executable instructions to:
flow a rich exhaust gas mixture through the turbine via adjusting an amount of fuel injected by the fuel injector and controlling air flow through the second passage; and
provide a stoichiometric gas mixture downstream of the turbine and upstream of the catalyst via controlling air flow through the first passage.

16. The engine system of claim 15 , wherein the turbine is coupled to a crankshaft of the Miller cycle engine via a turbine clutch, and wherein the controller further comprises non-transitory executable instructions to close the turbine clutch in response to a temperature of engine exhaust being greater than an exhaust component degradation threshold temperature.

Assignees

• Ford Global Tech Llc

Inventors

• Martin Douglas Raymond
• Rollinger John Eric

Classifications

• F02D41/0007

  for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12) · CPC title

• F01N3/204 Primary

  using an exhaust gas igniter, e.g. a spark or glow plug, without introducing fuel into exhaust duct · CPC title

• F02B39/12

  Drives characterised by use of couplings or clutches therein (using fluid slip couplings for varying gear ratio F02B39/08) · CPC title

• F02B37/166

  the auxiliary apparatus being a combustion chamber, e.g. upstream of turbine · CPC title

• F01N3/2046

  Periodically cooling catalytic reactors · CPC title