Method and system for turbocharging an engine

• US 9,470,182 B2
• Filed: 06/03/2014
• Issued: 10/18/2016
• Est. Priority Date: 09/09/2010
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Ulrey, Joseph Norman, Pursifull, Ross Dykstra
• Primary Examiner(s): Trieu, Thai Ba
• Application Number:
  US14/295,163
• Publication Number:
  US 20140283799A1
• Time in Patent Office: 868 Days
• Field of Search: 606/02, 606/052, 602/80, 602/78, 123/568.12, 123/316, 123 9015- 9018
• US Class Current: 1/1
• CPC Class Codes: F02B 2075/1816 four
• CPC Class Codes: F02B 37/00 Engines characterised by provision of pumps driven at least for part of the time by exhaust
• CPC Class Codes: F02B 37/18 by bypassing exhaust from the inlet to the outlet of turbine or to the atmosphere
• CPC Class Codes: F02D 13/02 during engine operation
• CPC Class Codes: F02D 13/0242 Variable control of the exhaust valves only
• CPC Class Codes: F02D 13/0249 changing the valve timing only
• CPC Class Codes: F02D 13/0257 Independent control of two or more intake or exhaust valves respectively, i.e. one of two intake valves remains closed or is opened partially while the other is fully opened
• CPC Class Codes: F02D 43/00 Conjoint electrical control of two or more functions, e.g. ignition, fuel-air mixture, recirculation, supercharging or exhaust-gas treatment
• CPC Class Codes: F02M 26/04 with a single turbocharger
• CPC Class Codes: F02M 26/05 High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor
• CPC Class Codes: F02M 26/13 Arrangement or layout of EGR passages, e.g. in relation to specific engine parts or for incorporation of accessories
• CPC Class Codes: F02M 26/15 in relation to engine exhaust purifying apparatus
• CPC Class Codes: F02M 26/22 with coolers in the recirculation passage
• CPC Class Codes: F02M 26/27 with air-cooled heat exchangers
• CPC Class Codes: F02M 26/28 with liquid-cooled heat exchangers
• CPC Class Codes: F02M 26/44 in which a main EGR passage is branched into multiple passages
• CPC Class Codes: F02M 35/1085 the combustion chamber having multiple intake valves modifying induction systems for imparting a rotation to the charge in the cylinder and having multiple air inlets F02B31/08; shape or arrangement of intake or exhaust channels in cylinder heads F02F1/42
• CPC Class Codes: F02M 35/112 for engines with cylinders all in one line
• CPC Class Codes: F05B 2220/40 in turbochargers
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A method for improving operation of a turbocharged engine is presented. In one embodiment, the method may reduce engine emissions and improve engine efficiency during an engine start.

Claims

1. A method for controlling exhaust gas of an engine comprising:

isolating blow-down gases of a cylinder to a first exhaust conduit and residual gases to a second exhaust conduit, the exhaust conduits coupled to the cylinder via first and second exhaust valves;

recovering heat from a first portion of the gases in the first exhaust conduit to a liquid via a heat recovery device, and then returning the cooled gases to the second exhaust conduit that is in communication with the first exhaust conduit downstream of the heat recovery device, the second exhaust conduit including a first catalyst and a second catalyst, the first catalyst upstream of the second catalyst;

directing a second portion of the gases in the first exhaust conduit to a turbine positioned in a third exhaust conduit; and

adjusting, via a controller, a turbine shut-off valve, positioned downstream of the turbine, based on an operating condition of the engine received at the controller, to flow exhaust from the third exhaust conduit into the second exhaust conduit, wherein the third exhaust conduit is coupled to the second exhaust conduit at a location between the first catalyst and the second catalyst.

2. The method of claim 1, wherein adjusting the turbine shut-off valve includes opening the turbine shut-off valve in response to an increase in an operator engine torque demand and closing the turbine shut-off valve in response to a decrease in the operator engine torque demand.

3. The method of claim 1, where a portion of the blow-down gases of the cylinder are directed to an intake manifold of a turbocharged engine.

4. The method of claim 1, where the heat is recovered via a gas-to-liquid heat exchanger.

5. The method of claim 1, further comprising combining the first portion of the gases with the residual gases at a location upstream of the first catalyst in a direction of exhaust flow.

6. The method of claim 5, further comprising directing the second portion of the gases to an intake manifold.

7. A method for controlling exhaust gas of an engine comprising:

while the engine is operating, isolating blow-down gases of a cylinder to a first exhaust conduit and residual gases to a second exhaust conduit via a first exhaust cam profile and a second exhaust cam profile, the exhaust conduits coupled to the cylinder via first and second exhaust valves;

recovering heat from a first portion of the gases in the first exhaust conduit to a liquid via a heat recovery device, arranged in a first branch of the first exhaust conduit, and then returning the cooled gases to the second exhaust conduit that is in communication with the first exhaust conduit downstream of the heat recovery device, the second exhaust conduit including a first catalyst and a second catalyst, the first catalyst upstream of the second catalyst; and

via a controller of the engine, opening a turbine shut-off valve to draw a second, remaining portion of the gases in the first exhaust conduit into the second exhaust conduit downstream of the first catalyst and upstream of the second catalyst via a turbocharger turbine, the turbine shut-off valve positioned downstream of an outlet of the turbine, and the turbine located in a second branch of the first exhaust conduit, the second branch positioned upstream of the heat recovery device.

8. The method of claim 7, further comprising transferring heat energy from the heat recovery device to engine coolant.

9. The method of claim 7, further comprising transferring heat energy from the heat recovery device to engine oil.

10. The method of claim 7, where the first exhaust cam profile opens a first exhaust valve and the second exhaust cam profile opens a second exhaust valve.

11. The method of claim 10, where the first exhaust cam profile includes a first exhaust valve opening duration and the second exhaust cam profile includes a second exhaust valve opening duration, where opening of the second exhaust valve occurs later than opening of the first exhaust valve.

12. The method of claim 11, where the first exhaust cam profile includes an exhaust valve lift that opens and closes the first exhaust valve before a piston of the cylinder reaches a bottom dead center (BDC) expansion stroke of the cylinder.

13. An engine system, comprising:

a camshaft including a first exhaust cam profile for a first exhaust valve of a cylinder and a second exhaust cam profile for a second exhaust valve of the cylinder, the first exhaust valve controlling exhaust flow to a first exhaust port of the cylinder, the second exhaust valve controlling exhaust flow to a second exhaust port of the cylinder;

a first exhaust conduit extending from the first exhaust port of the cylinder;

a second exhaust conduit extending from the second exhaust port of the cylinder, the second exhaust port isolated from the first exhaust port, the second exhaust conduit including a first catalyst and a second catalyst, the first catalyst upstream of the second catalyst;

a gas-to-liquid heat exchanger located in a first branch of the first exhaust conduit, an outlet of the gas-to-liquid heat exchanger directed to an intake manifold and the second exhaust conduit;

a turbocharger turbine located in a second branch of the first exhaust conduit, the second branch coupled to the first branch upstream of the heat exchanger;

wherein an outlet of the turbine is coupled to the second exhaust conduit at a location between the first catalyst and the second catalyst; and

a turbine shut-off valve located downstream of the outlet of the turbine in a third exhaust conduit positioned downstream of the second branch of the first exhaust conduit.

14. The engine system of claim 13, where the first exhaust cam profile includes a first lift amount and the second exhaust cam profile includes a second lift amount.

15. The engine system of claim 13, where the first exhaust cam profile includes a first opening duration and the second exhaust cam profile includes a second opening duration, where the first opening duration causes the first exhaust valve to open and close before a bottom dead center (BDC) expansion stroke of the cylinder and opening of the second exhaust valve occurs later than opening of the first exhaust valve.