Strategy for selectively bypassing a DPF in a hybrid HCCI combustion engine

• US 20060185353A1
• Filed: 02/22/2005
• Published: 08/24/2006
• Est. Priority Date: 02/22/2005
• Status: Active Grant

• Current Assignee: International Engine Intellectual Property Company, LLC (Volkswagen AG)
• Original Assignee: International Engine Intellectual Property Company, LLC (Volkswagen AG)
• Inventors: Liu, Zhengbai, Wei, Puning
• Granted Patent: US 7,631,489 B2
• Time in Patent Office: Days
• US Class Current: 60/297
• CPC Class Codes: F01N 3/031 having means for by-passing filters, e.g. when clogged or during cold engine start
• 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: F02D 41/3035 a mode being the premixed charge compression-ignition mode
• CPC Class Codes: F02D 41/3076 with special conditions for selecting a mode of combustion, e.g. for starting, for diagnosing
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

In a conventional diesel combustion mode, one or more cylinders (12) of an engine (10) is or are fueled to cause conventional diesel combustion in each such cylinder. The resulting exhaust gas is treated by a diesel particulate filter (36) in an exhaust system (34) before exiting the exhaust system. In an alternative diesel combustion mode, such as HCCI, one or more cylinders of the engine are fueled to create in each such cylinder an in-cylinder fuel-air charge that ignites by auto-ignition as the charge is increasingly compressed. Also a bypass valve (38) is opened so that the resulting exhaust gas bypasses the DPF as the exhaust gas passes through the exhaust system.

Claims

1. A method of operating a compression ignition engine comprising:

processing certain data to select between an alternate diesel combustion mode and a conventional diesel combustion mode, and

a) when the result of the processing selects the conventional diesel combustion mode, fueling one or more cylinders of the engine to cause conventional diesel combustion in each such cylinder, and causing the resulting exhaust gas to be treated by a diesel particulate filter (DPF) in an exhaust system of the engine before exiting the exhaust system, and

b) when the result of the processing selects the alternative diesel combustion mode, fueling one or more cylinders of the engine to create in each such cylinder an in-cylinder fuel-air charge that ignites by auto-ignition as the charge is increasingly compressed, and causing the resulting exhaust gas to bypass the DPF as the exhaust gas passes through the exhaust system.

2. A method as set forth in claim 1 wherein the step of processing certain data comprises processing data indicative of engine load.

3. A method as set forth in claim 2 wherein the step of processing certain data further comprises processing data indicative of engine speed.

4. A method as set forth in claim 1 wherein the step of causing exhaust gas resulting from conventional diesel combustion to be treated by the DPF comprises closing a bypass that is in parallel flow relationship to the DPF in the exhaust system.

5. A method as set forth in claim 4 wherein the step of closing the bypass comprises closing a valve in the bypass.

6. A method as set forth in claim 1 wherein the step of causing exhaust gas resulting from alternative diesel combustion to bypass the DPF comprises opening a bypass that is in parallel flow relationship to the DPF in the exhaust system.

7. A method as set forth in claim 6 wherein the step of opening the bypass comprises opening a valve in the bypass.

8. A compression ignition engine comprising:

a control system for processing data;

one or more combustion chambers;

a fueling system for injecting fuel into the one or more combustion chambers; and

an exhaust system comprising a diesel particulate filter (DPF) and a bypass in parallel flow relationship to the DPF;

wherein the control system controls the fueling system and the exhaust system using a result of the processing of certain data by the control system to select between an alternate diesel combustion mode and a conventional diesel combustion mode, and

a) when the result of the processing selects the conventional diesel combustion mode, the control system causes the fueling system to fuel one or more cylinders of the engine for causing conventional diesel combustion in each such cylinder, and causes the resulting exhaust gas to flow through the DPF and not the bypass before exiting the exhaust system, and

b) when the result of the processing selects the alternative diesel combustion mode, the control system causes the fueling system to fuel one or more cylinders to create in each such cylinder an in-cylinder fuel-air charge that ignites by auto-ignition as the charge is increasingly compressed, and causes the resulting exhaust gas to flow through the bypass and not the DPF as the exhaust gas passes through the exhaust system.

9. An engine as set forth in claim 8 wherein the certain data comprises data indicative of engine load.

10. An engine as set forth in claim 9 wherein the certain data comprises data indicative of engine speed.

11. An engine as set forth in claim 8 wherein the bypass comprises a bypass valve that is closed in the conventional diesel combustion mode.

12. An engine as set forth in claim 8 wherein the bypass comprises a bypass valve that is open in the alternative diesel combustion mode.

13. A compression ignition engine comprising:

a control system for processing data;

one or more combustion chambers;

a fueling system for injecting fuel into the one or more combustion chambers; and

an exhaust system comprising a diesel particulate filter (DPF), bypass in parallel flow relationship to the DPF, and a control valve for selectively controlling flow through the DPF and the bypass;

wherein the control system controls the fueling system and the exhaust system using a result of the processing of certain data by the control system to select between an alternate diesel combustion mode and a conventional diesel combustion mode, and

a) when the result of the processing selects the conventional diesel combustion mode, the control system causes the fueling system to fuel one or more cylinders of the engine for causing conventional diesel combustion in each such cylinder, and causes the control valve to allow exhaust gas to flow through the DPF, and

b) when the result of the processing selects the alternative diesel combustion mode, the control system causes the fueling system to fuel one or more cylinders to create in each such cylinder an in-cylinder fuel-air charge that ignites by auto-ignition as the charge is increasingly compressed, and causes the control valve to allow exhaust gas to flow through the bypass.

14. An engine as set forth in claim 13 wherein the control valve disallows exhaust gas flow through the bypass in the conventional diesel combustion mode.

15. An engine as set forth in claim 13 wherein the control valve disallows exhaust gas flow through the DPF in the alternative diesel combustion mode.