Methods for turbocharged engine with cylinder deactivation and variable valve timing

Patent metadata

Field	Value
Publication number	US-9739213-B2
Application number	US-201514670122-A
Country	US
Kind code	B2
Filing date	Mar 26, 2015
Priority date	Apr 4, 2014
Publication date	Aug 22, 2017
Grant date	Aug 22, 2017

Abstract

A system and methods are described for a turbocharged engine, comprising powering the engine using a first operating cylinder, supplementing the power using a second switchable cylinder, deactivating the second switchable cylinder responsive to a load below a first threshold, and closing a first shut-off valve downstream of a compressor during the partial deactivation to prevent a first turbocharger from imparting a delivery action into a second compressor during the partial deactivation. Embodiments are further described wherein a bypass line in a second exhaust line further serves as a short-circuit line to prevent the second compressor from imparting a delivery action against the closed first shut-off valve. A variable valve timing is then included to further optimize the combustion process during the partial deactivation.

First claim

The invention claimed is:

1. A method for a turbocharged engine, comprising:
powering the engine using a first operating cylinder with a first valve overlap,
supplementing the power using a second switchable cylinder, the second switchable cylinder switched based on load and providing a partial deactivation, the second switchable cylinder being deactivated responsive to a load below a first threshold and activated responsive to the load exceeding the first threshold,
closing a shut-off valve downstream of a compressor during the partial deactivation;
opening a second shut-off valve in a bypass line during the partial deactivation;
increasing valve overlap of the first operating cylinder relative to the first valve overlap to scavenge out residual gas therein;
actuating an inlet valve of the first operating cylinder to provide a valve lift before top dead center during charge exchange, wherein an exhaust gas is recirculated externally during operations; and
reducing the valve overlap of the first operating cylinder relative to the first valve overlap during the partial deactivation responsive to the load falling below a second threshold that is lower than the first threshold.

2. The method of claim 1 , further comprising, during the partial deactivation, closing the inlet valve at a first time during the charge exchange to expel part of a cylinder fresh charge responsive to the load falling below a third threshold that is lower than the second threshold.

3. The method of claim 2 , wherein the inlet valve is closed in a range of 15° CA to 70° CA after charge exchange bottom dead center.

4. The method of claim 2 , wherein the exhaust gas recirculated externally is reduced responsive to the load falling below the third threshold.

5. The method of claim 4 , further comprising, during the partial deactivation, closing the inlet valve at a second time earlier than the first time during the charge exchange responsive to the load falling below a fourth threshold that is lower than the third threshold.

6. The method of claim 5 , wherein exhaust gas is recirculated internally by allowing an exhaust valve to remain open during the charge exchange.

7. The method of claim 6 , further comprising opening the exhaust valve at least twice during the charge exchange.

8. The method of claim 7 , wherein one or more of an inlet valve and an exhaust valve of the second switchable cylinder remains closed during the partial deactivation.

9. A method for optimizing partial load operations in an engine with cylinders configured for deactivation, comprising:
operating the engine in a first operating mode with a first valve overlap by powering the engine with a first group of operating cylinders and supplementing the power with a second group of switchable cylinders, the second group of switchable cylinders being deactivated responsive to a load below a first threshold and activated responsive to the load exceeding the first threshold, and wherein the method includes closing a shut-off valve downstream of a compressor during the deactivation; and
operating the engine in a second operating mode with exhaust gas recirculation, responsive to the load falling below a second threshold that is lower than the first threshold, by reducing valve overlap of the first group of operating cylinders relative to the first valve overlap.

10. The method of claim 9 , further comprising operating the engine in a third operating mode by adjusting an inlet valve to close at a first timing during charge exchange, the first timing later than a timing at which the inlet valve is closed during engine operation in the first operating mode and a timing at which the inlet valve is closed during engine operation in the second operating mode, to expel part of a cylinder fresh charge responsive to the load falling below a third threshold that is lower than the second threshold.

11. The method of claim 10 , further comprising operating the engine in a fourth operating mode by adjusting the inlet valve to close earlier during the charge exchange responsive to the load falling below a fourth threshold that is lower than the third threshold.

Assignees

• Ford Global Tech Llc

Inventors

• Kemmerling Joerg
• Sommerhoff Franz Arnd
• Kuske Andreas
• Smiljanovski Vanco
• Kindl Helmut Matthias
• Willems Werner
• Herudek Claudia Katharina
• Forsting Michael
• Van Den Heuvel Bas Lambertus
• Hemink Wilbert
• Conee Claudia
• Fritsche Richard

Classifications

• F02M26/01

  Internal exhaust gas recirculation, i.e. wherein the residual exhaust gases are trapped in the cylinder or pushed back from the intake or the exhaust manifold into the combustion chamber without the use of additional passages · CPC title

• F02D13/0219

  by shifting the phase, i.e. the opening periods of the valves are constant · CPC title

• F02D41/005

  according to engine operating conditions · CPC title

• F02B37/001

  using exhaust drives arranged in parallel · CPC title

• F02D13/0265

  Negative valve overlap for temporarily storing residual gas in the cylinder · CPC title