Multi-level skip fire

• US 9,689,327 B2
• Filed: 10/21/2015
• Issued: 06/27/2017
• Est. Priority Date: 07/11/2008
• Status: Active Grant

• Current Assignee: Tula Technology, Incorporated (BorgWarner Incorporated)
• Original Assignee: Tula Technology, Incorporated (BorgWarner Incorporated)
• Inventors: Younkins, Matthew A., Serrano, Louis J.
• Primary Examiner(s): Vo, Hieu T
• Application Number:
  US14/919,018
• Publication Number:
  US 20160040614A1
• Time in Patent Office: 615 Days
• CPC Class Codes: F02D 13/0269 Controlling the valves to perform a Miller-Atkinson cycle
• CPC Class Codes: F02D 13/06 Cutting-out cylinders
• CPC Class Codes: F02D 17/02 Cutting-out cutting-out engines in multiple engine arrangements F02D25/04
• CPC Class Codes: F02D 2200/602 Pedal position
• CPC Class Codes: F02D 2250/18 Control of the engine output torque
• CPC Class Codes: F02D 2400/02 Four-stroke combustion engines with electronic control
• CPC Class Codes: F02D 37/02 one of the functions being ignition
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/126 transitional corrections at the end of the cut-off period
• CPC Class Codes: F02D 41/1401 characterised by the control or regulation method F02D41/1473, F02D41/1477 take precedence
• CPC Class Codes: F02D 41/266 the computer being backed-up or assisted by another circuit, e.g. analogue
• CPC Class Codes: F02P 5/1512 with particular means concerning an individual cylinder
• CPC Class Codes: F02P 9/002 Control of spark intensity, intensifying, lengthening, suppression by means of current control in the storage devices F02P3/05, F02P3/09, during starting F02P15/12
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

In one aspect, a method for controlling operation of an internal combustion engine is described. The engine is operated in a skip fire manner such that selected skipped working cycles are skipped and selected active working cycles are fired to deliver a desired engine output. A particular level of torque output is selected for each of the fired working chambers. Various methods, engine controllers, arrangements and systems related to the above method are also described.

Claims

1. An engine controller for an engine including a plurality of working chambers, each working chamber including at least one cam-actuated intake valve, the engine controller comprising:

a firing fraction calculator arranged to determine a firing fraction suitable for delivering a desired torque;

a firing timing determination module arranged to determine a skip fire firing sequence based on the firing fraction wherein the skip fire firing sequence indicates whether, during a selected firing opportunity, a selected working chamber is deactivated or fired and further indicates, for each fire, whether the fire generates a low torque output or a high torque output; and

a firing control unit that is arranged to operate the working chambers in a skip fire manner based on the firing sequence.

2. An engine controller as recited in claim 1, further comprising:

the firing control unit is further arranged to deactivate skipped working chambers during selected skipped working cycles based on the skip fire firing sequence to prevent pumping air through the skipped working chambers during the selected skipped working cycles.

3. An engine controller as recited in claim 1 wherein:

each of the plurality of working chambers includes the at least one intake valve and at least one exhaust valve; and

all of the intake and exhaust valves are cam-actuated.

4. A method of controlling the operation of an internal combustion engine having a plurality of working chambers to deliver a desired engine output, wherein each working chamber has at least one intake valve that is cam actuated and at least one exhaust valve, the method comprising:

operating the engine in a skip fire manner that skips selected skipped working cycles and fires selected active working cycles to deliver the desired engine output, wherein decisions whether to fire or skip each working cycle are dynamically determined during operation of the engine on a firing opportunity by firing opportunity basis; and

selecting a high or low torque output on the fired working chambers wherein decisions whether to use a high or low torque output are dynamically determined during operation of the engine on a firing opportunity by firing opportunity basis.

5. A method as recited in claim 4, further comprising:

deactivating skipped working chambers during selected skipped working cycles to thereby prevent pumping air through the skipped working chambers during the selected skipped working cycles.

6. A method as recited in claim 4 further comprising:

generating a skip fire firing sequence that indicates for each fire, whether the fire involves using a high or low torque output; and

operating the engine based on the skip fire firing sequence.

7. A method as recited in claim 4 wherein all of the intake and exhaust valves are cam-actuated.