IMPLEMENTING SKIP FIRE WITH START/STOP FEATURE

• US 20150369141A1
• Filed: 06/18/2015
• Published: 12/24/2015
• Est. Priority Date: 06/19/2014
• Status: Active Grant

• Current Assignee: FCA US LLC (Stellantis NV), Tula Technology, Incorporated
• Original Assignee: Ihab S. Soliman, Joseph B. Adams, Mark A. Shost
• Inventors: SOLIMAN, Ihab S., SHOST, Mark A., LE, Truc Trung, ADAMS, Joseph B.
• Granted Patent: US 9,725,082 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60K 6/24 characterised by the combustion engines
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/40 Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers power-up or power-down of the driveline B60W30/192
• CPC Class Codes: B60W 2510/0638 Engine speed
• CPC Class Codes: B60W 2510/0671 Engine manifold pressure
• CPC Class Codes: B60W 2510/0676 Engine temperature
• CPC Class Codes: B60W 2510/1015 Input shaft speed, e.g. turbine speed
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2710/06 Combustion engines, Gas turbines
• CPC Class Codes: B60W 2710/0644 Engine speed
• CPC Class Codes: F02D 17/02 Cutting-out cutting-out engines in multiple engine arrangements F02D25/04
• CPC Class Codes: F02D 2200/0406 Intake manifold pressure
• CPC Class Codes: F02D 29/02 peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers
• CPC Class Codes: F02D 41/3058 the engine working with a variable number of cycles
• CPC Class Codes: F02N 11/04 the motors being associated with current generators
• CPC Class Codes: F02N 11/0829 related to special engine control, e.g. giving priority to engine warming-up or learning
• CPC Class Codes: F02N 2011/0896 Inverters for electric machines, e.g. starter-generators
• CPC Class Codes: F02N 2200/022 : Engine speed
• CPC Class Codes: F02P 5/1506 : with particular means during starting
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y10S 903/905 : Combustion engine

Abstract

A variety of methods and arrangements for implementing a start/stop feature in a skip fire engine control system are described. In one aspect, the implementation of the start/stop feature involves automatically turning off an internal combustion engine under selected circumstances during a drive cycle. A determination is made that the engine should be restarted. During the engine startup period, the engine is operated in a skip fire manner such that a desired engine speed is reached.

Claims

1. A method for implementing a start/stop feature in a skip fire engine control system, the skip fire engine control system including an internal combustion engine having a plurality of working chambers, the method comprising:

implementing a stop/start feature that involves automatically turning off the engine under selected circumstances during a drive cycle;

determining that the turned off engine should be restarted; and

during an engine startup period, operating the engine in a skip fire manner until a target engine speed is reached wherein the skip fire operation of the engine involves firing at least one selected working cycle of at least one selected working chamber and deactivating at least one selected working cycle of at least one selected working chamber such that air does not pass through the at least one working chamber during the at least one deactivated working cycle.

2. A method as recited in claim 1 wherein the engine is operated in a skip fire manner until the target engine speed and a target operating load are reached.

3. A method as recited in claim 1 wherein the deactivation of the at least one working chamber involves not fueling and not passing air through the at least one working chamber.

4. A method as recited in claim 1 wherein the engine startup period begins immediately after the engine was started and is less than 2500 milliseconds.

5. A method as recited in claim 1 wherein the target engine speed is achieved while skipping at least one working chamber.

6. A method as recited in claim 1 wherein the target engine speed is achieved while skipping a desired number of working chambers wherein the desired number of working chambers is a number between zero and the total number of working chambers in the engine and wherein the desired number of working chambers is selected based on one or more operating conditions.

7. A method as recited in claim 1 wherein the target engine speed is an idle speed.

8. A method for implementing a start/stop feature in a skip fire engine control system, the skip fire engine control system including an internal combustion engine having a plurality of working chambers, the method comprising:

implementing a stop/start feature that involves automatically turning off the engine under selected circumstances during a drive cycle;

determining that the turned off engine should be restarted; and

during an engine startup period, operating the engine in a skip fire manner so that an engine speed substantially follows a desired engine speed restart profile wherein the skip fire engine operation involves firing at least one selected working cycle of at least one selected working chamber and deactivating at least one selected working cycle of at least one selected working chamber such that air does not pass through the at least one working chamber during the at least one deactivated working cycle.

9. A method as recited in claim 8 wherein the engine speed restart profile indicates predetermined increases in a engine speed over time during the engine startup period.

10. A method as recited in claim 8 further comprising:

selecting one of a plurality of predetermined engine speed restart profiles based on one or more engine parameters; and

operating the engine in a skip fire manner during the engine startup period based on the selected one of the engine speed restart profiles.

11. A method as recited in claim 10 wherein the selection of the one of the engine speed restart profiles is based on an accelerator pedal position.

12. A method as recited in claim 10 wherein the plurality of engine speed restart profiles require different rates of increase in a firing fraction during the engine startup period.

13. A method as recited in claim 8 wherein the engine speed at the end of the engine startup period substantially matches an engine idle speed.

14. A method for implementing a start/stop feature in a skip fire engine control system, the skip fire engine control system including an internal combustion engine having a plurality of working chambers, the method comprising:

implementing a stop/start feature that involves automatically turning off the engine under selected circumstances during a drive cycle; and

during an engine shutdown period in which the engine speed is dropping from a non-zero speed to a speed of zero, operating the engine in a skip fire manner until the engine speed reaches zero wherein the skip fire operation of the engine involves firing at least one selected working cycle of at least one selected working chamber and deactivating at least one selected working cycle of at least one selected working chamber such that air does not pass through the at least one working chamber during the at least one deactivated working cycle.