INTERNAL COMBUSTION ENGINE CONTROL FOR IMPROVED FUEL EFFICIENCY

• US 20100050986A1
• Filed: 11/09/2009
• Published: 03/04/2010
• Est. Priority Date: 07/11/2008
• Status: Active Grant

• Current Assignee: Tula Technology, Incorporated
• Original Assignee: Tula Technology, Incorporated
• Inventors: SILVESTRI, Chester J., TRIPATHI, Adya S.
• Granted Patent: US 7,886,715 B2
• Time in Patent Office: Days
• US Class Current: 123/406.230
• 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 41/1401 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: Y02T 10/40 Engine management systems

Abstract

A variety of methods and arrangements for improving the fuel efficiency of internal combustion engines are described. Generally, an engine is controlled to operate in a skip fire variable displacement mode. Feedback control is used to dynamically determine the working cycles to be skipped to provide a desired engine output. In some embodiments a substantially optimized amount of air and fuel is delivered to the working chambers during active working cycles so that the fired working chambers can operate at efficiencies close to their optimal efficiency. In some embodiments, the appropriate firing pattern is determined at least in part using predictive adaptive control. By way of example, sigma delta controllers work well for this purpose. In some implementations, the feedback includes feedback indicative of at least one of actual and requested working cycle firings. In some embodiments, the appropriate firings are determined on a firing opportunity by firing opportunity basis. Additionally, in some embodiments, an indicia of the current rotational speed of the engine is used as a clock input for a controller used to selectively cause the skipped working cycles to be skipped.

Claims

1. A method of controlling the operation of an internal combustion engine having at least one working chamber, each working chamber being generally arranged to operate in a succession of working cycles, the method comprising:

receiving a desired engine output signal indicative of a desired engine output; and

firing the at least one working chamber in a pattern that skips the firing of selected skipped working cycles and fires selected active working cycles to deliver the desired engine output, wherein feedback indicative of at least one of requested and actual working cycle firings is used in the determination of the working cycles to be skipped.

2. A method as recited in claim 1 further comprising generating a drive pulse signal that is synchronized with firing opportunities of the engine, wherein the drive pulse signal generally indicates requested working cycle firings indicative of when working cycles need to be fired to deliver the desired engine output, and wherein the firing pattern is based at least in part on the drive pulse signal.

3. A method as recited in claim 2 wherein feedback of the actual working cycle firings is used in the generation of the drive pulse signal.

4. A method as recited in claim 2 wherein feedback of the drive pulse signal is used in the generation of the drive pulse signal.

5. A method as recited in claim 2 wherein feedback of both the drive pulse signal and the actual working cycle firings is used in the generation of the drive pulse signal.

6. A method as recited in claim 1 wherein feedback or feed forward indicative of the output provided by each individual working cycle firing is used in the determination of the working cycles to be skipped.

7. A method as recited in claim 6 wherein the feedback or feed forward used in the determination of the working cycles to be skipped is dynamically adjusted to compensate for variations in at least one of manifold pressure, manifold temperature, spark timing, and valve timing.

8. A method as recited in claim 1 wherein:

the engine is operated in a skip fire variable displacement mode when selected working cycles are skipped, the engine having a plurality of distinct operational levels in the skip fire variable displacement operational mode;

the operational levels vary in their relative settings of a throttle;

at a first operational level, a substantially optimized amount of air and fuel is delivered during fired working cycles; and

at a second operational level reduced amounts of air and fuel are delivered during fired working cycles relative to the air and fuel delivered during fired working cycles at the first operational level such that less power is generated by firings at the second operational level relative to the first operational level.

9. A method as recited in claim 8 wherein:

feedback or feed forward indicative of the output provided by each individual working cycle firing is used in the determination of the working cycles to be skipped; and

the feedback or feed forward is arranged to compensate for variations in each of (a) engine speed, and (b) manifold pressure, and (c) the amount of fuel delivered to the working chamber in association with each firing.

10. A method as recited in claim 2 wherein:

the drive pulse generator includes a sigma delta controller having a first integrator; and

the desired engine output signal is multiplied by a feed forward multiplier signal that is scaled in accordance with the drive energy provided by each individual working cycle firing before the desired engine output signal is delivered to the first integrator of the sigma delta controller to compensate for variations in the drive energy provided by each individual working cycle firing.

11. An engine controller for controlling the operation of an internal combustion engine having at least one working chamber, each working chamber being generally arranged to operate in a succession of working cycles, the engine controller having a variable displacement operational mode that causes selected active working cycles to be fired and selected passive working cycles not to be fired, wherein the engine controller uses feedback control to provide a desired engine output, and the feedback utilized in the feedback control includes information indicative of at least one of requested and actual working cycle firings.

12. An engine controller as recited in claim 11 wherein the engine controller includes:

a drive pulse generator that provides a sequence of drive pulses that are synchronized with the engine speed and define a drive pulse pattern that generally indicates when active working cycles are appropriate to deliver the desired engine output; and

a sequencer that receives the drive pulse pattern and determines an actual firing sequence based at least in part on the received drive pulse pattern.

13. An engine controller as recited in claim 12 wherein the drive pulse generator is arranged to receive feedback indicative of the drive pulse signal and to utilize the feedback indicative of the drive pulse signal in the generation of the drive pulse signal.

14. An engine controller as recited in claim 13 wherein the drive pulse generator is further arranged to receive feedback indicative the actual working cycle firings and to utilize the feedback indicative of the actual working cycle firings in the generation of the drive pulse signal.

15. An engine controller as recited in claim 11 wherein the engine controller is arranged to receive feedback indicative of the actual working cycle firings and to utilize the feedback indicative of the actual working cycle firings in the determination of the active and passive working cycles.

16. An engine controller as recited in claim 11 further comprising an engine control block arranged to provide feedback or feed forward indicative of the output provided by each individual working cycle firing is used in the determination of the working cycles to be skipped.

17. An engine controller as recited in claim 16 wherein the feedback or feed forward provided by the engine control block is arranged to compensate for variations in manifold pressure.

18. An engine controller as recited in claim 16 wherein the feedback or feed forward provided by the engine control block is arranged to compensate for variations in engine speed.

19. An engine controller as recited in claim 16 wherein the engine control block includes:

a throttle controller arranged to control the position of an engine throttle;

a spark timing controller arranged to control the timing of the firing of the active working cycles; and

an injection controller arranged to control the amount of fuel delivered during each active working cycle.

20. An engine controller for controlling the operation of an internal combustion engine having at least one working chamber, each working chamber being generally arranged to operate in a succession of working cycles, the engine controller having a variable displacement operational mode that causes selected active working cycles to be fired and selected passive working cycles not to be fired, wherein the engine controller comprises:

a multiplier arranged to multiply a first signal indicative of a desired engine output by a factor defined by a second signal indicative of an amount of drive energy provided by each active working cycle firing, and to output a third signal;

a drive pulse generator arranged to receive the third signal and to output a drive signal that generally indicates when active working cycles are appropriate to deliver the desired engine output; and

an engine control block arranged to receive inputs indicative of a current state of the engine and to output the second signal.

21. An engine control block as recited in claim 20 wherein the inputs received by the engine control block include a signal indicative of current engine speed and a manifold air pressure signal and wherein the scale of the second signal is based at least in part on the current engine speed and a current manifold pressure.

22. An engine controller as recited in claim 20 wherein the engine control block includes:

a throttle controller arranged to control the position of an engine throttle;

a spark timing controller arranged to control the timing of the firing of the active working cycles; and

an injection controller arranged to control the amount of fuel delivered during each active working cycle.