초록 ▼

A variety of methods and arrangements for improving the fuel efficiency of internal combustion engines are described. Generally, selected combustion events are skipped during operation of the internal combustion engine so that other working cycles can operate at a better thermodynamic efficiency. In

A variety of methods and arrangements for improving the fuel efficiency of internal combustion engines are described. Generally, selected combustion events are skipped during operation of the internal combustion engine so that other working cycles can operate at a better thermodynamic efficiency. In one aspect of the invention, an engine is controlled to operate in a variable displacement mode. In the variable displacement mode, fuel is not delivered to the working chambers (e.g. cylinders) during selected "skipped" working cycles. During active ("non-skipped") working cycles, a maximum (e.g., unthrottled) amount of air and an optimized amount of fuel is delivered to the relevant working chambers so that the fired working chambers can operate at efficiencies closer to their optimal efficiency. A controller is used to dynamically determine the chamber firings required to provide the engine torque based on the engine's current operational state and conditions. The chamber firings may be sequenced in real time or in near real time in a manner that helps reduce undesirable vibrations of the engine.

대표청구항 ▼

What is claimed is: 1. An internal combustion engine comprising: a plurality of working chambers each arranged to operate in a succession of working cycles; a fuel delivery system arranged to facilitate the delivery of fuel into the working chambers; and a fuel delivery control unit that enables th

What is claimed is: 1. An internal combustion engine comprising: a plurality of working chambers each arranged to operate in a succession of working cycles; a fuel delivery system arranged to facilitate the delivery of fuel into the working chambers; and a fuel delivery control unit that enables the engine to operate in a variable displacement mode in which the fuel delivery system is controlled to selectively deliver fuel to the working chambers during a first selected group of fired working cycles and to skip delivery of fuel to the working chambers during a second selected group of skipped working cycles, wherein the fuel delivery control unit includes a predictive adaptive controller and is arranged to dynamically determine the fired and skipped working cycles on a working cycle by working cycle basis during operation of the engine based at least in part upon a feedback signal indicative of at least one of requested and actual working cycle firings in order to deliver a desired engine output, and wherein the amount of fuel selectively delivered to the working chambers during each of the first selected group of fired working cycles is substantially optimized for the amount of air delivered to the working chambers during the first set of the active working cycles. 2. An internal combustion engine as recited in claim 1 wherein the fuel delivery control unit includes: a drive pulse generator that includes the predictive adaptive controller and 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. 3. An internal combustion engine as recited in claim 1 wherein the predictive adaptive controller includes: a control circuit that receives an analog input signal indicative of a desired engine output and outputs a feedback modified digital representation of the analog input signal; and a synchronizer that receives the digital representation of the analog signal, and outputs a sequence of drive pulses, wherein the sequence of drive pulses that define the drive pulse pattern is synchronized with the engine speed. 4. An internal combustion engine as recited in claim 1 wherein: the engine further includes an air supply throttle and the throttle is fully open when air is delivered to the working chambers during the fired working cycles; and the amount of fuel delivered to the working chambers during the first selected set of fired working cycles is set to cause the fired working chambers to operate at substantially their maximum thermodynamic efficiency. 5. An internal combustion engine as recited in claim 1 wherein the engine operates on a cycle selected from the group consisting of: a diesel cycle, an Otto cycle; a Miller cycle; a Wankel cycle, and a mixed thermodynamic cycle. 6. An internal combustion engine as recited in claim 1 wherein the internal combustion engine is a reciprocating piston engine having a plurality of cylinders, each cylinder serving as one of the working chambers, and wherein each cylinder has an associated piston, intake valve, and exhaust valve, wherein the engine is selected from the group consisting of: a two stroke piston engine; a four stroke piston engine; and a six stroke piston engine. 7. An internal combustion engine as recited in claim 1 wherein the predictive adaptive controller is a sigma delta controller. 8. An internal combustion engine as recited in claim 7 wherein the sigma delta controller uses a clock signal that varies proportionally with engine speed. 9. An internal combustion engine as recited in claim 1 wherein the predictive adaptive controller receives: an input signal indicative of accelerator pedal position that is interpreted by the fuel delivery unit as a control input indicative of a desired engine output; and feedback indicative of at least one of proposed and actual working cycle firings. 10. An internal combustion engine comprising: a plurality of working chambers each arranged to operate in a succession of working cycles; a fuel delivery system arranged to facilitate the delivery of fuel into the working chambers; and a fuel delivery control unit that includes a sigma delta control circuit, a synchronizer, and a sequencer, the fuel delivery control unit enabling a variable displacement mode in which the fuel injection system is controlled to selectively deliver fuel to the working chambers during a first selected set of active working cycles and to skip delivery of fuel to the working chambers during a second selected set of passive working cycles, wherein, the sigma delta control circuit receives an analog input signal indicative of a desired engine output and outputs a feedback modified digital signal representation of the analog input signal, the synchronizer receives the digital signal representation of the analog signal, and outputs a drive pulse signal that is synchronized with the engine speed, wherein the drive pulse signal generally indicates when active working cycles are appropriate to deliver the desired engine output, the sequencer receives the drive pulse signal and determines the first and second sets of working cycles on a working cycle by working cycle basis based at least in part on the received drive pulse signal, and the air delivered to the working chambers during the first set of active working cycles is unthrottled or at a fixed throttle position. 11. An internal combustion engine as recited in claim 10 wherein: the amount of fuel delivered to the working chambers during each working cycle in the first set of the active working cycles is substantially optimized for the amount of air delivered to the working chambers during the first set of the active working cycles; and the fuel delivery control unit is further arranged to control the fuel delivery system to selectively deliver a second amount of fuel to the working chambers during a third selected set of active working cycles interspersed with the first set of active working cycles, wherein the second amount of fuel is less than the optimized amount of fuel. 12. A method of controlling the operation of an internal combustion engine having a plurality of working chambers, each working chamber being generally arranged to operate in a succession of working cycles, the method comprising operating the engine in a variable displacement mode that includes: delivering air to the working chambers during the active working cycles, wherein the air delivered to the working chambers is either unthrottled or delivered at a first set air throttle position; delivering fuel to the working chambers in a fuel delivery pattern dynamically determined on a working cycle by working cycle basis during operation of the engine that skips delivery of fuel during selected skipped working cycles and delivers fuel during selected active working cycles; wherein an amount of fuel delivered to the working chambers during a first set of the active working cycles is substantially optimized for the amount of air delivered to the working chambers during the first set of the active working cycles; and wherein the fuel delivery pattern is determined at least in part using predictive adaptive control to provide a desired engine output, and wherein the predictive adaptive control includes feedback indicative of at least one of requested and actual working cycle firings. 13. A method as recited in claim 12 further comprising: enabling the engine to operate in a second operating mode; and automatically determining whether to operate in the variable displacement mode or the second operating mode based at least in part upon the current operational state of the engine; and wherein in the second operating mode, the amount of air introduced to the working chambers is modulated by an air supply throttle, the amount of fuel introduced during specific working cycles is based at least in part on the amount of air introduced to the working chambers during such working cycles, and fuel is delivered to the working chambers during every working cycle of the engine such that none of the working cycles are skipped. 14. A method as recited in claim 12 wherein the selection of working cycles to be skipped is based at least in part on a current rotational speed of the engine. 15. A method as recited in claim 12 wherein the amount of fuel delivered to the working chambers during a second set of the active working cycles that are interspersed with the first set of working cycles is reduced relative to the amount of fuel delivered during the first set of active working cycles, wherein the selection of the working cycles in the second set of active working cycles is arranged to accomplish at least one of (a) smoothing the output of the engine, (b) helping reduce vibrations of the engine, (c) more precisely matching a desired engine output, and (d) reducing emissions from the engine. 16. A method as recited in claim 12 wherein the engine includes an air supply throttle and the throttle is operated at full throttle in the variable displacement mode.