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Skip Fire Transition Control

A technique for ignition fraction, transition process

Active Publication Date: 2020-01-10
TULA TECH INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

While NVH is reduced when operating at these firing fractions, NVH issues may arise during transitions between different firing fractions

Method used

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  • Skip Fire Transition Control
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Examples

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Embodiment Construction

[0024] When a limited set of firing fractions is available, transitioning between different firing fractions typically also involves adjustments to selected engine operating parameters. This is because, at any particular firing density, there will be associated operating parameters (eg, air charge, spark timing, etc.) that are suitable to effectively deliver the desired engine output. Therefore, when making changes to firing densities, it is typically desirable to substantially simultaneously adjust selected engine operating parameters to maintain desired engine output at the new firing fraction. Without such adjustments, operation at the same engine settings will typically result in more torque than would be desired when firing density is increased, and less torque than would be desired when firing density is reduced.

[0025] From a control standpoint, the firing density can be changed very quickly by simply changing the selection of the particular cylinder to fire, however ...

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Abstract

Methods and arrangements are described for controlling transitions between multiple firing fractions during skip fire operation of an engine to help smooth these transitions. In general, the transition in firing fraction is implemented gradually, preferably in a manner that relatively closely tracks the manifold fill dynamics. In some embodiments, the commanded firing fraction is changed for each firing opportunity. Another approach contemplates changing the commanded firing fraction by substantially the same amount per firing opportunity for at least a portion of the transition. These approaches work particularly well when the commanded firing fraction is provided to a skip fire controller that includes an accumulator function that tracks the portion of a firing that has been requested but not delivered, or vice versa. In various embodiments, the change in commanded spark fraction is delayed relative to the onset of the throttle position change to help compensate for the inherent delay associated with changes in manifold air pressure.

Description

[0001] Cross References to Related Applications [0002] This application claims priority to US Provisional Application No. 62 / 053,351 filed September 22, 2014, which is hereby incorporated by reference in its entirety. technical field [0003] The present invention generally relates to methods and arrangements for controlling transitions between multiple firing fractions during skip fire operation of an engine. Background technique [0004] The fuel efficiency of many types of internal combustion engines can be substantially improved by changing the displacement of the engine. This allows maximum torque to be available when required and also when not required, significantly reducing pumping losses and improving thermodynamic efficiency by using a smaller displacement. The most common method of changing displacement today is to deactivate a group of cylinders substantially simultaneously. In this approach, fuel is not delivered to deactivated cylinders, and their associate...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): F02D17/02
CPCF02D17/02F02D41/0087F02P5/1504F02D41/0002F02D2200/0402F02D2200/0406F02D2200/1004F02D2250/18Y02T10/40
Inventor 穆罕默德·R·皮尔雅伯里路易斯·J·塞拉诺袁欣史蒂文·E·卡尔森S·哈希米瑞安·A·库勒贝克
Owner TULA TECH INC