Abstract:
Various methods and data structures for managing transition between different firing fractions during skip fire operation of an engine are described. In some embodiments, transitions are constrained to occur when firing sequence segments of a designated length are shared by the first and second firing fractions. In a separate aspect, a data structure that uses current firing fraction phase as a first index and a target firing fraction as a second index may be used to determine a phase of the target firing fraction to enter at a transition. Is some circumstances transitions between a current and target firing fraction may be conducted as a series of steps through intermediate firing fractions.
Abstract:
A variety of methods and arrangements for operating an internal combustion engine and one or more motor/generators in a hybrid vehicle are described. Generally, the engine is operated in a variable displacement or skip fire mode. Depending on the state of charge of an energy storage device and/or other factors, the engine is operated to generate more or less than a desired level of torque. The one or more motor/generators are used to add or subtract torque so that the motor/generator(s) and the engine collectively deliver the desired level of torque. In some embodiments, the engine may be run with a substantially open throttle to reduce pumping losses and improve fuel efficiency.
Abstract:
An internal combustion engine capable of cylinder deactivation or skip fire control in combination with variable valve lift control. One bank of cylinders can be deactivated while the air induction of the other bank of cylinders is regulated using variable valve lift control to increase engine efficiency. An internal combustion engine with two cylinder banks, where control of one cylinder bank using skip fire control can be operating at an appropriate firing fraction in combination with variable valve lift control on the other cylinder bank. A single bank of cylinders can be controlled in a skip fire manner in conjunction with variable valve lift control.
Abstract:
Methods and arrangements for controlling hybrid powertrains are described. In one aspect, an engine is alternatingly operated at different effective displacements. One displacement delivers less than a requested powertrain output and the other delivers more. A motor/generator system is used to add and subtract torque to/from the powertrain to cause the net delivery of the requested powertrain output. In some embodiments, energy added and subtracted from the powertrain is primarily drawn from and stored in a capacitor (e.g., a supercapacitor or an ultracapacitor) when alternating between effective displacements. In another aspect a hybrid powertrain arrangement includes an engine a motor/generator and an energy storage system that includes both a battery and a capacitor. The capacitor stores and delivers electrical energy to the motor/generator unit during operation of the engine in a variable displacement or skip fire mode.
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
Abstract:
In one aspect, a system for reducing noise or vibration generated by an internal combustion engine is described. An engine controller is arranged to generate firing information suitable for operating the working chambers of the engine in a skip fire manner to deliver a desired amount of torque. A noise/vibration reduction unit is arranged to help reduce noise or vibration based on the firing information. The noise/vibration controller actively controls a device that is not a part of the engine to alter an NVH characteristic of the vehicle in a desired manner based at least in part on a skip fire characteristic
Abstract:
In one aspect, a method is described. An operational engine torque is calculated. The engine is operated in a skip fire or firing level modulation manner to deliver the operational engine torque. A reference engine torque is calculated using a torque model. The torque model involves estimating torque at a working chamber level. The reference engine torque is compared to the calculated operational engine torque to assess the accuracy of the operational engine torque calculation. Various embodiments of the present invention involve software, devices, systems and engine controllers that are related to one or more of the above operations.
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.
Abstract:
In one aspect, a skip fire engine controller is described. The skip fire engine controller includes a skip fire module arranged to determine an operational firing fraction and associated cylinder load for delivering a desired engine output. The skip fire engine controller also includes a firing controller arranged to direct firings in a skip fire manner that delivers the selected operational firing fraction. Various methods, modules, lookup tables and arrangements related to the selection of a suitable operational firing fraction are also described.
Abstract:
A variety of methods and arrangements for detecting misfire in a skip fire engine control system are described. In one aspect, a window is assigned to a target firing opportunity for a target working chamber. A change in an engine parameter is measured during the window. A determination is made as to whether a firing opportunity before the target firing opportunity is a skip or a fire and/or whether a firing opportunity after the target firing opportunity is a skip or a fire. Based at least in part on this skip/fire determination, a determination is made as to whether the target working chamber has misfired. In various embodiments, if the target working chamber is identified as persistently misfiring, the firing sequence is modified so that the target working chamber is deactivated and excluded from the firing sequence. In still other embodiments, a torque model is used to detect engine-related problems