Patent application number | Description | Published |
20140261317 | MISFIRE DETECTION SYSTEM - 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. | 09-18-2014 |
20140277999 | CAM PHASER CONTROL - Arrangements for stabilizing valve timing adjustment mechanisms such as cam phasers during operation of an engine are described. The described approaches are particularly well suited for use during skip fire control, although they may be used advantageously in other applications as well. In general, the phase of an adjustable phase camshaft is controlled relative to a crankshaft of an engine. In one aspect, at least one of (i) firing events in a skip fire firing sequence, and (ii) dynamically determined valve actuation events are used in the control of the camshaft phase during operation of the engine. In some embodiments, hydraulic pressure within a cam phaser is varied in a manner that maintains the phase of the camshaft substantially more stable through transitory variations in torque applied to the camshaft by the actuation of the valves than would occur without the variations in hydraulic pressure. | 09-18-2014 |
20140278007 | USING CYLINDER FIRING HISTORY FOR COMBUSTION CONTROL IN A SKIP FIRE ENGINE - Various methods and arrangements for determining a combustion control parameter for a working chamber in an engine are described. In one aspect, an engine controller includes a firing counter that stores a firing history for the working chamber. A combustion control module is used to determine a combustion control parameter, which is used to help manage combustion in the working chamber. The combustion control parameter is determined based at least in part on the firing history. | 09-18-2014 |
20150075458 | SYSTEM AND METHOD FOR SAFE VALVE ACTIVATION IN A DYNAMIC SKIP FIRING ENGINE - A variety of methods and devices for controlling the operation of the intake and exhaust valves in an internal combustion engine during skip fire operation are described. In various embodiments, an exhaust valve monitor or other suitable mechanism is used to detect exhaust valve actuation faults. When an exhaust valve actuation fault is detected for a particular cylinder, the corresponding intake valve is deactivated (or not activated) in circumstances when it would otherwise be activated in order to prevent the intake valve from opening into a cylinder that contains high pressure combustion gases. The described approach is particularly beneficial when skip fire operation is combined with cylinder deactivation so that air is not pumped through the cylinders during the skipped working cycles. | 03-19-2015 |
20150136082 | SYSTEM FOR MANAGING CATALYTIC CONVERTER TEMPERATURE - Various methods and arrangements for controlling catalytic converter temperature are described. In one aspect, an engine controller includes a catalytic monitor and a firing timing determination unit. The catalytic monitor obtains data relating to a temperature of a catalytic converter. Based at least partly on this data, the firing timing determination unit generates a firing sequence for operating the engine in a skip fire manner. Another aspect of the invention relates to an engine exhaust system that can help expedite the heating of a catalytic converter. | 05-21-2015 |
20150192080 | DETERMINATION OF A HIGH PRESSURE EXHAUST SPRING IN A CYLINDER OF AN INTERNAL COMBUSTION ENGINE - A variety of methods and arrangements for determining whether a high pressure exhaust spring is present in a cylinder of an internal combustion engine are described. For spark ignition engines, the electrical properties of the spark plug spark gap may be used to determine whether a high pressure exhaust spring is present. | 07-09-2015 |
20150233289 | VALVE FAULT DETECTION - Methods and systems are described for detecting valve actuation faults in internal combustion engines operating in a skip fire operational mode. In one aspect, a torque model is used to estimate an expected net torque during a selected operating window. The torque model considers an expected torque contribution from each of the cylinders and accounts for the effects of specific skip fire firing decisions that affect the expected torque contribution from each cylinder. A parameter indicative of the actual engine torque is also measured. Valve actuation faults can then be identified based at least in part on a comparison of the measured parameter to an expected parameter value that is based at least in part on the expected net torque. With the described approaches, the occurrence of the valve actuation fault can be made within one engine cycle of the initial occurrence of the fault. | 08-20-2015 |
20150322869 | INTERNAL COMBUSTION ENGINE USING VARIABLE VALVE LIFT AND SKIP FIRE CONTROL - 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. | 11-12-2015 |