Patent application number | Description | Published |
20140261309 | ENGINE DIAGNOSTICS WITH SKIP FIRE CONTROL - Methods and devices are described for performing engine diagnostics during skip fire operation of an engine while a vehicle is being driven. Knowledge of the firing sequence is used to determine appropriate times to conduct selected diagnostics and/or to help better interpret sensor inputs or diagnostic results. In one aspect, selected diagnostics are executed when a single cylinder is fired a plurality of times in isolation relative to a sensor used in the diagnosis. In another aspect, selected diagnostics are conducted while the engine is operated using a firing sequence that insures that no cylinders in a first cylinder bank are fired for a plurality of engine cycles while cylinders in a second bank are at least sometimes fired. The described tests can be conducted opportunistically, when conditions are appropriate, or specific firing sequences can be commanded to achieve the desired isolation or skipping of one or more selected cylinders. | 09-18-2014 |
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 |
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 |
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 |
20160024981 | 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. | 01-28-2016 |
20160061127 | ENGINE DIAGNOSTICS WITH SKIP FIRE CONTROL - Methods and devices are described for performing engine diagnostics during skip fire operation of an engine while a vehicle is being driven. Knowledge of the firing sequence is used to determine appropriate times to conduct selected diagnostics and/or to help better interpret sensor inputs or diagnostic results. In one aspect, selected diagnostics are executed when a single cylinder is fired a plurality of times in isolation relative to a sensor used in the diagnosis. In another aspect, selected diagnostics are conducted while the engine is operated using a firing sequence that insures that no cylinders in a first cylinder bank are fired for a plurality of engine cycles while cylinders in a second bank are at least sometimes fired. The described tests can be conducted opportunistically, when conditions are appropriate, or specific firing sequences can be commanded to achieve the desired isolation or skipping of one or more selected cylinders. | 03-03-2016 |
20160109330 | ENGINE ERROR DETECTION SYSTEM - A variety of methods and arrangements for detecting misfire and other engine-related errors are described. In one aspect, a window is assigned to a target firing opportunity for a target working chamber. There is an attempt to fire a target working chamber during the target firing opportunity. A change in an engine parameter (e.g., crankshaft angular acceleration) is measured during the window. A model (e.g., a pressure model) is used to help determine an expected change in the engine parameter during the target firing opportunity. Based on a comparison of the expected change and the measured change in the engine parameter, a determination is made as to whether an engine error (e.g., misfire) has occurred. | 04-21-2016 |