A method of controlling a gas engine that is operated under lean-burn conditions, the method adjusting ignition timing such that a delay calculation value of an actual knocking occurrence ratio becomes a target occurrence ratio, the method comprising: when a delay calculation value of a maximum pressure in a cylinder of the gas engine is greater than or equal to a reference value, converting the delay calculation value into a virtual knocking occurrence ratio greater than or equal to a value greater than the target occurrence ratio; and either adding the virtual knocking occurrence ratio to the delay calculation value of the actual knocking occurrence ratio and then comparing the resulting delay calculation value of the actual knocking occurrence ratio with the target occurrence ratio, or comparing the virtual knocking occurrence ratio instead of the delay calculation value of the actual knocking occurrence ratio with the target occurrence ratio.

Methods and systems are provided for identifying degradation of active engine mounts coupled to a vehicle engine. By correlating the monitored vibrational pattern to a selected active mounts operating mode, the conditions of active engine mounts may be distinguished. Timely diagnosis of active engine mounts may improve active engine mount health and prevent noise, vibration, and harshness (NVH) issues.

Methods and systems are provided for adjusting spark timing and fueling in an engine in response to an indication of exhaust gas recirculation (EGR) system degradation due to a disconnected upstream hose of an EGR differential pressure sensor. In one example, a method may include, responsive to an integrated knock intensity being greater than a threshold intensity and a fuel control correction being greater than a threshold enrichment, setting an EGR rate to zero and triggering an EGR differential pressure sensor upstream hose diagnostic routine to be performed. Further, spark timing and fueling may be set for zero EGR.

A magneto timing control system is described. The magneto timing control system can include an element configured to adjust tension of one of a first section of a belt and a section of the belt, wherein the belt is in communication with at least one magneto. The tension of the first section of the belt and the second section of the belt control a timing advance and a timing retard of the at least one magneto.

Methods and systems are provided for improving fuel usage while addressing knock by adjusting the use of spark retard and direct injection of a knock control fluid based on engine operating conditions and the composition of the injected fluid. One or more engine parameters, such as EGR, VCT, boost, throttle position, and CMCV, are coordinated with the direct injection to reduce torque and EGR transients.

Methods and systems are provided for improving fuel usage while addressing knock by adjusting the use of spark retard and direct injection of a knock control fluid based on engine operating conditions and the composition of the injected fluid. One or more engine parameters, such as EGR, VCT, boost, throttle position, and CMCV, are coordinated with the direct injection to reduce torque and EGR transients.

An engine kill switch and a throttle lever position sensor switch both remote from the engine and connected by a pair of wires to a microcontroller for controlling a spark initiated combustion of an air-fuel mixture in a cylinder of the engine. The switches may be received in the same housing and mounted in an operator handle housing of a hand held power tool.

An apparatus obtains waveforms representing measurements of a physical characteristic of a machine's operation and performance results of the machine corresponding respectively to the waveforms, each of the performance results being indicative of the machine's performance under conditions at which the measurement represented by the corresponding waveform was made. The apparatus calculates, for each of at least interval associated with each of the waveforms, an influence value that represents a degree of influence of the waveforms on the performance results over the interval.

An apparatus obtains waveforms representing measurements of a physical characteristic of a machine's operation and performance results of the machine corresponding respectively to the waveforms, each of the performance results being indicative of the machine's performance under conditions at which the measurement represented by the corresponding waveform was made. The apparatus calculates, for each of at least interval associated with each of the waveforms, an influence value that represents a degree of influence of the waveforms on the performance results over the interval.

An apparatus obtains a plurality of waveforms representing measurements of a physical characteristic of a machine's operation and a plurality of performance results of the machine corresponding respectively to the plurality of waveforms, each of the performance results indicative of the machine's performance under conditions at which the measurement represented by the corresponding waveform was made. The apparatus divides each of the waveforms into a common plurality of intervals and calculates, for each of at least one of the intervals, an influence value that represents a degree of influence of the plurality of waveforms on the plurality of performance results over the interval.