Methods and systems are provided for controlling an engine speed in a hybrid vehicle system during steady-state conditions and in response to transient acceleration and/or deceleration requests. In one example, an engine speed is controlled to an optimal engine speed for fuel economy during steady-state conditions, and in response to an acceleration or deceleration request, a target engine speed is obtained from a rate-limited optimal engine speed to vehicle speed ratio, and the engine is controlled to the target engine speed provided the target speed is below a threshold difference from optimal engine speed. In this way, the vehicle system may simulate a fixed ratio transmission during accelerations and decelerations, while maintaining optimal engine speed for fuel economy at steady state.

A method includes reducing automatically a speed of an engine from a first speed value to a second speed value in response to both the first speed value being at or above a first speed threshold value and a rate of change of one or both of (i) engine power and (ii) the engine speed is substantially zero for a designated period.

An integrated ignition and electronic auto-choke module for an internal combustion engine and an internal combustion engine including the same. In one aspect, the module includes a housing that is configured to be mounted to an engine block of an internal combustion engine. The housing may contain at least a portion of a first temperature sensor that measures a first temperature indicative of an engine temperature. The housing may also contain a controller and at least a portion of an ignition circuit. The controller may be coupled to the first temperature sensor and configured to determine a starting position of a choke valve based on the first temperature and operate an actuator to move the choke valve into the starting position accordingly.

A control method for an internal combustion engine which is a driving source of a vehicle in which a driving force is transmitted to a transmission when a clutch is engaged, the control method includes: when the internal combustion engine which is automatically stopped in a state where the clutch is disengaged is restarted, performing a torque down control to decrease a target torque of the internal combustion engine when the clutch is engaged; setting a predetermined torque release time period determined in accordance with a driving state; and ending the torque down control at a timing at which the torque release time period is elapsed from an engagement command of the clutch which is generated during the torque down control.

A method for safely capturing an engine RPM threshold in a spark-ignition internal combustion engine which may exceed the maximum safe unloaded RPM for that engine. Typical engines having a safe RPM high speed redline when coupled to a load, and a reduced RPM redline when decoupled and unloaded, can be set to activate ancillary equipment at a high redline, engine loaded RPM by deriving and processing data from the engine at a low, unloaded reduced RPM speed. The method requires operator reference to an existing OEM or after-market tachometer which enables the user to set a low RPM reference point while the engine is unloaded and running at a slow RPM. Raw data from the latter low RPM reference point selected by a user is safely captured to form a raw threshold while the engine is operating unloaded, and a higher RPM operating threshold is calculated and set from the raw threshold. The higher RPM operating threshold may exceed the maximum safe unloaded RPM for said engine.

The present invention relates to a work vehicle including an engine, a hydraulic pump, a hydraulic motor to drive wheels, an HST circuit in which the hydraulic pump and the hydraulic motor are connected to each other in the form of a closed circuit, a reducing agent sensor that detects the state of a reducing agent used to clean exhaust gas from the engine, and an engine restrictor that restricts the rotational speed of the engine based on the output from the reducing agent sensor, and the work vehicle further includes a control unit that changes the tilting angle of the hydraulic pump or the hydraulic motor independently of the rotational speed of the engine to a tilting angle associated with minimum travel drive force necessary for self-travel of the work vehicle when the control unit determines that the engine restrictor has restricted the rotational speed of the engine.

An internal combustion engine includes an ignition plug and an electronic control unit. The electronic control unit is configured to: (i) execute a lean-burn operation in a first operation region, (ii) execute an operation in a second operation region at an air-fuel ratio lower than an air-fuel ratio during the lean-burn operation, and (iii) control a gas flow in a cylinder so that a ratio of a change in a gas flow speed around the ignition plug during ignition to a change in an engine rotation speed in a first engine rotation speed region within the first operation region is smaller than the ratio in a second engine rotation speed region within the second operation region.

Methods and systems for reigniting an engine of an aircraft are described. An engine flameout event is detected during flight. Responsive to detecting the engine flameout event, an engine speed and a commanded engine operating state are monitored. The engine speed is compared to a predetermined threshold. A determination is made regarding whether the commanded engine operating state corresponds to an engine on state. When the commanded engine operating state corresponds to the engine on state, and when the engine speed is below the predetermined threshold, a predetermined ignition sequence for the engine is initiated.

A multipurpose vehicle includes an engine that has a plurality of cylinders, a traveling vehicle body that has a traveling device that is driven based on a driving force of the engine, a man-operable accelerator operating tool, a controller that controls a fuel injection quantity with respect to the plurality of cylinders of the engine based on an amount of operation of the accelerator operating tool, and a vehicle speed sensor that detects a traveling speed of the traveling vehicle body. If the traveling speed of the traveling vehicle body reaches or exceeds a set maximum traveling speed, the controller suppresses the fuel injection quantity supplied with respect only to one/some of the plurality of cylinders, irrespective of the amount of operation of the accelerator operating tool.

A retrofittable control system for controlling an engine and a clutch of a frost fan may include a data processing system, a thermostat, a human machine interface, a throttle control module, and/or a clutch control module. The control system may be configured to automatically start the fan when the thermostat detects a temperature below a user defined turn-on temperature, and to automatically shut down and park the fan when the thermostat detects a temperature above a user defined turn-off temperature. In some examples, starting up the fan may include running a clutch engagement sequence that engages the clutch at different speeds for different durations.