A method is provided for controlling the torque of an engine when a DPF is regenerated and includes detecting outputs of a gear pump and a main hydraulic pump as parameters for correcting a DPF regeneration condition, increasing the flow rate of the gear pump or main hydraulic pump, controlling the torque of an engine so as to reach a predetermined target engine torque value as the flow rate of the gear pump or main hydraulic pump is increased, starting DPF regeneration when the torque of the engine reaches the predetermined target engine torque value, allowing the number of revolutions of the engine to be increased on the basis of the target engine torque value during the DPF regeneration, and performing the DPF regeneration until the temperature of exhaust gas reaches a predetermined target DPF regeneration temperature.

Since a factor affecting an individual difference learning result is reduced or eliminated regardless of a valve body behavior, it is possible to highly accurately detect an individual difference of a fuel injector caused by the valve body behavior and to reliably detect the individual difference even when the fuel injector is replaced. When a valve opening/closing timing of the fuel injector is learned by a learning unit, a unit of interrupting the learning if a predetermined condition is established, a unit of prohibiting the learning of the valve closing timing using the learning unit if a predetermined condition is established, or a unit of prohibiting the learning of the valve opening/closing timing of the fuel injector using the learning unit if a fuel pressure of a common rail supplying a fuel to the plurality of fuel injectors changes by a predetermined value or more within a predetermined time is provided.

An engine operation control apparatus includes a controller configured to: decide an engine operation time point based on a lookup table in which a learning value that is previously learned is stored when a request to switch to an HEV mode occurs; determine whether to engage an engine clutch by comparing an engine RPM when a speed of an engine is synchronized with a speed of a motor with a first motor RPM; operate the engine at the engine operation time point and control engagement of the engine clutch depending on the determination; and store the engine operation time point based on a second motor RPM at a synchronization completion time point when a learning condition of the engine operation time point is satisfied when the speed of the engine and the motor are synchronized.

The invention relates to a method for adapting the composition of a mixture of fuel and combustion air. The mixture is supplied to a combustion chamber of a mixture-lubricated combustion engine in a work apparatus. The fuel is supplied to the combustion engine via a controlled fuel valve. In an operating state (I) of the combustion engine, the quantity of fuel is metered by the fuel valve. For the purpose of adapting the composition of the mixture, the combustion engine is shifted into a special operating state (II) which differs from the normal operating state (I). After starting, the combustion engine is operated in a first rotational speed range (B) for a prespecified operating time (T.sub.min), wherein, after the prespecified operating time (T.sub.min) has elapsed, the operating state (II) for adapting the composition of the mixture is initiated by a prespecified user action.

Various embodiments include a method for starting an internal combustion engine comprising: in a first phase after a starting process, setting a throttle valve to a value near to zero so the pressure in the intake tract is lowered below the ambient pressure and injecting a fuel into the intake tract above a rich combustion limit at which the fuel/air mixture would still just be combustible; in a second phase, reducing the fuel mass as a function of the pressure; in a third phase shorter than the second phase, further reducing the fuel mass and increasing the opening of the throttle valve to increase the pressure in the intake tract; and in a fourth phase, increasing the fuel mass as a function of rising pressure in the intake tract.

Provided are a work machine, a power unit, and a diesel engine of a work machine that make it possible to reduce emitted noxious substances to levels below reference values stipulated by exhaust gas regulations in advanced countries and regions while also omitting or simplifying a post-treatment device. A hydraulic pump is driven by a diesel engine that limits maximum output torque in a low revolution speed region lower than a high revolution speed region including a rated revolution speed in such a manner that the maximum output torque has a characteristic of intermediate torque lower than torque of a maximum output horsepower point at the rated revolution speed, and a hydraulic actuator is driven by hydraulic fluid delivered from the hydraulic pump.

The air-conditioning control device is configured to control an air conditioner for a vehicle having a radiant heater and to output a cancel signal that allows an engine, which has been stopped in response to an idling stop control, to restart. The radiant heater is configured to be supplied with power to heat an occupant in a vehicle compartment of the vehicle. The air conditioner is configured to heat an interior of the vehicle compartment using cooling water for the engine. The air-conditioning control device is configured to extend a stop time from stopping the engine in response to the idling stop control to outputting the cancel signal, which allows the engine having been stopped in response to the idling stop control to restart, to be longer with the radiant heater being operated than with the radiant heater being stopped.

There are provided a start determinator for determining whether or not the vehicle has started, an elapsed timer for measuring elapsed time since start of the vehicle determined by the start determinator; and a start controller for adjusting an engine output by changing the output in multiple stages until the elapsed time measured by the elapsed timer reaches a control time determined in advance if the start of the vehicle is determined by the start determinator.

In a case where a control device receives a stop signal instructing stopping of an engine and the control device determines that the engine temperature is lower than a predetermined temperature based on a signal from a timer or based on a signal from a cooling water temperature sensor, an operation control is maintained until the control device determines that the engine temperature is the predetermined temperature or higher. This way, an engine is provided which is capable of restraining generation of blowby condensate water without stopping a cooling water pump during the operation of the engine.

A method of operating a forced induction gaseous-fueled engine includes mixing gaseous-fuel and engine intake air to form a mixture at a fuel mixer. The method includes delivering the mixture to an intake manifold by at least partially bypassing a charge air cooler.