A control device for an internal combustion engine is programmed, during a catalyst warm-up control, to perform first fuel injection by an injector in an intake stroke, control an ignition device so as to generate a discharge spark in a predetermined period in an expansion stroke, and perform second fuel injection, at a timing retarded from a compression top dead center, such that its injection period overlaps with at least a part of the predetermined period and an end timing of the injection period is advanced from an end timing of the predetermined period. Further, the control device is programmed, during the catalyst warm-up control, to control an actual tumble ratio depending on a result of determination using a first index value representing a speed of initial combustion accompanying an ignition by the ignition device and a second index value representing a speed of main combustion accompanying the ignition.

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.

A method of controlling fuel injection subsequent to engine start, comprises: a) at, or after synchronization, in respect of a potential upcoming firing or injection event for a particular cylinder, determining or selecting a first injection profile; b) determining if there is sufficient time for the first injection profile to be implemented; and c) if so, implementing the said first injection profile with respect to said event.

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.

A microcomputer determines that an abnormality has occurred in calculation functions regarding calculation of an injection amount command value and the like, based on a deviation of the injection amount command value, in an increasing manner, from a monitoring injection amount. The microcomputer calculates, based on a cooling fluid temperature of an engine, a start-up injection amount such that the start-up injection amount becomes smaller when the cooling fluid temperature is high than when the cooling fluid temperature is low, and uses the start-up injection amount as the injection amount command value immediately after the completion of start-up of the engine. Besides, the microcomputer uses the smaller one of a start-up injection amount calculated this time and a monitoring start-up injection amount calculated last time, as a monitoring start-up injection amount that is used as the aforementioned monitoring injection amount immediately after the completion of start-up of the engine.

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.

A fuel-supply system has a fuel pump, a pressure controller, a signal output device and a power switch. The pressure controller adjusts the observed fuel pressure of the fuel and may electronically communicate with a motor driving the fuel pump to regulate the supply of fuel from a fuel tank of the fuel-supply system to an engine. In detail, the pressure controller performs feedback control of a voltage applied to the motor such that the pressure of a fuel pumped from the fuel pump approaches to have a first target and/or ideal fuel pressure value. Further, the signal output device outputs the first target fuel pressure value to the pressure controller. Activation of the power switch supplies power, from a power source, to the pressure controller, the motor and the signal output device. Further, the pressure controller may perform feedback control based on a second target fuel pressure value.

In an engine starting system, a first controller activates, in response to a driver's starting request, a first starting device to rotate the rotating shaft of an engine. A second controller is communicably connected to the first controller. The second controller recognizes rotation of the rotor of a second starting device resulting from an activation of the first starting device. The second controller starts a power running operation of the second starting device based on the recognition of the rotation of the rotor. The first controller determines whether the power running operation of the second starting device has been started. The first controller deactivates, when it is determined that the power running operation has been started, the first starting device before a rotational angular position of the rotating shaft of the engine arrives at a compression top dead center of the engine.

There is provided a configuration in which a cylinder which is in an inlet stroke when an internal combustion engine is in a stop (automatic stop) state is determined and stored, and when starting the engine upon detection of a start request, the fuel injection of an initial cycle to the cylinder, which has been determined as having been stopped in the inlet stroke when the engine was in the stop state before starting, is split into a plurality if injections at least including an injection before engine rotation, to thereby perform injections. As a result, startability is improved while suppressing pre-ignition at the time of starting.

Embodiments of the present invention provide a controller for a starter motor operable to receive a first input indicative of an engine shutdown being required, a second input indicative of a change-of-mind event having occurred after initiation of engine shutdown and a third input indicative of the engine position. After receipt of the first input the controller is operable to monitor the third input and to determine an expected engine rotation direction indicative of the expected rotation direction of the engine after a predetermined delay. If the expected engine rotation direction is positive and the second input is received then the controller is configured to control the output means to cause the starter motor of the engine to be actuated upon receipt of the second input. If the expected engine rotation direction is negative and the second input is received then the controller is configured to delay controlling the output means to cause the starter motor of the engine to be actuated until a determination is made that the expected rotation direction is positive. Advantageously, the controller calculates the expected engine rotation direction before receipt of the input indicative of the change-of-mind event having occurred, thereby reducing the time required to determine whether or not the starter motor can be actuated.