An intake valve device capable of implementing two-stage switching of a gas distribution phase and a diesel engine. The intake valve device comprises a cam (1), a tappet guide rod component (2), a rocker arm (3), a variable valve bridge (7), and an intake valve (12) connected in sequence, and further comprises an intake valve drive piston (5), the intake valve drive piston (5) being capable of abutting against the rocker arm (3), a piston cavity accommodating the intake valve drive piston (5) is provided in the variable valve bridge (7), wherein communication between the high-pressure end of the piston cavity and a main oil path (10) can be established or broken by means of a high-pressure oil path (8), while the low-pressure end of the piston cavity is communicated with the main oil path (10) by means of a low-pressure oil path (11), and in order to ensure the formation of the pressure in the piston cavity to ensure that there is sufficient pressure to open the intake valve (12), an one-way valve (7) communicating from the low-pressure end to the high-pressure end is formed in the piston cavity. The cam (1) is a multi-lift cam having high and low cam molded lines, and can meet the requirements for the gas distribution phase under two working conditions, thereby achieving optimal engine performance and emission target. Moreover, the provided intake valve drive piston (5) and hydraulic oil path implement switching of the lifts of the cam (1).

A variable valve lift (VVL) system for an internal combustion engine is provided that utilizes hydraulic fluid supply pressure feedback to provide noise free operation. The VVL system includes a high pressure pump, a solenoid valve, a pressure translating device, a one-way valve, and a hydraulic fluid pressure sensor. The high pressure pump is fluidly connected to the solenoid valve and pressure translating device by at least one fluid gallery that forms a high pressure chamber. The solenoid valve selectively fluidly connects the high pressure chamber to a middle pressure chamber formed by at least one fluid gallery that fluidly connects the one-way valve to the solenoid valve. The hydraulic fluid pressure sensor is arranged to detect a hydraulic fluid supply pressure of the one-way valve and provides feedback to an electronic controller that determines a proper fluid intake opening timing of the solenoid valve.

A control device for an engine is provided, which includes a combustion chamber formed by a cylinder and a piston, an intake air amount adjuster that adjusts an intake air amount supplied to the combustion chamber, a controller switchable of a combustion mode between a fuel-lean first combustion mode and a stoichiometric second combustion mode based on an engine operating state, and an intake air cooler that cools the intake air supplied to the combustion chamber. The controller controls the intake air cooler to start intake air cooling in response to a request for switching the combustion modes, and after the intake air cooling is started, controls the intake air amount adjuster to start the switching of the combustion modes, and then controls the intake air cooler and the intake air amount adjuster so that the switching of the combustion modes ends after the intake air cooling is finished.

Methods and systems for maintaining a temperature of catalyst above a threshold temperature during vehicle braking and coasting is described. In one example, engine pumping work may be increased without increasing flow of cool fresh air through the engine's exhaust system to provide a desired level of engine braking. The net air flow through the engine may be reduced via activating a decompression actuator.

Embodiments of the present disclosure relate to a method and device for valve travel switching control of an internal combustion engine supercharged by an exhaust-gas turbocharger having a wastegate valve. This valve travel switching control includes: determining the current sensitivity of the charge pressure at a current operating point, at which a current valve travel, a current wastegate valve position and a current charge pressure are present, to changes in the wastegate valve position; determining the minimum valve travel necessary to set a desired operating point, taking into account the determined current sensitivity of the charge pressure; and switching the valve travel if the minimum valve travel necessary to set the internal combustion engine to an extended range with respect to the desired operating point differs from the current valve travel. By means of these measures, the fuel saving operating range of the internal combustion engine is enlarged.

A method for controlling the air-fuel ratio of a vehicle includes: calculating the air amount charged in a cylinder of an engine by using a fresh air amount, a residual air amount remaining inside the cylinder of the engine, and a backflow gas amount flowing back into the cylinder upon the valve overlap of an intake vale and an exhaust valve of the engine, correcting it with the purge gas flow rate supplied to an intake manifold of the engine when the active purge system is operated, calculating the final fuel amount by correcting the fuel amount injected by a fuel injection device with the amount of the fuel component contained in the purge gas when the active purge system is operated, and controlling the air-fuel ratio based on the final air amount and the final fuel amount.

Methods and systems for increasing exhaust gas temperatures of an engine are described. In one example, engine exhaust gas temperatures may be increased via deactivating cylinders and flowing exhaust gases through deactivated cylinder. Engine pumping losses may be reduced via the exhaust gases that flow through the deactivated cylinder so as to reduce engine fuel consumption while heating an exhaust gas after treatment device.

Embodiments are directed toward an engine. In some embodiments, the engine includes a water pump and a balancer shaft. In some embodiments, the water pump has a plain bearing. In some embodiments, plain bearing is supplied with pressurized oil. In some embodiments, the balancer shaft drives the water pump as well as cam shafts.

A method of operating a rocker arm assembly in a cylinder deactivation mode according to one example of the present disclosure includes providing a two-step variable valve lift rocker arm assembly and a deactivating lash adjuster. Operation of the rocker arm assembly in cylinder deactivation mode is selected. The rocker arm assembly is operated in low-lift mode based on the selection of the cylinder deactivation mode. Subsequent to or concurrently with operating the rocker arm assembly in the low-lit mode, the deactivating lash adjuster is operated in the unlatched mode. A first amount of the total lost motion required for cylinder deactivation mode is accounted for by lost motion of the rocker arm assembly operating in the low-lift mode and a remainder amount of the total lost motion is accounted for by lost motion of the deactivating lash adjuster operating in the unlatched mode.

In an internal combustion engine provided with an electro-hydraulic system for variable actuation of the intake valves of the engine, each cylinder has two intake valves, which are associated with two intake conduits and are controlled by a single cam of a camshaft through a single hydraulic circuit. The communication of the hydraulic actuators of the two intake valves with a discharge channel is controlled by two electrically-actuated control valves, both of an on/off two-position type, arranged in series with each other along a hydraulic line for communication between the a pressure volume and the discharge channel.