Methods and systems are provided for deactivating a valve actuation mechanism. In one example, a system may include a hydraulic gallery that may deliver a restricted flow of hydraulic fluid from a hydraulic flow restrictor to a pressure relief valve within a valve deactivation oil control valve, and during a second condition may deliver an unrestricted flow of hydraulic fluid from the valve deactivation oil control valve to the hydraulic flow restrictor. The hydraulic flow restrictor may comprise two vertical bores within the camshaft carrier that are fluidically coupled via a restrictive groove on the bottom surface of the camshaft carrier.

The aim of the invention is to ensure that a hydraulic drive (10) for accelerating and braking a gas exchange valve (20) of internal combustion engines or other reciprocating engines operates in a simple, reliable and recuperative manner. To this end, a first pressure tank (41) for providing a first pressure p.sub.1, a restoring energy accumulator preferably embodied as a spring (25), and at least one hydraulic basic pressure tank (40) having a lower pressure p.sub.0 than the first pressure tank (41) are provided. A controllable opening (49) of a first valve (46) is arranged with at least one non-return valve (47) located upstream or downstream of the opening in the flow path, in a connection line (48) between the first hydraulic pressure tank (41) and the working cylinder (22), said non-return valve allowing the pressure medium (30) to flow towards the working cylinder (22) but preventing it from flowing back towards the pressure tank (41). In order to also initiate the closing movement or the braking of the gas exchange valve in a hydraulically simple and reliable manner, a controllable opening (59) of a second valve (56) is arranged in a second connection line (58) between the first pressure tank (41) and the working cylinder (22), with a non-return valve (57) that prevents flow towards the working cylinder (22) but allows backflow towards the pressure tank (41).

The aim of the invention is to ensure that a hydraulic drive (10) for accelerating and braking a gas exchange valve (20) of internal combustion engines or other reciprocating engines operates in a simple, reliable and recuperative manner. To this end, a first pressure tank (41) for providing a first pressure p.sub.1, a restoring energy accumulator preferably embodied as a spring (25), and at least one hydraulic basic pressure tank (40) having a lower pressure p.sub.0 than the first pressure tank (41) are provided. A controllable opening (49) of a first valve (46) is arranged with at least one non-return valve (47) located upstream or downstream of the opening in the flow path, in a connection line (48) between the first hydraulic pressure tank (41) and the working cylinder (22), said non-return valve allowing the pressure medium (30) to flow towards the working cylinder (22) but preventing it from flowing back towards the pressure tank (41). In order to also initiate the closing movement or the braking of the gas exchange valve in a hydraulically simple and reliable manner, a controllable opening (59) of a second valve (56) is arranged in a second connection line (58) between the first pressure tank (41) and the working cylinder (22), with a non-return valve (57) that prevents flow towards the working cylinder (22) but allows backflow towards the pressure tank (41).

This invention is a camshaft and a valve actuation mechanism of an engine. The camshaft includes a first cam and a second cam that are adjacently arranged for an intake or exhaust rocker arm. A flange is arranged between the two cams, and is positioned at a position with a lift of the first cam and the second cam. No flange is arranged in a B section where both of the cams are base circles. When the rocker arm roller is shifted to another cam, since blocking of the flange between the two cams, shifting may be performed when the camshaft is rotated to a position where both of the cams are base circles, which ensures reliability. In addition, one solenoid may control a plurality of actuators, and thus the cost is low. The two cams may implement the functions of the engine, such as, variable valve or engine brake or others.

The disclosure relates to a valve train for an internal combustion engine and to an internal combustion engine. The valve train has an inlet valve actuation mechanism for the periodic actuation of an inlet valve of the internal combustion engine. The valve train also has a delay element, which is in contact with the inlet valve actuation mechanism and which has a hydraulic chamber for delaying a closing movement of the inlet valve by means of a hydraulic medium. The valve train has a hydraulic feed for feeding the hydraulic medium into the hydraulic chamber, the hydraulic feed having a control shaft, and the control shaft being mechanically driven by the internal combustion engine. The control shaft has an axially extended cavity for the hydraulic medium, and at least one opening for intermittently feeding the hydraulic medium from the cavity to the hydraulic chamber.

A compression release type engine brake includes an exhaust rocker arm including a roller which is mounted at one end portion thereof, and the exhaust rocker arm rotating around a rocker arm shaft by the rotation of the exhaust cam, a valve bridge disposed on the other end portion of the exhaust rocker arm and connected to an exhaust valve, a brake module mounted between the exhaust rocker arm and the valve bridge, contacting with the roller and the brake cam lobe according to inflow of selectively supplied operation oil to open the exhaust valve by the exhaust cam, and the brake module including a reset valve closing operation oil inside therein, and a reset piston slidably mounted on the second end portion of the exhaust rocker arm and protruding out of the second end portion of the exhaust rocker arm according to the supply of reset oil to push the reset valve to expel the operation oil in the brake module outwards.

A driving tool includes a main body, a trigger, a contact member and a control unit. The main body has a combustion chamber configured to be filled with fuel and compressed air. The trigger is configured to operate an ignition device to combust a mixture of the fuel and the compressed air filled in the combustion chamber. The contact member is brought into contact with a driving target member to enable an operation of the trigger. The control unit is configured to start an injection of the fuel when the contact member is turned on, and to complete an injection of the air after the trigger is turned on.

A pressure fluid handling system includes a closed pressure fluid circuit. The pressure fluid circuit includes, connected in series, a compressor and a pressure sink and a primary pressure fluid route from the compressor to the pressure sink and a secondary pressure fluid route from the pressure sink to the compressor. The pressure fluid handling system further includes a pressure fluid accumulator connected to the pressure fluid circuit via a first pressure fluid accumulator conduit. The first pressure fluid accumulator conduit includes a pump configured to pump pressure fluid from the pressure fluid circuit to the pressure fluid accumulator to lower the pressure levels in the pressure fluid circuit, and in that the pressure fluid handling system includes a controllable component for returning the pressure fluid from the pressure fluid accumulator to the pressure fluid circuit to increase the pressure levels in the pressure fluid circuit.

A fully variable valve train with a rotary plunger for an internal combustion engine. A motor actuates a high-pressure oil injection pump; when a timing driven electromagnetic valve connected to an oil inlet is opened, high-pressure oil enters a hydraulic cylinder; and when the force applied to a plunger by the hydraulic oil is larger than the force of a valve returning spring, the plunger is pushed to move down, so that a valve is opened. When the valve is required to be return, the timing driven electromagnetic valve connected to the oil inlet is closed, and the timing driven electromagnetic valve connected to the oil inlet is opened; the valve moves up under the action of the valve spring, pushing the plunger to move up and thereby discharging the low-pressure oil out of the hydraulic cylinder, then the plunger and the valve return to the initial positions.

A fully variable valve train with a rotary plunger for an internal combustion engine. A motor actuates a high-pressure oil injection pump; when a timing driven electromagnetic valve connected to an oil inlet is opened, high-pressure oil enters a hydraulic cylinder; and when the force applied to a plunger by the hydraulic oil is larger than the force of a valve returning spring, the plunger is pushed to move down, so that a valve is opened. When the valve is required to be return, the timing driven electromagnetic valve connected to the oil inlet is closed, and the timing driven electromagnetic valve connected to the oil inlet is opened; the valve moves up under the action of the valve spring, pushing the plunger to move up and thereby discharging the low-pressure oil out of the hydraulic cylinder, then the plunger and the valve return to the initial positions.