摘要:
A hydraulically controlled actuator for actuation of an exhaust-side gas exchange valve of an internal combustion engine, containing a control piston that is displaceable within a cylinder and, with piston sides facing away from one another, delimits pressure chambers, of which the one pressure chamber impinges upon the gas exchange valve in the closing direction and the other pressure chamber impinges upon the gas exchange valve in the opening direction. In the actuator is provided at least one spring element, which can be brought into a preloaded state by the control piston moving in the closing direction of the gas exchange valve, and whose stored potential energy accelerates the gas exchange valve in the opening direction at least at the beginning of an opening phase, is provided. This results in a reduction in the energy expended in the context of valve actuation.
摘要:
A device for controlling an opening cross section in the combustion cylinder of an internal combustion engine is provided, the device having a gas exchange valve integrated into the combustion cylinder and having an actuator which drives the valve element to execute a closing stroke and an opening stroke. A valve brake which is active during a residual closing stroke of the valve element is provided for the purpose of reducing the impact velocity of the valve closure member of the valve element on the valve seat in the closing stroke of the valve element. The valve brake has a hydraulic damping element with a fluid displacement volume which flows out through a throttle cross section of a throttle opening, and a control unit for controlling the throttle cross section as a function of the viscosity of the displacement volume.
摘要:
An internal combustion engine having at least one combustion cylinder that includes a combustion chamber provided with gas-exchange valves, and an electrohydraulic valve control device having valve actuators that actuate the gas-exchange valves. To reduce manufacturing costs and/or the installation space required for the electrohydraulic valve control device, at least two synchronously controlled gas-exchange valves are connected using a coupling element to a common valve actuator, and the connection sites of the gas-exchange valves are flexibly formed on the coupling element.
摘要:
A device for controlling gas-exchange valves of an internal combustion engine is provided, which device has hydraulic valve actuators each allocated to one gas-exchange valve. Each valve actuator has an actuating piston acting on the gas-exchange valve, and two hydraulic working chambers delimited by the actuating piston, of which the first working chamber acting upon the gas-exchange valve in the closing direction is constantly filled with fluid under pressure, and the second working chamber acting upon the gas-exchange valve in the opening direction is able to be alternately filled with fluid under pressure and relieved via two electric control valves. For the purpose of cost reduction, provided for each valve-actuator pair is a single first electric control valve that is acted upon with the fluid pressure on the intake side, and is connected on the outlet side to the second working chamber of one valve actuator. The second working chamber of the other valve actuator is filled with fluid with the aid of a switchover valve and the fluid pressure in the second working chamber of the one valve actuator.
摘要:
A device for controlling gas-exchange valves of an internal combustion engine is provided, which device has hydraulic valve actuators each allocated to one gas-exchange valve. Each valve actuator has an actuating piston acting on the gas-exchange valve, and two hydraulic working chambers delimited by the actuating piston, of which the first working chamber acting upon the gas-exchange valve in the closing direction is constantly filled with fluid under pressure, and the second working chamber acting upon the gas-exchange valve in the opening direction is able to be alternately filled with fluid under pressure and relieved via two electric control valves. For the purpose of cost reduction, provided for each valve-actuator pair is a single first electric control valve that is acted upon with the fluid pressure on the intake side, and is connected on the outlet side to the second working chamber of one valve actuator. The second working chamber of the other valve actuator is filled with fluid with the aid of a switchover valve and the fluid pressure in the second working chamber of the one valve actuator.
摘要:
A device for controlling gas exchange valves of an internal combustion engine, which has hydraulic valve positioners, each having a positioning piston acting on the gas exchange valve and two hydraulic working chambers, delimited by the positioning piston, of which the first working chamber, for closing the gas exchange valve, is continuously filled under fluid pressure and the second working chamber, for opening the gas exchange valve, is alternately filled and emptied with pressurized fluid via a first and second electrical control valve. To reduce the number of control valves, which may be necessary, for a valve pair, the filling of the second working chamber of the second valve positioner is performed via the second working chamber of the first valve positioner, which is connected to the first control valve, after a predetermined stroke of the positioning piston of the first valve positioner to open the assigned gas exchange valve.
摘要:
An apparatus for controlling gas exchange valves includes at least one valve positioner, associated with a gas exchange valve, and a pressure supply device which supplies the valve positioner with a fluid under high pressure. The valve positioner encompasses a working cylinder having a positioning piston, coupled to the gas exchange valve, which delimits an upper pressure space for opening the valve and a lower pressure space for closing the valve, and encompasses a control valve controlling the hydraulic pressure in the pressure spaces. In order to reduce the manufacturing costs and electrical energy demand of the apparatus, the upper pressure space is connected directly, and the lower pressure space via a restrictor throttle, to the pressure supply device; and the control valve is connected to the lower pressure space and to a relief line. Depending on the switch position, the control valve additionally connects the lower pressure space to the relief line or blocks it off from the relief line.
摘要:
A throttle element for installation in a fuel carrying conduit, which is embodied as a screwed in insert with a head that constitutes an annular gap in relation to a cylindrical circumference wall of the conduit and this annular gap is disposed as a filter upstream of the throttle of the throttle element.
摘要:
A fuel injection system for internal combustion engines is proposed, in which with the aid of a high-pressure pump fuel is pumped at high pressure into a high-pressure fuel reservoir (6), from which electrically controlled fuel injection valves (9) are supplied. The pressure in the high-pressure fuel reservoir is maintained in such a way that a first pump element (16) pumps fuel into the high-pressure reservoir with a variable pumping quantity, and a second pump element (17) as needed pumps a constant high-pressure fuel quantity into the high-pressure reservoir. A simple, economical system is thus obtained for furnishing high fuel pressure for injection by the fuel injection system (FIG. 2).
摘要:
A piston pump of the roller tappet type for high-pressure fuel delivery in fuel injection systems of internal combustion engines, particularly in common rail injection systems. A drive shaft that is supported in the pump housing and has a number of cam-like projections in the circumference direction. At least one tappet that is disposed in a cylinder chamber radially with regard to the drive shaft and in its radially inner end region has a rotatable roller which is supported so that it can roll in the circumference direction against the drive shaft in the region of its projections in order to reduce the wear in the region of the roller bearing. The pump is embodied so that a lubricant supply opening that leads from the circumference of the tappet and feeds into the radially inner tappet end region supporting the roller and at least during a part of the stroke, communicates with a lubricant supply line of the housing, which line feeds into the cylinder chamber.