Abstract:
Hydraulic engine valve lifter (10) includes a pair of pistons (Pcf, Pvd) defining a pressure chamber (Cp) therebetween and a separate lash adjusting piston (Pla) which defines a lash adjustment chamber (Cla) with one of the pistons in the pair. One-way valve structures (V) permit fluid to flow from the pressure chamber (Cp) into the lash adjustment chamber (Cla) thereby displacing the lash adjusting piston (Pla) to, in turn, adjust valve lash. Motion damping functions during a downstroke of the lifter pistons (Pcf, Pvd, Pla) are also provided by a valve damper chamber (Cd) and fluid passageways (90b, 112) between the pressure and damper chambers (Cp and Cd, respectively). Structure (126 and 90c/120) is provided which opens communication between the pressure and damper chambers (Cp and Cd, respectively) during upstroke of the lifter pistons (Pcf, Pvd, Pla) (thereby precluding motion damping) and then closes communication at a predetermined location during downstroke (thereby providing motion damping).
Abstract:
A control arrangement for, and a method for controlling the closing movement of, a valve operating assembly in a piston engine adapted between a cam device (5) of a camshaft (4) of the engine (1 ) and an inlet valve mechanism (6) arranged to open and close the inlet valve (3) in association with a cylinder of the engine. The control arrangement (7) comprises a body part (8), in which a piston de¬ vice (9) is movably arranged to be in force transmission connection with the camshaft (4) and the valve mechanism (6), the body part (8) and the piston device (9) together defining a first chamber (13), into which hydraulic medium can be selectively fed for providing a delay in the closing of the inlet valve (3). The body part (8) is provided with a first duct (16) for releasing of pressure in the first chamber (13) under control of a gu ide member (10) movably arranged in the body part (8) between the cam device (5) and the piston device (9). The guide member (10) includes a third chamber (18), which is arranged to be in communication with the first duct (16) and a control piston (20) located in said third chamber (18) and movably arranged with regard to the guide member (10) for controlling pressure medium flow through said third chamber (18).
Abstract:
The invention relates to a control arrangement for an inlet valve in a piston engine adapted between a cam device (5) of a camshaft (4) of the engine (1 ) and an inlet valve mechanism (6) arranged to open and close the inlet valve (3) in association with a cylinder of the engine, which control arrangement (7) comprises a body part (8), in which a piston device (9) is movably arranged to be in force transmission connection with the camshaft (4) and the valve mechanism (6), said body part (8) and the piston device (9) together defining a first chamber (13), into which hydraulic medium can be selectively fed, and a second chamber (19) connected to the first chamber via duct means (18,18', 18"), the flow of hydraulic medium from the first chamber (13) to the second chamber (19) being controlled for providing a delay in the closing of the inlet valve (3). The body p a r t ( 8 ) i s provided with two or more flow ducts (18a,18b,18c;18'a,18'b;18"a,18"b,18"c) for arranging different routes for the flow of hydraulic medium from the first chamber (13) to the second chamber (19). Control means (17, 17', 17") are provided for selecting the route of flow to be utilised in each case to provide different closing delay.
Abstract:
A damping mechanism for a lost motion hydraulic actuator utilizes a thin edge orifice (66) in cooperation with a communication passageway (62) between the upper (46) and lower (48) chambers and controls the damping of the upper piston (38) on closure. The upper piston is operatively connected to the engine valve of an internal combustion engine. A communication port (64) from the upper chamber to the communication passageway is closed off as the upper piston returns to its normal position forcing the flow of the hydraulic fluid through the thin edge orifice. In this manner the viscosity of the hydraulic fluid does not control the damping of the actuator and the noise factor is substantially reduced.
Abstract:
The invention relates to a control arrangement for gas exchange in a piston engine adapted between a cam device (5) of a camshaft (4) of the engine (1) and an inlet valve mechanism (6) arranged to open and close the inlet valve (3) in association with a cylinder of the engine, which control arrangement (7) comprises a body part (8), in which a piston device (9) is movably arranged to be in force transmission connection with the camshaft (4) and the valve mechanism (6). The cam device (5) includes a cam profile (5') having a portion (5c) arranged under a base circle (5a) of the cam profile (5'). Said portion (5c) of the cam profile (5') is arranged to control gas exchange through the inlet valve (3), specifically for providing a delay in the closing of the inlet valve (3).
Abstract:
The invention proposes a push-rod valve train having an adjustable valve tappet (1). This has an outer part (2a, 2b), an inner part (8) and a lost-motion spring (10), which forces the inner part (8) towards a relative position, at least one retainer ring (23), which is fixed in an annular groove (21) of the outer part (2a, 2b) and which interacts with a stop face (22) of the inner part (8), being provided for fixing the relative position, said retainer ring having lugs (28) extending radially inwards and separated by a fitting gap (27). In this the free movement of the valve push rod (15) relative to the lugs (28) is assured by the provision of a torsional locking means (30a, 30b), which serves to fix the radial position of the fitting gap (27) inside the annular groove (21).