Abstract:
The valve lifting arrangement for opening an exhaust valve (1) of an internal combustion engine comprises a cam (2) having a first lobe (2b) and a second lobe (2c), a reciprocating cam follower unit (3), force transmission means (4, 6, 7, 11) for transmitting movement of the cam follower unit (3) to the exhaust valve (1), at least one hydraulic fluid chamber (5), a first piston (6) that is in mechanical connection with the cam fol- lower unit (3) for pressurizing the fluid in the chamber (5), a second piston (7) that is in mechanical connection with the exhaust valve (1) and movable by the hydraulic fluid that is pressurized by the first piston (6), means (8, 9) for introducing hydraulic fluid into the space (5, 5b, 13) between the first piston (6) and the second piston (7), and a control valve (10) for controlling outflow from the space between the first piston (6) and the second piston (7). The invention also concerns a method for operating the valve lifting arrangement.
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 cam device (5) and the valve mechanism (6), and a guide member (10) arranged in the body part (8) between the cam device (5) and the piston device (9) to be movably responsive with the movements of cam device (5). The control arrangement includes means for adjusting timing of valve opening of the inlet valve, said means cooperating with said piston device (9).
Abstract:
The disclosure relates to a method for starting a four-stroke reciprocating internal combustion piston engine. The present disclosure further concerns a four-stroke reciprocating internal combustion piston engine for implementing the method. The description is based on the idea of providing an airflow into the combustion cylinder during an instroke of the respective piston, so as to expel any remaining liquid from the combustion cylinder via the exhaust valve.
Abstract:
The multi-cylinder piston engine (20) comprises at least one cam-operated valve lifting device (4) for each cylinder (19) of the engine (20), the valve lifting device (4) being arranged to open a gas exchange valve (24, 25), and a starting arrangement comprising a pressure medium source (18), at least one starting valve (10) for introducing pressure medium into a cylinder (19) of the engine (20), means (26) for connecting the pressure medium source (18) to the starting valves (10), and a control valve (12) for each cylinder (19) that is provided with a starting valve (10) for controlling the operation of the starting valve (10). Each control valve (12) is arranged to be operated by a gas exchange cam (1) of the respective cylinder (19).
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:
An attenuator (7) for damping pressure fluctuations in a hydraulic system, which attenuator comprises a body (8) with a chamber (9), in which a movable piston (10) loaded by a spring (11 ) is adapted, a fluid space (17) inside the chamber (9), which space is delimited by the piston surface (19) of the piston (10), an inlet conduit (13) for feeding hydraulic fluid into the fluid space (17) and an outlet conduit (15) for discharging hydraulic fluid from the fluid space (17). The flow resistance in the inlet conduit (13) is higher than the flow resistance in the outlet conduit (15).
Abstract:
The gas exchange valve arrangement for a piston en- gine comprises at least one gas exchange valve (1), a cam (2) for operating the valve (1), and force trans- mission means (3, 4, 5, 6, 7, 8, 9) between the cam (2) and the valve (1). The arrangement further comprises a piston (10) having a piston surface (11) delimiting a fluid chamber (12), the piston (10) being configured to be operated independently from the cam (2) by hy- draulic pressure applied to the piston surface (11) for creating opening force for additional opening of the gas exchange valve (1), a pressure medium source (13) for supplying pressure medium into the fluid chamber (12), means (14, 15, 15a) for controlling flow from the pressure medium source (13) into the fluid chamber (12), and means (14, 15, 15b) for controlling pressure release from the fluid chamber (12).
Abstract:
The gas exchange valve arrangement for an internal combustion engine comprises a gas exchange valve (1, 1'), a pressurizing chamber (9), a reciprocating piston (7) that protrudes into the pressurizing chamber (9), a receiving chamber (5, 5') that is arranged around the valve stem (1b, 1b') of the gas exchange valve (1, 1'), and a hydraulic fluid duct (6, 6') for connecting the pressurizing chamber (9) to the receiving chamber (5, 5'). A piston surface (1d, 1d') is arranged in the receiving chamber (5, 5') in connection with the valve stem (1b, 1b'), and a second piston surface (1e, 1e') is arranged in connection with the valve stem (1b, 1b') and exposed to the pressure in the gas exchange duct (2) for facilitating closing of the gas exchange valve (1, 1'). The invention also concerns a gas exchange valve (1, 1').
Abstract:
The valve actuator arrangement of an engine comprises a cam-driven piston device (3), which divides a pressurizing chamber (4) into at least two sections (4a, 4b, 4c, 4d) and pressurizes hydraulic fluid in the chamber (4) for opening gas exchange valves (1, 1'). The piston device (3) is used for driving at least one additional valve (9, 10) other than a gas exchange valve (1, 1').
Abstract:
A gas exchange valve arrangement for a supercharged internal combustion engine, which arrangement comprises a gas exchange valve (1) having a valve head (2) and a valve stem (3) connected to the valve head (2), the arrangement further comprising a valve spring (4) being arranged around the valve stem (3) for creating a force for closing the valve (1), a chamber (5) being arranged around the valve stem (3), and thrust means (6, 19) being attached to the valve stem (3) and being movable in the direction of the longitudinal axis of the valve stem (3) together with the gas exchange valve (1). The arrangement comprises means (7, 14) for introducing pressurized charge from an air intake duct (10) of the engine air into the chamber (5) between the thrust means (6, 19) and the inner end of the chamber (5) for assisting in keeping the valve (1) closed. The invention also concerns a cylinder head (9).