Internal-combustion engines – Poppet valve operating mechanism – Hydraulic system
Patent
1992-02-26
1994-02-22
Cross, E. Rollins
Internal-combustion engines
Poppet valve operating mechanism
Hydraulic system
1231971, 251 3004, 251 635, 92175, 2395333, 2395851, F01L 902, F02M 4704, F15B 908, F15B 1520
Patent
active
052878295
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to fluid actuators which in one particular aspect are applicable to the control of various mechanisms in internal combustion engines, for example exhaust and inlet valves or fuel injectors and which in a further aspect are applicable to the extraction of power from reciprocating pistons of internal combustion engines. The actuators of the invention however may be applied to other situations for example as servomechanisms or for accurate control of movement.
BACKGROUND ART
Conventional internal combustion engines are provided with a number of different operating mechanisms for controlling inlet and outlet valves for the engine cylinders or in the case of fuel injected engines for controlling the injectors. Usually such mechanisms take the form of cam shafts, rockers, return springs or other mechanical actuating elements. Such mechanism suffer a number of disadvantages and limitations including in the case of valved engines poor valve cooling, poor lubrication, a lack of ability to maintain alignment of the valves with their seats, poor control over movement of the valve and an excessive amount of power which is required to overcome the valve seating springs.
Particular disadvantages associated with fuel injectors include lack of flexibility of injection timing, excessive mechanical components in the injector drive train, an excessive amount of power wastage in operating the injectors and their drive train and a lack of ease of assembly and removability of the injectors and associated drive train from the engine during maintenance.
Conventional internal combustion engines usually also include reciprocating pistons which are coupled to a crank shaft via piston rods, however, this form of mechanical connection has limitations resulting in limitation of transmission of usable energy from the piston to the crank shaft caused by changes of the lever arm at the crank shaft from zero at the start of the stroke through a maximum at approximately half stroke to zero at the end of the stroke. Further disadvantages arise because of side thrust friction losses causing cylinder and piston wear induced by thrust angles of the connecting rods relative to the cylinder bore centre line during rotation of the crank shaft. Lack of flexibility in the control of the rate of expansion of the gases of combustion also occurs due to utilization of a rotating crank shaft rigidly attached to the reciprocating pistons by connecting rods consequently leading to a considerable loss in the recovery of usable energy from the gases of combustion.
SUMMARY OF THE INVENTION
The present invention aims to provide a fluid actuator which may be applied to the many different applications where accurate control of movement is required. In one application, the fluid actuator of the invention may be used for the control of the inlet and exhaust valves of internal combustion engines so as to give increased control over movement of the valve and allowing for variable timing of the valve operating cycle. The present invention also aims to provide an arrangement which in the latter application reduces the reciprocating mass of the valve operating mechanism and reduces the rate of wear of the valve and its guides whilst increasing valve cooling and obtaining improved control over valve alignment with their seats. The present invention also aims to provide an actuator which when applied to the operation of fuel injectors enables simple control of injection timing, reduces the mass of injector drive train, which decreases the power required to operate the injectors and improves ease of assembly and disassembly of the injectors and their drive train to and from the engine.
In its applicability to the extraction of usable energy from the reciprocating pistons of internal combustion engines the present invention provides an actuator which permits greater recovery of usable energy, reduces side thrust friction losses and consequent rates of cylinder tear and provides a degree of flexibility to control the rate of exp
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patent: 4974495 (1990-12-01), Richeson, Jr.
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Cross E. Rollins
Lo Weilun
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