System and method for controlling the amount of lost motion between an engine valve and a valve actuation means
AssigneeDiesel Engine Retarders, Inc.
InventorsJoseph Vorih, Haoran Hu
Life of this patent
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Abstract
An internal combustion engine lost motion valve actuation system is disclosed. The system includes a variable length connection means connecting a force imparting means and an engine valve. The connection means may assume plural lengths to provide plural amounts of lost motion. The connection means may provide a maximum amount of lost motion which provides some minimum level of valve actuation suitable for a limp home operation of the engine. The connection means is operable for both engine positive power and engine braking modes of operation.
Claims33
An internal combustion engine lost motion valve actuation system, comprising:
- a variable length connection means for transmitting a valve actuation force from a force source to a valve, said connection means having an internal hydraulic fluid chamber of variable volume and being adapted to assume a predetermined minimum length for providing at least one minimum valve opening event which is greater than zero;
- and
- a control means for controlling the length of the variable length connection means, said control means being adapted to vary the length of the connection means one or more times per cycle of said engine by selectively blocking and unblocking a hydraulic fluid drain in communication with said chamber independent of the position of the force source.
In an internal combustion engine valve actuation system, a hydraulic system for controlling the amount of lost motion between a means for opening an engine cylinder valve and a valve, comprising:
- a source of pressurized hydraulic fluid having an outgoing fluid feeding conduit;
- a variable length tappet having an internal expansible chamber in communication with the fluid feeding conduit and with a fluid bleeding conduit, and being adapted to assume a minimum operable length;
- and
- means for selectively blocking and unblocking said fluid bleeding conduit at a sufficient rate to vary the length of the tappet at least once per cycle of the engine independent of the position of the means for opening the engine cylinder valve,
- wherein the blocking of the fluid bleeding conduit causes said chamber to retain fluid and expand thereby increasing the length of the tappet and decreasing the amount of lost motion between the means for opening and the valve, and wherein the unblocking of the fluid bleeding conduit causes said chamber to drain off fluid and contract, thereby decreasing the length of the tappet and increasing the amount of lost motion between the means for opening and the valve.
An internal combustion engine comprising:
- a valve train including a hydraulic linkage operably coupled between an engine cylinder valve and an engine cam, said valve train and hydraulic linkage being provided to transmit a force for opening the valve from one or more lobes on said cam to the valve;
- and
- a hydraulic linkage control for selectively controlling the length of said hydraulic linkage to selectively modify the openings of said valve in response to a force transmitted from said cam lobes, said hydraulic linkage control being carried out independent of the position of the engine cam
- wherein said hydraulic linkage comprises a master piston and a slave piston, each of which are slidably disposed in the hydraulic linkage relative to each other such that the hydraulic linkage may selectively assume plural lengths, and
- wherein said engine cylinder valve is an exhaust valve and said lobes include one or more of the group consisting of an exhaust lobe, a compression release lobe and an exhaust gas recirculation lobe, and wherein said hydraulic linkage control is responsive to whether said engine is in a positive power mode of operation or a compression release engine braking mode of operation by controlling the length of the hydraulic linkage so that the exhaust valve opens in response to one or more of the group consisting of said compression release lobe and said exhaust gas recirculation lobe only when said engine is in said compression release engine braking mode.
In an internal combustion engine valve actuation system, a method of controlling the amount of lost motion between a means for opening an engine cylinder valve and a valve during engine operation, comprising the steps of:
- a) providing hydraulic fluid to an internal expansible chamber of a variable length tappet disposed in a valve train linking the means for opening and the valve;
- and
- b) selectively bleeding hydraulic fluid from the expansible chamber to decrease the amount of hydraulic fluid in the chamber and decrease the length of the tappet, to thereby increase the amount of lost motion between the means for opening and the valve,
- wherein the step of selectively bleeding is controlled such that the amount of hydraulic fluid in the chamber may be varied one or more times per cycle of the engine and independently of the position of the means for opening an engine cylinder valve.
Dependencies are inferred from the claim text.