Valve train for internal combustion engine
AssigneeHonda Motor Co., Ltd.
InventorMasahiko Tashiro
Life of this patent
Estimating the term…
Abstract
A valve train includes a primary rocker arm 50 oscillating about a primary oscillating center line L4 in response to the rotation of an inlet cam 21, a secondary rocker arm 60 oscillating about a secondary oscillating center line L5 so as to transmit a valve drive force via the primary rocker arm 50 to the inlet valve 14 and a holder 30 which supports the primary and secondary rocker arms 50, 60 in an oscillatory fashion in such a manner that the primary and secondary oscillating center lines L4, L5 oscillate together. A cam profile 55 has a lost motion profile 55a a drive profile 55b are formed on an abutment portion 54 of the primary rocker arm 50. A sectional shape of the lost motion profile 55a is an arc-like shape which is formed about the primary oscillating center line L4.
Claims16
A valve train for an internal combustion engine, comprising:
- a valve operating cam rotating around a rotational center line in synchronism with a rotation of an engine;
- an engine valve including at least one of an inlet valve and an exhaust valve;
- a transmission mechanism for transmitting a valve drive force of the valve operating cam to the engine valve so as to operate the engine valve in open and close states, the transmission mechanism including;
- a primary oscillating member oscillating about a primary oscillating center line;
- a secondary oscillating member oscillating about a secondary oscillating center line through abutment with the primary oscillating member so as to transmit the valve drive force via the primary oscillating member to the engine valve, and
- a holder supporting the primary and secondary oscillating members thereon in an oscillatory fashion;
- wherein the primary and secondary oscillating center lines oscillate together with the holder, and
- a drive abutment portion of the primary oscillating member abuts with a follower abutment portion of the secondary oscillating portion;
- a driving mechanism for driving the holder so as to control valve properties including opening and closing timings and maximum lift amount of the engine valve in accordance with a position of the holder which is driven by the driving mechanism,
- wherein the holder oscillates about a holder oscillating center line which differs from the rotational center of the valve operating cam in response to the operation of the driving mechanism,
- a cam profile having a lost motion profile for maintaining the engine valve in the closed state by abutting the drive abutment portion with the follower abutment portion and a drive profile for driving the engine valve in the open state is formed on at least one of the drive and follower abutment portions, and
- in a sectional shape of the lost motion profile in a plane which intersects at right angles with the primary oscillating center line is an arc-like shape of which center is the primary oscillating center line.
A valve train for an internal combustion engine comprising:
- a valve operating cam rotating around a rotational center line in synchronism with a rotation of the engine,
- an engine valve including at least one of an inlet valve and an exhaust valve;
- a transmission mechanism for transmitting a valve drive force of the valve operating cam to the engine valve so as to operate the engine valve in open and close states, the transmission mechanism including:
- a primary member which abuts with the valve operating cam;
- a rocker arm which oscillates about an oscillating center line by virtue of abutment with the primary member, and having a valve abutment portion having a valve abutment surface which abuts with the engine valve thereon;
- and
- a holder supporting the rocker arm in an oscillatory fashion and oscillating about a holder oscillating center line which differs from the rotational center line of the valve operating cam in response to the operation of the drive mechanism,
- wherein the oscillating center line oscillates together with the holder, and
- the rocker arm whose oscillating position relative to the holder is regulated by the primary member,
- a driving mechanism for driving the holder so as to control valve properties including opening and closing timings and maximum lift amount of the engine valve in accordance with a position of the holder which is driven by the driving mechanism,
- wherein in a rest state which is defined where the primary member which is in abutment with the valve operating cam abuts with the rocker arm, and where the rocker arm does not oscillate relative to the holder, a sectional shape of the valve abutment surface on a plane which intersects at right angles with the holder oscillating center line is an arc-like shape which is formed about the holder oscillating center line.
Dependencies are inferred from the claim text.