Internal-combustion engines – Poppet valve operating mechanism – With means for varying timing
Reexamination Certificate
2001-01-16
2002-09-10
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
With means for varying timing
C123S090390, C074S559000
Reexamination Certificate
active
06446589
ABSTRACT:
This invention relates to a cam actuated continuous simultaneously variable valve timing and lifting assembly for operating the valves of an internal combustion engine.
Further, this invention relates to a cam actuated continuous simultaneously variable valve timing and lifting assembly provided in operative engagement with a rocker arm so as to be cam actuated at one end thereof and to be in operative engagement with a spring loaded valve lifter at the opposite end thereof.
Further, this invention utilizes a slider provided with teeth which coacts with a rotating gear, connecting rod and actuator so as to keep distance between a roller and rocker arm shaft pivot at any desired distance and at any desired time.
Still further, this invention also provides for cam actuated continuous simultaneously changing timing and valve lifting distance as desired.
In addition, this invention changes timing and lifting simultaneously so that the changes occur continuously as desired.
Further, this invention can be adapted so as to be used on intake and exhaust valves as desired. This invention can also easily be adapted to any engines with rocker arms and overhead cams.
The use of this cam actuated continuous simultaneously variable valve timing and lifting assembly will create an engine that can perform to achieve the desired horsepower and torque at any RPM with the most efficiency in terms of horsepower and/or fuel economy.
Another embodiment of this invention comprises a hexagonal shaft having a spherical end portion which coacts with a rotating gear to actuate the movement of the slider as desired.
None of the known prior art engine valve driving devices have a capacity of the instant invention which provides cam actuated continuous simultaneously variable timing and lifting valve capability as desired.
It is therefore an object of this invention to provide a cam actuated continuous simultaneously variable valve timing and lifting assembly for operating the valves of an internal combustion engine.
Since the inception and development of internal combustion engines used to power vehicles such as boats, automobiles, racing cars and the like, it has been the goal to achieve more power and fuel economy in the same engine.
In the late 20s and early 30s, “hot rods” and the like ruled the streets. However, as automobile racing came on stream, racing car engine designers developed more powerful engines by incorprating larger displacements through the use of bored-out cylinders, larger valves to provide more combustion air into the cylinders, thus achieving more power from the engines.
Thus aggressive cam action with higher lift, advance timing is a must in car racing to obtain maximum power from the racing car engine.
However, the drawbacks of such design changes is a rough engine and less fuel economy especially at low RPM operations.
Various combustion engine manufacturers such as Honda, Porsche and Lexus have tried to eliminate such drawbacks.
The Honda design tries to solve the problem by employing two cam lobes and two hydraulic lifters per valve. At low RPM, one lifter is pressurized to engage low lifting and less advance in timing to obtain smooth running and more torque. At higher RPM, the other lifter will be pressurized and take over the resultant advance in timing and more lift enables the same engine to produce more horsepower and higher RPM. At no time is there continuous change of timing and lifting.
Porsche attempts to advance timing by putting tension on one side of the timing belt or chain. Here again there is not change of lifting.
Lexus attempts to advance timing with the use of a device at the head of the camshaft by turning the camshaft ahead of the cam sprocket. Here there is no change of lifting.
In summary, none of the known prior art devices have a cam actuated continuous simultaneously variable valve timing and lifting assembly which operates at a continuous rate as desired at any moment such as utilized in the instant invention. This is achieved by the use of a pre-programmed computer controller unit whereby the engine can simultaneously reduce timing and lifting at low RPM and continuous simultaneous advance timing and lifting action as the engine increases RPM. The instant invention can reduce part of timing simultaneously with lifting to achieve fuel economy once the desired speed of the vehicle is reached.
For example, when a vehicle is required to accelerate to 70 MPH, the engine needs to produce all the power it can to achieve 70 MPH with the minimum time required. Once the desired speed is reached, the engine can reduce the timing simultaneously with the lifting to produce just enough power to maintain the desired MPH with resultant greater fuel economy.
Other objects and advantages found in the construction of the invention will be apparent from a consideration in connection with the specification description, the accompanying claims and the accompanying drawings.
REFERENCES:
patent: 4841799 (1989-06-01), Entzminger
patent: 5197447 (1993-03-01), Dick
patent: 5349929 (1994-09-01), Shimizu et al.
patent: 5572962 (1996-11-01), Riley
patent: 5791306 (1998-08-01), Williamson
patent: 5809951 (1998-09-01), Kim
patent: 5899180 (1999-05-01), Fischer
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