TWO STROKE ENGINE WITH REGULAR LUBRICATION SYSTEM

MOTEUR A DEUX TEMPS AVEC SYSTEME DE LUBRIFICATION ORDINAIRE

English Abstract

The invention is a two-stroke engine that incorporates advantages of both the
two-stroke and
four-stroke types of engines. The crankcase is sealed and uses an oil pump to
lubricate the
piston, connecting rod and crankshaft. The combustion air does not flow
through the crankcase.
Instead, the engine uses two camshafts, one for the intake valve located on
the cylinder head and
the other for the exhaust valve located on the side of the cylinder. The
engine has a compressor,
powered by the engine battery to compress ambient air before it enters into
the combustion
chamber. Additionally, the engine has an exhaust powered turbine connected to
an alternator,
which provides additional power for the engine battery. The engine is equipped
with one or
plurality of fuel-injection nozzles. The piston is of the two step type, which
reduces friction
between the piston and the cylinder.

French Abstract

Linvention concerne un moteur à deux temps qui comporte des avantages des types de moteurs à deux temps et à quatre temps. Le carter de moteur est scellé et utilise une pompe à huile pour lubrifier le piston, une tige de raccordement et un carter de moteur. Lair de combustion ne sécoule pas à travers le carter de moteur. Au lieu de cela, le moteur utilise deux arbres à cames, un pour la soupape dadmission située sur la tête de cylindre et lautre pour la soupape déchappement située sur le côté du cylindre. Le moteur possède un compresseur, alimenté par la batterie du moteur pour compresser lair ambiant avant quil entre dans la chambre à combustion. En outre, le moteur possède une turbine alimentée par léchappement connectée à un alternateur, laquelle offre une alimentation supplémentaire pour la batterie du moteur. Le moteur est doté dun ou dune pluralité dinjecteurs de carburant. Le piston est du type à deux temps, ce qui réduit la friction entre le piston et le cylindre.

Claims

Embodiments of the invention in which an exclusive privilege and property is
claimed are:
1. A two stroke internal combustion engine comprising: a cylinder head having
an intake valve,
a cylinder with an exhaust valve, an intake passage connected to the intake
valve and having an
electric motor driven compressor for pressurizing the intake air, an exhaust
passage connected to
the exhaust valve and having a turbine that drives an alternator to produce
electricity, and a step
type piston that seals the combustion chamber defined by the cylinder and
cylinder head from the
crankcase wherein there is a lengthwise scavenging from the cylinder head down
to the exhaust
valve when the piston is proximate bottom dead center.
2. The engine set forth in claim 1 further comprising: camshafts driving the
intake and exhaust
valves
3. The engine set forth in claim 1 further comprising: an ECU controlling a
fuel injector located
in the cylinder head
4. The engine set forth in claim 3 further comprising: an rpm sensor with a
crankshaft driven by
said piston and a pressure sensor in a pressure chamber located in the intake
passage; the sensors
connected to the ECU
5. The engine set forth in claim 3 wherein: the ECU controls the operation of
the compressor and
the turbine
6. The engine set forth in claim 3 wherein: the compression ratio defined by
the engine structure
is adapted for compression ignition
7. The engine set forth in claim 1 wherein: the piston has piston rings that
never go past the
exhaust valve
8. The engine set forth in claim 1 wherein: the piston covers the exhaust
valve except when
proximate bottom dead center.
4

Description

TWO STROKE ENGINE WITH REGULAR LUBRICATION SYSTEM
Technical Field: The present invention is related generally to engines and in
particular two
stroke engines
Background of the Invention:
Previous two stroke engines deliver intake air through the crankcase to the
combustion chamber
by the pumping action of the piston. Generally, lubricating oil is mixed with
the intake air so as
to lubricate the crankshaft and piston. The result is increased oil
consumption and emissions
compared to a conventional four stroke engine. There are two stroke engines
with sealed
crankcases. However, these have both the intake and exhaust valves in the
cylinder head with the
result of increased problems of scavenging the products of combustion. The
present invention
solves the scavenging problem by locating the exhaust valve proximate bottom
dead center for
lengthwise scavenging and solves the oil consumption problem by sealing the
crankcase with a
step type piston. The step piston having piston rings located only at a
bottommost portion and a
body portion defining the rest of the piston wherein it is spaced from the
cylinder wall.
Summary of the Invention:
This is a new design for two stroke engines that incorporates advantages of
both the two-stroke
and four-stroke types of engines. The engine is lubricated exactly like a four-
stroke engine; it has
piston rings that lubricate the piston and the cylinder, i.e. the oil control
ring, as well as all the
customary lubricating parts such as the oil pan with the oil pump and the oil
distribution system.
The engine uses two camshafts, one for the intake valve and the other for the
exhaust valve. The
engine has a compressor, powered by the engine battery to compress ambient air
before it enters
into the combustion chamber. Additionally, the engine has an exhaust powered
turbine connected
to an alternator, which provides additional power for the engine battery. The
engine is equipped
with one or plurality of fuel-injection nozzles. The piston is of the two step
type, which reduces
friction between the piston and the cylinder. The operation of the engine is
controlled by a
computer, the Engine Control Unit (ECU).
According to one aspect of the invention there is provided a two stroke
internal combustion
engine comprising: a cylinder head having an intake valve, a cylinder with an
exhaust valve, an
intake passage connected to the intake valve and having an electric motor
driven compressor for
pressurizing the intake air, an exhaust passage connected to the exhaust valve
and having a
turbine that drives an alternator to produce electricity, and a step type
piston that seals the
combustion chamber defined by the cylinder and cylinder head from the
crankcase wherein there
is a lengthwise scavenging from the cylinder head down to the exhaust valve
when the piston is
proximate bottom dead center.
Brief Description of the Drawings:
FIG. 1, FIG. 2, FIG. 3, and FIG. 4 are cutaway views of the engine design;
they all have the
same elements, numbered the same, with the only difference being in the
position of the moving
parts. Therefore, element descriptions are the same for FIG. 1, FIG. 2, FIG. 3
and FIG. 4, which
are as follows:
TABLE-US-00001 Element Number Description ¨1 Injector connected to ¨80 (ECU)
¨72
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Ambient air inlet ¨71 Compressor ¨73 Compressed air chamber ¨74 Compressed air
pipe ¨77
Electric motor connected to ¨80 (ECU) ¨80 Engine Control Unit (ECU) ¨81
Pressure sensor
connected to element ¨80 (ECU) ¨46 Intake valve ¨41 Intake camshaft ¨45 Intake
cam ¨40
Piston ¨82 rpm sensor ¨60 Exhaust turbine ¨61 Alternator connected to element
¨80 (ECU) ¨56
Exhaust valve ¨55 Exhaust cam ¨51 Exhaust camshaft ¨10 Cylinder body ¨12
Compression
area
FIG. 5 is a cutaway view of the piston which fits inside the cylinder (FIG. 1
.about.10). Element
.about.42 is the lower part of the piston and consists of three rings shown as
elements .about.43
and .about.44. Element .about.41 is the upper part of the piston.
Detailed Description
The cycle begins when the ignition key is turned to the start position and the
electric motor (FIG.
1. .about.77) starts to drive the compressor (FIG. 1. .about.71) which drives
the fresh ambient air
into the compressed air chamber (FIG. 1. .about.73). The pressure sensor (FIG.
1. .about.81)
delivers the information to the ECU (FIG. 1. .about.80) which, when the
pressure in the
compressed air chamber (FIG. 1. .about.73) reaches a certain defined amount,
turns the engine
over, thereby starting the operation of the engine. Initially, the start phase
lasts a few seconds,
but in subsequent engine starts, that phase is shorter as there is already
some pressure in the
compressed air chamber (FIG. 1. .about.73). Compressed ambient air enters the
cylinder (engine
is turning), in the top piston position the intake and the exhaust valves are
closed and the
pressure necessary for ignition is achieved. The injector (FIG. 1. .about.1)
injects the fuel into the
compression area (FIG. 1. .about.12) and the air-fuel mixture is ignited.
Pressure pushes the
piston (FIG. 1. .about.40) down. Just before the piston reaches the bottom
position, the exhaust
valve (FIG. 2. .about.56) is opened, exhaust gases leave the cylinder driving
the exhaust turbine
(FIG. 2. .about.60), which in turn drives the alternator (FIG. 2. .about.61)
that charges the
battery, which, in turn, is mostly used to run the electric motor (FIG. 2.
.about.77) and the
compressor (FIG. 2. .about.71). A moment later, but still before the bottom
piston position, the
intake valve (FIG. 3. .about.46) is opened. Ambient air enters the cylinder
but exhaust valve vent
(FIG. 3. .about.56) is still opened for a brief moment so that last remaining
exhaust combusted
mix is pushed out with some of the fresh ambient air. Exhaust valve vent (FIG.
3. .about.56)
closes at the bottom position of the piston and as the piston moves up the
intake valve (FIG. 4.
.about.46) closes as well, allowing the piston to compress the fresh ambient
air into the
compression area (FIG. 4. .about.12). This cycle repeats indefinitely while
engine operates. The
ECU continuously monitors the rpm through an rpm sensor (FIG. 4. .about.82),
pressure in the
air compression chamber (FIG. 4. .about.73) through a pressure sensor (FIG. 4.
.about.81), and
the charge level in the battery thereby creating optimal conditions for engine
operation.
The piston has a unique form: the lower part has rings (FIG. 5. .about.42)
that lubricate and seal
the piston to the cylinder, while the upper part above the rings (FIG. 5.
.about.41) is slightly
narrower than the cylinder, and it that upper part it never touches the
cylinder walls. The size of
the volume of the upper part is intended to provide for enough pressure in the
combustion
chamber. The wrist pin could be placed in the upper part of the piston (FIG.
5. .about.42), which
would allow for a shorter engine.
There is an alternative, cheaper variant, which like a traditional two-stroke
engine brings air into
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the crankcase. The advantage of this variant is that it would not need a
compressed air chamber
(FIG. 1 .about.73), and the compressor (FIG. 1 .about.71) and the exhaust
turbine (FIG. 1
.about.60) would be smaller and cheaper. The disadvantages are that a more
expensive form of
lubrication, such as dry-sump, would be necessary, and that the overall engine
operation would
be less efficient, leading to higher operating costs.
The traditional lubrication system used in four-stroke engines has proven to
be the most effective
solution to the problem of lubricating the moving, mechanical-power generating
parts of an
internal combustion engine. Until now this system was not available for two-
stroke engines. The
proposed engine combines the best features of both the two and the four-stroke
types of engines:
lubrication system is simple and effective as in the four-stroke, the exhaust
is clean as in the
four-stroke, and for the same displacement the proposed engine would have more
than twice the
power.
The proposed engine is described above in its diesel version, but with minor
modifications it can
be made into a gasoline one. The gasoline version would use a direct fuel-
injection system (NO
carbureted version is possible), and would have a smaller compression ratio.
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Representative Drawing