[0001] Internal combustion engines with rotary valves have been known since 1910 with the
conception of the Burt McCollum engine. There has been influence on this concept from
Minerva, Panhard and Levassor and Mercedes producing this combustion engine - patented
by Knight - till 1939. Due to sealing problems the concept of the Burt McCollum engine
had to be abandoned. Conventional cylinder heads with oscillating valves have the
well known disadvantages of offering restricted performance and discontinuous supply
of fuel-mixture. Major drawbacks result from the valves, the ignition and. the sealings,
that need constant surveillance and maintenance with the involved costs.
[0002] US 2 245 743 discloses a rotary valve assembly for internal combustion engines with
a head of a valve member mounted to rotate about
its axis in a coacting conical surface of the head whilst its stem
is carried by two roller bearings. Major drawbacks result from the valves being exposed
with their
frontal surface to the combustion chamber and thus being exposed to heavy pressure
and thermal loads. Another drawback is to
be seen in the conical surface of the valve that
serves as passageway and as slide bearing without clearly separating these
two functions.
[0003] The present invention is aiming at internal combustion engines with rotary valves
overcoming the above mentionned disadvantages while offering advantages for the construction
and the efficiency of the engine.
[0004] The present invention proposes internal combustion engines with rotary valves with
the features of claim 1. Preferred embodiments of the present invention are outlined
in the subclaims.
[0005] According to the present invention is provided an internal combustion engine with
rotary valves in axial bores to control opening and closing of transfer ports in a
cylinder head or cylinder block for fluid communication between the ports and a combustion
chamber of the engine, and a valve drive shaft arranged perpendicular to the rotary
valves, the shaft being provided with helical gaps to cooperate with gears fixed to
the free ends of the rotary valves for driving the rotary valves in accordance with
the operating cycle of the engine with each rotary valve being provided with a passage
duct in the valve head opening into the ports.
The respective axial bores of the cylinder head or cylinder block are formed as a
casing around the rotary valves such that the rotary valves are only exposed via the
ports to the combustion chamber of the engine. With the axial bores in the cylinder
head or cylinder block providing a casing the rotary valves are protected from the
alternating high pressure pics and the thermal load from the operating combustion
chamber. The rotary valves being shielded from the combustion cycles of the engine
is providing for smooth operation and improved endurance of the rotary valves, the
drive of the rotary valves and the entire engine. The internal combustion engine with rotary valves according to the present invention
is less consumptive while emitting less exhaust gases and presenting a higher perfomance
due to the continuous and constant supplie of fuel mixture. The rotary valves according
to the present invention may be implemented onto an existing engine with a cylinder
head replacing conventional oscillating valves after changes in the cylinder head,
i. e. replacing the conventional cam shaft(s) with the valve drive shaft arranged
perpendicular to the rotary valves and altering the cylinder head to accomodate the
rotary valves.
[0006] According to a preferred embodiment of the present invention the respective axial
bores are accessible for the rotary valves from the side of the cylinder head or cylinder
block remote from the combustion chamber of the engine. With the respective axial
bores being milled into the cylinder head or cylinder block remote from the side of
the combustion chamber a better shielding and an improved mounting procedure for valve
assemblies can be achieved.
[0007] According to a preferred embodiment of the present invention the valve drive shaft
is driven by the crankshaft of the engine or by a separat electro motor allowing better
electronic control.
[0008] According to another preferred embodiment of the present invention the cylinder block
is an integral unit comprising intake and exhaust channels, comprising the bores for
the rotary valves and comprising the side walls till the casing of the crankshaft
of the engine. A cylinder head sealing is obsolete with this new concept of an internal
combustion engine with rotary valves.
[0009] According to another preferred embodiment of the present invention each rotary valve
is being held in position in the cylinder head or cylinder block by a ball bearing
remote from the ports and conically shaped slide bearings above and below the ports.
With the inventive arrangement of bearings there is substantially no leakage around
the rotary valve, being smoothly spinning at low resistance levels.
[0010] According to another preferred embodiment of the present invention each rotary valve
is provided with spring means abutting against the ball bearing and the conically
shaped valve head in the bores. The spring is biasing the rotary valve into the conically
shaped valve seat in the cylinder head or cylinder block thus providing for improved
sealing at reduced length of the stem of the rotary valve allowing thus reduced height
of the cylinder head or cylinder block and thus less encumbrance for the entire new
internal combustion engine with rotary valves. The spring is abutting against the
central member of the ball bearing rotating with the rotary valve and is thus free
from sheer forces.
[0011] According to another preferred embodiment of the present invention each rotary valve
is provided with a central passage duct in the conically shaped valve head opening
into the ports in accordance with the operating cycles of the engine.
[0012] Additional features of the invention will become apparent and a fuller understanding
obtained by reading the following detailed description made in connection with the
accompanying drawings.
- Fig. 1
- shows a transversal section through an internal combustion engine with rotary valves
according to the present invention,
- Fig. 2
- shows a schematic perspective view of a possible configuration of a rotary valve and
a valve drive shaft for engine manufacturers according to the present invention, and
- Fig. 3
- shows a rotary valve according to the present invention.
[0013] Fig. 1, 2: An internal combustion engine 1 has rotary valves 2, 3 in axial bores
4, 5. Transfer ports, i. e. an intake port 6 and an exhaust port 7 in a cylinder block
8 allow fluid, i. e. fuel mixture, to communicate between the ports 6, 7 and a combustion
chamber 23 of the engine 1. A piston 14 is connected to a crankshaft 21 via a rod
22.
[0014] The cylinder block 8. is an integral unit or is equipped with a cylinder head gasket
(not shown), according to the engine manufacturers wishes, comprising the intake and
exhaust ports 6, 7, comprising the bores 4, 5 for the rotary valves 2, 3 and comprising
the side walls 20, 15 till the casing of the crankshaft 21 of the engine 1.
[0015] Each axial bore 4, 5 consists of a first section with a cylindrical shaped body 27
and a second section 24 with a bevel shaped body occupying the transfer ports 6, 7.
The axial bores 4, 5 are drilled into the cylinder block or cylinder head 8 from the
side remote to the combustion chamber 23 of the engine 1. The axial bores 4, 5 are
entirely embedded in the cylinder block or cylinder head 8 apart from the surface
accesssed by the ports 6,7.
[0016] Each rotary valve 2, 3 is being held in position in the axial bores 4, 5 of the cylinder
block 8 by a circumferential member of a ball bearing 16 remote from the ports 6,
7. Conical shaped slide bearings 17, 18 are arranged above and below the ports 6,
7. A helical spring 19 is abutting against the central member of the ball bearing
16. Helical spring 19 is biasing the conically shaped valve head 13 into the second
section 24 of the bores 4, 5.
[0017] The respective axis of rotation 25, 26 of the rotary valves 2, 3 are perpendicular
to each other.
[0018] A valve drive shaft 9 is arranged perpendicular to the rotary valves 2, 3. The shaft
9 is provided with helical slots 10 around its entire surface to cooperate with gear
wheels 11 fixed to the respective free ends of the rotary valves 2, 3. Each rotary
valve has a central passage duct 12 in the valve head 13.
[0019] The valve drive shaft 9 is driven by the crankshaft of the. engine or by a separat
electro motor (not shown).
[0020] Fig. 3: Each gear wheel 11 is fixed by a screw 27 to a threaded free end of the rotary
valves 2, 3. A ball bearing 16 is mounted with its central member to a stem 28 of
each rotary valve 2, 3. Each rotary valve has a central passage duct 12 in the bevelled
valve head 13.
[0021] Operation of the internal combustion engine 1 with rotary valves 2, 3
[0022] In the following the rotary valves will be described in the context of their use
with reciprocating type internal combustion engines. However neither some of the known
nor the rotary valve embodiments in accordance with the present invention are limited
to such applications.
[0023] Step 1: During the intake stroke the rotary valve 2 in intake port 6 is rotated by
the helical slots 10 of valve drive shaft 9 in an angular position to open intake
port 6 via its central passage duct 12. Exhaust port 7 remains closed by rotary valve
3.
[0024] Step 2: During the compression stroke the rotary valves 2, 3 in transfer ports 6,
7 are rotated by the helical slots 10 of valve drive shaft 9 in angular positions
to close intake port 6 and exhaust port 7.
[0025] Step 3: During the ignition and expansion stroke the rotary valves 2, 3 in transfer
ports 6, 7 are rotated by the helical slots 10 of valve drive shaft 9 in angular positions
to keep closed intake port 6 and exhaust port 7.
[0026] Step 4: During the exhaustion stroke the rotary valves 2, 3 in transfer ports 6,
7 are rotated by the helical slots 10 of valve drive shaft 9 in angular positions
to keep closed the intake port 6 but to open exhaust port 7 via the central passage
duct 12 of rotary valve 3.
[0027] With the next stroke the operating cycle starts again with step 1.
1. Internal combustion engine (1) with
rotary valves (2, 3) in axial bores (4, 5) to control opening and closing of transfer
ports (6, 7) in a cylinder head or cylinder block (8) for fluid communication between
the ports (6, 7) and a combustion chamber (23) of the engine (1), and
a valve drive shaft (9) arranged perpendicular to the rotary valves (2, 3), the shaft
(9) being provided with helical slots (10) to cooperate with gears (11) fixed to the
free ends of the rotary valves (2, 3) for driving the rotary valves (2, 3) in accordance
with the operating cycle of the engine (1) characterized in that the
respective axial bores (4, 5) of the cylinder head or cylinder block (8) are formed
as a casing around the rotary valves (2, 3) such that the rotary valves (2, 3) are
only exposed via the ports (6, 7) to the combustion chamber (23) of the engine (1).
2. Internal combustion engine (1) according to claim 1, characterized in that the respective axial bores (4, 5) are accessible for the rotary valves (2, 3) from
the side of the cylinder head or cylinder block (8) remote from the combustion chamber
(23) of the engine (1).
3. Internal combustion engine (1) according to claim 1, characterized in that the valve drive shaft (9) is driven by the crankshaft (21) of the engine (1).
4. Internal combustion engine (1) according to claim 1, characterized in that the valve drive shaft (9) is driven by an electro motor or by timing-belt, chain
or gear.
5. Internal combustion engine (1) according to claim 1, characterized in that the cylinder block (8) is an integral unit comprising intake and exhaust ports (6,
7), comprising the bores (4, 5) for the rotary valves (2, 3) and comprising the side
walls (20, 15) till the casing of the crankshaft of the engine (1).
6. Internal combustion engine (1) according to claim 1, characterized in that each rotary valve (2, 3) being held in position in the cylinder head or cylinder
block (8) by a ball bearing (16) remote from the ports (6, 7) and conically shaped
slide bearings (17, 18) above and below the ports (6, 7).
7. Internal combustion engine (1) according to claim 1, characterized in that each rotary valve (2, 3) is provided with resilient means (19) abutting against the
ball bearing (16) and the conically shaped valve head (13) in the bores (4, 5).
8. Internal combustion engine (1) according to claim 1, characterized in that each rotary valve (2, 3) is provided with a central passage duct (12) in the conically
shaped valve head opening in the ports (6, 7).