Internal-combustion engines – Rotary – With compression – combustion – and expansion in a single...
Reexamination Certificate
2000-08-02
2001-11-27
Denion, Thomas (Department: 3748)
Internal-combustion engines
Rotary
With compression, combustion, and expansion in a single...
C418S152000
Reexamination Certificate
active
06321713
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to rotary vane pumping machines. More particularly, the present invention relates to a hot wall combustion insert for improving combustion parameters in a rotary vane internal combustion engine.
2. Description of Related Art
This class of rotary vane combustion engines includes designs having a rotor with slots with a radial component of alignment with respect to the rotor's axis of rotation, vanes which reciprocate within these slots, and a chamber contour within which the vane tips trace their path as they rotate and reciprocate within their rotor slots.
The reciprocating vanes thus extend and retract synchronously with the relative rotation of the rotor and the shape of the chamber surface in such a way as to create cascading cells of compression and/or expansion, thereby providing the essential components of a combustion engine. For ease of discussion, a rotary vane engine will be discussed in detail.
A prior combustion design was described in pending U.S. patent application Ser. No. 08/398,443, to Mallen, filed Mar. 3, 1995, entitled “SLIDING VANE ENGINE,” now issued as U.S. Pat. No. 5,524,587 on Jun. 11, 1996 (the '587 patent). The '587 patent generally describes the operation of a sliding vane engine. The operation of a vane engine using this prior combustion design will now be described.
FIG. 1
is a side cross sectional view of a conventional rotary-vane combustion engine.
FIG. 2
is an unrolled view of the cross-sectional view of FIG.
1
.
As shown in
FIG. 1
, the rotary engine assembly includes a rotor
10
, a chamber ring assembly
20
, and left and right linear translation ring assembly plates (not shown in full).
The rotor
10
includes a rotor shaft
11
, and the rotor
10
rotates about the central axis of the rotor shaft
11
in a counterclockwise direction as shown by arrow “R” in FIG.
1
. The rotor
10
has a rotational axis, at the axis of the rotor shaft
11
, that is fixed relative to a stator cavity
21
contained in the chamber ring assembly
20
.
The rotor
10
houses a plurality of vanes
12
in vane slots
13
, and each pair of adjacent vanes
12
defines a vane cell
14
. The contoured stator cavity
21
forms the roughly circular shape of the chamber outer surface.
The linear translation ring assembly plates are disposed at each axial end of the chamber ring assembly
20
, and each includes a linear translation ring
31
. Each linear translation ring
31
itself spins freely around a fixed hub
32
located in the linear translation ring assembly plate, with the axis of the fixed hub
32
being eccentric to the axis of rotor shaft
11
.
A combustion residence chamber
26
is provided in the chamber ring assembly
20
. The combustion residence chamber
26
is a cavity within the chamber ring assembly
20
, radially and/or axially disposed from a vane cell
14
, which communicates with air or a fuel-air charge in the vane cell
14
at about peak compression in the engine assembly. The combustion residence chamber
26
creates an extended region in communication with the vane cell
14
during peak compression.
The combustion residence chamber creates a source of ignition in the vane cell
14
where the combustion residence chamber
26
meets the vane cell
14
, which ignition must spread substantially throughout the entire vane cell
14
. It is important that the combustion time be of a sufficient duration for proper operation of the combustion residence chamber.
One or more fuel injecting or delivery devices
27
may be used and may be placed on one or both axial ends of the chamber and/or on the outer or inner circumference to the chamber and/or in an intake manifold upstream of the intake port to the engine. Each injector
27
may be placed at any position and angle chosen to facilitate equal distribution within the cell or vortices while preventing fuel from escaping into the exhaust stream.
Fresh intake air or a fuel-air charge, “I” is provided to the vane engine through an intake port
23
formed in the linear translation ring assembly plate and/or chamber ring
20
. Similarly, combusted air or fuel-air charges, i.e., an exhaust gas, “E” is removed from the vane engine through an exhaust port
25
, also formed in the linear translation ring assembly plate and/or chamber ring
20
.
The rotation of the rotor
10
in conjunction with the linear translation rings automatically sets the radial position of the vanes
12
at any rotor angle, producing a single contoured path as traced by the vane tips resulting in a unique stator cavity
21
shape that mimics and seals the path the vane tips trace.
The illustrated internal combustion engine employs a two-stroke cycle to maximize the power-to-weight and power-to-size ratios of the engine. The intake of the fresh air “I” and the scavenging of the exhaust gas “E” occur at the regions as shown in FIG.
1
. One complete engine cycle occurs for each revolution of the rotor
10
.
Fresh air can be mixed with fuel during the compression stage in alternate embodiments.
In operation, the vane engine shown in
FIGS. 1 and 2
operates as follows.
The combustion charge is introduced into the vane chamber
14
through the intake “I” during an intake cycle
510
. This combustion charge is preferably air or a fuel-air mix, and may have fuel added to it by the fuel injection device
27
. The mixed fuel and air are then compressed in the vane chamber
14
during a compression cycle
520
, as the rotor
10
continues its motion.
As the vane chamber
14
reaches the combustion residence chamber
26
, a combustion cycle
530
is performed. During the combustion cycle
530
, the air and fuel are combusted, causing a dramatic increase in heat and pressure. An initial combustion reaction is initiated by hot gases exiting the combustion residence chamber
26
and this jet is introduced to the vane chamber
14
during the combustion cycle
530
as a source of ignition. This combustion reaction then spreads circumferentially and radially throughout the vane chamber
14
until the air and fuel in the vane chamber have been substantially combusted. The combustion residence chamber is then automatically re-pressurized or primed with hot combusted gases for this combustion process to begin again with the subsequent vane cell. Sufficient time must be available for the combustion within the vane cell to be substantially complete and for the combustion residence chamber to be primed for the subsequent vane cell.
The combusted fuel and air are then expanded in an expansion cycle
540
, and removed via an exhaust cycle
550
.
FIG. 2
simply shows the operation of
FIG. 1
in an ‘unrolled’ state, in which the circular operation of the vane engine assembly is shown in a linear manner. The progression of the cycles
510
,
520
,
530
,
540
, and
550
can be seen quite effectively through FIG.
2
.
In conventional designs spark plugs and glow plugs would initiate the combustion cycle
530
. These methods of initiating combustion may be described as point ignition sources. Point ignition activates combustion of the fuel-air mixture at a local site in a given vane cell
14
. However, the large surface area of the chamber wall surrounding the vane cell
14
, results in a large distance that must be traversed by the propagating flame front before the combustion cycle can be complete.
As a result of this limitation and the low energy of the ignition method, point ignition devices such as glow plugs and spark plugs are unable to combust the ultra-lean mixtures necessary for ultra low emissions and best fuel economy. An important reason for the difficulty in achieving such flame propagation through an ultra-lean mixture is due to Damköhler number effects. For a discussion of Damköhler number effects on flame propagation, see “Blowout of Turbulent Diffusion Flames”, J. E. Browdwell, W. J. A. Dahm, & M. G. Mungel, 20
th
Symposium (International) on Combustion/The Combustion Institute, 1984, pp. 303-310.
In short, however, point ignition d
Denion Thomas
Jones Volentine, P.L.L.
Mallen Research Corporation
Trieu Thai Ba
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