contents of this page are
from "ELEMENTS OF FRASCA ROTARY ENGINE DESIGN"*
combustion engines, FRE do not have intake and exhaust valve
*Copyright © 1998 by Joseph F. Frasca
FRASCA ROTARY ENGINE (FRE)
i.e. FRE do not have intake
valves, timing chains, camshafts, valve springs, etc. and the engine
support elements required for their function.
The fresh air intake pathway in
FRE and the high pressure intake pathway(s) in the 2-cycle FRE is
unobstructed and direct to the VVC (working chambers) in the engine's
cavity intake regions.
The FRE exhaust gas pathway(s)
the VVC in the exhaust region(s) of the [engine's] annular cavity to
the engine and are also always unobstructed.
The complex ignition systems
required in other
internal combustion engines types are not needed in FRE;
i.e. FRE do not need a
ignitor plugs, coils, complex ignition wiring, distributors,
drive elements, and the structural support configurations required for
Only a primitive ignitor is
require to initiate
combustion in the FRE.
Once initiated, combustion is
in a FRE.
Combustion is initiated in each
FRE VVC (working
chamber) as soon as injected fuel is available.
The flow of combustion involved
hot gases under
pressure through the gap at the partition separating the VVC being fuel
injected from its combustion involved neighbor VVC effects the ignition
of the injected fuel.
Fuel is supplied to the FRE VVC
simple throttle controlled steady flow injection.
Both liquid and gas fuels may
be used to fire
Instead of using a complex high
fuel injection system with high pressure metering and injection
and injectors at each working chambers typical to other engine, the FRE
has fuel injected into the its VVC (working chambers) via a steady flow
through a single injector nozzle (set) located in the rotor.
As each VVC traverses the fuel
location it intercepts the injector's steady fuel stream.
This continuous fuel injection
of the FRE permits the vaporization of liquid fuels by exhaust gas heat
prior to injection so that the liquid fuel enters the VVC as high
This type of liquid fuel
handling system eliminates
the very high liquid fuel injection pressures required in other fuel
systems to attain proper fuel droplet size for proper combustion.
There are no wiping (wiping
abutments) or fixed
seals between the relatively moving parts of FRE working chambers (the
i.e. A FRE does not have
sealing abutments (e.g. piston rings, valve seats and keeps) in the
extremes of temperature and pressure required in other internal
The FRE has no need for
pressure rings, oil
barrier rings, valve to valve seat sealing, valve keeps, etc. or their
supporting engine structures.
Therefore, parts wear, inter
part heat transfer
and mechanical stresses are greatly reduced in FRE.
The lack of wiping abutments in
the FRE also
permits a less expensive use of high temperature engineered ceramic
Machining tolerances are larger
and the use
of ceramic materials permits higher and more efficient engine operating
For the environmental agency
engine designer, most FRE designs can accommodate fresh air purging
The purging air intake is used
to supply sufficient
air to the VVC in the annular cavity exhaust region(s) to complete
of the exhaust gases during their purge, to eliminate residual exhaust
gases in the VVC and to cool the VVC.