Section 1 - General Information
This manual provides complete information for the installation, operation, and
maintenance of the ELLISON Throttle Body Injector (TBI).
This device offers improved aircraft engine performance and economy when installed and
operated in accordance with this manual.
|The ELLISON TBI described herein is not FAA
approved. Its use in standard category aircraft is prohibited.
The ELLISON Throttle Body Injector (TBI) is a variable venturi, diaphragm controlled,
fuel metering device configured to supply the fuel and air requirements of several popular
aircraft engines. It will operate in any attitude and through a wide range of G-loads,
making it an attractive replacement for carburetors or fuel injectors.
The ELLISON TBI is available in the five models listed in Table 1-3. Adjacent to each
model is a list of engines having airflow and fuel flow requirements compatible with that
||HAPI, Revmaster,Great Plains, and other VW derivatives
||Lyc. 0-235, 0-290, Cont. 0-200, 0-300, Subaru
||Lyc. I0-320, 0-320, 0-340
||Lyc. I0-360, 0-360
||Lyc. 0-540, Cont. 0-470
||Lyc. I0-540, Cont. I0-550
The TBI shown in cut-away in figure 1-4 is a unique fuel metering in that fuel is
injected in the plane of maximum airflow velocity, through a matrix of very small metering
holes located in a tube extending across the entire width of the airflow passage. Fuel is
admitted to this metering tube by a demand regulator, designed to maintain a slightly
negative fuel pressure in the metering tube. The metering tube is positioned in a bore
through the throttle slide. Movement of the throttle slide thereby controls fuel flow as
well as airflow by changing the number of metering holes exposed to the air stream.
Rotation of the metering tube through a maximum angle of 90 degrees changes the
orientation of the fuel metering holes with respect to the airflow. This rotation serves
as the pilot's mixture control. Full lean occurs when the holes are facing directly into
the on- coming airflow, and a progressively richer mixture is obtained as the holes are
rotated away from the zero angle of attack position.
Because the fuel pressure in the metering tube is maintained below ambient pressure,
fuel will not flow from the metering holes unless induction air is flowing through the
inlet bore. This feature permits the engine to be shut down without the necessity of
turning off the main fuel valve.
Idle fuel is dispensed by an idle fuel jet whose discharge rate is adjusted by a
conventional needle valve located in the regulator end of the body.
The ELLISON TBI has been designed specifically for aircraft use and has been thoroughly
tested with aviation fuels. Auto or agricultural fuels should NOT be used
with the ELLISON TBI.
It is suggested that prior to beginning the installation of the TBI, the aircraft be
flown through the flight test outlined in Section 5-1 of this
manual steps 3 through 13 using the aircraft's original fuel metering system. Later
comparison of this data with post-installation data will quantify the performance benefit
or penalty resulting from the TBI installation.
In order to assure accuracy, it is very important that the test be flown in smooth air,
preferably in the morning. It is also important that the aircraft be properly trimmed and
allowed several minutes of hands-off level flight to stabilize its speed before any
performance data is recorded.
To Section 2