System Description
© 2018 Avco Corporation. All Rights Reserved
Page 8
October 2018
TEO-540-A1A Engine Installation and Operation Manual
Table 2 (Cont.)
Sensors
Sensor Name
Abbr.
Qty.
Description
Induction Manifold Air
Pressure Sensor
MAP
1
Measures induction air manifold pressure.
Primary Compressor Inlet
Pressure Sensor
CIP-P
1
Redundantly measures the pressure of the
induction air entering the turbochargers.
Secondary Compressor Inlet
Pressure Sensor
CIP-S
1
Redundantly measures the pressure of the
induction air entering the turbochargers.
Knock Sensor
KNOCK
6
Used to detect detonation in each respective
engine cylinder.
Cylinders
Each of the six engine cylinders has rings, pistons, push rods, valves, valve springs, and hydraulic
roller tappets.
The valve-operating mechanism uses a conventional camshaft above and parallel to the crankshaft.
The camshaft operates the hydraulic roller tappets. These tappets adjust for expansion and
contraction in the valve train. The roller tappets use push rods and valve rockers to operate the
valves.
The connecting rods have replaceable bearing inserts in the crankshaft ends. Two bolts/nuts attach
the bearing caps to the crankshaft end of each rod.
Each cylinder is air-cooled by integral cooling fins. Cylinder baffles push air through the cylinder
fins. Refer to Appendix A for the cylinder cooling airflow and pressure differential curve.
Crankcase
The crankcase is made up of two reinforced castings divided at the centerline of the engine. The
castings are attached by a series of thru-studs, bolts and nuts. The mating surfaces of the two castings
are joined without a gasket.
The crankcase forms the bearings for the camshaft. The camshaft operates the roller tappets that
control opening and closing of the intake and exhaust valves. The camshaft has an integral spur gear
that drives the propeller governor output shaft.
The main bearing bores are machined for precision-type main bearing inserts. The crankshaft main-
bearings are pairs of inserts installed in the crankcase at each journal.
The crankshaft is within the crankcase. The crankshaft has journals and counterweights. The
counterweights decrease torsional vibrations as the crankshaft turns to operate the propeller. The
crankshaft has one 5
th
order and one 6
th
order pendulum-type counterweights.
Pressurized oil flows through oiling passages in the crankcase and bearings to lubricate the
crankshaft journals and to supply the propeller governor oil circuit and the hydraulic propeller pitch
control circuit. The crankcase has a breather for ventilation to the atmosphere to prevent excess
pressure in the crankcase. The crankcase breather connection is on the accessory housing.
The filler cap and oil level gage are installed in the crankcase. An optional filler extension is
available.
