Rotax 912 i Series Maintenance Manual page 376

SYSTEM DESCRIPTION
GENERAL NOTE
In order to ensure that the engine is in the desi-
red operating state and in full working order, a
number of sensors are placed on it and used for
the Engine Management System (EMS). The
information captured by the sensors is transmit-
ted to the ECU where it is processed, and the
corresponding signals are sent on to the actua-
tors.
SENSORS
1 Pressure/temperature sensor –
ambient pressure
Wiring harness designation: AAPTS
Ambient air pressure and ambient temperature
are measured with a combined pressure/tempe-
rature sensor. These measurement values are
used to compensate for the different altitude and
external temperatures.
1 Pressure sensor – oil pressure
Wiring harness designation: OPS
The pressure sensor measures the oil pressure
of the engine.
2 Pressure sensors – airbox
Wiring harness designation: MAPS_1/MAPS_2
The pressure sensors measure the pressure of
the intake air in the airbox.
2 Temperature sensors – airbox
Wiring harness designation: MATS_1/MATS_2
The temperature sensors measure the tempera-
ture of the intake air in the airbox.
4 Temperature sensors – exhaust
Wiring harness designation: EGT_1/EGT_2/
EGT_3/EGT_4
The temperature sensors measure the tempera-
ture of the exhaust gas and are used to regulate
the injection quantity.
1 Temperature sensor – cooling system
Wiring harness designation: CTS
Effectivity: 912 i Series
Edition 1/Rev. 0
BRP-Powertrain
MAINTENANCE MANUAL
The temperature sensor measures the coolant
temperature directly in the cylinder head of cylin-
der 4.
1 Temperature sensor – oil temperature
Wiring harness designation: OTS
The temperature sensor measures the oil tem-
perature.
1 Knock sensor
Wiring harness designation: KNOCK
"Knocking" means uncontrolled combustion in
petrol engines, which is caused by auto-ignition
of the mixture in the combustion chamber. This
undesirable combustion results in increased
mechanical loads in the engine.
Operation in this condition over a long period
can damage or even destroy the piston. Charac-
teristic frequencies are generated during kno-
cking. These frequencies are detected by the
knock sensor and sent to the control unit (ECU).
1 Potentiometer – throttle valve
Wiring harness designation: TPS
The potentiometer measures the position of the
throttle valve in the throttle body.
4 Double ignition coils
Wiring harness designation: COIL_1/COIL_2/
COIL_3/COIL_4
Each double ignition coil supplies 2 spark plugs
with high voltage.
2 Crankshaft position sensors
Wiring harness designation: CPS_1/CPS_2
The control unit (ECU) requires the current posi-
tion of the crankshaft for exact control of the igni-
tion and injection points. The crankshaft position
sensors measure the revolutions of the cranks-
haft and give the ECU information about the
position of the pistons and the position of the
crankshaft.
.
76-70-00
Page 6
July 01/2012