Engine Management System - Rotax 915 i A SERIES Operator's Manual

Generators 1
and 2
Malfunction

7.5.1) Engine Management System

Parts
Page 7-10
December 01 2017
The two generators (Generator 1 and Generator 2) are
mounted electrically isolated on one stator. Each generator is
connected with a regulator mounted on the Fusebox. The Fuse-
box takes care of the energy management and allows selecting
whether the EMS is supplied by an external power source (e.g.
Battery) or one of the generators. The selection which of the
generators is powering the EMS depends on the engine status
and can only be done by the Engine Control Unit (ECU).
During the engine start an external power source is needed to
power the EMS. After the engine speed is high enough to power
the EMS with the Generator 2, for running the engine the exter-
nal power source is only required in emergency situations. If a
defined engine speed threshold has been reached for a certain
time Generator 1 takes over to supply the EMS. After this, Gen-
erator 2 can be used to supply the Airframe (e.g. instrumenta-
tion). In no operation state Generator 1 can be used to supply
the airframe.
In case of an malfunction of Generator 1 the internal electric
supply system changes to fail-safe mode where Generator 2
again is in charge to supply the EMS. In fail-safe mode Genera-
tor 2 is not able to charge external power sources or supply the
airframe.
The EMS is not capable of supervising the power provided to
the airframe. If the EMS is powered by Generator 1 and Gener-
ator B fails no indication is provided from engine side.
The Engine Management System has following main
functionality
• Ignition control
• Fuel injection control
• Fault detection
• (Internal-) Generator management
Parts of the Engine Management System are Sensors, Actua-
tors, the ECU and the wiring harness. The core of the EMS is
the engine control unit (ECU), which consists of two modules.
These modules will be denoted by Lane A and Lane B, each
one capable of taking over control, regulation and monitoring of
the engine. In error-free engine operation, both Lanes are
turned ON.
During engine control by Lane A, Lane B ensures that the en-
gine operation can be maintained even after a failure or re-
duced functionality of Lane A. Depending on the activity and the
failure status of the two Lanes, the ECU automatically selects a
BRP-Rotax Effectivity: 915 i A Series
Edition 0 / Rev. 0