One of the main development targets for modern e-drive transmission
systems is improving efficiency while, at the same time, guaranteeing a life-time
of reliable operation. Although modern e-drive transmissions are al-ready
very efficient, every new improvement and refinement offers great
benefits. Vehicle range, in particular, is one of the most im-portant
performance attributes of electric vehicles and can
be heavily impacted by transmission losses.
Transmission losses can be divided into two groups. The
first are mechanical losses resulting from friction in, among
other things, the gears, bearings, sealings, and clutches. And
the second group are churning losses, which result from oil
splashing inside the transmission. Loss levels and the ra-tio
between mechanical and churning losses are dependent
1 6 e-mobility
Using AVL simulation tools
for holistic optimization
of e-drive transmission
efficiency in mechanical,
flow and thermal domains.
on the vehicle operating conditions. These are defined by the transmitted
torque level and speed, as well as the operating temperature and parame-ters
like oil type and oil level. To perform detailed analysis of these loss-es
you can use AVL eSUITE™. A bundle of tools that contains, among
others, a 3D multi-body dynamic simulation and a 3D flow and thermal
simulation tool.
The latest addition to the eSUITE portfolio of tools is AVL EXCITE™
for e-axle. EXCITE features a new user interface that allows you to eas-ily
set up a dynamic simulation model of the transmission. Alternatively,
you can quickly import your model from any transmission design tool
that supports the widely accepted Reusable Engineering EXchange Stan-dard
(REXS) file format.
This dynamic model contains all
the body shape and motion infor-mation
for the transmission com-ponents,
and this information can
be passed to a CFD model thanks
to its new export functionality. Per-forming
dynamic simulations with
EXCITE for e-axle allows you to
understand and reduce mechanical
power loss for all friction contacts,
such as bearings and gears.
The second tool, AVL FIRE M™,
is a 3D CFD solution that can per-form
fluid multiphase flow model-ling,
as well as multidomain struc-ture
and fluid thermal simulation.
The latest version of FIRE M of-fers
an extremely simplified model
and mesh set-up using so-called
Embedded Body technology. This
enables you to automatically set up
the mesh inside the transmission
housing without needing to consid-er
moving transmission parts. You
can then import transmission com-ponent
information from EXCITE
VISUALIZING
EFFICIENCY