Automotive Engineering - July/August 2020 - 6

TECHNOLOGY
REPORT
PROPULSION

Mercedes-AMG ready with electrically-assisted turbocharger
For the new Mercedes-AMG
eTurbo, the electric motor acts
directly on the turbocharger
shaft to accelerate the turbine
when exhaust energy is low.

SAE INTERNATIONAL
BOARD OF DIRECTORS
Todd Zarfos
President
Paul Mascarenas, OBE
2019 President
Jeff Hemphill
2021 President Elect
Pascal Joly
Vice President - Aerospace
Ken Washington, PhD
Vice President - Automotive

6 July/August 2020

48-volt companion

The eTurbo is accompanied by a 48-volt electrical system to provide the requisite power,
although the Mercedes-AMG did not detail the
energy demands of the electric motor. The turbocharger and its integral electric machine, as
well as the accompanying power electronics,
are cooled by the engine's thermal-management circuit.
"We have clearly defined our goals for an
electrified future," said Tobias Moers, chairman of the board of management of
Mercedes-AMG GmbH in a release announcing
the brand's pending release of its eTurbo. "In
a first step, this includes the electrified turbocharger - an example of the transfer of
Formula 1 technology to the road, something
with which we will take turbocharged combustion engines to a previously unattainable
level of agility," he asserted.
Although Mercedes-AMG developed its electrically assisted turbocharger with Garrett
Motion, other turbocharger developers also are
underway with similar technology. One, BMTS
Technology (formerly Bosch Mahle Turbo
Systems), detailed for media in mid-2019 an
electrically assisted turbocharger that it is targeting for early 2024 production. That unit, said
Nisar Al-Hasan, BMTS director, growth & strategy, is designed to achieve a maximum speed of
216,000 rpm and requires approximately 2.2 kW
of power. The turbocharger also is designed to
act as a generator to recuperate electricity and
return it to the system's battery when exhaust
energy is in excess. Al-Hasan said BMTS' cost
target for the unit was a less than $100 more
than a conventional turbocharger.
Bill Visnic

Andrew Jeffers
Treasurer
David L. Schutt, PhD
Chief Executive Officer
Gregory L. Bradley, Esq.
Secretary
Landon Sproull
Jeff Varick
Rhonda Walthall
SAE International Sections

SAE International Sections are local
units comprised of 100 or more SAE
International Members in a defined
technical or geographic area. The purpose
of local Sections is to meet the technical,
developmental, and personal needs of the
SAE Members in a given area. For more
information, please visit sae.org/sections
or contact SAE Member Relations Specialist
Abby Hartman at abby.hartman@sae.org.

SAE International
Collegiate Chapters

Collegiate Chapters are a way for SAE
International Student Members to get
together on their campus and develop
skills in a student-run and -elected
environment. Student Members are vital
to the continued success and future of
SAE. While your course work teaches
you the engineering knowledge you
need, participation in your SAE Collegiate
Chapter can develop or enhance other
important skills, including leadership,
time management, project management,
communications, organization, planning,
delegation, budgeting, and finance. For
more information, please visit students.
sae.org/chapters/collegiate/ or contact
SAE Member Relations Specialist Abby
Hartman at abby.hartman@sae.org.

AUTOMOTIVE ENGINEERING

MERCEDES-AMG

In announcement signaling automakers continue
significant R&D for internal-combustion propulsion, Mercedes-AMG said it is preparing to launch
a new, electrically-assisted turbocharger for engines to power its next vehicle generation.
Confirming that the new turbocharger design will
soon be fitted in a "series production" model line,
the company said the electrically augmented
turbocharger delivers enhanced driving dynamics while also improving efficiency.
Mercedes-Benz and other automakers already have launched auxiliary electric compressors to augment conventional turbochargers, but this design integrates the strategy by
using the electric machine to act directly on
shaft connecting the turbine and compressor
wheels: the 1.6-inch (41-mm)-wide motor sits
between the exhaust-driven turbine and the
impeller that compresses the intake air directed into the engine. It can spin to a conventional
turbocharger rate of up to 170,000 rpm.
The company said the electrically assisted
turbocharger, dubbed eTurbo, was developed
in partnership with Garrett Motion and the
technology "comes straight from Formula 1
[racing] and resolves the conflicting goals of a
small, fast-reacting turbocharger, with relatively low peak performance, with a large turbocharger capable of high peak performance,
while effectively eliminating the presence of
turbo lag."
The design is claimed to significantly improve response from idle, when there is low
exhaust energy to drive a conventional turbocharger and also is adept at retaining boost in
engine low-load and transient situations, such
as coasting or braking, that are prone to turbo
lag when the driver again asks for acceleration.

Michael Weinert
Vice President -
Commercial Vehicle

https://www.sae.org/participate/membership/sections https://www.sae.org/participate/membership/collegiate-chapters

Automotive Engineering - July/August 2020

Table of Contents for the Digital Edition of Automotive Engineering - July/August 2020