Garrett’s e-turbo tech helping push the plug-in hybrid efficiency envelope

Garrett Motion’s revolutionary and award-winning E-Turbo technology is boosting a European Union project that aims to redefine fuel consumption and emissions performance in plug-in powertrains, targeting an indicated peak efficiency of 47 percent.

The PHOENICE project, which was launched in 2021, brings together eight global automotive industry leaders. It has just reached a significant milestone, with a prototype dual dilution gas engine now in testing.

PHOENICE runs until 2024 and is focused on maximising the fuel efficiency and emissions reduction potential for plug-in hybrid vehicles in real world driving conditions. The partners are collaborating to integrate innovations in waste heat recovery, after-treatment, variable valve actuation, high pressure fuel injection, compression ratios, exhaust gas recirculation and thermal management to meet the challenging 47% engine efficiency target.

To validate the output from these new functionalities for steady state calibration, six representative operating points were identified for a first engine bench test, covering ICE speed (rpm) and brake mean effective pressure. For the prototype engine, Garrett introduced its variable nozzle turbine E-Turbo innovation, paired to a new prototype exhaust line.

The E-Turbo embeds a high-speed electric motor (>200k rpm) directly on the turbo shaft between the compressor and the turbine, powered and controlled by Garrett’s own inverter. Powerful algorithms switch the phase currents at frequencies up to 30kHz, delivering near instantaneous response (<1s).

In the current steady-state engine calibration test, the technology provides the aerodynamic flexibility to optimize the effect of the dual dilution combustion strategy, which leverages the benefit of exhaust gas recirculation and excess air (lean). At the same time, low friction bearings allow low speed spin-up of the turbo at cold-starts, delivering a faster warm-up of the exhaust after-treatment system.

“We are delighted our E-Turbo innovation is helping to push the fuel efficiency, emissions reduction and performance envelope of plug-in hybrid gas powertrains,” said Garrett’s Chief Technology Officer Craig Balis. “The progress made by PHOENICE so far is very exciting and we look forward to continuing our collaboration with other technology leaders to develop sustainable solutions for the auto industry, public agency stakeholders and the wider mobility community.”

In step with PHOENICE workplans, an additional engine prototype has been built for transient calibration.

Garrett’s award-winning E-Turbo innovation, developed by engineers at the company’s Electrification Center of Excellence, is a significant technological advance in hybrid powertrain electrification. As such, it is in demand among automakers as a contributor to fuel efficiency and emissions compliance without any compromise in performance.