Mercury 2.1-liter outboard selected to serve as E1-X foundation
Mercury Racing completed work on the E1-X, a prototype electric outboard for the E1 Series, a new powerboat racing series expected to debut in 2023. Mercury Racing joins the E1 Series as Official Propulsion and Propeller Partner and, as part of that partnership, will contribute to development of the propulsion architecture and propeller. This is part two of a blog series on the partnership.
The midsection and gearcase of a Mercury Marine 2.1-liter outboard were selected to serve as the foundation for the Mercury Racing E1-X powertrain. The internal combustion powerhead was removed and replaced with a 200hp (150 kW) electric motor and an inverter.
“It was important to minimize the powertrain weight, and the 2.1-liter platform is the lightest motor in the Mercury portfolio that would accommodate the electric motor and inverter,” explained Jeff Broman, Mercury Racing Director of Engineering. “The gearcase has good hydrodynamics and is stout enough to handle the torque of the electric motor. The available gear ratios are also a good match for the motor RPM, which was important because creating and validating all-new gears is a time-consuming process.”
The electric motor has a peak speed of about 7000 RPM, only about 1000 RPM faster than a 2.1-liter internal combustion engine. The Mercury Racing team selected the 2.07:1 gear ratio for the project and sent a variety of propeller models and sizes for the initial rounds of testing.
Mercury Racing created a billet aluminum adaptor plate that rests on the outboard midsection to support the electric motor, which needs to be positioned to align its output shaft with the drive shaft in the lower unit. The inverter (the blue box seen in photos) is positioned on top of the electric motor. The inverter converts the DC flow of electrons from the battery into the AC flow required by the motor. The combination of motor and inverter take up less space than the 2.1-liter powerhead, and the original outboard cowl and pan was used for prototype testing. A lightweight, and distinctively styled, cowl will be created for outboards used in the E1 Series
Both the inverter and the electric motor are liquid cooled, so the Mercury Racing team had to devise that system as well. The E1-X cooling system will be the subject of a future Mercury Racing blog post detailing the development of the new electric competition propulsion system!