2023 Oxe Hybrid 450 Outboard Engine Unveiled

The new diesel-electric engine, officially only a concept, uses a traditional belt-driven alternator to provide electrical power for the boat, much like an engine used in a road-going vehicle. 

However, the alternator can stop charging and act as an electric motor to either drive the boat under full electric power alone, or help the diesel outboard engine during its more fuel-heavy roles, such as when accelerating onto the plane.

The result is that it boosts the 300hp Oxe diesel outboard engine’s performance up to a staggering 450hp – the same output as the recently updated, petrol-fuelled Yamaha 450 XTO Offshore.

This is known as a parallel hybrid system, as the electric motor can power the propeller independently of the diesel engine. It differs from a series system where the electric motor can only help the engine, and is not able to turn the prop on its own.

“The electric motor is strategically located under the cowling, connected to the drive belt for seamless operation. Not only does this enhance performance, but it also allows the motor to serve as an alternator, providing the ability to charge the batteries while running in diesel mode,” Oxe said.

“This advanced technology sets the Oxe Hybrid 450 apart from the competition, offering a superior boating experience.”

The engine block is based on a road-going 3.0-litre inline six-cylinder diesel produced by road car specialist BMW. This is nothing new, with the likes of Honda, Yamaha and Kawasaki adapting engines produced for either cars or motorbikes, and even Mercury using Volkswagen-sourced engines for sterndrives, commonplace in the industry.

The intercooler turbocharged engine alone produces 300hp at 4200–4400rpm and 680Nm from 1750rpm, meaning the electric motor – electron-fuelled drive systems are renowned for putting out maximum torque from almost idle – would be best suited helping out the diesel below that mark on the tachometer.

The Oxe Hybrid 450 electric motor will add another 150kW and 230Nm to the diesel’s performance, although the power supplied to the motor will need to step up to 400V, meaning the boat will need a hefty lithium-ion battery system onboarded to handle the hybrid technology.

Oxe says this battery can also serve as a house battery for the boat.

“The OXE Hybrid 450 combines the best of both worlds, the energy efficiency of diesel operation with the electric motor’s steep torque curve and the possibility of a completely emission-free operation,” Oxe Marine Chief Executive, Anders Berg, said.

“Thanks to its flexibility, our concept engine provides reduced fuel consumption and reduced carbon dioxide emissions, while also being able to deliver additional power when needed, for example during acceleration when the fossil engine’s consumption is extra-high.”

There are kick-on benefits, too, especially for keen fishers who will be able to use the boat’s full-electric mode just like a trolling motor, meaning the boat can move at a slower speed, and more quickly, than if it was running on diesel.

The engine will be developed working alongside fellow Swede, boatmaker Nimbus, who will provide the test platform, a 9.0-metre Nimbus T9 walkaround dayboat, for the diesel-electric hybrid.

Oxe says it plans to have the Oxe 450 Hybrid in series production as early as the second half of this year.