The Avadi MA-250 might look small, but it’s shaking up everything we thought we knew about engines.
It’s not just about size. This machine is proving that normal combustion engines still have a few tricks left up their sleeves, even in a world racing towards electric power.
And when it comes to fuel efficiency, it’s making big players like gasoline, diesel, and even hydrogen take a step back.
Michael Arseneau first dreamed up the Avadi engine 20 years ago. He believed that he could create something lighter, stronger, and cleaner.
When the dream became a reality
It took around a decade before the company, Avadi, started turning that dream into reality in 2015. What they came up with isn’t just another rotary engine. It’s something completely different.
Unlike traditional engines, where pistons move up and down inside cylinders, this one does something quite different.
The piston itself rotates within the engine case. Instead of using a crankshaft, it relies on two connecting rods that move like scissors, transferring power to a set of pinion gears.
These gears, in turn, connect to a fixed ring gear, which directly drives the output shaft. It’s a completely fresh approach to internal combustion.
Because of this design, the Avadi MA-250 is just very lightweight. A 250cc motorcycle engine can weigh between 50 and 80 pounds, but this one? Just 23.6 pounds. That’s less than half the weight of most competitors.
But it is punching way above its weight. The MA-250 produces 15.8 horsepower at 3,700 RPM and 22.3 lb-ft of torque at 3,500 RPM.
That’s more torque than Honda’s CRF300L, an off-road bike. And it’s delivering that power at much lower RPMs, making it an absolute beast in situations where low-end torque matters.
Torque isn’t the only thing that sets this engine apart. Its efficiency is also kind of turning heads. Avadi claims a brake thermal efficiency of 42.12%.
To put that into perspective, Toyota made headlines when it hit 39% efficiency with its A25K-FKS four-cylinder engine (Toyota is still trying to get this number higher though).
This was big news because most regular gasoline engines struggle to hit 20%. Even hydrogen engines don’t come close to these numbers.
Is this really so revolutionary though?
So what does this mean? It means the Avadi engine is burning fuel in a way that wastes less energy, making every drop of fuel go further.
This could be a game-changer in a world looking for ways to cut down on fuel consumption without ditching internal combustion altogether.
Of course, not everything has been smooth sailing. The Avadi team ran into some big problem with the engine’s rotary valve system.
It turned out the airflow wasn’t working as they’d hoped, which ended up significant performance issues.
In May 2023, Avadi replaced Arseneau as Chief Technology Officer with Dimitrios Dardalis. Since then, they’ve been working on a new valve design that fixes the problem.
For a while, it seemed like Avadi had gone quiet. After making an appearance at CES in January 2022, updates were not seen. Their last big announcement in 2023 promised a new prototype with the reworked valve design by the end of the year. As of June 2024, we finally have a bit of an update. Avadi’s CEO, Landon Wilkinson, has confirmed they’ve seen positive compression results with the new design and are preparing for test runs.
The big question now is: Can this engine find its place in an industry that’s rapidly shifting towards electric vehicles? Avadi thinks so. They see their engine being used in motorcycles, utility vehicles, and developing-world transportation.
Even if the world is heading towards electrification, combustion engines aren’t disappearing overnight (at least the FIA doesn’t think it should). There are still millions of vehicles running on fuel, and efficiency improvements like this could extend their relevance for years to come.
