Avadi New Engine
Emir Ballard
Combustion engines will probably be with us for a long time. Automakers like Toyota have announced new investments into gasoline powertrains, while enterprising companies like Avadi are radically redesigning them for a more sustainable future. Avadi's new engine prototype reimagines the rotary, replacing the spinning Dorito with a rotating piston.
The 0.25-liter, four-stroke engine has two independent, self-balancing connecting rods that attach the single rotating piston to a pair of pinion gears. They work in a scissor-like fashion to facilitate the rotation. The pinions ride on a fixed ring gear in the crankcase, resulting in a lighter, more powerful engine with less than half the number of moving parts of a traditional one.
The company believes its new engine design could be used in several applications, including passenger cars, but we shouldn't expect it to save combustion power. Avadi imagines the engine, which has scalable displacement, could be an onboard power generator for electric vehicles. It measures 12.0 inches long, 10.0 inches high, and 8.0 inches wide, weighing 23.6 pounds while producing 15.8 horsepower and 22.4 pound-feet of torque. That might not be enough to replenish a massive battery, but it's a start.
With EV sales slowing, automakers are launching new hybrids that utilize onboard generators, like the Mazda MX-30 and the new Ram 1500 Ramcharger. Mazda uses a 0.83-liter rotary engine that makes 74 horsepower to recharge the crossover's battery. Ram went a bit further in the power department, installing a 174-hp 3.6-liter V-6 engine in its hybrid pickup, but both are evidence that automakers are playing with powertrain configurations.
The engine is just a prototype for now, but Avadi says on its website that it anticipates "the possibility of delivering customer engines in the near future." Even if we never see it in a passenger car, it could power motorcycles, ATVs, drones, lawnmowers, numerous recreational vehicles, and more.
Michael Arsenaeu designed the Avadi engine 20 years ago in the hopes of creating an entirely new engine design to be efficient as well as reduce emissions. In 2015, Avadi began the build and development.
Rotary might be a good name for this sort of engine, if the name wasn't already taken. Everything inside the crankcase rotates, but unlike a Wankel-style rotary engine, this design uses a piston with two connecting rods that have a scissor-like movement attached to pinion gears at the back of the engine.
All of this rotates on a fixed ring gear connected directly to the output shaft. It uses a valve disk that also rotates to complete a four-stroke cycle of intake, compression, combustion, and exhaust as everything rotates internally.
According to Avadi's website, "two connecting rods and their corresponding pinion gears reside in what we call a 'halfshaft.'... the halfshaft can be likened to the heart of the Avadi design, it is essentially the housing where up-and-down piston motion is translated to rotational motion."
Looking at it in motion does make me wonder if the low mechanical advantage from the connecting rods to the pinion gears might constitute a long-term reliability issue from the torsion factor on a narrow, short stroke. I also wonder how efficient it could potentially be with a better mechanical advantage in transferring the up-down motion from the piston to the rotation of the output shaft.
We say the prototype "was producing" those figures, because after Avadi made an appearance at CES in January of 2022, little has been heard from the small Washington, USA company. A single blog-style post on its website dated May 28th, 2023 tells us that Avadi has replaced Arsenaeu with Dimitrios Dardalis as Chief Technology Officer, and the rotary valve design had "unsurmountable deficiencies in airflow," which Avadi believes it has solved with a reworking of the valve design, which the company expected to demonstrate with a new prototype slated for testing by the end of 2023.
We reached out to CEO and Co-Founder, Landon Wilkinson, to see where things stand in June 2024. "The revised engine design is coming along nicely," replied Wilkinson. "We achieved positive compression results last week with the new valve design and anticipate run tests in the near future."
We look forward to the results. It's gotta be tough trying to break through into a rapidly electrifying world with a new combustion engine, but at the same time there's plenty of ICE engines out there, and there will be for some time yet.
Meanwhile, enjoy the video below. Especially the part at 1:56, where you can wonder together with us whether Avadi really meant to leave a shot in the video where somebody appears to either arc out a spanner on the engine, or grind it on a moving part...
While that output clearly indicates the MA-250 is not ready to power a full-sized automobile, Avadi claims the engine should be able to run a motorcycle or ATV, some generators, farm equipment, and light sport aircraft, among other things. Those uses alone should make the MA-250 engine a compelling option for consumers looking for an eco-friendly ICE to power such vehicles/devices.
As for the MA-250's ability to one day power a full-sized automobile on its own, Avadi claims the engine could be scalable to the point of eventually being able to do so. Likewise, the engine's overview claims it may already be a serviceable on-board solution for generating power in electric cars and trucks.
Possibilities aside, based on its current level of practical applications, you may already be asking how you can get your hands on one of Avadi's MA-250 engines. However, the engines do not appear to be ready for purchase individually, whether through Avadi's website, or any other retail platform. Rather, when you click the "Order" tab on the Avadi site, it directs you to a contact page which essentially tells you that the engines are not-yet available for customers. The Contact page also recommends that you reach out to the Avadi team, telling them what you intend to use the engine for and what power needs are required, so they can develop a list of options available to prospective customers.
That may be a hoop many aren't interested in jumping through without the guarantee of actually purchasing an engine from Avadi. Perhaps more problematic for some potential buyers is that the cost of an MA-250 is not listed anywhere on Avadi's site, with prices potentially varying depending on a consumer's individual needs. Despite the fact that the Avadi MA-250 does not appear to be customer-ready, it still appears to be an innovative, eco-friendly engine with intriguing potential.
Even as companies continue to develop renewable energy sources designed to reduce the world's reliance on fossil fuels, we are likely still decades away from phasing out the internal combustion engine (ICE), and in some parts of the world, ICEs may never completely disappear. As such, some engine designers are seeking instead to build ICEs that are lighter and more fuel-efficient than those from generations past.
One of those outfits is Avadi Engines Inc. based in Yakima, Washington. Avadi has developed an innovative single-piston, 4-stroke engine that it claims ranks among the lightest and most fuel-efficient in the world. It's called the MA-250, and it's capable of producing an impressive 15.8 horsepower at 3700 rpm and 22.3 lb-ft of torque at 3500 rpm. While not yet powerful enough for full-size cars and trucks, such output should make the MA-250 an intriguing option for anyone looking for a fuel-efficient ICE to power smaller vehicles and machinery.
As it happens, getting your hands on an MA-250 could be tricky, as Avadi is still in the early stages of production and has not yet made the engine available on the consumer market. In fact, as of this writing, the company is asking that you contact them directly with the specs and scope of your power needs to determine if an MA-250 is a good fit. But if you're interested in eventually getting your hands on one anyway, here are a few practical applications for the MA-250, according to the Avadi team.
Over the last couple of decades, many automakers have turned to hybrid and electric cars, trucks, and SUVs to sway consumers away from vehicles that run exclusively on internal combustion engines. While great strides have been made in the hybrid and plug-in hybrid market, these vehicles still require a secondary onboard power source to generate enough energy to run the vehicle's drive motor and help serve any internal power needs. To achieve this, an ICE is often the go-to secondary power generator.
The problem with that solution is, of course, that ICEs operate by burning fossil fuels, thus negating, in part, the goal of eco-friendly vehicles. While hybrids help limit harmful emissions generated by ICEs, some consumers may still be annoyed at the vehicle's emissions footprint. As Avadi's MA-250 is a fossil-fuel burning ICE itself, the engine will not solve this problem entirely. But according to Avadi, the engine's lightweight build and innovative design make it far more fuel-efficient than a traditional ICE, which should greatly reduce the amount of harmful emissions produced.
Per Avadi's claims, their engine should also be scalable enough to potentially one day power a car, truck, or SUV. But even if the MA-250 is not quite at that stage of development, the current build could still prove a significant upgrade as a secondary power source for hybrids and plug-in hybrids.
While Avadi's MA-250 may not be ready to power a full-size automobile, the tiny engine should be more than capable of helping smaller vehicles rev up and hit the road. For instance, the MA-250's power output could easily power some two- and three-wheel motorcycles as well as many of the various mopeds currently available on the consumer market.
To be clear, the MA-250 will not generate anywhere near the powerful output of an engine like Harley-Davidson's famed Screamin' Eagle or its various Milwaukee-Eight builds. So, if you're on the hunt for an engine that'll get your Harley or street-racer cruising down the freeway in a flash, Avadi's engine will likely not suffice. But for smaller bikes and mopeds primarily used for kicking around the city at a comfortable pace, an MA-250 could very well do the job while also limiting the air pollutants created by traditional ICEs.
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