Small engines that are used to run leaf blowers, lawn mowers and even smaller industrial equipment are known for being very loud and not very powerful.
But a company in Connecticut is developing a new type of tiny engine that is very quiet, very powerful, and has only two primary moving parts.
Nicknamed the “X Mini”, the 70 cc engine sounds like something out of science fiction. But for the developers at LiquidPiston who are testing a prototype of the engine at its Bloomfield, Connecticut, headquarters, this tiny new engine could actually change the way small engines are used in the future.
The Little Engine that Could … Change Everything
The X Mini is a rotary engine, meaning it has no pistons. But what it does have is a lot of punch: five horsepower and an astonishing 15,000 RPM. Yet it’s 30% smaller and lighter than the smallest piston engine in use today.
The engine can on either gasoline or diesel. Because it’s designed for small engine applications such as landscaping equipment, under its current design it runs on a mixture of gasoline and oil, the same mixture that’s currently used in most motorized lawn equipment that provides lubrication and power simultaneously.
The concept of the X Mini may seem familiar. Remember those old television commercials for Mazda cars that said, “Mazda engine goes Hmmm”? Those were Wankel engines that powered Mazda’s RX series of sports cars.
Like the Wankel, the X Mini has just two moving parts: A rotor and a shaft that transfers power from the engine. Because there are so few moving parts, the engine can be smaller, lighter and more reliable than a traditional piston-fired motor.
It also has much less vibration, which minimizes the amount of noise it creates. And anybody who has ever used a leaf blower or weed whacker can tell you what an advantage that is.
A Lesson in Mechanics
So how is the X Mini different? Here’s a video that explains how:
In a conventional four-stroke reciprocating piston motor, a piston moves up and down within a cylinder. This movement is caused by airand fuel drawn in with a downstroke and compressed in an upstroke. As the mixture is detonated, the piston reaches the top of the cylinder. This explosion forces the piston down, providing power . Exhaust gasses are then purged on the following upstroke and the whole process is repeated.
The X Mini doesn’t have a piston. Intead, it has a rotor that looks like a rounded triangle. This is a shape known as an epitrochoid.
This rotor rotates in an eccentric orbit within an oval chamber. Each rotation results in three power “strokes”. This type of motor has a much higher power to weight ration. It’s also lighter and much simpler than a traditional piston motor.
To keep weight down even lower, the X Mini is composed of 95% aluminum. Plus it uses a pair of counter-balancers to minimize vibration.
While right now, it is intended to be used to make landscaping equipment that is quieter yet more powerful, other applications could include powering drones, scooters and even industrial equipment.