fbpx

Toyota developing free-piston engine linear generator for electric drive vehicles

linear generator

A team at Toyota Central R&D Labs is developing a prototype Free Piston Engine Linear Generator (FPEG), which they described at the recent SAE 2014 World Congress in Detroit.

Unlike a traditional ICE, which propels a drive shaft, the FPEG is designed to generate electricity directly. It consists of a two-stroke combustion chamber, a linear generator and a gas spring chamber. The piston is moved by the combustion gas, while magnets attached to the piston move within a linear coil, converting kinetic energy to electrical energy.

The Toyota FPEG is based on a double piston system – at one end is the combustion chamber, and at the other, an adjustable gas spring chamber, which is responsible for returning the piston for the subsequent combustion event.

A portion of the kinetic energy of the piston is stored in the gas spring, and extracted on the return stroke to the combustion chamber side. A magnetic “mover” is mounted at the outer periphery of the piston. The linear generator is a permanently excited synchronous machine consisting of the stationary coil, the mover (based on neodymium-iron-boron magnets) attached to the piston, and iron-core stator. The power electronics drive the machine as both a motor and a generator.

Video: View an animation of Toyota’s FPEG here >

The researchers achieved output power of 10 kW with 42% thermal efficiency. Toyota envisions that a pair of such units (20 kW) would enable B/C-segment electric drive vehicles to cruise at 75 mph. The prototype achieved stable operation for more than 4 hours without any cooling and lubricating problems.

 

Source: Toyota Central R&D Labs via Green Car Congress

Comments
Create Account. Already Registered? Log In

EV Engineering Webinars

The free webinar sessions from our Spring 2022 Virtual Conference are now available to view on-demand. Register for a session below to watch the recording and download the presentation.

LOAD MORE SESSIONS