Folsom Introduces Continuous Variable Transmissions for Hybrids

Folsom Technologies recently introduced its newly-developed line of hydromechanical continuously variable transmissions (CVTs), which offer infinite ratio coverage from full reverse through neutral to full forward. Because the CVTs utilize high-efficiency, low-cost hydraulic pumps and motors, they can form the core element of hydraulic hybrid drivetrains. The CVTs are designed to be drop-in alternatives for existing transmissions.

"Combining the known benefits of a continuously variable transmission with hydraulic energy recovery has the potential to maximize vehicle efficiency gains," said President of Folsom Technologies, Lawrence Folsom. "The ability to operate and maintain an engine at its ‘sweet spot' will drastically reduce emissions and CO2."

According to Folsom Technologies, the CVT needs to be paired with a set of accumulators and flow control valves for hydraulic hybrid application. In passenger car applications, the CVTs should enable mild parallel hybrid functions such as regenerative braking, launch assists, acceleration assist, and engine starting for a start-stop function.

The company's 50/100 hp City Car CVT is designed for front wheel-drive passenger vehicles of up to 100 hp. However, it is also suitable for application in small city cars of 50 hp or lower due to its compact size and weight. According to the company, testing of the City Car equipped with its CVT has demonstrated significant economy and performance benefits over the same vehicle fitted with its five-speed manual transmission.

Folsom's 50/100 hp CVT (above) and 350 hp CVT (below). Credit: Folsom Technologies

Also in the newly-developed line is the second-generation of a 350 hp full-size rear-wheel drive passenger vehicle CVT, specifically designed to be integrated into a hydraulic hybrid system. The 350 hp CVT, developed under a co-funding agreement with the New York State Energy Research and Development Authority, was originally designed to suit the Ford Crown Victoria and is planned to be installed as part of a hydraulic hybrid program in a New York City taxi to conduct durability trials.

"Increasing vehicle fuel efficiency and emissions reduction is a high priority, and many technologies are becoming available to facilitate these goals," said Folsom. "Hydraulic braking energy recovery, which is an available feature of our CVT, offers significant gains in fuel economy and reductions in emissions, as well as greatly reduced brake wear. For operating duty cycles that have frequent start/stops, such as taxis, school buses, garbage haulers, etc., the fuel savings can be greater than 50 percent."

Folsom Technologies is located in Castleton, New York. The company describes itself as "an innovative service oriented company, providing specialist solutions to the research, design, engineering and manufacturing community." More information can be found at www.fti-cvt.com.