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Marmon-Herrington's infinitely variable transmission (iVT) combines the benefits of hydrostatic and automatic transmission in a single unit.

Marmon-Herrington launches infinitely variable transmission, variable power divider at ConExpo

Marmon-Herrington introduced at ConExpo 2017 its infinitely variable transmission (iVT) and variable power divider (VPD) technologies, both part of the company’s HydroMech family of products for Class 6 through 8 trucks. The company’s new HydroMechiVT hydro-mechanical transmission maximizes the advantages of both hydrostatic and mechanical transmission technologies, while its new HydroMechVPD eliminates the need for an auxiliary diesel engine in applications where a second power source has traditionally been required.

By combining the benefits of low-speed hydrostatic drive and high-speed mechanical drive, Marmon-Herrington’s iVT is expected to provide fleets a reduction in operating costs, maintenance, fuel consumption, and greenhouse gas (GHG) emissions, as well as associated driver benefits.

“The HydroMechiVT is specifically designed for applications where performance is limited by torque converter waste and inefficiency,” said Rick Blair, president of Marmon-Herrington’s OEM division. “Market-specific application of this technology will provide fleets a significant reduction in operating costs such as brake wear and maintenance.”

“Our hydro-mechanical iVT offers meaningful drivetrain efficiency improvements, most notably in start-stop applications,” says Nathan Webster, Marmon-Herrington engineering manager. “When applied to the duty cycle for a standard New York City garbage truck, calculated efficiency improvements of 11% have been identified with improvements of over 15% in other cities.”

Marmon-Herrington says it is working with key customers within the agriculture, refuse, and defense industries for development and testing. Thousands of test hours have been successfully completed on multiple vehicles with the goal to begin iVT production as early as 2018.

By dividing the truck’s diesel engine into propulsion power and auxiliary power, the Marmon-Herrington VPD is said to reduce operating costs, maintenance, and GHG emissions for fleet managers while providing driver-friendly benefits to equipment operators.

“A hydrostatic variator is fundamental to this patented technology,” said Webster. “Because the VPD allows the engine and auxiliary device to run independently of each other, customers benefit immensely from the elimination of the second engine. The VPD is capable of running the auxiliary device up to and above full engine rpm while also allowing the driver to vary the vehicle speed as normal. This saves time, money, and complexity.”

“The HydroMechVPD is specifically designed as a single-engine solution to save fleets money and simplify operation,” said Blair. “We expect customers to see additional benefits through reduced weight and improved packaging.”

The company is currently focusing on key opportunities within aircraft rescue & firefighting, street sweeping, agriculture, defense, and other markets that can benefit from this technology.

The VPD is produced in Louisville, KY, at Marmon-Herrington’s Magisterial Drive location, which is where the iVT will be produced.

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