ERC Researchers Help Bring Novel Hydraulic-Hybrid Technology to Market

Achievement date: 

Researchers affiliated with the Center for Compact and Efficient Fluid Power (CCEFP), an NSF-funded Engineering Research Center (ERC) headquartered at the University of Minnesota, developed a novel and efficient hybrid system for commercial vehicles. Unlike most current hybrid systems, which are electric, this research produced a hybrid hydraulic system featuring a hydro-mechanical transmission (HMT). The results of this development have now been commercialized by the company that funded the research.


The largest potential benefit for a hybrid system is in the commercial vehicle market  due to the higher weight of those vehicles, their lower fuel economy, and more severe usage (e.g., higher miles/year, stop-and-go driving). The ERC's hydraulic-hybrid technology is initially targeted at medium-duty package delivery vehicles like those used by UPS. In that type of vehicle the hybrid HMT provides more than 50% better fuel economy. Significant fuel savings from the hybrid HMT, coupled with broad market acceptance, can help lower U.S. dependence on foreign oil and reduce greenhouse gas emissions.

Recognizing the advantages of the hybrid approach, Parker Hannifin created a new division, Hybrid Drive Systems (HDS), located in Columbus, Ohio, to design and manufacture hydraulic-hybrid systems. (See accompanying figure.) HDS currently employs about 80 people, including more than a dozen former CCEFP students.


Millions of hydraulic transmissions are working around the world today in demanding duty cycles, such as agriculture, construction, forestry, and mining. Hydraulic transmissions are robust, offer continuously variable transmission functionality, and can deliver high amounts of power in a relatively small package. The hybrid HMT, which has two paths for energy to be transferred through the transmission, leverages the proven strengths of hydraulic transmissions and brings the technology into the 21st century. Research leading to the hybrid HMT was led by Professor Monika Ivantysynova (Purdue University) and funded by Parker Hannifin Corporation.

The vast majority of hybrid vehicles sold today are in the passenger vehicle market. The challenge has been that savings created by hybrid-electric systems (less fuel used), when compared with the costs of such systems, provide a payback period too long for most companies to consider. In contrast, the hybrid HMT offers a reduced payback period that is broadly acceptable to users of commercial vehicles.

In summary, this novel technology was created in the United States, systems using it are being built here, and it is creating a new market segment for hydraulics. The end result leads to good paying U.S. jobs in addition to the operational benefits described. CCEFP is proud to work with visionary companies like Parker Hannifin to help create innovative products.