United Parcel Service (UPS) has begun converting 50 of its gasoline-engine delivery trucks in the Chicago-metro area to hydraulic-hybrid propulsion. The first converted vehicles recently entered service equipped with Lightning Hybrids’ hydraulic hybrid system featuring an energy recovery system (ERS).

A hybrid hydraulic vehicle blends two propulsion systems to provide benefits including improved fuel economy and emissions reductions. According to UPS, the standard-gasoline-fueled ICEs are combined with Lightning Hybrids’ ERS, a system designed for medium- and heavy-duty vehicles with a front-engine/rear-drive layout, therefore suitable for this subset of the UPS fleet.

The hybrid systems are converting the 50 Freightliner MT-55s into cleaner and more fuel-efficient units, claims Lightning Hybrids. According to the company, the hybrid systems provide additional torque and reduce internal engine stress, which subsequently allows UPS to use less-expensive gasoline engines rather than diesels, substantially reducing NOx emissions in the process.

The Lightning Hybrids' patented, parallel hydraulic-hybrid arrangement has no electric batteries. Hydraulic pumps and a lightweight accumulator perform much of the vehicle's braking function, store braking energy and then deploy the stored energy to provide power to the wheels. In doing so, fuel is saved and harmful emissions are reduced, the company claims. (See SAE Standard J2898 Hydraulic Hybrid - http://standards.sae.org/j2898_201211/ for information on industry standard terms, definitions, abbreviations, and acronyms to enable common terminology for diagnostic tools and publications.)

“We are pleased that our hydraulic hybrid is part of UPS’s ‘Rolling Laboratory,’ which represents world-class sustainable vehicle technologies,” said Tim Reeser, CEO of Lightning Hybrids. “We will show such a compelling ROI from these systems that we expect UPS to adopt our product on a worldwide scale. This order, along with other larger customer orders, has allowed us to reduce our price substantially, further improving ROI, making it viable even in cases without government subsidies. It is exciting to be part of their efforts to serve their customers with vehicles that support clean air in urban communities.”

UPS first trialed the Lightning Hybrids product with a six-month pilot in 2014 that demonstrated 100% hybrid-system uptime, the company claimed. Additional trials then occurred, including a trial in the U.K. that remains underway. Fuel efficiency gains ranged from 18-34% during the pilot program, the company reported.

The benefit of hydraulic hybrid technology has been well-established for vehicles in specific duty cycles and has been deployed in various demonstration fleets. For certain duty cycles, hydraulic-hybrid designs have proven significant advantage over battery-electric hybrids. (See http://articles.sae.org/9333/ and http://articles.sae.org/2329/.) Supplier Eaton was one of the original developers and promoters.

The UPS and Lightning Hybrids program is partially funded by Drive Clean Chicago, which aims to accelerate the adoption of alternative fuel vehicles and infrastructure in the city.