Tenneco Pursues Waste Heat Recovery for Trucks

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Transport Topics  /  September 24, 2017

ATLANTA — Vehicle supplier Tenneco Inc. wants to help bring waste heat recovery systems to heavy-duty trucking even though it is not an immediate possibility.

Organic Rankine cycle technology is not new, said Tenneco Chief Technology Officer Ben Patel, but putting one under the crowded hood of a Class 8 tractor is an elusive engineering challenge.

“No one uses it now,” Patel said of a Rankine system. “It’s complicated. People are pulling their hair out over this. So we’re trying to find a way to use this that’s not a terror,” he said.

The Lake Forest, Ill.-based corporation works mainly in emissions controls and thermal management but is also a major supplier of shock absorbers. Its presentation came at a Sept. 24 press conference here at the North American Commercial Vehicle Show.

Waste heat recovery captures the unused power of diesel combustion to boil a fluid, probably an ethanol-water mix. The hot gas would then power a turbine for propulsion power and the spent gas gets compressed back into a liquid for another round.

While better engine efficiency is most helpful in cutting emissions of carbon dioxide, a greenhouse gas, it is also linked to technology for reducing nitrogen oxides.

Patel said heat is “the friend” of emission-control systems. Burning hot improves fuel efficiency and reducing CO2. It also helps minimize soot, or particulate matter. But burning hot also generates a lot of NOx.

Therefore, Patel said, the ideal emission system for a truck would combine high-efficiency selective catalytic reduction aftertreatment — for cutting NOx — with a fiery hot engine that is both efficient and a low-level producer of particulate matter.

One avenue for improvement, he said, would be better dosing of the exhaust with diesel exhaust fluid, or DEF.

Such a truck engine has been a goal of the California Air Resources Board. Patel said Tenneco has been working with CARB on trying to develop a system that can meet California’s NOx goal of 0.02 gram per brake horsepower-hour — a 90% reduction from the current standard of 0.2 gram, which has been in place since January 2010.

As for a timeline, Patel said most new U.S. heavy-duty engines are 50% efficient as measured by brake thermal efficiency. He said the target of 55% might be achievable around 2022-2025, and that waste heat recovery with Rankine cycle technology could play a role.

“When there is a market for this, Tenneco will be ready,” he said.

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Tenneco Highlights Waste-Heat Recovery, Ride-Improvement Solutions

Heavy Duty Trucking (HDT)  /  September 24, 2017

ATLANTA. Tenneco Inc. showed off its latest array of emssions-related and ride-performance products at a press conference held here on Sept. 24, ahead of the North American Commercial Vehicle Show.

“Tenneco is pleased to showcase its global expertise in complete design, engineering and systems integration for the commercial vehicle market,” said Ben Patel, vice president and chief technology officer, He explained that the company’s global range of commercial-vehicle “clean air solutions reduce emissions, contribute to improved fuel economy, and enhance vehicle performance” while its ride-related products range from coil and air spring dampers for cabs, rear axles and seat dampers to lightweight torque rods and elastomer suspension bushings.

According to Patel, the concept box is part of Tenneco’s focus on developing waste-heat recovery systems for commercial vehicles. He explained that waste-heat recovery helps speed up chemical reactions and that allows captured and stored heat from a vehicle to be leveraged to enhance engine operating efficiency.

At NACV, Tenneco is also showcasing the newest member of its XNOx Liquid Urea Selective Catalytic Reduction product family-- an integrated dosing-control unit concept that integrates the pump, motor, injector, controller, sensors, water cooling, and control software in a single device.

Patel said that the company’s current production XNOx urea-dosing system, first introduced in 2011, now offers “expanded thermal range,” which means the system can be placed closer to the turbocharger without compromising dosing quality and performance. “The return flow design provides superior thermal tolerance without added complexity.”

He said other enhancements include an optional controller that features a flexible engine interface design and can predict engine-out NOx and account for ammonia storage and catalyst degradation.

Moving onto thermal management solutions, Patel said that as efficiency improvements and new low-NOx standards continue to drive the need for ultra-high efficiency SCR, Tenneco’s cold start thermal unit offers “an optimal solution that provides active heat management for rapid catalyst light-off and efficient NOx conversion through the full range of operating conditions.”

He added that Tenneco is also showing off its latest family of mixing solutions designed to efficiently process injected DEF into gaseous ammonia without the formation of undesired deposits, even at low engine loads, which helps meet NOx efficiency requirements for low or non-EGR calibrations as well as emission targets under “real field” operations. 

As for the ride-improvement side of its business, Patel noted that the company’s 45mm axle dampers, used primarily as rear axle dampers for vehicles with GGVWs above 15 tons and on trailers, boast a new valve system that provides “increased tune-ability and allows higher compression damping force while maintaining the lifetime performance typical of Tenneco dampers.”

He also pointed out that new designs of Tenneco’s Clevite Elastomers spring eye bushings, which “serve as key pivots in vehicles with leaf-spring suspensions, that reduce mass while improving bushing function and fatigue life are currently undergoing validation. These designs pair a high radial and conical spring rate with low torsional breakaway to produce pivots ideally “ideally suited for optimal suspension performance.”

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