With the atomic number 1, hydrogen is the lightest element in the Periodic Table. However, its rapidly becoming a heavyweight for the future of mobility. Development of hydrogen fuel cell vehicle (HFCV) and hydrogen-fueled combustion engines for commercial-vehicle use is driving demand for specialized testing and validation facilities. Allison Transmission is in the vanguard of this movement, recently launching a comprehensive hydrogen test capability at its 60,000-ft2 (5574 m2) Vehicle Electrification + Environment Test Center in Indianapolis..
Prior to the official debut, SAE Media was given an exclusive look at the new facility, which also includes compressed natural gas (CNG) testing, courtesy of David Proctor, the facility's general manager, and Tim Szilveszter, Allison’s sales account manager.
“With this facility, we got a head start on the industry from a testing perspective; we’ll be able to capitalize on those gains with this hydrogen capability,” Proctor said. “From conversations with our OEM customers, we got a clear sense that hydrogen was coming, part of the industry’s move to new propulsion and alternative-fuel technologies.” After investigating what it would take to implement, Allison’s leadership green-lighted the investment for hydrogen and CNG testing as a late addition to the construction program.
The hydrogen capability was completed in two phases. The first phase installed the safety systems that are vital to detect and manage hydrogen gas or flames in the test cell, with similar capability for CNG safety. Phase two added a hydrogen delivery system that feeds the gas, at low pressure, from tanker trailers connected outside the facility directly into the fuel cell onboard the test vehicle. This setup enables long-duration test runs with minimal downtime for re-fueling, according to Proctor.
With the addition of hydrogen and CNG test and validation, Allison now is able to support customer programs for vehicles powered by most major propulsion type including battery-electric systems. The Indy facility currently is one of only two in North America that integrate hydrogen testing with chassis dynamometers and full environmental chambers (the other is at Canada’s Emissions Research and Measurement Laboratories in Ottawa). But others are entering the scene. In 2021 Volvo Group broke ground for a new U.S. laboratory complex that will include hydrogen. The Hagerstown, Maryland, facility is scheduled to launch in 2023, supporting Volvo, Mack, and Prevost (bus) development. Automaker Toyota and the U.S. Dept. of Energy are collaborating on hydrogen and fuel cell development and testing in Colorado. Europe’s most modern testbed for fuel cell systems, a joint project by AVL and HyCentA (Hydrogen Center Austria, TU Graz) launched in late 2016.
Ensuring test safety
Earlier this year, Allison completed its first hydrogen vehicle test — a new Class-8 road tractor, as SAE Media has independently confirmed. The test was as much a learning experience for Allison’s cross-functional team of 12 engineers and technicians as it was for their OEM counterparts. Allison had not yet completed installation of the Phase Two hydrogen fueling system, so the customer brought its own fueling equipment. Otherwise, teething glitches were few, Proctor noted. Both customer and Allison deemed the HFCV testing successful overall, with key learnings in fuel-cell heat generation under load and the water-vapor byproduct.
As Szilveszter explained, the facility's two environmental chassis dyno cells (sourced turn-key from AVL) are “fuel agnostic.” One cell has a 72-in-diameter (1829-mm) back roll and a 48-in. (1219-mm) front roll. The front roll can handle 500 kW of power; the rear roll is capable of handling 900 kW. The second cell, configured for the most powerful vehicles, has two 72-in. rolls, capable of handling 900 kW and 1180 kW. The dynos are calibrated to regenerate electric power back into the grid, and their rollers can be moved 330 in. (838 cm) longitudinally in their subfloor saddles to accommodate long vehicle wheelbases, such as those found on hydrogen and battery-electric buses.
“We can test from Class 3 delivery vans to very heavy vehicles,” Szilveszter noted, in a temperature range from -54 deg. F to 125 deg. F (-49 to 52-deg.C), with full simulation of altitudes up to 18,000 ft (5,486 m) and replicating duty cycles necessary for regulatory compliance.
The largest chunk of investment for the Vehicle Electrification + Environmental Test Center’s hydrogen/CNG testing was aimed at ensuring that safety is paramount in all testing related to the gaseous fuels. During SAE Media’s tour, Proctor detailed the integrated technologies that virtually wallpaper the dyno cells, as well as those related to the in-plant fueling system. “We’ve implemented hydrogen-gas detection in case of leak in our chassis test cell, including thermal imaging cameras. Hydrogen burns invisibly,” he explained. “If you have a leak and it ignites, you may not know it.”
The camera array covers the entire vehicle as it sits in the dyno cell. The camera inputs are sent to a sophisticated monitoring system that will trigger an alarm when a leak is detected. The system’s sensing capabilities also detect methane, in the case of a leak during CNG engine testing. A 2,500-CFM exhaust-scavenge system clears the dyno cell air “very quickly” when a trace of gas is detected, Szilveszter said.
“It’s been a little more than what we anticipated when we planned to add the Hydrogen test component, but it’s essential for a safe test environment,” Proctor said.
H2-fueled ICE testing
Allison Transmission is also interested in testing hydrogen-fueled combustion engines, based on discussions with OEM customers. “We’re looking into whether our emissions equipment can support hydrogen-ICE testing,” Proctor said. “The flow rates of a fuel call and ICE are different. Unlike a fuel cell, burning hydrogen in an ICE creates a byproduct. We’re learning more about the consumption of hydrogen; we might have to expand our system to add an accumulating tank for constant flow, to keep up with the demand. But we’re open to testing anything that’s got a hydrogen system on a chassis.”
According to Szilveszter, there is a growing list of OEMs seeking HFCV testing with Allison's full environmental test capabilities. “We’ve prepared our capabilities to be ready for the needs of alternate-fuel testing and emission standards. While the regulatory community is still in the process of determining what the industry’s needs are and the technical reality [for future rulemaking] is, with this new facility Allison is positioned to meet the needs of alternate-fuel development at the chassis level.”Continue reading »