Chevy ZH2 – The Element of Surprise

Meet the Hydrogen-Powered Chevy ZH2. One-off Prototype or Prelude to the Future of Transportation?

Photos by Robert McGaffin

When it comes to describing the Chevy ZH2, we hesitate to label it with the term “concept.” Most vehicles bearing that moniker never seem to get beyond being displayed on a carousel at auto shows with sultry-voiced booth babes telling everyone it’s the next generation of automotive engineering or something else grandiose.

After all, even though we’ve seen several concept versions, we’re still waiting for the El Camino’s comeback so we can relive our high school days in full midlife crisis mode.

In the case of the Chevy Colorado-based ZH2, there’s no bait and switch. We’ve seen it, we’ve heard it (after listening very carefully), and believe it’s a sign of things to come. It’s easy to be skeptical whenever advancements this drastic go from drawing board to testing environments, which led us to question how this idea was hatched.

Development
We discovered that GM already has more than a decade of experience collaborating on fuel-cell research demonstration programs with the U.S. Army Tank Automotive Research, Development and Engineering Center (TARDEC) — an organization focused on ground-vehicle applications for the U.S. Army. Now that TARDEC has committed to putting the ZH2 through a year of extreme field testing, there’s far too much at stake for shortcuts. Yes, you read that correctly. We may see ZH2’s on the battlefield one day.

Believe it or not, hydrogen fuel-cell technology has been around for quite a while. Introduced in 1966, the Electrovan was the first fuel-cell vehicle ever, also developed by GM. It didn’t end up being practical for mass production at the time, but after a gap of roughly 25 to 30 years things really got serious again.

In 2007, a fleet of more than 100 hydrogen fuel-cell Chevy Equinoxes were created and given to various user groups to test the technology in real-world situations with real-world drivers. Although the program ended in 2010, a few of them are still on the road and some ran for more than 140,000 miles.

“The fleet amassed over 3 million miles and that’s what gave the confidence for GM and the Army to see that it’s suitable for further evaluations. The natural progression was to see where the technology could take us with an off-road vehicle,” says Chris Colquitt, senior engineering manager for the ZH2. “TARDEC was looking to test the vehicle in a capable off-road package to see the suitability of the technology to put into future vehicle platforms.”

So why would anyone want a hydrogen-powered vehicle and why aren’t they already on the streets? “We haven’t come to market with a fuel-cell vehicle yet because you have a little bit of a chicken and egg situation over infrastructure right now in terms of where to get hydrogen to fuel the vehicle,” says Alan Adler, Manager, Advanced Technology Communications for GM. “Some of our competitors have also dipped their toe into that water, but it’s very low production at this point. The infrastructure piece is huge, has to get solved, and has to be done in conjunction with demand.”

“To do the nation you’d need about the same number of outlets that you’d need to for electric vehicles,” says Adler. “Each of these stations today is about $2 million, so that’s a pretty big undertaking. What you’ll probably see is what’s happening in California where you have certain regions that will have hydrogen infrastructure, and so the vehicles, at least initially, will largely be sold in those areas. Right now it’s California, maybe next it’s the northeast, but it’s not likely to become as ubiquitous as a gas station anytime soon.”

Practicality
The sheer mention of something hydrogen powered being used in combat applications probably brought images of an infamous fiery zeppelin to many readers’ minds. While the exact cause of the Hindenburg explosion has been debated ad nauseam, GM believes hydrogen fuel-cell vehicles are as safe as conventional vehicles.

“It has a number of inherent safety advantages, including being lighter than air, which results in it dissipating upward very quickly,” says Adler. “Fuel-cell vehicles use multiple safety systems to minimize the consequences of vehicular collisions. We have conducted extreme abuse testing of hydrogen canisters. It took a .50-caliber bullet to puncture the canister. Escaping hydrogen shot upward at about 45 mph and, as the lightest element known, was inflammable at that point.”

So what are the other benefits of using hydrogen power? First off, efficiency. “A fuel cell is about twice as efficient as a combustion engine. For every gallon equivalent of hydrogen you put in your fuel-cell vehicle’s tank, you’d end up going twice as far on that gallon,” Colquitt says.

The ZH2 also has an exportable power source in the trunk, which can take the DC fuel-cell power and convert it over to 240- and 120-volt AC power. The unit can be used as a mobile generator to make 25 to 50 kilowatts of exportable electricity. This can be used to power any equipment that might be needed out in the field. The vehicle’s low heat signature is another advantage for military applications. A lot more of the energy in the fuel is converted into useful energy as opposed to wasted inefficiencies of friction and heat losses that combustion engines produce.

In terms of noise, the ZH2 is on par with a hybrid, so the reduced sound output is also beneficial for field use and something that conventional vehicles can’t offer.

Function
So how does it differ from a conventional combustion vehicle? The ZH2 utilizes the same Gen 0 fuel-cell system as the aforementioned Equinox fleet. Unlike a traditional engine, it has no cylinders and displacement/power isn’t measured in cubic inches or centimeters. It’s measured in terms of kilowatt output, and the ZH2’s power system is rated at 93 kilowatts of DC power. An onboard hybrid battery provides an additional 35 kilowatts.

Although it looks like an octopus eating an air conditioner, this is what the fuel cell looks like. It’s come a long way from GM’s Electrovan developed in the ’60s. Makes us wonder if technical schools will begin offering hydrogen engineering courses as part of the curriculum.

The fuel cell is a box about the size of a suitcase under the hood of a ZH2. If you were to cut the fuel-cell stack in half, you’d see a stack of plates and membranes. By flowing the hydrogen across one side of the membrane and air across the other, you’re converting hydrogen into electricity and that’s what powers everything in the vehicle. Think of it like a hydrogen-fed battery.

The three-phase AC electric motor takes the DC fuel-cell power and inverts it to AC power. A single planetary gearset takes 236 lb-ft of torque and multiplies that up over five times through a spline going directly into the transfer case. Starting with the transfer case, all other ancillary components come from the Chevy Colorado ZR2, giving it a full complement of four-wheel-drive options. It was given an in-between wheelbase from the two Colorado variants and the cab was moved back about 4 inches to make room for the bigger tires.

A traditional combustion engine has to get up to a few thousand rpm to see the peak power output. With an electric-drive device, the highest torque is instantly available at 0 rpm and the torque band remains pretty flat, meaning you have access to that same amount of torque pretty high up to the ZH2’s max speed of approximately 60 mph.

The exportable power unit weighs 200 pounds and can be removed from the truck and used to power auxiliary equipment.

The cab is a four-door crew cab carryover from the ZR2. Body panels are Kevlar-reinforced carbon fiber to keep weight down. Inside, the dash layout is basically the same as a Colorado with Recaro racing seats. While the ZH2 is hovering right about 6,000 pounds, we’re sure refinements will continue be made in the speed-to-weight ratio area.

Onboard, hydrogen is stored in tanks as compressed gas. Combined with oxygen in the outside air, the fuel-cell stack converts hydrogen into the electricity that powers the drive system and your other traditional accessories: water pump, alternator, air conditioner, etc. There are no emissions, except for near-potable water vapor, which can be trapped and stored on the vehicle if need be.

What Does the Future Hold?
“They are capable, ready for prime time, and we’re to the point where there’s not a lot of science left to figure out,” says Adler. “When you think about the abundance of hydrogen around us, which is the most common element in our universe that we know of. When we get to a point where we’re not craving carbon-based fuels, hydrogen will be a major player, but we’re talking decades more for that. The gasoline infrastructure has been around for over 100 years so you’re not going to replace all that tomorrow,” says Adler.

“When you look at hydrogen as an energy carrier, there’s a really diverse number of feedstock you can get hydrogen from,” says Colquitt. “You can get it from any traditional hydrocarbon petroleum product — all the usual suspects we’re used to seeing, such as gasoline, diesel, propane, and natural gas. You can also get hydrogen from any type of renewable electricity.”

“There are so many things you can do with the fuel and technology — sustainability, energy security,” says Colquitt, “but at the end of the day, the fuel-cell vehicles themselves are fun to drive. All that torque, that smooth acceleration, all those capabilities that fuel cells provide, they check a lot of boxes from a regulatory standpoint, and they’re pleasurable vehicles — that’s what can help solidify the enjoyment in people’s minds about what the technology can be.”

While it’s impossible to be clairvoyant, hydrogen power may very well be where transportation is headed. Commercial sale of this technology could happen as early as 2020. GM’s manufacturing joint venture with Honda will begin mass-producing fuel cells around that time. Now if the auto industry can only enlist the help of Dr. Emmett Brown to create time-traveling vehicles that fly and run on empty beer cans, our prayers will truly have been answered.

Chevy ZH2
Engine: Three-phase AC electric motor
Power ouput: 93 kW of DC power w/ auxiliary 35 kW hybrid battery
Exportable power: 25 kW continuous (50 kW peak) w/240V and 120V outlets
Drivetrain: 4WD six-speed automatic
Torque: 236 lb-ft
Horsepower: Approx. 170
Fuel capacity: 4.2 kg at 10,000-psi storage pressure
Range: Approx. 142 miles
Top speed: Approx. 60 mph
Tires: 37-inch BFGoodrich mud terrain tires
Wheels: 17-inch beadlock rims
Height: 79.8 inches
Width: 80.3 inches
Length: 210.5 inches
Curb Mass: 6,038 pounds
Wheelbase: 133.5 inches
Payload capacity: 1,300 pounds
URL: www.gm.com

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