Nearly every vehicle maker is working to meet increasingly tough global emission-reduction requirements by developing electric powertrains. Yet electrification is costly. And those big battery packs are heavy, which hurts performance and cargo capacity.
Garrett Motion Inc., a pioneer in turbocharging, thinks it has a solution for many applications. It’s one that won’t break the bank or the scales and can keep internal combustion engines in the game.
The company has developed a lightweight, compact electric turbocharger, called eBoost, for gas, diesel and natural gas hybrid powertrains. Garrett also has scaled it to work as a lightweight but powerful compressor for fuel cell electric powertrains.
Market potential for both systems is significant, said Sam Abuelsamid, advanced propulsion systems analyst at Navigant Research.
“There’s definitely a market for e-boosters” as emissions rules across the globe get more restrictive, Abuelsamid told Trucks.com.
The fuel cell vehicle market is developing at a slower pace, but China “is pushing it hard,” he said.
Garrett’s electric compressor has a big advantage. It is “significantly smaller, lighter and quieter than the compressors used on prior generations of fuel cells,” Abuelsamid said.
HOW IT WORKS
A turbocharger’s job is to compress air. The compressed air mixes with fuel to improve fuel combustion. That in turn provides cleaner exhaust and a more powerful explosion in the cylinders.
Turbos also help improve efficiency because they are powered by exhaust gas produced after fuel is burned. And they don’t siphon engine power like mechanically driven superchargers do.
Their downside is so-called turbo lag. It takes from a fraction of a second to several seconds for the exhaust gas to spin a turbocharger’s impeller to full speed.
Electric turbos cure that lag. They are initially driven by a small electric motor that gets them working in a fraction of the time exhaust gas takes.
Garrett isn’t the only e-turbo producer. But its version places the electric motor inside the turbo casing. The company claims creates a smaller, lighter and less complex package.
The company’s fuel cell compressor is used in a system that doesn’t have tailpipe emissions, so an electric motor supplies all the power. The compressed air flows into the vehicle’s fuel cell stack. That’s where it combines with hydrogen to produce electricity. It also helps cool the system.
The first production version of Garrett’s eBoost system will launch in 2021 on a major-brand passenger vehicle. SUVs, pickups and commercial trucks will follow, Rob Cadle, Garrett’s director of innovation, told Trucks.com. He didn’t disclose the manufacturer.
It uses a small electric motor mounted inside the turbo housing to almost instantaneously spin the compressor to operating speed. When exhaust gas pressure is sufficient to drive the compressor, the turbo stops using power from the electric motor.
When not driving the turbo, the electric motor is used as a generator to produce energy that’s stored in the hybrid’s battery. That allows the vehicle to operate with electric power assistance more often.
An added benefit of turbochargers is that they reduce engine back-pressure by diverting waste exhaust gas. That can allow for more efficient fuel combustion and a cleaner exhaust stream under most load and operating conditions.
Because its electric motor goes to work immediately, Garrett’s system works even at idle, making it particularly beneficial in reducing diesel emissions, Cadle said.
Garrett also is testing the eBoost turbo system in a number of heavier applications, including a Class 8 truck.
FUEL CELLS, TOO
The company sees a huge potential for its fuel cell compressor in China. It is also working with North American and European clients, Cadle said.
The compressor is essentially an oversized turbocharger run by its internally mounted electric motor. It was developed for fuel cell electric passenger vehicles but also has applications in fuel-cell powered transit buses and commercial trucks, he said.
Fuel cells produce electricity by passing hydrogen and oxygen through a catalyst, peeling off the electrons in each atom. The compressed air that provides the necessary oxygen also helps cool things down. Power from the fuel cell runs the vehicle’s electric motor.
Garrett’s compact design makes its compressor easier to fit into vehicles, Cadle said.
COMMERCIAL TRUCKING BONUS
The compressor’s light weight is a bonus for commercial trucking. There, every pound lost from the powertrain can translate to an extra pound of revenue-producing cargo capacity.
Production versions of Garrett’s fuel cell compressor will lighten a typical fuel cell system by more than 30 pounds, the company said. The compressor takes up less than one cubic foot of space.
Numerous truck and engine developers including Toyota Motor Co. are experimenting with fuel cell powertrains. But only one has set a firm date for launching widespread retail sales. Arizona-based Nikola Motor says it will bring Class 8 fuel cell trucks to market by 2022.
In China, however, fuel cells already are running a large number of trucks and transit buses.
“We don’t see much about it in our news here in the U.S., but China is really pushing,” Cadle said.
Cadle saw an area that held “at least 500 fuel cell trucks, lined up and ready to go” while visiting a client there last year. That represented just one company in just one region of China. That compares with just a handful of experimental fuel trucks across the entire U.S.