Focus on Future Vehicles


Global vehicle population is growing at a faster rate than world population, from about 720 million units today to a little over 1.1 billion vehicles projected in 2020, according to Edward P. Becker of General Motors Powertrain Division. And while internal combustion engines that use conventional fuels and lubricants won’t disappear overnight, drivers are seeing a greater array of propulsion technologies to choose from.

In a webinar sponsored last week by the Society of Tribologists and Lubrication Engineers, Becker described the splintering variety of new automotive technologies as well as their benefits and issues. He noted that growth in vehicle population is greatest in developing countries, while developed countries like the United States and Japan are in “replacement” mode for their fleets.

Since 1980, he pointed out, engine designers have managed to deliver greatly increased horsepower while engine size has remained about the same. This means that engine efficiency as measured by the ratio of horsepower to displacement (HP/cubic inch) has steadily increased. In 1975, typical output was about 0.5 HP/ of displacement. As of 2005, this had passed 1 HP/ and new engines currently get about 1.15 HP/

Many innovations in engine and vehicle drivetrain design have occurred over the last 20 to 30 years, continued Becker, who is a mechanical engineer and also past president of STLE. However, the impact of innovations usually is not felt for about 15 to 20 years. “There’s a very consistent time lag between when a technology is introduced and when it reaches its maximum penetration in the market,” he said.

For example, American-made front-wheel-drive vehicles debuted around 1980, but after five years only 20 percent of vehicles sold were front-wheel drive. It wasn’t until about 1995 that market penetration reached more than 80 percent of production. Today, primarily SUVs and pickup trucks still retain rear-wheel-drive powertrains.

Variable valve timing, port fuel injection and multi-valve engine designs are further examples of technologies that gradually penetrated the marketplace, Becker said. New technologies being studied include more advances in variable valve timing (including lift and duration), cylinder deactivation, direct gasoline injection, six- and seven-speed automatic transmissions, continously variable transmissions and hybrid engines.

“The technology that’s been getting an awful lot of press is the hybrid powertrain,” Becker continued. “This is a combination of an internal combustion engine, either gasoline or diesel, with an electric motor.”

He explained that GM chose to focus on larger hybrid vehicles such as SUVs and pickups as opposed to the small-vehicle mix targeted by other automakers, because SUVs offer greater potential fuel savings than small passenger cars. At the upper end, GM’s Allison Transmission segment has developed a hybrid bus for commercial use, and has more than 600 of these in service worldwide. These 600 buses save as much fuel as 34,000 passenger car hybrids, Becker stated.

All-electric vehicles also have a great future, he went on. The newest electric vehicles such as the Nissan Leaf can go about 100 miles on a four-to-six-hour battery re-charge. For many applications, that is adequate for daily use since most commutes are less than 20 miles each way. Consumers are used to the 350 to 450 mile range of most internal combustion engines, however, so they want the same range from electrics. All-electric vehicles cannot deliver such distances at present, Becker said, and some breakthrough in battery technology will be needed to achieve this goal.

General Motors’s own entry in this field is the 2011 Chevrolet Volt, an electric car with a gasoline engine recharging system. The Volt can go about 40 miles on its fully charged battery alone, Becker pointed out. When the battery charge drops to a low level, the engine engages and runs a generator to recharge the battery. Starting with a full battery and full fuel tank, the Volt has a range of about 360 miles — equivalent to most of today’s vehicles.

Alternative-fuel or flex-fuel vehicles are also needed, he said. Flex-fuel vehicles can use gasoline/ethanol blends up to 85 percent ethanol, well beyond the 10 percent ethanol blends currently used. Other alternatives are compressed natural gas or liquefied natural gas.

The ultimate alternative fuel is hydrogen, which is not as dangerous as many believe, Becker said. Being a gas, hydrogen burns upward not outward as does gasoline or other liquid fuels. However, the spectacular Hindenburg disaster of 1937 continues to cloud hydrogen’s prospects.

Hydrogen fueled engines would be essentially emissions free, Becker said, and a great addition to the automotive product mix. He pointed out that former California governor Arnold Schwarzenegger had his own Hummer converted to hydrogen power, which shows it is possible to build the vehicles.

The biggest drawback is the lack of a distribution system to supply hydrogen to the driving public. Given the rule of thumb that it takes 20 years to fully incorporate new technology, we might expect to see hydrogen fueled vehicles on the road in quantity by 2030, Becker added.

A better use for hydrogen may be in fuel cells, he said. “What the GM engineers did is they asked themselves the question, ‘If we were designing a hydrogen fuel celled vehicle from the ground up and we didn’t have 100 years of vehicle design behind us, what would it look like?'” The answer was GM’s Autonomy concept car, powered by a hydrogen fuel cell and having a projected range of 300 miles using about 5 kg of hydrogen. The Autonomy is several years away from production, but a working model has been developed and is being tested, Becker added.

On the subject of lubricants for vehicles, he foresaw little change ahead for internal combustion engine oils. Fuel economy, durability and improved emissions performance will continue to drive engine oil development and standards. Ethanol could have an impact, but only if blend levels in gasoline increase substantially. Older engines in particular could feel this impact.

Automatic transmission fluids will continue to evolve, with the emphasis on newer transmission designs and as a lubricant for the electric motors, said Becker. Chassis lubrication will remain the same.

In the end the question was raised as to which one of the future propulsion systems will be successful. Becker’s answer was succinct and clear: Economics and availability will determine the winner.

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