Concordia Journal Home > Archives > March 6, 2008 issue >

Mechanical hybrid engine revving up 

By Dawn Wiseman

Despite all the media hype, hybrid cars like Toyota’s Prius account for only 1.2 per cent of global automobile sales, and that’s a big problem according to Sheldon Williamson. Forget the smaller carbon footprint. In his view, it’s all about resource availability.

“Within 10 years, there will be one billion cars on the road worldwide,” he explained. If more than 98 per cent of those vehicles are still powered solely by internal combustion engines, “there will be no oil for gasoline within 30 years.”

Williamson understands the hybrid’s small market share. “The best we can say about hybrid cars is that they work.” On the plus side, the potential for improvement is tremendous, and this is where his research is focused.

Williamson is a power electronics engineer with a specialty in automotive power systems, electric motor drives, and renewable energy systems. He came to Concordia immediately after finishing his PhD in 2006 because the university “has a rich heritage in power electronics and world-class labs.”

“We can compete with anyone,” he said.

Hybrid vehicles combine two or more energy sources in order to increase efficiency and reduce emissions. Most commercially available hybrids combine mechanical and electrical systems (and are known as HEVs), but there are other options.

Williamson has a graduate student starting in September 2008 who will study a mechanical hybrid vehicle configuration, which involves combining an internal combustion engine with a mechanical flywheel system. This arrangement recovers and stores kinetic energy from a moving vehicle that is otherwise wasted during deceleration and braking.

“This is a very feasible system,” Williamson said. “It has none of the drawbacks of electric hybrids in terms of battery life and battery disposal.”

Still, for the moment, HEVs remain the most cost-effective and efficient option for alternative-energy vehicles. Williamson and colleagues at the Illinois Institute of Technology clearly demonstrated their superiority over fuel cell cars in a detailed fuel cycle efficiency analysis that was named Best Paper of the Year in automotive electronics by the IEEE Vehicular Technology Society in 2006.

His current research involves improving efficiencies of HEV electric drive trains, based on power electronics intensive systems and optimal power sharing algorithms.

Right now, most commercially available HEVs are designed so that the mechanical engine operates at its sweet spot all the time (thereby reducing gas consumption), while the electrical systems function well below their maximum efficiency.

“I believe the key to improvement is fundamentally a power electronics and control systems issue,” Williamson said. “So we are looking at smarter algorithms and power electronic intensive systems to more effectively manage charge and discharge cycles in batteries, as well as better power converter design.”

He and the other members of the power electronics team in Electrical and Computer Engin-eering are also starting to look at the potential of plug-in hybrid electric vehicles (PHEVs).

Owners would literally plug these vehicles into a wall socket each night and wake up to a fully charged car each morning. By eliminating the need for battery charging from the cars’ mechanical systems, these vehicles would use less fuel directly.

“PHEVs are a good option in Quebec, where our electricity is generated by hydro and is largely emission-free. Unfortunately, hydro is location-specific, and most places generate electricity by burning carbon-based fuels or crops,” Williamson explained.

The team has recently linked with the Canadian Solar Build-ings Research Network (led by Concordia’s Andreas Athienitis) to study the improvement of photovoltaic cells that harvest solar energy.

“Ultimately, we’re looking at using all-electric vehicles, which can be plugged into home-based solar charging stations, but that’s a long way off.”

In the meantime, “There are lots of exciting avenues to explore and numerous opportunities for research.” And there’s lots of interest among students. Williamson’s new class in Hybrid Electric Vehicles has attracted 75 students in its first term.

“The enthusiasm I see in students is amazing,” he said. “It’s clear they are very interested in the potential of these future technologies.”