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The Nissan Leaf electric car. (The Canadian Press)
The Nissan Leaf electric car. (The Canadian Press)

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Emission impossible? Add to ...

The internal combustion engine has been under attack for more than four decades - it's under fire for consuming a large portion of a limited resource (fossil fuels) and contributing to greenhouse gas emissions and related health issues.

Modern emission and consumption regulations have resulted in a vastly different engine in 2010 than existed only 10 years ago, but pending legislation regarding both fuel economy and emissions will make it even more difficult for IC engines.

This will mean more hybrids and a fresh push for plug-in hybrids and pure electric vehicles. The biggest hurdle facing both is batteries.

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The bulky and heavy nickel-metal hydride units in current hybrids are being replaced by lighter, longer-lasting lithium-ion units that pack more punch per pound as the next generation of hybrids reach the market. Lithium-ion batteries developed by a Nissan-Panasonic partnership will serve as the power source for the Nissan Leaf, which promises to be the first pure electric vehicle from a major manufacturer to reach the market, starting in some fleets next year.

The next advance appears to be lithium-polymer batteries, which promise further weight and size reduction in conjunction with increased power and longevity. LG Chem of South Korea says they are also less expensive to produce. It has developed lithium-ion batteries for current Hyundai and Kia vehicles and lithium-polymer batteries for upcoming Hyundai Sonata and Kia Magentis hybrids. LG Chem will also supply batteries for the Chevrolet Volt, GM's plug-in electric promised for late this year; it will open a plant in Michigan to produce battery packs.

The problem with electric vehicles remains range. The Leaf promises up to 150 kilometres on a full charge. Use accessories or drive in cold weather and that range will shorten considerably. The Volt will use a tiny IC engine to recharge the battery pack to provide an extended range.

Hydrogen fuel cell vehicles are widely believed to be the ultimate solution, but the problem there is major - the lack of infrastructure. It will be possible to develop hydrogen refuelling stations in high-density areas, but it is highly unlikely we will see them outside major population centres or traffic corridors for decades to come.

That leads us back to the good old internal combustion engine as either the primary or secondary (in hybrids) source for motivation for many more years.

But how will this be possible with pending emission and economy regulations that call for the fuel efficiency of cars, SUVs and light trucks to improve by an average of more than 4 per cent every year from 2012 through 2016, with even greater cuts for the next period until 2020? That compares to the average of a 1.6 per cent improvement in the decades from 1987 to 2006. Those new rules are the chief reason for the big emphasis on hybrids and fuel cells.

But the short- to medium-term solution remains the IC engine and innovation, investment, research and development. Changes made to the IC engine to date have resulted in a phenomenal reduction in emissions and improvement in mileage. The trick is squeezing more energy out of each drop of fuel, leaving less behind to emerge as harmful emissions.

Thanks to advances in electronics and cleaner fuel, today's engines produce more power from less fuel and produce fewer emissions in the process. Continued pursuit of more complete combustion, in particular the control of the fuel-air mixture and how it is presented for combustion, has led to direct injection, which has started to replace conventional injection. Once again, the mantra is more power and fewer emissions from a given amount of fuel.

Cylinder deactivation, variable valve timing and the growing number of gears in transmissions, have all contributed to recent advances. We will see more advances in and use of forced induction - superchargers and turbochargers.

The next big step will likely be some form of homogeneous combustion ignition that replicates how diesel engines work - compress the fuel-air mixture to the point it self-ignites due to the heat produced.

The most efficient gasoline engines in wide use today convert only 25 per cent of the energy in a unit of fuel to power. More than half of that lost energy is heat, half out the exhaust system and the other half through the engine itself. Friction is a major issue along with the usual culprits - rolling and aerodynamic resistance. These are the areas where scientists and engineers are hard at work.

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