The growing market for cars in the developing world is influencing future engine development.
Instead of complex hybrid powertrains, automakers are looking toward simple, low-cost engines that are clean and fuel-efficient.
Speakers at the annual Vienna Motor Symposium last month said improved gasoline and diesel engines are realistic alternatives to gasoline-electric hybrids.
The production of cost-effective engines is essential if automakers are to capitalize on the growth potential of the developing world, said Herbert Demel, president of Volkswagen Brazil.
Most future auto sales growth will be in the developing countries of Asia, South America and Africa rather than in the mature economies of Europe, North America and Japan, Demel said.
But incomes in developing countries will remain low, so those markets will be much more price sensitive, Demel told the conference's 1,000 engineering delegates. So reducing costs in developing markets is even more important than in mature markets.
In the opening lecture, VW group Chairman Bernd Pischetsrieder said VW would apply many of the technologies from its '1-liter' concept car unveiled last month in future vehicles. But VW won't build the car itself because it would be too expensive. The '1-liter' car - so called because it uses only a liter of fuel every 100 kilometers - is built from a mix of carbon fiber and aluminum. Its bodyshell weighs only 500kg. Power comes from a rear-mounted, three-cylinder turbodiesel that automatically switches itself off when the car is coasting or in heavy traffic.
'We are a global group but we will never build a world car,' said Pischetsrieder. 'Our modular technology enables us to build low-cost cars that are specially designed for each market.'
Fritz Indra, executive director of powertrain advanced engineering at General Motors, said several simple technologies could improve the fuel efficiency and emission levels of traditional engines.
These solutions include variable valve adjustment; turning off engine cylinders when only a small power output is required; and non-stratified direct injection. Indra said hybrids and stratified direct-injection technologies are often inflexible and work best under laboratory conditions.
In real-world use, simpler technologies usually function better, he said. And they can work anywhere in the world because they don't require sulfur-free fuel, he said.
Combining variable-valve adjustment and direct-injection technologies substantially improves economy, performance and emissions for powerful engines, said Leo Spiegel, Porsche's director of research and development.
Porsche test results suggest that the company's VarioCam system and non-stratified direct-injection technology could work in mass-market engines with relatively small changes in existing valve trains and injection units. Porsche has an engineering and design subsidiary that several other automakers use.
DaimlerChrysler engineers are taking a similar route. D/C presented a new 1.8-liter M271 gasoline engine with a supercharger instead of a turbocharger to provide more low-end torque. It comes with stratified direct injection for countries where low-sulfur fuel is available. Elsewhere, it uses a conventional fuel mixture of one gram of gasoline to 14.7 grams of atmosphere, a stoichiometric measurement to maximize complete combustion of fuel and minimize emissions.
Hans-Joachim Schöpf, head of product development at Mercedes-Benz, said DaimlerChrysler plans engines that use non-stratified direct injection, adjustable valve adjustment, and cylinder shutoff. Some Mercedes-Benz V-8 and V-12 engines already use cylinder shutoff.