Smaller and lighter. Yet far more powerful and efficient. Oh, and cleaner.

That's the challenge for engineers around the world as they design the next generation of internal combustion engines.

Electric and fuel-cell cars attract most of today's buzz – and mountains of government cash – but they're expected to account for a small fraction of vehicle sales for the next decade or more. So if carmakers are to meet new European and American emissions and fuel-economy standards they'll have to squeeze more out of their tried and true gas burners.

I've previously written about direct injection, weight reduction and other tricks of the trade, but more is happening all the time. Renault, for example, claims to have its little Clio diesel down to 3.7 L/100 km (74 m.p.g.h) by changing gear ratios, reducing friction within the motor and improving aerodynamics.

I recently heard from the Argonne National Laboratory, a major research institute near Chicago, about work it's doing for Chrysler. The beleaguered carmaker is viewed as trailing the pack in innovation. But the Argonne work suggests things are happening under the radar.

The research, supported by the U.S. Department of Energy – don't expect much of this from Canada's government – aims to produce a turbocharged 2.0-litre, four-cylinder motor for minivans that will perform as well as the latest generation of V6 engines.

It's being done, in part, by blurring the distinction between gasoline and diesel engines, says Steve McConnell, the project's lead engineer. Instead of using a spark plug to ignite gasoline in the cylinder, it does the job with a tiny blast of burning diesel fuel, acting like a blowtorch.

One result is that while the gasoline burns more quickly and effectively, the combustion temperature stays below 2,000C. That means that, unlike lean-burn engines – the current watchword in internal-combustion efficiency – it produces far less nitrous oxide, a major source of smog and its deadly health impacts.

Daimler Benz and other makers remove the pollutants by injecting additives into the exhaust system.

Turbocharging and improved valve timing will provide plenty of power for the minivan engine, while the smaller size means it can operate for longer periods at its most efficient throttle setting.

A family hauler with this engine should get Prius-like mileage, McConnell says.

One drawback: the engine requires regular gasoline and a small amount of diesel. Drivers must fill up with both – although pit stops for diesel will likely be far less frequent than for gas, depending on the size of tank provided.

Chrysler will have to decide how to handle the two-fuel issue; whether, for example, to add the diesel during regular servicing or making drivers do it themselves.

This is a simplistic explanation of complex technology that's years off: McConnell is to have a demonstration model ready in three years.

These cars will be cheaper than those relying on batteries, so they'll be crucial for hitting the coming fuel-economy targets. At the same time, they could curb enthusiasm for electric vehicles, making it harder to justify the added cost.

On the other hand, the new motors might be incorporated into hybrid or plug-in systems, making them even better fuel misers.

In this game, you run marathons at sprint speed just to keep from falling behind.

peter.gorrie@sympatico.ca