IC Engine Technology Paths

Assuming a conventional gasoline engine is about 25% efficient, that means for each liter of fuel we put in we can expect 1/4 of a liter’s worth of work out of it. Moving forward we have to strive for 30%, 40%, 50% efficiency and beyond – whatever is possible.

Despite all the alternative propulsion sources, they all have to be cost effective, reliable, durable, perform well, and be efficient. The internal combustion engine will probably still go strong for another decade or two as the benchmark by which all others are compared.

So what kinds of improvements can we expect to see in that arena? It appears there are basically 3 trends that will continue. Reduction of friction, use, and weight, which ultimately leads to reduced fuel consumption and increased efficiency.

First, we’ll see more use of efficient fuels on a cost basis (say Joules/$). Diesel will probably gain marketshare from gasoline engines, with government subsidies on alternative biofuels a wildcard.

Next, the way the fuel is burned will be a factor. We’re seeing more and more direct-injection and a lot of research into areas of combustion. HCCI (Homogeneous Charge Compression Ignition) and other methods of combining the best of two and four cycle engines are understudy.

Also, forced induction (primarily through turbocharging) is gaining in popularity as a means of moving more fuel and air through smaller engines. It is the dominant induction method in heavy trucks in North America, an industry known for efficiency. Useful recovery of waste heat can also help recapture some of the energy that would otherwise be lost.

Further, we’ll see smaller displacements and lower weights. A lot of vehicles will probably step down a notch or two in cylinder counts and engine sizes. Examples include Cadillac going from V8 engines to V6 engines, the next generation Corvette and BMW M3 among others.

Then there’ll be lower friction through improved coatings and materials. Who knows. Maybe we’ll see a day of engines without any lubricating oil at all.

Finally, decoupling methods will continue to proliferate with improvements in electronics and software. Examples of this include variable valve timing which will next probably lead to engines with valves actuated electronically, cylinder deactivation (running on fewer than all cylinders under light loads), idle reduction at traffic lights through stop/start algorithms.

Ford (and others) is putting into place some of these elements under the name Ecoboost, and will surely continue to do so. Any company that already makes engines is no doubt reviewing their product mix and R&D plans with more emphasis on efficiency than ever before.