Why an Internal Combustion Engine?

“Aren’t we all going to drive electric cars soon?”

That’s the question I often get when I tell someone that I work for Achates Power, a company that’s developing a clean, more fuel-efficient diesel engine. My answer: “not likely”.

Since the 1860s, the internal combustion engine (ICE) has played a significant role in transportation. Just recently, the U.S. Department of Energy released its Quadrennial Technology Review, which said: “the performance, low cost and fuel flexibility of ICEs make it likely that they will continue to dominate the vehicle fleet for at least the next several decades”.

So why an internal combustion engine and not a battery-electric powertrain? The reason is simple: as long as vehicles have to carry their own energy source, it’s hard to beat the forms of energy that have the most density (by both weight and volume), are easily accessible and are cost effective. Liquid hydrocarbons are just that. Diesel fuel has about 100 times the gravimetric energy density as a lithium-ion battery. The batteries of the Tesla Roadster, for example, weigh 450 kg and have the same amount of energy capacity as less than 1.5 gallons (4.5 kg) of diesel fuel. Adding weight and size to vehicles makes them less efficient. Moreover, batteries are expensive—from what I’ve read, around $36,000 for Tesla and $8,000 for Chevy Volt batteries.

An additional advantage of internal combustion engines is that diesel and gasoline, as liquids, are easily transported, widely available and can be re-fueled quickly. The same can’t be said for their battery-electric counterparts. With one billion vehicles on the road today, and a projected two billion in the future, there’s no infrastructure in place currently to support the re-fueling needs of electric vehicles. And, with re-charge times of up to eight hours, fueling is challenging at best.

Going forward, I expect that some passenger and commercial vehicles will see an increase in electrification as manufacturers look for ways to improve efficiency.
When it comes to long haul trucks, however, electrification isn’t an option. The amount of energy needed to carry 80,000 pounds across the country is far too much for batteries. The challenge increases for ships and planes, which is why we’ll use liquid hydrocarbons—a near ideal way to store energy—for a long time, even if eventually the liquid hydrocarbons come from non-petroleum sources like algae, biofuels or gas-to-liquids.

Internal combustion engines aren’t going away. Just read the report from former U.S. Secretary of Transportation, Norman Mineta, which says that “the quickest and most cost-effective way to achieve our energy usage goals is through faster adoption of fuel-efficient downsized gasoline and diesel engines”. At Achates Power, we’re developing a more efficient internal combustion engine that not only reduces fuel consumption but also meets stringent emissions standards. There’s a very real concern about the future availability of petroleum, and we don’t discount that. But, we do understand the need to build a better engine, one that is both economically and environmentally sustainable.