Auto efficiency: Not much of the gas goes down the road

 Oil futures closed on another record high today, and where barrel prices go, gas-at-the-pump prices are sure to follow*. So, where does all the energy in a gallon of gas go after you put it in your car’s tank? Here’s what the US Department of Energy’s fuel economy web site says: Less than 13% of the energy from the fuel you put in your tank serves to actually move your car. The rest of the energy is lost to engine and driveline inefficiencies, idling, and a little bit to run accessories such as air conditioning.  Here’s the overall breakdown:

… leaving 12.6% to actually move you down the road. I’m not saying to prove that the car is a hugely inefficient way of moving around – it is what it is, and mass transit and bikes are not universally practical – but to point out the enormous potential for improving automobile efficiency. Some of the improvements will come from aerodynamics and mechanical improvements, but a lot will depend on new electronic controls. For example, using an integrated starter that turns the engine off at a stoplight and automatically restarts when you step on the gas can improve on that 17% lost to idling.

Even without the move to hybrid vehicles, the imperative to make cars more efficient is accelerating the adoption of more and more electronic control into cars.

*I just learned of the “Rockets and feathers” metaphor, as used by Chris Knittel of the Institute for Transportation Studies at UC Davis: “Prices actually follow rises in crude oil prices very closely. They tend to lag behind decreases in the price of crude. This is a phenomenon we call rockets and feathers. Gas prices shoot up when crude oil goes up, but they float down slowly when crude oil prices fall.”