3 ms·
Most likely it is theoretical fuel efficiency and not real world. A car will get it best fuel economy when traveling at the lowest speed where the engine can re
by sbradford26 5y ago
Most likely it is theoretical fuel efficiency and not real world. A car will get it best fuel economy when traveling at the lowest speed where the engine can reach its peak efficiency band. You are fighting the least amount of air resistance and consuming the least amount of energy. Now in the real world this doesn't work out as well since where you drive at lows speeds tend to have a lot of stops. Where usually as once you hit 45-50 mph the roads will most likely have fewer stops.
- hansvm 5y agoAh, so maybe their models are just too simple? The 40-50 band being more efficient isn't just a function of stopping frequency -- you can directly measure it on your favorite long, stop-free stretch of road. Your engine has a nonlinear efficiency with respect to throttle position and load, and at low speeds those dominate fuel economy rather than increased air resistance. An engine optimized for efficiency would of course drive as slowly as possible, but other factors also contribute to the design of modern car engines.