MaineFusion Report post Posted September 10, 2013 This shows the impact of speed on fuel economy. At 60 MPH the car will cycle in and out of EV mode, using the generator to load up the ICE to its peak efficiency when running. Above 62 MPH the hp needed to overcome the wind likely made it rare for it to be more efficient to run with the ICE off. At 70 MPH the wind resistance alone is plenty load for the ICE to be operating in its most efficient range. Above 70 MPH and the ICE starts running inefficiently because the load is too high. See this post for more info on what I'm talking about. A perfect example of this is my ability to consistently do over 60mpg (typically around 63mpg) when driving country roads between 35-45 mph. This past weekend I intentionally puttered around country roads between Saco and Portland Maine to pad extra MPG on in an effort to break the 600mi in one tank barrier. Plus it was a nice day and I really badly wanted to go for a drive. In the course of 100.1 mi with plenty of stops (e.g. engine cooling down), I averaged 61.8mpg and was in EV mode over 70% of the time. When I'm doing normal highway driving I'm lucky to be in EV mode 50% of the time, because when I am in EV mode at highway speeds it requires more electricity to keep the car up to speed. Quote Share this post Link to post Share on other sites