Tips for Hybrid-Electric Driving

Monday, May 21, 2007

From John Frantz, RENEW board member, physician, and member of the National Association of Science Writers:

The first tip for getting good gas mileage applies to all vehicles: slow down gradually in anticipation of stopping to minimize the use of the brakes—any heat produced in the brakes is wasted energy. The friction of engine braking, as in down-shifting for steep downhill runs, is also wasted energy, but the brakes are spared wear and overheating. . . .

Now to understand the most subtle point in achieving the very best fuel economy in hybrid vehicles: imagine traveling through rolling hills on cruise control driving one of these cars. The cruise control will maintain speed uphill with gasoline power; relatively little electric power will be used because maximum gasoline power is greater than maximum electric power. The result will be a nearly fully charged 200 volt battery at hilltops preventing recovery of a maximum amount of electrical energy on the downhill portions. This problem can be overcome by using more electrical energy on the uphill by permitting loss of speed as the top of the hill is approached (turn the cruise control off). One’s overall progress can be nearly normal by gradually speeding up on the downhill portions (if the speed limit permits). Remember, if electrical motor power is sufficient for any assigned task for the hybrid system, the gasoline engine will not be invoked. Rather exact monitoring of this procedure is possible by keeping the instantaneous gas mileage readout at or only slightly above the expected consumption (experience will soon be close enough). . . .

As you learn more by experience, I will appreciate hearing from you so I can add your new discoveries to these tips (after I test them out for myself).

John Frantz, NASW, April 26, 2007
john.frantz@monroeclinic.org

You can read the complete article at www.frantzmd.info.