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Thread: MPG Tips
05-21-2007 11:58 PM #1
- Join Date
- Oct 2006
Tips for better MPG in your FEH/MMH.
1. Face Out: Back into your parking space in EV because the engine is going to run as soon as you restart to head out again. Gas is wasted backing up to change direction.
2. Use Electric Motors: During a cold start or after the vehicle as been parked for more than a few minutes, the electric motors will provide acceleration torque while the engine idles. Take advantage of the electric acceleration by NOT accelerating hard. Hard acceleration is always bad for MPG, and during the electric assist will break the idle of the engine sooner.
3. Avoid Routes With Stops: Even though the FEH/MMH will go electric to and at a stop, the energy (gas or electric) lost accelerating back to speed will cost you MPG. Our Town has recently started the use of “Round A Bouts” where you can yield with traffic at an intersection. These work great with timing the speed with traffic, and turning into the direction your going.
4. Pulse & Glide: P&G is an excellent way to save gas. Pulse is the acceleration portion of P&G. Glide is the coasting portion of P&G. About two years ago, I worked with Wayne Gerdes (the best hypermiler on the Planet) to find the best ways to accelerate (RPM wise) and glide.
Using a Scangauge instant MPG gauge, the factory Charge/Assist needle and the Nav. Sys. battery level, I found a number of factors to consider during the Pulse (acceleration) phase. The Scangauge “Load” gauge revealed that max load (99%) of the engine was at a very low RPM during acceleration. The electric motors start to assist the engine at max load which can also be seen on the Charge/Assist needle. So when the Assist needle begins to move to that side, the FEH/MMH engine is at max load. The bottom line is, when you accelerate to the point that the assist needle is in the assist position, your burning the most gas possible at that RPM and load, plus electric energy depending on the amount of assist. This energy loss is either coming from the HV battery storage or being diverted from the battery to the traction motor from the small generator.
What I’ve found to be the best all around acceleration was from using the torque curve for guidance and the Assist needle. Traffic permitting, I accelerate at 1800 RPM as much as I can. This means I hold the gas pedal so that I maintain that RPM until I get to my target speed. Traffic may require a faster acceleration, so the torque curve jumps to 2300-3000 RPMs for the best acceleration, but your going to get electric assist in that range. Stay out of 2000-2200 and 3000-3500 RPM’s where the torque curve is flat.
Pulse to your target speed, but remember the faster you go above 20mph, the gas mileage could be decreased. The best MPG seems to be using the P&G in the 20-35mph range. My best 20 mile round trip was 70.3mpg so far. When I’m on roads with faster speed requirements, I like going EV at the top speed of 40mph and gliding down to 30-35mph and holding at that EV speed until a engine restarts by a low battery or gust of wind.
All my gliding is in neutral with the engine on or off, but of course I prefer the engine off as much as possible. That’s All for now, any questions? GaryG