Question from Energi owner: steady state gasoline at low speeds

[gladeplugin]

Hi all,

 

I am trying to build a fuel efficiency at speed table and in Energi, I can't drive at steady state with the gasoline engine below 45mph, the hybrid system will keep switching between gasoline and electric.

 

I was wondering if Hybrid behaved the same way. I would expect our cars to behave the same when I run down to 0% EV and switch to hybrid mode, but don't know for sure.

 

If you can drive at lower speeds than 45 at steady state, could you measure MPG at 40, 35, 30?

[mwr]

My experience is that I can't depend on my FFH operating in any particular mode at any particular time. The computer and its software controls it all. I can predict (from experience) certain modes for a short time, but not for long.

[Waldo]

Your data will be meaningless unless you also consider the charging rate of the battery. If you run at steady state 45mph with a low battery you will burn a lot more fuel than running at steady state 45mph with a full battery.

[lolder]

The fuel efficiency improves almost linearly with lower speed on down to below 20 mph where it is about 70 mpg. At 50 mph it is about 50 mpg at 60º F.. Colder temperatures lower mpg by 2 mpg for every 10º F. drop in temperature.

[Waldo]

The fuel efficiency improves almost linearly with lower speed on down to below 20 mph where it is about 70 mpg. At 50 mph it is about 50 mpg at 60º F.. Colder temperatures lower mpg by 2 mpg for every 10º F. drop in temperature.

 

But you're talking about the hybrid as a system, not the ICE on it's own. An ICE powered car's fuel efficiency is actually worse at lower speeds up to about 35pmh where it then starts to get better. Of course that's really the whole point of a hybrid, to get out of that low efficiency condition.

 

Sounds like what the OP really wants to do is compare the relative merits of gasoline vs electric power, but you really can't do that on a car like the Energi or FFH because the two systems are dependent upon each other and optimized to work together.