[loborojo]

Maybe put his under the gamification of driving. What are your thoughts choosing a route based on elevation change and slope? I watched a Top Gear episode a few years ago where they debated what was best for fuel efficiency - flat or 'what goes up must come down'. I found a website, https://www.flattestroute.com/, that maps a trip and has elevation and slope but you have to do some calcs to get totals.

My guess is that it is a wash due to commutative law [minus system efficiencies] but wonder if anyone played around with this as part of driving strategies. I have a trip in a few weeks over the continental divide and choosing a route.

Thanks.

 

[Qinsp]

As soon at you touch the brakes, use engine braking, or regen, you become less efficient. Or if the downhill exceeds the target speed, that burns energy as well since speed increases are not proportional when it comes to energy lost.

So for gentle rises, not a big deal. For steep grades, you take a big hit.

Another item is cross wind. People assume that if you a roundtrip with a crosswind, you don't lose anything. But, it effectively increases the frontal area and increases the CD too.

Head winds and tail winds also hurt a roundtrip. Say your target is 65mph and the wind is 5 mph. Going with the wind gives you a drag equal to 60mph. Going into the wind gives you 70mph. The difference in drag from 65 to 60 is less than the drag difference from 65 to 70. The higher the windspeed, the more the effect.

 

[BAZINGA]

Ahh the joy's of living in flat land Illinois (our highest elevation is 631 feet ASL) so my GOM is in the 60's most of the year.

 

[kns]

Departing from a flat route, or uniform grade from start to finish, can substantially cut electric range.

Lifting 1 pound 1 foot takes 0.737 watt-seconds. Lifting 4000 pounds 1000 feet takes 2,948,000 watt-seconds or 0.819 kw-hrs.

Since losses drawing from the battery and then putting energy back into the battery via regen could be 25% or more even low rolling hills can add up to significant loss of range.

KNS

 

[Barry]

If you are talking about planning a long trip, I would just choose the shortest drive time or the route you prefer for scenic value. I would guess that routing around higher elevations would add distance that would offset the efficiency gains.

 

[wordptom]

This question may enter the realm of gamification quickly with vehicles such as the Volt that have on-demand access to more than one fuel source.

Consider this: when driving a Volt down a mountain, favorable conditions may enable the downhill regeneration to create enough electricity to both power the car and recharge the battery with sufficient power to use to drive for several miles after reaching level terrain. Those distances are thus fueled by neither gas nor grid electricity. If your battery still has some grid power as you arrive at the top of the hill, you can choose whether you want those regen-powered distances to count as Electric Miles or as Gas Miles.

By switching into Hold mode at the top of the hill (if you’re not already in Hold), your battery’s state of charge doesn’t drop back to the Hold set point level until after you’ve driven those several miles at the bottom of the hill. That total regen-powered distance increases your Total Gas Miles without increasing Total Gas Used, thus increasing your MPGcs (gas mileage when using gas).

By remaining in Normal (or switching back to it from Hold) before heading downhill, the kWh Used will decrease as you head downhill (net kWh Used = +regen added - grid power used). Once you reach level ground, you continue in Electric Mode. Now the kWh Used will again increase, eventually returning to where it was at the top of the hill. At that point, you’ve added that downhill plus regen distance to your Total Electric Miles without increasing Total kWh Used, thus increasing your potential AER (and miles/kWh average).

Choosing Hold before heading down a long hill results in higher MPGcs and lower AER. Choosing Normal results in lower MPGcs and higher AER. Neither choice affects the trip MPG.

 

[deeks]

Surprised your GOM does not read higher-must be the outside air temp.Despite hills here (Big Island) where generally we use HOLD on uphill return home,going into town on downhill sometimes uses 7 e miles to do 22 actual.Of course,moderate driving/slower speed limits & that warm outside temp.helps a lot.The uphill on electric is somewhat disheartening,and our solar/batt. system load is a concern to avoid using Utility power.When batteries are eventually replaced we will have better and more of them.
Don('17 VOLT LT)