We live at 6000+ feet, and go up and over the tail end of the rockies when we drive to a nearby town about 47 miles away. Today was our first drive there using the Prime. The trip started out in the day time in the 70sF while the return was at night in the 50sF. Each leg gains about 1800 feet elevation and then drops back down to ~ starting elevation Final result for the r/t using one full charge: 113 mpg over 97 miles. For the most part I drove in the high 50s, low 60s mph. The outward bound leg I started out in EV and switched to HV when half the SoC was used. On the way back I used EV on the climbs to avoid pushing the ICE into the power zone but then relatively long distances with the ICE shut off had me fretting that the ICE was cooling off too much. It was interesting (read: annoying) to note that the Prime does not blend EV and ICE well. Even EV-auto stayed in EV mode during a long and fairly steep ascent.
Great MPG and drive. I think we fret too much over the internal combustion engine cooling off too much. In a regular car that just has the gasoline engine, it is cool until you start it and then it warms up to operating temperature. So too with the Prime's engine....so it is cool when not used but will warm up soon enough. The few short minutes it takes to warm up should not cost too many MPG.
The Prime does have active grille shutters so it won't cool as fast as a regular car because the shutters would be closed. Alternatively, you can use CHG mode to gain 10 miles back (depending on how far you have to go to your destination after the descent).
I will disagree on your post about blending part ICE vs EV And engine to stay in warm parameters If you have the tools to measure and record you will see That after Going on EV and before ECU decide it is time to switch to HV (battery is running low) it will fire up engine and go trough warm up cycle for catalyst and engine before it will load engine to assist in powering wheels This will also happen if you make changes on drive options ...in your scenario use HV after you drop to 10 miles..... It will go trough warm up cycle mentioned above and act as generator to have slight load to engine and ensure much faster warm up..than what use to be in older generation This is type of work i do for living...so trust me i know what I'm speaking here Posted via the PriusChat mobile app.
My 2004 doesn't do that, due to the 10kW limit on Ev. Just driving up the hill at the end of my block will force the engine to be loaded even if it only starts on the hill. In other words, it gets loaded during the warm up period if you demand too much for the electric system to provide or if the battery is too low.
On prime model...i can't speak about older models...what you actually hear and what is really happening under the hood is misleading experience With Prime model....if you demand a lot of power when engine is in warm up cycle it will rev up to increase current to the electric motor and crank shaft load will be limited in this instance Posted via the PriusChat mobile app.
You are correct that the firmware reduces ICE load during the warm-up cycle by pulling from the battery, but there is no way to avoid the fact that an ICE is less efficient until it is warmed-up. And every time the ICE cools down, that lesser efficiency is in play until the ICE warms up. Again. Yep I wish I could monitor ICE temperature, then I would know if my fretting was for aught. I thought about it, but the conversion efficiency hit dissuaded me. Keep in mind that this maybe problem is very locale and climate specific. Or if I had enough experience, I would know where in the route to flip to EV and not run out of battery juice until the end of the trip. Or if the Prime did a better job of blending ICE+battery on climbs I could keep the ICE warmed up and avoid using the ICE in the inefficient part of its power curve.
That is true... Hybrid type car can't stay at full 100% efficiency That is why BEV are future But you don't need to worry about running engine when is cold... They have control over load on crank shaft...so if engine is speeding up at cold state...load to engine is reduced Posted via the PriusChat mobile app.
I've yet to find a use for EV-Auto mode. Perhaps Toyota will swap it out to an HV-Auto mode for me instead ? My version of HV-Auto would draw from the battery any time needed to avoid running the ICE on the inefficient part of the power curve.
Toyota approached a small group of us in 2010 to form this group. Honestly, I'm not sure if Toyota has any plans to expand the group or not. (There was talk of it 5 years ago) That lack of documentation for EV Auto is a bit annoying for enthusiasts. We really would like to know what the benefit of EV Auto is other than "it's best for efficiency in both electricity and petrol consumption".
I presumed that my battery range results and HV MPG varied by similar proportions to EPA. Doing so worked out to 33 miles of battery range and 74 mpg in HV mode. I'm pretty happy.
