Quote:
Originally Posted by UTpiper
Thanks for the excellent and detailed posts. As I am not a hypermiler (and will likely never be due to my driving requirements) a good deal of this is over my head. However, it is quite helpful in allowing me the opportunity to see what impacts my driving "style" may have on my overall FE. Basically, what the data (and your responses) seem to indicate is that once the ICE has been engaged, either above or below 42 mph, the impact to my fuel economy is the same. The best case scenario I can achieve at that point (assuming I can’t simply glide to slower speeds) is to maintain a yellow arrow to the battery as often and as long as possible. It also seems to indicate when the ICE is engaged my best FE will occur when I remain below 40 mph or above 45 mph consistently. Hovering between 39 and 45 mph means I will run the risk of turning the ICE on and off frequently, thereby reducing my overall FE.
Also, as I reviewed the link above, it was interesting to note the key temperature thresholds of 40C (100F) and 70C (160F) where the ICE may shut down based on the demand put on the ICE. Given these hard wired thresholds, it would be nice to have a temperature gauge as part of the standard equipment in a Prius. It would certainly allow the driver more specific data in attempting to manage their FE numbers. . . . |
You've got the big picture right but performance below 42
mph and especally under 39
mph has some subtle, unique to Prius/TSD/HSD drive operation:
- electric vehicle EV mode - when the ICE is off and the stored battery energy is sustaining speed; gliding; or regenerative braking. No fuel is being burned, a GOOD THING!
- ICE powered mode - when the ICE is on providing motive power AND recharging the battery. One of the subtle aspects is the additional load on the ICE moves the performance into a relatively higher engine efficiency band (aka., you get nearly the maximum energy per unit of fuel burned!) My measurements indicate that round-trip battery efficiency is ~94%, a very good thing!
- automatic transition between EV and ICE modes - the Prius will transition between these states automaticly. The 'clever' driver learns how to adjust their driving style to maximize the "EV" and minimize transitions. <GRINS>
But as far as the big picture is concerned, you've got the major elements. The rest is just practice and getting used to 22nd century, automotive technology. <GRINS>
Bob Wilson