Another Cyberwagon update. 150 or so miles into this tank of gas and I'm still sitting just above 47 mpg. Pretty happy with that.
One of the genius things about the Prius is the information it shows you about the power systems and being able to see how you're driving habits effect your efficiency. It almost feels like a game trying to be as efficient as possible.
@kelbot welcome to the world of hypermiling :)
@donblanco Ha, yeah I've been reading a little bit on a Prius forum and some of them take it very seriously. Apparently there is a method of driving called Pulse and Glide that is supposed to achieve maximum mpg. It involves accelerating to 5-10mph above the speed limit and coasting down to 5-10 below the limit and then repeat.
That sounds extremely annoying to other drivers and once you factor in traffic and lights, turns etc I would say the benefit is hardly worth it. I won't be doing it.
@kelbot @donblanco There's a few other tricks that a hybrid lets you do, too, especially at lower speeds (I'm not sure what the maximum EV speed is on the Prius v - it's claimed at 110 km/h or 68 mph on the Gen 4 Liftback, I've seen it go into EV as high as 73 mph).
So, fundamentally, what pulse and glide is doing is it's keeping the engine at its optimum efficiency. Light load is really inefficient for an internal combustion engine, especially gasoline engines.
@kelbot @donblanco The hybrid system helps you out, though, because it automatically shuts off the engine at light loads and low speeds, and you can use battery power to even keep propelling the vehicle during a glide phase. (This will start arguments on Prius forums, calling powered glide a glide. The engine's off, it's a glide, damnit.)
So, you can lose a lot less speed, then use the engine to recharge the battery, and gain less speed in the pulse.
@kelbot @donblanco This gets even more effective when you can combine it with traffic conditions. Note that the hybrid system will always aim for the most efficient engine operation, making things easier.
So, on say city surface streets, accelerate moderately, keeping the engine at 2000-2200 RPM or so, until you're almost up to speed, then lift off and run on electric, depleting the battery. Recharge the battery with gentle to moderate braking at the next stop.
@kelbot @donblanco Of course, in my Gen 4, I get scolded by the car's efficiency guide for accelerating too hard when doing that, resulting in hilarious screenshots like the first attachment.
For knowing the RPM... well, Prii don't have tachs, so you need something like a ScanGauge that can get various stats over OBD-II. The RPM and the high voltage amps are the most important tools IMO (aim for 0 HVA during acceleration, as negative as possible under braking).
@bhtooefr
Oh cool, so they really do make it like a game with scores and everything! I don't think mine has that feature. It's a gen 3 v wagon.
@donblanco
@kelbot @donblanco I think this stuff was introduced on the Prius c, FWIW.
@donblanco @kelbot I just wish you could make an X-Gauge by multiplying two X-Gauges together, so I could multiply the HVV and HVA gauges I have, to get battery kW
@bhtooefr
Yes, having that power gauge and indicators showing you what is providing the power and your battery level makes it possible to really adjust your driving techniques for efficiency.
@bhtooefr
I try to do a moderate pulse and glide technique. I accelerate at a moderate but relatively normal pace until I'm about 5 over the limit. Then I back off the throttle and keep it just below the line where the engine kicks on. This allows me to maintain or slowly drop my speed without using the engine until I need to stop or turn. I just use cruise control on the interstate at or slightly below the limit.
@donblanco
@bhtooefr
This has me beating Epa estimates so far without doing anything drastic.
@donblanco
@kelbot @donblanco (Gasoline engines close their throttle plate to reduce the amount of air/fuel mixture going into the engine, which means that the engine has to work against that plate to get its air and fuel. This takes power, and reduces efficiency.)
Pulse and glide done ideally shuts the engine off during glides, so no energy is consumed during those glides, and pulses are performed at the optimum efficiency for the engine (high load, low/moderate RPM).