Why low mpg on 2013 prius 3?

Hi Bill, I have nowhere to charge the Volt so I am sure that I would average much lower MPG's than with the prius. I also find prius very reliable, we still have to wait some time to see how the Volt does. Volt also feels like a smaller car. Not so much room on the inside. And most of all: try to drive for 500 miles on the highway without charging, what would your mpg be? I guess prius is still better (best) car for many of us.

Andrej

 

drysider, I assure you your great mpg is a function of your otherwise sound techniques and a slow average speed in town. You have upside by minimizing EV and maximizing kinetic energy through gliding (no HSI bar).

Think about riding a bike: would you accelerate repeatedly and brake (assume it has regen), or would you accelerate once, maintain speed, then glide to a stop?

The work a vehicle does is: acceleration of a mass, overcoming rolling resistance, overcoming wind resistance, lifting the vehicle up hills, and an accessory load for electronics and AC, etc. Reducing the acceleration to a single event is the biggest thing we can do for higher mpg.

Your hills are an exception: you want to drain the EV charge going up and allow regen to control speeds down, if the hill is that steep and long. Otherwise, you get to engine braking and friction braking to control speed down, and that is a waste.

 

Correct. I did those benchmarks running the same course in opposite directions. This takes out the worst of the wind effects and altitude changes. I also used cruise control to maintain a constant speed.

I'm sorry you don't have a way to replicate the chart.

Bob Wilson

 

You do realize I was being wildly sarcastic in my post? If not, my apologies if I offended you.

 

andre,
Funny you should say 'drive 500 miles on the highway'. That's exactly what I did when I picked it up in DFW and drove it back to MCI in 'Hold' mode (holds the battery charge for later), which makes it a Prius. Drove it at +5 mph
(gps) posted speed limits, 81 mph thru parts of OK!!
35.8 MPG for that trip. My Prius would have done that trip at ~41-43 mpg.
I was saving the battery charge for when I got back to town so I could play with it as an EV around town that evening.
But, since that trip over a month ago I still have 3 gal left on the 9 gal tank that I filled when I arrived in KC to check the trip mpg. A typical commuting day (46 mi) I use 0.1 gal. But soon I will be able to plug in at work.

A Volt would make no sense at all if you can't plug in at home or work.

Face it, it is a leap in technology over the Prius.
Technology marches on! The PiP does not even compare. Either 13 mi or 62 mph, but not both and don't go faster or you start burning gas from OPEC.

To me if feels like it has sportier handling and yet a smoother, more comfortable ride (don't know how those two go together) and is INCREDIBLY quiet and way faster than,, the leading hybrid.
I feel like I am driving in 2023 everywhere I go!!

kss,
Too true, I can't see how pulse and glide works with charging and discharging a battery. There are big loses.

Bob,
No, I can't replicate your chart anymore. And I doubt others could either with that figure of '58 mpg @60-65 mph'.

And that, my old friends is how the future looks !!!!!!

 

Plus, I'm pretty sure the transaxle is made by the same supplier as the Prius's.
Only,, the Volt transaxle is a leap in technology!! ( Me and Lutz love that expression!!)
But way more complicated compared to the Prius's. I like how simple the Prius transaxle is.

 

I'm sure there must be a Volt forum around somewhere.

 

kss,
Too true, I can't see how pulse and glide works with charging and discharging a battery. There are big loses.


Pulse & glide does not charge or discharge the battery. It uses the ICE to gain speed to top of range, then glide engine off to bottom of range. Some of the perceived gain is just a lower average speed compared to cruise control. There are acceleration losses that must be outweighed by efficient use of the ICE (vs continual loafing) to get a net benefit. It does allow outstanding mileage while helping to fit in with other traffic if used selectively.

 

Apologies in advance for the off-topic reply...

It sounds like your Volt hadn't finished going through it's warm up cycle after a cold startup while you were driving on city streets. The Prius will do exactly the same thing -- it will continue running the engine while stopped at an intersection on a cold startup until the engine finishes its initial warm up. The only difference is that the Prius may finish its warm up cycle a bit quicker under the same environmental conditions. This is presumably done by Toyota and GM for multiple reasons No need for a SW change.

 

First off, I'm glad you like the Volt but something I've learned from John1701a:

I understand the PiP can 'save charge'. In effect, the car can reach 60+ mph and the owner can trigger the ICE to start the warm-up during this first couple of miles at speed while in EV mode. The absolute fuel burn is warm-up related but at 60 mph, the effective MPG is going to be pretty good.

Now I don't have a PiP to confirm this mode but I'll send a note to John1701a and ask if I got it right.

Once the engine is warmed up, switching to hybrid mode gives a car with better than 60 MPH for the remaining part of the trip. Thus the car has the long-range MPG by mitigating the warm-up cost, diluted by running initially in EV mode.

Talk about teaching an old dog new tricks, a former Ford Fusion Hybrid owner clued us to a way to shorten the OPEN LOOP stage in the Prius. I've still got to do the metrics but this may provide a trick to further reduce the Prius warm-up cost.

This is just a hypothesis but it looks like using this early CLOSED to OPEN LOOP trick might be very handy when the cold weather returns. Also, it incorporated as a default in the Prius control laws, it could provide another 'step' function to improve Prius MPG.

Bob Wilson

 

Actually, I was not willing to get close enough to the truck to get much drafting. From what I have read, the closer the better...not very safe. The cruise control was at 73+/-mph.