Do I really get 99.9MPG with engine running?

[mikepaul]

So I'm driving around, and glance down at the Energy Monitor, and it shows the engine providing power to the wheels and to the electric motor which is sending some to the battery, at 99.9MPG.

This is rather counter-intuitive. I'd think if the engine is running, odds are I'm using fuel. The two go together. When I'm warming the car up, I see the Consumption MPGs go down, so I know that is working properly.

I do see MPGs between 50 and 99 all the time, going down the road as fast as 75MPH. A small downhill slope, and the MPGs shoot through the roof for a short duration. What I don't understand is how the engine can be powering the wheels and still I get 99.9MPG...

[Wolfman]

Yes, it's possible. The requirements to move the car are at a bare minimum on a downhill run, yet the hill isn't long enough to allow the ICE to shut off. The concept is really no different than coasting downhill in a normal vehicle.

[olends]

also at 75 mph, the ice must spin, albeit using no fuel, and under no compression, just to prevent a mechanical overspin of MG2.

and a mechanical overspin of an electric motor= way way way above redline on an ice, and we all know over red line is [size=18]BAD

[mikepaul]

Originally posted by olends
also at 75 mph, the ice must spin, albeit using no fuel, and under no compression, just to prevent a mechanical overspin of MG2.

I'd like an update for the display software, so the little ICE visibly vibrates when it's running. You''d pull up to a light and it'd be vibrating, then you'd feel the ICE cut off and see the display 'shut off' too.

Just seeing the animated lines isn't quite informative enough for me...

[xevious]

Another thing to keep in mind is that the display reads "99.9" whenever the calculated mileage is equal to or greater than 99.9 MPG. When in stealth mode, your instantaneous MPG is actually hovering somewhere near the outer reaches of infinity (that is, the "miles" figure is accumulating while the "gallons" stay in the tank), so the 99.9 is way off in this case.

When the display reads 99.9 with the ICE running, your actual MPG could be 101, 120, 200, or higher. Point is, the impact on fuel consumption is minimal and (according to the ECU) you are indeed getting at least 99.9 MPG.

[Wolfman]

I actually got a surprise on the way home yesterday. I was driving a downhill stretch of road that I had always asumed that the engine had cut off due to the maxing out of the graph, and the steepness of the grade. I was surprised to find out when I switched over to the energy monitor to find the engine running, and supplying power, electric motor running, supplying power, AND power being drawn off of the battery. The climate control system was off, as I only run it just enough to clear the windshield in the mornings.

[jeffrey]

Now that its warming up a bit here in New England, I've noticed that on my consumption screen I've actually received three five minute periods of 99.9mpg in the last couple days. Generally I seem to get five minute intervals of just over or under 50, ranging from a low of 35ish (first five minutes of the run) to fairly steady five minute blocks of 45-55. Then, all of a sudden, I'll get a block of 99.9. I guess I'm wondering why not 85, or 75, or 95. It seems I don't get any blocks of anything much over 55 or so, unless I get one of these (relatively new) 99.9 anomolies.

Anyone have any thoughts, or observe anyting similar?

Peace

[cybele]

It seems I don't get any blocks of anything much over 55 or so, unless I get one of these (relatively new) 99.9 anomolies.

I get intermittant blocks of 60, 75 or something that I figure is 85 or 90. I guess it all depends on the math. Those are usually stretches where I get a lot of 99.9 and then a few brief periods of acceleration to get to cruising or coasting speed (which is why I guess it would average to less than 99.9).

But it's much warmer here ... my morning commute starts at anywhere between 48 to 55 degrees and then in the evening it's usually around 55 to 70 degrees. I do much better on my evening commute, even though it's pretty much uphill.

[daniel]

I was cruising around a parking lot for ten minutes at 6 mph, hoping someone would leave so I could park. As it was a rare warm (35-degree) day and the car was warmed up and the heater was off because the bright sun was keeping the cab warm, the car stayed in stealth mode the entire 10 minutes. By the time I gave up and left, I had two 5-minute segments of 100 mpg and my battery was at about half.

It was cool because it was the first time I'd been able to turn the heater off, and so was the first time I'd seen extended stealth mode.

I wonder if pedestrians can tell that the engine is not running. My dealer tells me there are 4 other 2004 Prius in Fargo. I've never seen any of them.

[USK]

I think ,
it shows the engine providing power to the wheels and to the electric motor which is sending some to the battery.
There are the two occasions.
The One is the full power with bad mpg.
The next is the high speed (over 42 mph ) motor mode when the engine start to need with no power because the THS System limitation.
It may be over 150 mpg. in Japanese monitor about over 65 Km/L , so not 99.9.

_______________________
USK Bordeaux mica 2001
20,668.29 miles / 353.55 ga. = avg. 58.5 mpg 3/5/04