Actually, trying to use stealth too much can hurt mpg. Someone on another group compared it to trying to borrow your way out of debt, as the electricity must be replaced somehow, and all of the energy used to propel the prius is ultimately derived from gas consumption.
I was getting mid to high forties for mpg in my 2004 through the winter months, without doing much special other than increasing my tire pressures to 44 front, 42 rear, switching to synthetic oil, and driving at or below the speed limit. Then in March we saw a flurry of tips on the 2004 groups that combined with warmer temperatures allowed me to dramatically increase my mpg. My last three tanks have been at or above 60 mpg and my current tank shows 60.5 mpg at 240 miles. As I've mentioned before here, I have the advantage of a 35 mile commute, with the first 14 miles near-deserted rural roads, then a lightly travelled interstate until my final mile to work on a flat I generally run in stealth after coasting down the ramp.
These tips have been shared before, but are worth mentioning again.
Increase tire pressures as high as you feel comfortable, remembering to keep two pounds more pressure in the front than the rear.
Use synthetic oil
Avoid short trips if possible, combining several errands into one drive.
From there it depends on how much energy you want to put into improving your mpg. The general advice to drive gently and keep your speed down is sound. Others have determined that 35 mph is the maximum mpg speed for the 2004, and at anything over 42 the ICE (internal combustion engine) must spin to avoid over-spinning one or both of the electric motors, even if you're in stealth or coasting, so there is some loss of efficiency. In most circumstances cruise control can do a better job than your foot at efficiently maintaining a constant speed, although I've notice that cruise does not do well in rolling terrain compared to driving without it. The closer you stay to 35 the better your mpg will be. And driving as slow as you feel comfortable with on the interstate also helps a lot.
If you really want to maximize mpg, use your energy screen to achieve 'gliding' (no arrow showing on the screen at all, accomplished while coasting by a slight pressure on the accelerator) and to utilize 'deadband' acceleration (no arrows to or from battery while accelerating, accomplished by pushing the pedal a touch further than you would otherwise to accelerate, then backing off enough to make the arrows disappear or flip back and forth).
Gliding provides significantly less resistance than coasting with your foot off the accelerator. You don't regenerate, but you can go surprisingly far with only a slight decrease in speed, and no energy consumed. Deadband acceleration means you are accelerating using the ICE at maximum efficiency. If you use the cruise control lever to accelerate the computer will usually deadband accelerate for you, which gives you a feel for the easiest range to find when you do it manually. You can also deadband more aggressively, but generally by the time you find the sweet spot you're already up to speed. Works well for hills and on-ramps, though.
It seems counter-intuitive at first, but the highest mpg are achieved when you DON'T utilize the hybrid system, ie simply drive using the ICE at its most efficient. But it makes more sense when you recognize that although the hybrid system captures energy otherwise lost during coasting and braking, and gives it back later to supplement the ICE, there are always losses involved when you swap energy back and forth to and from the battery, so negating the need is even more efficient.
The final aspect for the mpg dedicated is to drive in harmony with road conditions and traffic patterns. That means anticipating stops well in advance so you can coast or glide up to them, trying not to need to use your brakes any more than necessary, easing off the accelerator before reaching the tops of hills so you glide over the crests, etc.... It all adds a lot more effort to the driving experience, and perhaps more than most would consider worth the return, but it's always good to know what you COULD be doing, even if you don't choose to.
Of course if you drive in heavy traffic most of the time, you won't have the luxury of attempting many of these techniques, and it's always important not to let yourself get so distracted by the energy screen that you compromixe driving safety, but I've been getting a real kick out of maximizing mpg.
Hope this helps,
Date: Wed, 02 Jun 2004 04:32:51 -0000
From: "Bill H." <gojoe283@...
Subject: Re: Unfortunate mileage
I would glance at the Consumption monitor screen (but keep your eyes
on the road!) and you can determine when you get the best mpg, which
is to accelerate briskly and then let off the gas a bit, going
into "stealth" mode as long as you realistically can. I'm learning
how to maximize my mileage that way, and driving in Brooklyn, New
York rush hour I'm getting around 42 miles per gallon, which is
nothing to sneeze at.
Avoid hard acceleration; the car will respond but gas miles plummets.
Drive conservatively and you should get decent mileage...Bill H.