824 mile tank!!!

wow. I am impressed. I just filled up for the first time on a car purchased 6/22/13. Nine gallons and 404 miles (with A/C in automatic), with one bar left on the gauge. I went to a second click, then rounded to nearest 25 cents on the bill to get a sense of the relation between the gauge and the tank's actual contents. Back-of-the-envelope math would suggest I still had nearly 3 gallons left, but I'm not going to tempt fate until I have more miles under my belt to get familiar with my new toy. My dash said I had 50 miles to go until empty, so filling at one bar is probably the practice I'll adopt. Again, congrats on a remarkable bit of mileage

 

Great driving.
I'd agree about not overfilling. A lot of $ could be lost by harming the system vent system.

 

fyi - if you overfill the fuel tank - there is a risk of fuel loss via the venting system in very hot temperatures if you don't use the *extra* fuel immediately .

 

Wow great results!!

I was unaware of that tip to use electric to 10-15 if traffic allows, I'd thought it best to use the engine to cruising speed. I will give that a try, thanks for sharing.

 

The general recommendation is you should use ICE when you need the extra power and switch to battery when you don't. The should give you the best MPG.

 

Yes I thought about that road rage thing...it's a real concern. Even if you don't get road rage, you do stand a significant chance of a rear-ender as people, once they start moving, tend to accelerate at the relatively same speed and our electric motors can't give that rate of acceleration. Since 3/4 of the folks are texting at the stop light and just using peripheral vision to get going, the chances of getting rear ended are pretty high I think!

I think I'll leave this method to the times when nobody is behind me.

 

You could google for the exact numbers. The general rule is that the ICE is least efficient when it's running at low RPM. To get max MPG, this is something to avoid regardless of car speed. Like other Prius drivers, I start off slow by using the motor but once the ICE kicks in, I press the gas pedal harder to increase the ICE's RPM to a more efficient level. Once I get to cruising speed, I let go the gas completely to shut off the ICE. I then gently press the gas pedal again to start the gliding. The more you could glide and the more you could run your ICE at an efficient RPM, the better it is.

When traffic is not congested, I glide in neutral on flat roads. I discovered that I could increase my MPG by a few miles.

 

WOW that is crazy that's got to be a record

 

Dept of Energy did some lab test for the 3rd gen and after the ICE is warmed up the Atkinson Cycle engine is energy efficiency between 900 rpm to 1800 rpm ( this is a pretty wide range, an Otto cycle engine sweet range is usually about 100 to 200 rpm and is harder to control ). Bob Wilson did some really good experiments on energy efficiency wrt to the pre-warm up stage - there's more involve than just the ICE , too.

If you glide in neutral on flat roads you eliminate the internal drag from the ICE but it is illegal in many states to glide in neutral going down hill....

 

Thanks for the info you provided. I got the following from wiki which explains things better than I could. I believe that laws are there for a reason. I don't usually glide in neutral going downhill. However, it's no more dangerous than someone who accelerates going down hill beyond the speed limit. IF I ever decide to glide in neutral going down hill, I would still obey the speed limit.

"At idle, the thermal efficiency is zero, since no usable work is being drawn from the engine. At low speeds, gasoline engines suffer efficiency losses at small throttle openings from the high turbulence and frictional (head) loss when the incoming air must fight its way around the nearly closed throttle; diesel engines do not suffer this loss because the incoming air is not throttled. At high speeds, efficiency in both types of engine is reduced by pumping and mechanical frictional losses, and the shorter time period within which combustion has to take place. Engine efficiency peaks in most applications at around 75% of rated engine power, which is also the range of greatest engine torque (e.g. in the 2007 Ford Focus, maximum torque of 133 foot-pounds (180 Nm) is obtained at 4,500 RPM, and maximum engine power of 136 brake horsepower (101 kW) is obtained at 6,000 RPM). At all other combinations of engine speed and torque, the thermal efficiency is less than this maximum."

 

This year I have been playing around with the ScangaugeII xgauge LOD which provides the load/energy efficiency rate of the Prius. From the forums in Cleanmpg.com - a hypermiling forum - I have read that during acceleration cycles - a hypermiler should try to get LOD between 70 to 80 in order to get the highest fuel efficiency from the ICE or hybrid. I find that LOD range difficult to maintain during accelerations ( and when going uphill from a dead stop - the Prius acceleration above 25 mph peters out quickly when LOD < 80 which can be annoying to others in heavy traffic ) so my LOD is more often between 65 to 85; however, it does look to me that keeping my LOD close to 75 does seem to be helping with the fuel efficiency. However, my biggest challenge in maintaining LOD = 75 is because the throttle level- forces needed for LOD =75 seems to vary constantly - that is to say the ICE RPM and GPH tend to be all over the place going back and forth - I am guessing here but I suspect that this variation is caused by the Prius electric motors might be going off-and-on in an intermittently fashion to provide load assistance - and this changes the load on the ICE intermittently. I drive on very hilly and curvy roads and I suspect this may exacerbates the need for intermittent electrical motor power assistance.

 

I realize getting that many miles out of a tank (impressive number!) is a game, and I'm all for games, but I'm glad to read that you don't plan to overfill the tank again. Couple of reasons that people brought up, plus, it's not good for the environment. The fuel going into your car is very cool, because it's coming out of underground tanks. When you put it into your car, it will get warmer, especially in the summer, and the expanding fuel can get into your vapor filter and can run onto the ground. Certainly not what you want. As they say in CA: "stop at the click." OK, I stop at the second click in case the first click was a mistake, but usually, that's like 25 cents.

I'm too much of a noob to post a link, and this site is pretty good at figuring out a spelled out link. There's a nice summary at that web site associated with the Tappit Brothers, if you search for "top off tank."