I am a new owner of a 2007 Barcelona Red Touring Ed. Pkg. 6. I flew to Oregon to get this configuration, and I drove the car back home to North Texas.

Some things I'm still not sure about:

When does the engine transition from electric to ICE? I can't tell that there is a certain speed that it kicks in, or if it's a certain amt. of time after you begin to accelerate or what. I can't seem to figure out which engines (and the battery) are supposed to work under what driving conditions, or why. Meaning, I can see the diagram on the nav screen & know what's working when, just not figure out the... explanation of the technology, I guess.

I am getting between 38 & 40 mpg right now. Most of my daily driving right now consists of shorter trips, with lights and stop signs, so that doesn't really surprise me, I guess, after reading a little in these forums (short trips=worse gas mileage, right?). Soon, though, I will be making a 50-mile-each-way highway trip to and from Plano twice a day (I'm in Sherman). I should be able to expect better mileage than that using some of the tips around here, shouldn't I?

When I coast down hills, should I put the car in neutral or keep it in drive? It feels like (and seems confirmed by tachometer) that when I keep it in drive, the friction actually slows the car down. Is that desirable or not?

I'm not promising this will be the end of my ding-dong newbie questions, but they are the most pressing ones right now! Thanks, all!

Welcome! Congrats on the new Prius

I would suggest poking around the FAQ in the Prius forum to get some answers to some of your questions.

The ICE kicks in around 42mph, or if you've accelerated faster than the electric engine can propel you. It's basically an on-demand type power boost. Slower acceleration will give you longer periods of electric only acceleration.

Yes, as you suggested, shorter trips means lower mileage, mainly because it takes some fuel to start the ICE up when you power on the car. This can be gotten around by installing the EV mode button, which will allow you to start in EV mode and drive for a period of time on the battery alone. This does void your warranty though, so it's not the ideal solution for most people.

The better solution is to schedule most of your stops in one trip so that you don't have to start the car numerous times when the engine is cold.

People have different strategies for going down hills and driving on flat ground etc. Do what you feel works best. I typically try to feather the accelerator into the no bar mode on the MFD which is essentially neutral. Some people prefer to switch into neutral. The choice is yours. If you just let off the accelerator, you will be in regen mode, and will be slowing down. You can give it a bit of gas to get into the neutral or battery modes and that will help you coast farther.

Just a few quick answers, I'm sure you will get about 30 responses

Big help for short trips, get an engine block heater.

Wayne

Welcome to the CLUB!

In October 2005, I flew to Fort Worth Texas to pickup my used, 2003 Prius and drove 800 miles back to Huntsville AL. I broke up the trip into ~2 hour segments and using cruise control, measured the MPG. My first segment was 39 MPG and I briefly thought about going back. Instead, I continued the trip and used different cruise control settings that led to my first MPG vs MPH chart:


Since then, I used my own spreadsheet and the Greenhybrid database to figure out how this car actually works.

As others have pointed out, 42 mph is critical speed between two control laws. Below 42 mph after the ICE is fully warmed up, about 5 minutes, the car can cycle between electric and engine power. The key is the load on the car. If you're on a flat road below 42 mph, the engine will, if there is enough battery charge, turn off and you'll get great mileage. But it usually works best if you keep a 'guard band' below 42, say 38 mph, so you avoid triggering the other set of control laws.

From 42 mph and above, the ICE turns constantly even when going down grades. In fact, there are cases when a little battery power will be used to keep the ICE spinning (rare but it happens) with the fuel off. But the real challenge is to keep the engine in 'the sweet spot' by keeping the speed closer to 65 mph and under 70 mph. Don't forget to include headwinds as part of the vehicle speed.


We've tried to collect the lessons learned and put them in the FAQ. In my case, I changed tires a year later and put Sumitomo, low rolling resistance tires that I can run at 50 psi (check your sidewall maximum pressure.) I also change my own oil and it is always at 3/4 between the fill marks. These two maintenance tricks help a lot.

This is one area of debate. There are folks who belong to the 'feathering the accelerator' school but I'm not one of them. But going down a grade, I prefer to let the regenerative drag built into the car moderate the speed. It isn't friction but actually a charge being put on the battery that can later be used for electric mode.

There are only a few times when I used "N": (1) morning warm-up without a block heater, and (2) coasting to a light. Without a block heater, I will get to neighborhood speed, 25 mph, and slip the car into "N" to coast down the street. My instrumentation shows the ICE continues to run but the fuel burn goes down from ~7 grams/sec to ~3 grams/sec of throttle air flow. As I approach a stop sign, I slip back into "D" to get the battery regeneration. However, I have practice with my car so it is almost second nature.

The other time I use "N" is when I'm looking at say a couple of blocks to what is likely to be a stop. I'll let off on the accelerator to get the ICE to stop and then use "N" for a totally energy free coast. Using "N" turns off all MG1/MG2 operation, effectively turning off the electric vehicle (EV) mode. So if the ICE is off, it stays off and if the ICE is on, it stays on because MG1 is used to 'de-spin' the ICE.

No problem because as you ask questions, I think about whether or not the subject has been covered in the FAQ. The challenge is balancing information, the details, without blowing the FAQ out into something too big and intimidating. You are always welcome to ask questions and the good folks here will do their best to answer. In the dialog, we all learn something.

BTW, I would recommend recording your mileage in the database. Over time, it will give you insights about what works and doesn't work. It is the best teacher.

Bob Wilson

Operation Iraqi Oil Freedom:

Automatic, stock, project car.

My other 1500 cc car:

Automatic, stock, backup car.
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