At startup, the backup requires at least two starts from a dead stop. However, startup with a straight pull-out avoids one full stop. Unfortunately, the ICE is running in an inefficient state so starting from a stop is especially energy expensive.

Bob Wilson

 

Backing up does not use the ICE. If you are talking about the ICE warmup, it was going to do that anyway. and besides, the backing up is complete before the ICE starts for warm up.


Pulling straight in and backing out uses 2 starts from a dead stop, both on leaving.

backing in uses 2 starts from a dead stop, one when going into reverse from a stop after passing the spot, the other when you leave.

Stephen

 

I think backing in has the potential to be more beneficial in the HCH (what Hot Georgia drives) than the Prius. However, it can still be beneficial in the Prius. If you do not back in, there is a greater chance that your ICE will start while you are not moving forward and are in EV mode. This is not good use of the ICE in regards to fuel economy. I think the best case scenario is that when your ICE does start, it is at least being used to propel the car.

Of course, if backing in takes you more time and attempts than pulling in face first, the benefits may be lost. This could happen if you are backing into a tight spot.

 

Let me share some data recorded to quantify what is going on. One caveat, I drive an NHW11, 03 Prius, and the North American NHW20 with thermos has an improved warm-up cycle.

From memory, I'm seeing the ICE initially run very rich with a throttle airflow rate at ~4.5 grams/sec to warm-up and light-off the ICE. Within the first minute, this drops down to about 3.1-3.5 grams/sec and eventually down to 2 grams/sec just before it is warm enough to begin hybrid operation. It is during this first minute of very rich, warm-up that back-out versus pull-out has an advantage. Once the car is warmed up, at the end of a trip, it is not an issue.

BTW, back-in is dependent upon safety. We have a 75 ft driveway and backing in from the street is a challenge. So often, I'm backing out in the morning, which isn't much better. But at work, I can easily back into my parking space. Without a backup camera, I like the improved view when pulling out.

In the morning, I typically start the ICE which runs very rich, +4 g/s, without the vehicle moving. I put the car in reverse and it does shutdown the ICE once I'm going ~5 mph or faster. If I creep out, the ICE remains running. Once I reach the street and brake, the ICE starts up again, in the +4 g/s burn rate. The following chart shows what I mean:


The next mile is driven through the neighborhood at speeds ~25 mph with maximum use of "N". In "D", the ICE burn rate during warm-up is significantly higher than in "N" at the same speeds. There is no accelerator 'feathering' that can mitigate this extra fuel burn. It appears to be a load on the ICE by MG1/MG2 to accelerate warm-up.

Pull-out parking is not a universal solution versus ordinary backup. It is most effective when the ICE is stone cold but certainly safety comes first. Individual terrain and patterns can often make backing out a better answer.

Bob Wilson

 

Always run your ac fan at the lowest comfortable level after cool down.

Always set your temp. to the highest comfortable level.

Only use your headlights when required.

1. The air will be colder as the fan is not heating up the coils as fast.

2. The draw on the battery will be less with slow fan speed.

3. The ac compresor will cycle on and off if the system hits the low level cut off reducing eng. drag and battery draw.

If running heat also use low fan speed and only use defrost when needed.

Hope this helps.
08 FEH

 

Can you explain this more? How significantly does the battery drain FE? We have a very long drive on weekdays (100 miles one way) and use the electrical socket regularly. If we stopped using the socket, would FE increase significantly?

 

I own the TCH so this might not apply to you. However, I have noticed that I consistently get at least 42 mpg on my daily trips to and from work. The following is my strategy:

(1) I accelerate to 40 mph with the instant mpg meter at 20mpg. After 40 mph I slowly back my foot off the pedal till the instant mpg meter is at 30 - 40 mpg(Do this wisely!! If you are approaching an upward hill, keep up the pressure to maintain speed at minimum), do not impede with traffic! This means do this on the far right lane. I continue to my desired speed which is typically 70 - 80 mph.

(2) At this point I am @ 80mph and the instant mpg meter is most likely @ 40mpg. I gradually back off (I do not fear losing speed at this point, because the limit on NJ Turnpike is usually between 55 and 65mph) the accelerator and watch the instant mpg meter go up to 50mpg. I stay at 50mpg for as long as the car stays above 65 mph. If I feel it trying to drop below 65mph, I depress the accelerator gently till I reach a position that maintains that speed and back off accordingly until I reach 50 mpg. I never let the meter go all the way to 60 mpg (too little power most of the time) and try to keep it between 45 mpg and 55 mpg.

(3) If you are in a city setting, do not accelerate to stop lights!!! It is dangerous and a waste of gas!! Let the vehicle coast for as long as you can. If possible, accelerate to 40 mph briskly and let go of the accelerator and watch the car get into EV mode (depends on SOC of battery). Try to maintain this speed in EV mode for as long as you can and watch your FE rise!!!

 

The more the draw on the battery the less mpg you will get.

If you use the ac try to get it to cycle the compresser on and off.

If coasting turn the ac to max if you need more cool air.

When pulling up a hill just use the fan not ac.

These tips will only give a small increase in mpg (1-2) but they are safe and easy.

When pulling up a hill use your foot not cc and try not to increase the pressure on the gas. You will slow down but going down you will increase speed and mpg.

Hope this helps.

 

deleting my post about speeding...

 

What did you say in your post????