Gas Mileage No Better than Civic HyBrid?

Probably the most counter-intuitive aspect of these cars is that you want to use the battery as little as possible.
The two things that you mention that I'd get away from are 1) using the "B" selection on the shifter and 2) working hard to stay in EV mode.
Number 1 is because while there is some battery regen while you do this, you can recover much more of your kinetic energy by simple braking. If traffic permits, try to brake early enough to keep the regen area of the HSI a little less than full.
The car has its own strategy regarding the state of charge for the traction battery. There's no sense trying to manipulate it.
EV mode is efficient in stop and go traffic and other slow (say, 30 mph or less) mostly because using the engine isn't so efficient in those speed ranges. At any other time try to push into the upper half of the ECO range so that the engine is doing the bulk of the work. Whatever you pull from the battery for EV use was put in by the engine (with some lost) and more is lost in driving the motor with it. The 100 mpg you're seeing as you first start off is because the engine hasn't started yet. As seductive as the "100 mpg" indication is, there's no free lunch. Your engine already did the work to put that energy into the battery and you're only getting part of it back.
You no. 7 observation is perfectly normal. It feels like you're getting no electric boost mainly because you're using ECO mode. I go through phases in which I can't stand ECO mode. You might do better to turn that off to see if it helps.

Sorry about all the words. Let me summarize:
- Don't worry over the rate you accelerate at. You might as well keep up with traffic while you're accelerating.
- Coast when you can. If you don't need to slow down, put a little pressure on the gas to get out of the regen zone.
- Brake early so you can brake gently.
- Unless you need to accelerate gently, push enough to get the engine involved in any accelerating you do.

- Chris

P.S. - Welcome to PriusChat!

 

Chris is correct.

Stop trying to maximize regen during braking. Instead, coast/glide for as long as possible. You should only touch the brake just before you stop. In theory anyway.

Do not try to keep the car in EV. You want to use as little energy as possible and this includes EV power.

If you wanted max efficiency you should have skipped the Persona model and the mpg sucking 17" wheels. Do you know which tires you have? I pray that you don't have the Primacy MXM4 upgrade.

I would also make not of how quickly the engine shuts down at a stop light with the A/C and heater off. If it takes a long time for it to shut off despite the engine being warmed up then you could have a bad 12v battery. Sometimes the dealer showcases the car and wears out the tiny 12v battery prematurely. This can have a negative affect on fuel economy. If you or the dealer ever had to jump the car I would be very suspect about the battery condition. This happened to my Plug In so I made them exchange the battery as a condition of the sale.

 

Absolutely.
My daily commute gives me the choice between 23 miles all freeway (including a mile or so surface streets at each end) or 20 miles at a slower speed (mostly 45-50 mph of Woodward Ave) of which about 6 miles is freeway at one end. I reliably will get 5-7 mpg better on the second route.
If you opt for the freeway you'll do noticeably better at 65 mph than 70 mph but you might not be comfortable travelling much slower than the general flow.

 

Interesting. I had not seen the Bridgestones offered as an OEM option for the 17" wheels. I don't know what to expect in terms of mpg with those tire.

The OE Toyo Proxes A20 incur a 1.5-2mpg hit it seems and the Primacy MXM4 is about a 3-4mpg hit. All compared to the OE 15" tires.

You don't mention your usual commute. How many miles do you drive per trip?

 

Chris is correct

1. Do not use B mode stay in D mode.
2. Do not use ECO or EV mode
instead use Normal or Power mode.

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The Regenerative braking normally recaptures about 10% to 40% of the braking energy the rest is lost as heat - it is a lossy power conversion. Even more so than with the Honda Civic Hybrid, it is more energy efficient to slowdown the Prius gradually without using eithe the regenerative brakes or the hydraulic brakes.

Recharging a depleted HV battery via the gas engine is not energy efficient. In stop and go traffic jams that is likely to longer than 5 minute use the gas engines and avoid using the electric motors.

On flat roads, the electric motors work to assist acceleration at speeds under 25 mph. However, if the Prius is going downhill whill accelerating the the electric motors can accelerate the Prius has high as 45mph before the ICE jumps in.

 

"I do use the "B" mode on the shifter when I see traffic slowing and go back to "D" for normal driving"

Just keep it in Drive...slowing traffic IS normal driving. I don't know why you would think you need to shift it into B for slowing traffic.

My understanding is "B" is suppose to be used very rarely, on long descents down hills or mountains.

 

well done! highway is tough, mostly related to speed.

 

When I drive, I get 55-60 MPG (indicated, suburban/city only) and I'm usually one of the faster ones on the road (limit+10MPH). When a family member drives it, exactly 40 MPG (again, indicated). It's all about the driving. I always watch HSI to accelerate fast and as short as possible and coast as much as possible.

 

While its well known fact that higher the speed reduce fuel efficiency - there is some other factors at play that can change overall fuel efficiency.

This year while studying hypermiling at superhighway speeds I learned that one of the key factors in getting good fuel efficiency (high MPGs) is to avoid a rich/saturated fuel mixture while still going fast enough that you are not impeding traffic (the ScangaugeII xgauge LOD is suppose to identify when the ICE is using a rich/saturated fuel mixture). This however is only half the story since the fuel mixture represents only the how efficient the energy demand rate is and does not equate to how efficient the final output of the engine is. That is to say - how hard you have to run the gas engine to get a certain speed is dependent on the timing of when you press the accelerator to gain or maintain momentum/speed which dependent on variations in the output efficiency of a motor vehicle due to changes in the speed, elevation, road conditions/surface , weather, and traffic. There is a balancing act of sort between demand efficiency (when the Prius power plant operates most efficiently) and output efficiency ( when the driving conditions allow Prius gains speed/momentum more efficiently). At superhighway speeds both the Prius and the Civic Hybrid rely more on their gasoline engines-transmission and aerodynamic design (which are approximates if not in the same class) than their hybrid tech. High Speed negates most of a hybrid's advantages so that the biggest factor in getting the best fuel efficiency ends up being the driver and not the car.

 

I thought gen iii didn't do fuel enrichment, unless cold or maybe when near the rpm red line.

 

On freeways, I could easily get 55 to 60 mpg. On local roads with low speed limits, I could get as high as 70 mpg. Of course, in order to get high mpg, I had to put the car in "Eco" mode and take it easy on the gas pedal. Furthermore, I also use pulse and glide even on the freeways whenever there's no cars behind me. Gliding on the freeways is less efficient than on local roads but still will save you gas. I generally like to glide below 40 mph, that's when the computer stop the ICE from turning completely. When you're gliding above 40 mph, the ICE will turn even though no fuel is fed into it. Having the ICE turning will increase drag and as a result, you wouldn't be able to glide as far.

 

The 3rd gen Prius burns quite a bit of fuel during warm up(to heat up the catalytic converter) and when the HSI display is in the Power area. The 3rd gen Prius liftback is a very heavy at +3000 pounds and require quite a substantial amount of power to accelerate quickly especially on hilly terrain ( because a Prius c is lighter this is less of a problem and because the Prius v is heavier this is more of a problem). Because the Prius' electric motor's ability to assist in acceleration is limited mainly at lower speed except when going downhill (this is due to the NiMH battery pack which can't provide enough current/power - this electric power limitation is less apparent on a Plug in Li-Ion battery pack) - accelerating quickly and hard over 30 mph will cause the Prius' Atkinson Cycle ICE to burn more fuel. Accelerating the Prius for any extended time period in the POWER (rightmost end) of the HSI display (>= 2.00 gallons per hour , >= 2000 Revolutions per minute ) is normally very inefficient

The hypermiling technique I am using modulates the accelerator pressure so that the ScangaugeII xgauge LOD needs to be more often than not between 70 to 80 percent . When doing this the RPM and GPH will vary widely depending on the speed of the car and the grade of the road, but the combination energy usage meter HSI display is normally slightly to the left of the "ECO" capsule to right dab in the center of the HSI display.

 

Weird.

My wife is avg. 45+ in our GenII.

I'm avg. 55 in our Gen III.