Observations -- Toyota Camry Hybrid

[jrbjrb]

Ran 150 miles today starting at 4200', over and back 5280' pass at 60 deg f, mostly at 3000' with slower speeds than speed limit when not in traffic. Got 44 MPG. The motor-battery-wheels picture was very interesting and EV mode works at higher speeds than I expected. Watching the power flow arrows can be mesmerizing so don't get "pilot fever" and watch the instruments too much :-)

[jrbjrb]

Met a guy who uses Prius's for delivery vehicles (he's also a truck stop mechanic/business owner) and as I've only seen one other 2012 Camry Hybrid and her owner wasn't mechanically inclined I decided to do an unauthorized test. I apologize for not posting more often (two other sites have annoying glitches) while this one is well designed....I'll be back more often. BUT the subject today is my 97 mile (vehicle has 3500 miles on it now) hypermilng test yesterday from 4200' to Trona in California and back. As maybe I mentioned before Toyota claims they won't have the front alignment specs until July and my partner doesn't want me changing anything so I merely raised the tire pressure in all 4 tires to 50 PSI for yesterdays test. Cross winds weren't present so there was no 'dancing front end'. Started out at 90+ degs F and read 102 deg, 108 deg (Trona) 104 deg half way back, and 97 deg at the end. Used air conditioning 98% of the time and ran a Dometic freezer in the trunk off the auxiliary battery set on 0 deg F. Final mileage was 52.4 mpg and the trip took 50% longer than it would be normally driven complying with other traffic. Normal mileage with 30 psi front and 40 psi back is around 38 to 42 mpg. I'll keep the tires at 50 psi and report back in a thousand miles or so. More road noise is heard at the higher tire pressure so I'll probably buy a light weight -high quality compressor and change tire pressure often. PS...the liter of Mountain Dew in the freezer (set on 0 deg F) only went down to 35 deg F as it was so warm in the trunk space with the dark grey exterior paint color. To use this freezer more efficiently it must be up front (where it will also reach the front 12V socket).

[jrbjrb]

The most significant thing I forgot to mention......starting up from a full stop in EV mode with 50 psi in the tires is now doable without tripping the motor to run. This is the biggest fuel saver compared to normal and lower pressures. Happy hypermiling!

[brick]

Don't go overboard with the EV starts. Once you hit ~15mph you should be letting the ICE pull the load.

[jrbjrb]

How about explaining that after 15mph go with the gas engine/ICE? I figure for economy/hypermiling anytime the engine isn't running is the best. So, I'm developing skills that control the ICE's operation, and the only reason to have the engine running is to charge the battery. This causes a lot of actions/decisions by me concerning traffic, elevation change, wind, and is affected by my guess of what is ahead. I have still not learned or seen how to do this best (sweet spots, technical performance peaks, etc). But 52.4 mpg is amazing to me in a 2012 Toyota Camry Hybrid LE. I can't believe that my wallet is not deflating when I tank up once a month (I don't drive it often).

[jrbjrb]

For people considering hybrid hypermiling the the most important factor is the number of lanes available in the direction you are going and secondly the inconvenience you impose on your fellow drivers. Out here on the desert 2 lane roads (one lane each way) cause high speed people to get 'jangley/pissed' if you force them to slow down. On the freeway during rush hour the only time you will hypermile is when your stuck at 0-10 mph in a jam. Back up to whatever the traffic forces you to do won't be hypermiling. And add 50% to your driving time for going slow (more economical) for hypermiling. My wife kicks the ecodrive off and never EV's so she drives it just like her 1998 Camry and gets 40 mpg ---more or less.

[ItsNotAboutTheMoney]

Originally Posted by jrbjrb

How about explaining that after 15mph go with the gas engine/ICE? I figure for economy/hypermiling anytime the engine isn't running is the best. So, I'm developing skills that control the ICE's operation, and the only reason to have the engine running is to charge the battery. This causes a lot of actions/decisions by me concerning traffic, elevation change, wind, and is affected by my guess of what is ahead. I have still not learned or seen how to do this best (sweet spots, technical performance peaks, etc). But 52.4 mpg is amazing to me in a 2012 Toyota Camry Hybrid LE. I can't believe that my wallet is not deflating when I tank up once a month (I don't drive it often).

Hybrid 101: all charge in the battery is ultimately obtained from the running the engine so it usually the case under load that EV is less efficient than using the engine. To use EV you go engine-power split-inverter-battery-inverter-power-split-wheels instead engine-power split-wheels and there's energy loss in the extra electrical steps.

In particular, engines are inefficient at low speed and under very low load; electric motors are efficient at low speed and batteries are efficient at low load so if you can accelerate in pure EV at low speed it's good. However, there comes a point at which use of the engine is more efficient.

I don't know if the 15mph advice is correct for a Camry Hybrid but it's correct for a Gen 2 Prius. A Gen 3 Prius can, I believe, be more efficient in light EV to 17mph. With the Camry's larger, less efficient engine, it may be that slow acceleration in EV is better to higher speeds. Perhaps Wayne can answer that question.

[Bennett]

In the HCH we don't get the luxury of an off-the-start EV mode, as the ICE kicks in from autostop once the brake is released, but I take advantage of the EV torque along with the ICE for at least the first 15mph and sometimes up to 30mph if I'm in traffic and some bugger is on my tail - after that I "cancel" the assist and run on ICE only for the rest of my acceleration/cruise.

" Cancelling" it basically means lifting off the throttle a bit, rpm drops and the CVT moves up a bit, then re-apply throttle and car stays at same speed, no EV assist, lower engine load and higher mpg. If you're careful you can re-accelerate at the new CVT ratio without re-engaging the assist, but it's slow and that's why I don't do it in busy traffic. Keeping out of the battery pack is one way I've improved my mpg significantly.

[jrbjrb]

The engine does not start when the 2012 Toyota Camry Hybrid is in EV mode from a dead stop if light acceleration is used. Not sure what an autostop is.

[Bennett]

Autostop is basically when the HCH cuts out the ICE at low speeds - it does have an EV mode of sorts but nothing like you get with the toyotas. Under certain conditions it won't autostop so you're forced to just turn off the car yourself (FAS - forced autostop) to save gas.