Electric threshold

[seamusbleu]

Has anyone else noticed that for the first couple of minutes after "starting", the level of electric power is very high? When I first start my car, I back out of my garage, and then put it in drive. By this time, the ICE has usually started. As I go forward, I can hit the accelerator quite hard, and the ICE RPM's don't increase and the electric power level goes way up. This mode continues for about a couple blocks of driving, and then the further use of the accelerator starts to result in the more normal ICE rev'ing.

 

For example, in the engage dashboard setting, I can normally get no more than 3 bars in the electric side of the power meter. In the "early morning mode", I can get it at least twice that high, and get no increase in rpm's. Because I'm in a residential area at this time, I'm quickly up to 30 MPH, and I can safely continue to accelerate, so I don't know what the limits are.

 

I would love it if I could get that level of electric power during normal driving. As it is, you can only accelerate _very_ gently to keep the car in electric-only mode. Heck, even a small increase in the electric-only threshold would be great.

 

I wonder if there will ever by a "chip" for the FFH that will allow those kind of changes.

[fordfever]

I don't know if a chip is available, but I do notice that accelerating to stay in EV mode must be done with a light pedal. I also notice that when in reverse, you can accelerate faster in electric mode than going forward. Seems to have more torque when in reverse. If that was availalbe going forward would be awesome!!

[seamusbleu]

Well next time you do a cold (not winter cold, but just not warm) start, see what kind of EV acceleration you can get for the first, say, 30 seconds.

[lolder]

Has anyone else noticed that for the first couple of minutes after "starting", the level of electric power is very high? When I first start my car, I back out of my garage, and then put it in drive. By this time, the ICE has usually started. As I go forward, I can hit the accelerator quite hard, and the ICE RPM's don't increase and the electric power level goes way up. This mode continues for about a couple blocks of driving, and then the further use of the accelerator starts to result in the more normal ICE rev'ing.

 

For example, in the engage dashboard setting, I can normally get no more than 3 bars in the electric side of the power meter. In the "early morning mode", I can get it at least twice that high, and get no increase in rpm's. Because I'm in a residential area at this time, I'm quickly up to 30 MPH, and I can safely continue to accelerate, so I don't know what the limits are.

 

I would love it if I could get that level of electric power during normal driving. As it is, you can only accelerate _very_ gently to keep the car in electric-only mode. Heck, even a small increase in the electric-only threshold would be great.

 

I wonder if there will ever by a "chip" for the FFH that will allow those kind of changes.

This is not an electric car. It is more efficient to use the ICE to accelerate. The EV components are used solely to allow the ICE to run most efficiently. They provide regenerative braking, transient acceleration until the ICE revs up, and duty cycling of the ICE at low speeds so that the ICE doesn't run continuously at light loads. EV mode is generally less efficient than the ICE at higher speeds and during acceleration. The system is carefully balanced as it is and any "chip" changes that improve some aspect will make another worse (like battery life). Reverse is all EV even if the ICE is running. The ICE appears to be limited in rpm at low throttle settings for a brief period during warmup probably for emissions and they allow more EV assist then. Remember EV mode in a hybrid is inefficient despite what the mpg reads. There is more loss in the generate, charge, discharge, motor EV cycle.

[seamusbleu]

...snip...The ICE appears to be limited in rpm at low throttle settings for a brief period during warmup probably for emissions and they allow more EV assist then. Remember EV mode in a hybrid is inefficient despite what the mpg reads. There is more loss in the generate, charge, discharge, motor EV cycle.

I agree with your guess about the ICE being limited for a brief warmup - that was my thought exactly. I only partially agree with your next statement. EV mode is inefficient when the ICE is used for charging. Otherwise, its very efficient. That's part of the reason hybrids work so well. In high torque situations, like initial acceleration from a standstill, electric is especially beneficial. It would be nice to have the ability to trade off between the existing configuration, and one in which you could get more intense (even if less frequent, or shorter duration) EV mode.

[lolder]

I agree with your guess about the ICE being limited for a brief warmup - that was my thought exactly. I only partially agree with your next statement. EV mode is inefficient when the ICE is used for charging. Otherwise, its very efficient. That's part of the reason hybrids work so well. In high torque situations, like initial acceleration from a standstill, electric is especially beneficial. It would be nice to have the ability to trade off between the existing configuration, and one in which you could get more intense (even if less frequent, or shorter duration) EV mode.

The ICE is ALWAYS used for charging. The only other source is regen braking. All the energy comes from gas and the EV energy comes via the ICE/ generator/charge/discharge/electric motor/drive wheels cycle. This is less efficient than a directly geared ICE/drive wheel cycle. At initial acceleration, MG1 becomes a generator and assists the HVB in powering MG2 until the ICE can provide enough torque. The HVB power is much less than MG2 can handle. If you wanted more EV only acceleration, you'ld need a bigger HVB, more cost, more weight. I don't think US automotive engineers have been very innovative in the last few decades, but these hybrids have had exhaustive design analysis by Toyota, Ford and others. The combination of an Atkinson cycle ICE, eCVT and EV components is brilliant. The idea had been around a long time and computer technology finally allowed it. The overriding consideration was HVB life that would rival the ICE and Transmission and they believe they have achieved that. There will be HVB as well as ICE and eCVT failures. Ford and Toyota say the HVB will last "The Life of the Car". Let's hope they're right.

[oldschool1962]

...............and Toyota say the HVB will last "The Life of the Car". Let's hope they're right.

 

Lee,

 

First off a disclaimer. I don't doubt or challenge what info you have provided and my knowledge about batteries and systems ends with what info I've been given here and in reports available to any consumer. I have no technical experience but only practical from owning the top 2 Hybrids

 

That said.......

 

When we purchased our Prius (09/2009).....it was explained to us that the HVB would last for approx 8 years or at least the duration of the warranty. After that........... we should be prepared to replace it. Something we just expected even when we bought the FFH. So we were a bit surprised when......knowing the similarities between the two systems.........the FFH system didn't perform similar to the Prius. Technically speaking and not fuel economy....the numbers were clearly explained on the window sticker.

 

As far as the HVB is concerned.......We did a break down and based on costs today, our driving habits and fuel savings.......we found that the increased fuel economy that we get in the Prius is just about an even trade for replacement at 8 years. The FFH would take us an additional 3 years of savings to replace the battery. Now....if the economy could be increased to the level we get in the Prius.........we're pushing 58-60 from fill-up to fill-up. I wish I could give you a number for the FFH but I seem to fluctuate between 37-43. The reasons for that have been over explained and it should all end for us in a week or so....... so I'll leave it at that.

 

For now it can be considered reasonable to claim "life of the vehicle" because of the cost and available battery tech but in the not so distant future I can see batteries improving and if an after market one become available that would help the car perform better....then I would welcome a chip to change things. Then again the battery....HV or LV is the one thing I personally would not expect to last much past the warranty period. Then again they may design a battery that fits what we are asking for now AND last the life of the vehicle. It's an open field but....no wait....the oil companies are buying up all the battery tech.

 

We would trade the lowered life.....8 years for the increased economy....that is if things stay relative.

[lolder]

A better HVB would have marginal effects on the fuel economy of the FFH and only to the extent that it had slightly lower charge/discharge losses and was lighter. The charge/discharge losses of the FFH HVB appear already to be the lowest in the industry. See: http://avt.inl.gov/hev.shtml. Under "Baseline Performance, Performance Statistics, Driving Cycle Range" compare the amp hour in/out ratios (you have to calculate them) for the 2010 Prius and 2010 FFH. The Prius has better fuel economy because it is 20% lighter, has better aerodynamics and has a lower power to weight ratio. Toyota designed for low speed EV use and Ford designed for higher speed EV use. They are both excellent designs. The HVB is expensive and integral to the operation of a hybrid, the LV battery is not. Aside from some small number of failures, the hybrid HVBs appear to be going 200-300,000 miles at least. The DOE report on 160,000 mile Honda's and Priuses showed even with as much as a 60 % battery capacity loss in a Prius, fuel economy was unaffected. See: http://avt.inel.gov/pdf/hev/end_of_life_test_1.pdf. Another test of a Nissan Altima hybrid actually showed some characteristics of the HVB had IMPROVED at 160,000 miles. The companies went out on a limb to make these cars with long HVB life and it looks like they have succeeded. If you want to talk about plug-ins, the whole equation changes and the size and efficiency of the HVB is paramount. That is not the case with the gas/hybid. Long HVB life is crucial to both.

Edited May 8, 2010 by lolder

[Grey]

If I were to keep my FFH beyond the battery warranty period and it had a battery failure. I would be able to replace or repair it for under $2,500. Some people are not as resourceful and will pay a lot more.

 

I am encouraged by the fact that many FEH battery packs have gone over 250,000 miles, that I won't face that expense.

Edited May 8, 2010 by Grey

[TonyPSchaefer]

When I first start my car, I back out of my garage, and then put it in drive. By this time, the ICE has usually started. As I go forward, I can hit the accelerator quite hard, and the ICE RPM's don't increase and the electric power level goes way up. This mode continues for about a couple blocks of driving, and then the further use of the accelerator starts to result in the more normal ICE rev'ing.

Yes. Warm-up cycle. Everyone's correct on that one. The Prius does the same thing. If you want to reduce the battery draw, drive your car the long way around a parking lot before hopping on the road. This will give the ICE time to warm up without the hefty draw on the battery (will will need to be regened).

 

Ford and Toyota say the HVB will last "The Life of the Car". Let's hope they're right.

When we purchased our Prius (09/2009).....it was explained to us that the HVB would last for approx 8 years or at least the duration of the warranty. After that........... we should be prepared to replace it.

Your dealer shouldn't be selling Prii if that's the approach he takes. I agree with Lee in that the Prius battery - barring manufacturing impurities or unnatural destruction - will last the life of the vehicle or longer. I have read multiple posts at Priuschat.com of batteries in Gen1 Prii still running strong. There's are multiple Prius taxis that have clocked well over 200,000 miles with nary a drop in charge capacity. Feel free to start a thread asking this question at Priuschat.com and see if you get any different reply by the masses.