Toyota salesman claiming 2010 will get 1.8 L engine

my GS350 AWD does around 17l in the city - which is still bad, but not as bad as 20l, in supposedly more efficient engine .

Otherwise, Prius was the winner with 6.xl and next up was Fiat500 with 9.5l. .

 

it is city... thats how it works. Yaris 1.0 would get 7l-8l.
European cities are very different from NA - a lot of stop and go driving, only 300m between traffic lights, etc, etc.

Their findings pretty much matched what I saw on our Toyotas - Rav4 and Auris. Almost exactly the same numbers.

 

Hmm, "Improved NiMH battery" makes me wonder if they are going for something like the Hybrio technology that Uniross use in small capacity batteries.

Standard NiMH batteries lose a lot of charge in the 24h after being charged whereas Hybrios don't and still have something like 70% charge after 12 months (according to their marketing).

Anyone know if the existing battery already has this feature? Hybrio and similar (other makers also offer similar technologies) seem to be a fairly recent innovation.

 

Standard NiMH batteries do not lose "a lot" of charge every day. They typically lose about 1% of their charge a day, or 30% a month.

Low-discharge batteries won't make much of a difference for most people who drive their car at least every couple days or so.

What would make a difference is an improvement in maximum charge/discharge rates by using cells with lower internal resistance. This would allow for more regenerative braking under higher loads and also allow more output from the motor to avoid starting the engine for brief surges of power.

 

Spot the difference:

Please respond to what I said, not what you think you read.

Nickel-metal hydride battery - Wikipedia, the free encyclopedia

 

So Wikipedia says that a typical NiMH cell loses 5-10% of it's capacity after the first 24 hours due to self discharge.

This sounds high to me based on experience with consumer grade AA NiMH cells. Perhaps I'll have to run some actual tests to verify.

Regardless, I assume that the 5-10% after the first day is on a fully charged battery. Since hybrid very rarely sees a completely full battery, I don't think that this particular characteristic is all that important. If we were talking about batteries for a PHEV, then yes, it may be, but then again, you'd typically leave your PHEV plugged in until you're ready to use it. And even then, to maximize battery life you would avoid fully charging the cells.

The existing battery in the Prius does not use low-self discharge technology.

So again, I think that any improvements in battery technology will be in reducing the internal resistance and increasing maximum power output of the pack.

Currently, the generators in the Prius could pump out about 67hp, but are limited to about 30hp because of power limitations of the battery pack.

The current Prius is using battery technology from the year 2000. NiMH battery technology has improved significantly since then (back in 2000 you could only get ~1500mAH AA cells, now you can get cells with about double that capacity).

 

If you are going to quote Wikipedia, here is the full Wikipedia response ...

Self-discharge
NiMH historically had a somewhat higher self-discharge rate (equivalent to internal leakage) than NiCd in the past. However, this is no longer the case. The self-discharge is 5-10% on the first day, and stabilizes around 0.5-1% per day at room temperature.This is not a problem in the short term, but makes them unsuitable for many light-duty uses, such as clocks, remote controls or safety devices, where the battery would normally be expected to last many months or years. The rate is strongly affected by the temperature at which the batteries are stored with cooler storage temperatures leading to slower discharge rate and longer battery life. The highest capacity cells on the market (> 2700mAh) are reported to have the highest self-discharge rates.

Low Self Discharge Batteries

Main article: Low self-discharge NiMH battery
A new type of nickel-metal hydride battery was introduced in 2005 that reduces self-discharge and, therefore, lengthens shelf life. By using a new separator, manufacturers claim the batteries retain 70 to 85% of their capacity after one year when stored at 20 degrees Celsius (68F). These cells are marketed as "ready-to-use" or "pre-charged" rechargeables. Besides the longer shelf life, they are otherwise similar to normal NiMH batteries of equivalent capacity and can be charged in typical NiMH chargers.
Some brands that are currently available on the market (Nov 2007) are Accupower Acculoop, Ansmann MaxE range, Camlink Ready 2 Go, Duracell Pre-charged, Gold Peak ReCyko, Kodak Pre Charged, Nexcell EnergyOn, Panasonic R2, Rayovac Hybrid, GE/Sanyo Eneloop, Sony CycleEnergy, Titanium Power Enduro, Uniross Hybrio, Vapextech Instant and VARTA Ready2use. As there are only three manufacturers of this new type of cell (Sanyo, Panasonic, Yuasa-Delta) most of these brands are rebranded OEMs.
Low self discharge batteries have lower capacity than standard NiMH batteries. The highest capacity low self discharge batteries have 2000-2100mAh and 850mAh capacities for AA and AAA batteries, respectively, compared to 2800mAh and 1000mAh for standard AA and AAA batteries. However, after only a few weeks of storage, the retained capacity of low self discharge batteries often exceeds that of traditional NiMH batteries of higher capacity.

A note that these are stats for AA AAA etc batts. But the important statement is...

The self-discharge is 5-10% on the first day, and stabilizes around 0.5-1% per day at room temperature.This is not a problem in the short term.

Now I realize that the HV battery is just a boatload of small cells placed in a series / parallel configuration, however read the above full Wikipedia and it makes sense, well at least to me!

Have Fun All de Pat KK6PD

 

Panasonic is leading battery manufacturer in the world, so you can rest assured that whatever battery tech Prius gets, it is going to be state of the art for that time... Otherwise, what other NiMH batteries last as long and can be recharged as long as Prius?

 

I did think that perhaps the initial self-discharge might only happen from full charge, but I don't know that to be true. It's certainly plausible.

I use a lot of NiMH AA batteries for powering GPS units and the amount of energy wasted keeping the batteries topped up continually is not good. I recently started using low self discharge batteries and it means I don't have to waste energy keeping them topped up. I can charge them ahead of time and be confident they will only lose a small amount of energy.

I would think that I high self discharge in the first 24h could be a concern if you are using the car maybe only every other day or so. You have to replace that 5-10% from somewhere, and it comes out of your pocket. However I worked out at our petrol prices (about £1.15 a litre) even if you lost 10% of the total rated capacity that's only about 100Wh. Assuming only 50% efficiency that would still only come to about 2p in petrol costs.

I can't quite decide if I want a Prius or not. I almost bought an 08 model but I think if you are only doing 5K miles a year then the cost/benefit ratio isn't so good. My 12yo car is also capable of over 40mpg (US gallons) and getting a little bit more but using a lot of resources to do so doesn't seem that clever at the moment.

 

IMO, it is not about the cost benefit ratio. It is about reducing dependence on oil. It is about reducing emissions. It is about reversing the fuelish extremism that predominates in the US. The Prius is the first step towards a fully electric/alternative engine. Money is better spent on other things, like clean fuel sources.

 

Sure - US or UK (where I live) oil dependency is a big problem. But I do 5K miles by bicycle (actually this year I might even hit 7K, I already have 4360 miles logged), and ~5K miles by car. If I bought a Prius to replace the 5K miles done by car then I don't know that I'd ever recoup the energy cost (that's what I really mean by cost/benefit) of the new car. The old car still works, it's a lot smaller and simpler than the Prius. We're not talking Hummer vs Prius here.

Once it gets to the point of the old car being beyond economic repair then the equation will balance up a bit, since it will need to be replaced. That's one reason why I'm interested in seeing what the 2010 model will be like because I think my car might just about manage to last that long. Or it might not.

(Sorry for the thread hijack, it's gone a bit off course now)

 

Sorry but thats just silly. The 2010 is being redesigned from the ground up as a completely new car. What difference does it make what kind of battery is in it? Anyone who has spent some time looking at it quickly realizes that for HEVs, there is very little advantage to Li-ion over NimH anyway. HEV performance is not a strong function of battery capacity. People have doubled the capacity of the Prius battery and it makes almost no difference. The US Gov found that even with the battery capacity degraded by 1/2 there was little if any difference in mileage (gen 1 @ 160k). Taking advantage of Li-ion's specific energy density to cut the weight of the battery modules in half would save you a whopping 32 lbs. If you can improve specific power or lower resistance that would help, but the modules in the Prius are no slouch at 1.3kW/kg. That rivals many Li-ion battteries. Particularly as a Li-ion pack of the same capacity and half the weight would have to have double the specific power just to put out the same current.

My biggest hopes are that they can take what they have learned from the Camry and Lexus hybrids to improve the Prius' regen efficiency and lower emissions. The fact that the GS450h and RX400h have lower tailpipe emissions than the Prius is a little embarassing As far as the engine size, as others have indicated there is lot more going on in the Prius than just displacement. A newer, more sophisticated 1.8L could easily be more efficient than an older 1.5L. Beyond that the key in an HSD is matching the engine properly to the rest of the system so that it stays in its peak efficiency range as much as possible. A smaller engine working harder to supply the required power could easily be less efficient.

Sources have indicated that the new design is taking Li-ion and the plug option into account, so when the time is right they can transition to the new pack without another major redesign.

Rob

 

maybe a new design 1.5 or even maybe all new 1.2 will be better then a 1.8
wy not make a all new 1.2? better then the current old 1.5

 

or why not design new 1.8 that is better than current 1.5?

Small engines are not at home at highway - they have to run at higher rpm, which means bigger consumption. Thats why they made it 1.8.

 

Hi All,

RPM is not the whole story. Cylinder size effects efficiency, due to the finite size of molecules, and rates of burning effected by the molecule sizes and density. I am no expert, but there is probably an optimum cylinder size for low-altitude combustion. Fewer parts are cheaper. So why do they make V6s and V8s ? Its probably to be able to keep the speed of the piston up fast enough to work with the combustion.

But, most likely the reason they made the engine 1.8 liter is so its a common block with the Corrola and Matrix. Toyota is known for putting together cars with common parts amoungst several cars. This reduces the cost of the parts. Engine blocks are very scale dependant parts. One article I read is that Toyota had like 1/4 th the seat rail part numbers than Chrysler. At the time of the design, the Yaris was not known to be as high a volume car as the Corrola and Matrix. Does anybody know if the Pontiac Vibe uses the Toyota 1.8 liter engine ? If so, that would be a clincher.

If they were going to do an engine specifically for fuel economy, one might see a 3 cylinder 1.5 liter. But, it would be a custom engine only used in the Prius, and as such probably add 2 or 3000 dollars to the Price.

 

Pontiac Vibe is basically the same car as the Matrix with different sheet metal, so yeah, the engine should be the same, too.

 

the current prius runs between 1200-2200 rpm on the highway
dont think that is high for a 1.5