What did we learn from the Chief Engineer?

Perhaps it's time for me to design an after market package.

Tom

 

The difference is a large portion of car buyers will pay extra to get a moonroof. How many even know about blocking the grill for quicker warmup and better fuel economy. How many people would be willing to pay for such a feature? Not many.

 

Exactly. Suppose this was an optional feature that had a product cost of $50, so Toyota charged $200 MSRP. How many members here would bitch & moan, saying they could go to Home Depot and buy pipe insulation for $5.

 

There was a period in the late nineteen twenties when many cars had thermostatically (or manually) controlled louvres in front of their radiators. Cadillacs ca. 1930 had these. Something like that would make a great after-market accessory for the Prius.

 

Everyone would benefit. Toyota could advertise even better mileage and efficiency, lower emissions, faster cabin heating...and, moveable aerodynamic devices are really cool. Or hot, in this case.

 

Wouldn't stopping water pump have same effect? The pump is electric...

 

x1234,

In case it was missed; Welcome to PriusChat.

I suspect trying to control engine heat with the electric water pump could lead
to localized hot spots at the top of the cylinders/head.

That sounds a somewhat risky.

qbee42,

Yes, by all means, see what you can come up with, I'll be one of the first in line.

 

It's standard equipment on all new BMWs excluding the Z4 roadster and the 'M' series cars, and 'M Sport' models of the regular cars. See BMW's EfficientDynamics microsite, and the Standard Equipment section. They call it 'Active Aerodynamics'.

It's not impossible and it's certainly not ridiculously expensive.

BMW are actually trying, a bit, although within the bounds of conventional spark petrol engines and diesel engines. Anything BMW calls a hybrid is just a mild hybrid with auto start/stop. (Now standard on 1 and 3 series, which also have electric power steering.)

 

I've covered up half my radiator with cardboard. I'll be lucky if the auto A/C turns the heat up to medium before I finish my drive home tonight.

 

I agree with you 100%. But here's another approach: Toyota could have included thermostatically-controlled grill louvers as standard equipment (ie - not an option), with a resultant boost to overall MPG, just like they did with exhaust gas recirc. What if Toyota didn't include EGR, with some smart PC enthusiasts subsequently wishing for EGR as an "option". You could say the masses wouldn't understand its usefulness and wouldn't buy it.

Perhaps Gen 4 Prius will have the thermostatically-controlled grill louvers. But until then, this is a prime opportunity for an after-market accessory. For $200, I'd buy one, even if it was manually-controlled.

 

An EGR valve reduces NOx emissions, most vehicles have them. A liquid-cooled EGR valve is not new either, my 2003 VW has one. If a EGR valve wasn't required, the public would not pay for it as it has no visible benefit and reduces fuel economy. Since it is required, the public and Toyota have no choice but to include it.

Yes, Toyota could have included thermostatically controlled grill louvers as standard equipment but they didn't. They most likely weighed the benefit to mileage and emissions to the cost and asked "will the buyer be willing to pay for this". Toyota has publicly stated that they expect to make normal margins on the 3G Prius. They can't do this by fitting features that the public isn't willing to pay for.

 

I think your right about that, we really don't know whats going on in there yet. Two stage is definitely not the same as two speed, but I'm not sure its as simple as that. In the link Ken sent out, they certainly seem to imply a two speed like behavior. The "THSII w/ Reduction Device" graphic and bullets sound like just what you would expect from a simple gear reduction. Output shaft speed is decreased, and torque is increased. The next graphic and bullets describe the two-stage reduction device. This seems interesting to me for a number of reasons. Here's the link again for reference:
TOYOTA: Company > Technology

1. A simple reduction device is functionally equivalent whether it is in one or two stages internally. If they are functionally equivalent and the only difference is smaller internal gear sizes, why bother to separately describe its functionality?

2. Several of the bullets do seem to claim a functional difference beyond just smaller packaging. "Use of the two-stage motor speed reduction device supports both high output and high vehicle speed." This claim is not made under the single stage reduction device, which describes only the classic reduction gear type behavior. Another unique claim is that the two stage "utilizes the motor’s high-efficiency region more widely than before." Neither of these claims seem consistent with a simple reduction device. A simple reduction device would offer higher torque output, but not support effective operation at higher vehicle speed. A simple reduction gear would also not spread the motors high efficiency operating region over a wider operating speed range, it would generally do just the opposite compacting it into a narrower range. Spreading would require a two speed like behavior.

3. The graph on the left for the two stage case also seems to imply a two-speed operating behavior. They show both the a "low gear" curve and a "high gear" curve. If the high gear curve is simply the internal intermediate output, why show it? It would be irrelevant. If only the final output, the "low gear" curve is available, it clearly narrows the peak output range relative to the single stage graph, which contradicts the claim above. It also clearly offers higher torque output, but reduced high speed effectiveness, which also contradicts the claim above. The only way to get the graph to agree with the stated claims, is if you combine both the red and blue curves. Compared to the single stage curve, this then gives you a wider peak output range, higher low speed torque output, and a higher maximium effective operating speed. To be able to combine the curves, the outputs of both the intermediate "high gear" and final "low gear" outputs would have to be available to the PSD.

I have no idea how such a two speed operation would be accomplished, and fully admit that my mechanical understanding of the PSD is minimal. Damn it I'm an EE, not a mechanic Jim! I do find these hints of a two speed type operation very curious though! I also thought I had seen discussions in the media (not specifically talking about the '10 Prius) that Toyota's latest version of the THS/HSD basically had all the advantages of GMs two-mode system, with essentially none of the disadvantages of added complexity and cost. That also seems to imply two speed operation to me.

Rob

 

How about page-16 of following LS600h PDF...
http://www.toyota.co.jp/jp/tech/new_cars/lexus/ls600h/pdf/all.pdf

Ken@Japan

 

Maybe I've mixed up the acronym EGR with something else. In the original Toyota press release, it was stated: "an exhaust heat recirculation system reduces heat waste by warming engine coolant during cold startup, for improved performance. It also heats up the passenger cabin more efficiently." Is this "exhaust heat recirculation" different from "exhaust gas recirculation"? If it is, then my bad.

 

A term "two-stage" and "two-speed" are different in general, but Toyota uses "two-stage" term as "two-speed".
Please refer to page-10 of following PDF.
http://www.toyota.co.jp/en/ir/presentation/2008/pdf/080905presen_2.pdf

using clutches

I don't know.
Anyone who test drived GS450h/LS600h?

There are two cluches.
Does anyone hear GS450h/LS600h HSD clutch problem?

Ken@Japan

 

An EGR Valve (Exhaust Gas Recirculation) directs exhaust gases back into the intake manifold to pass through the engine again. What is an EGR Valve - What Does My EGR Valve Do - Where is My EGR Valve

This Exhaust Heat Recirculation is something different. It seems be an extra circuit in the cooling system that runs the coolant around or through the Catalytic Convertor to warm up the coolant faster. This would improve emissions and fuel economy, especially during the certification testing.

Both are mentioned in the press release.

 

Much as I respect you opinions in general Patrick, I think you are wrong on this one. Those of us that have gone the pipe insulation route (and especially since I don't have a ScanGuage) HAVE to block conservatively, therefore less than max efficiency. It might be 25F in the morning and 55F later in the day. According to a chart I found in CleanMPG, I could block 100% in the morning but only 50% in the afternoon. What if I'm on a long trip, how much blocking would I need at various speeds and temps? Do I buy a ScanGuage and pull over to the side every time the engine temp pushes up to 190 and pull out another row of foam? I would MUCH prefer an auto system.

As hyo silver said, advertise it for the consumer benefit of 'warmer faster' and even better MPG. Cabin warms faster, heat for defrost available faster. ALL GOOD. I wouldn't pay $1 for a sun roof, but I would gladly pay $100 for an auto blocking system. With auto blocking and heat recovery, the Prius would be the envy of any car owner that drives in sub 40F temps.

 

Thanks for the extra details, Ken! Seems like that clears up a lot, the only remaining thing to confirm is that this is indeed the same as the system in the new Prius. It certainly sounds likely though.

Rob

 

I think Lexus uses "Dual Stage".