Comparison of the Insight and Prius

The CVT reference is extremely misleading. There are actually two types, without almost nothing in common. The predicted MPG is just plain wrong. Toyota has only stated a combined value, never making reference to city or highway. Motor specs for the new model were left out. At minimum, there could have been a mention of increased power since engine info was included. And of course, emissions were missing. Smog reduction is a major objective.

In short, it was a run-of-the-mill review.

But like usual, any attention is helpful. Just look at how little BAS and Two-Mode get written about for perspective.
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You are too kind to call it "run of the mill." It is a nonsense review:

• "as I predicted in earlier posts, it does not offer a lighter-weight lithium-ion" - the author tosses up a straw-man, the 'great and all powerful' lithium-ion and then knocks it down. Bah, humbug!
• Honda "1.3-liter ... 98 horsepower", Prius "98-horsepower ... 1.8-liter" - yet he fails to do a compare and contrast of what that means between the two vehicles
• totally missing: exhaust heat recovery, cooled exhaust gas recirculation, electric water pump, 20% reduction in transaxle loss, 10% more efficient than 1.5L engine - <grumble><grumble><grumble>

I would not be so kind but suggest there are better reviews around.

Bob Wilson

 

2010 Prius will have the technology to increase MPG in extreme weather conditions. Whether it be the extreme cold or the extreme hot. Prius will be able to maintain MPG close to the new 2008 EPA test procedure. These next-era technologies will enable a boost in the real-world MPG.

Cold temperature and short trip conditions are mitigated by recovering heat energy from the exhaust (normally lost to the environment). The idea is similar to regen braking to recover energy. Instead of recovering electricity, EHR recovers heat... otherwise it would take more gas or battery to create the needed heat.

Hot temperature conditions are mitigated by the optional solar panel that would remove the heat built-up in the cabin. In addition to it, the remote with A/C button can cool down the interior as you approach the car. This is a luxury feature for the driver (especially with leather seats) that can boost real-world MPG as well as pride in supporting renewable solar energy.

Cooled Exhaust Gas Recirculation should virtually eliminate fuel enrichment. This would allow peak efficiency even in those sudden accelerations (highway passing).

The HSD powertrain in the 2004 Iconic Prius created synergy (by integrating and seeing as one) the gas engine, electric motors, battery pack and the transmission. 2010 Prius will extend this synergy to include the exhaust and the cabin creature comfort. In short, the synergy will no longer be in the powertrain but the entire car!

Honda Insight II will not have this level of maturity or robustness as the 2010 Prius. The way I see the two are like an economy hybrid vs. state of the art luxury hybrid.

 

"2010 Prius will have the technology to reduce MPG in extreme weather conditions."
I jumped in fear at the lead line on the thread..I know you mean increase an not reduce MPG
We don't want some outsider quoting you !

 

Thanks for the catch snead_c. I fixed it to say "increase". I meant to say "reduce MPG loss" but it would be a bit confusing... so I changed it per your suggestion.

 

The Winding Road article on the new Insight is a worthy read. The Insight and Prius seem to be vehicles for different markets within the hybrid arena. I'm not sure that decontenting the Prius will match the Honda however if I were in the market for a small, inexpensive (if Honda dealers don't pad the sticker which they usually do with desirable cars), and high MPG car, I'd at least drive one.
I happen to like a proven technology that meets my hauling and quality needs.
I happen to love our Prius :cheer2:

 

Official EPA mileage estimates for 2010 Honda Insight have been made public. Here they are:

2010 Insight City/Highway/Combined fuel conomy: 40/43/41 MPG

Compare these with the

2009 Prius City/Highway/Combined fuel economy: 48/45/46 MPG

and

2010 Prius City/Highway/Combined fuel economy: ~ ?/?/50 MPG (estimated)

So, could anyone please explain to me why other automobile manufacturers can't come even remotely close to Prius in making a truly fuel-efficient hybrid -- a respectable hybrid that is?

 

EGR is used at low loads/engine output to reduce the oxygen content of the gas entering the cylinder (as exhaust gas has virtually no oxygen remaining, it all having been burnt on the previous cycle). Reducing the oxygen means that the amount of fuel injected can be reduced while still keeping the ideal ratio for combustion, meaning that NOx and CO formation are as low as possible.

The conventional way to restrict oxygen levels in the engine is to restrict the amount of air entering, by varying the area of the intake pipe, done by closing the throttle. This, however, makes the engine work harder - compare drinking through a straw versus directly from the cup - and therefore loses power. In contrast, recirculated exhaust gas is pumped out by one cylinder into another. EGR virtually eliminates the throttle plate (it's kept for startup, additional control, and if EGR fails).

Fuel enrichment is for ensuring that every last scrap of oxygen is used up when the throttle is wide open, at maximum load. At this point no exhaust gas would be recirculated - we want the maximum oxygen possible in the cylinder.

EGR helps when the engine is running at average loads - such as steady-state driving at highway speeds.

 

And 2003 Prius City/Highway/Combined fuel economy: 42/41/41

The parts that are under the painted sheet metal are the difference:

• Prius: greatest percentage of electric power to ICE power
• Prius: 12 years of control law refinement with four, distinct releases: NHW10, NHW11, NHW20 and now 2010
• Prius: replace engine driven accessories with electric air conditioner, NHW20, and electric water pump, 2010
• Prius: recovery of otherwise wasted exhaust heat, 2010
• Toyota: in one word: kaizen - Toyota never stopped hybrid improvements and is only in competition with themselves

The only serious, mileage competition, are:

• plug-in hybrids - starting with modified Prius
  • add $10,000 to Prius cost
• electric cars with small engine - the Volt, Fisker, e.t.c.
  • Prius price * 2 or 3 or 'not yet for sale'
• Ford Fusion ('not yet for sale') - the only other manufacturer who continued hybrid development and sales

So when I look at the Honda Insight, a four seat vehicle in the Honda Civic class of vehicles, let's look at the history of the Honda 4-5 seat vehicles:

40/43/41 - 2010 Honda Insight automatic
40/45/42 - 2009 Honda Civic automatic (Huh?)
38/45/41 - 2003 Honda Civic manual
​

Honda continues to compete with the NHW11 Prius, not the NHW20 nor the 2010 model.

Bob Wiilson

 

Reducing the amount of air in the combustion chamber can also be achieved through variable valve timing.
NOx emissions are reduced by EGR due to separating the fuel and oxygen molecules by exhaust gas slowing the progress of the flame front across the combustion mixture reducing combustion chamber temperatures to a point where NOx is not formed, all the oxygen in the combustion chamber reacts with hydrogen and carbon atoms not with nitrogen.

I found this after I wrote the post above
http://www.autoshop101.com/forms/h61.pdf

 

Thanks Mike. It all make sense now.

Dual stage HSD allows the ICE to spin slower at highway speed. 1.8 liter ICE creates more torque at lower RPM to keep the PSD balanced. EGR lowers fuel consumption at low to average loads.

The result is higher MPG.

 

The combination of Atkinson cycle and EGR seems to have synergy effect probably not existed in the Otto cycle EGR. Below is a piece from the RX450h press release:

 

I think this is a misprint:

I could believed "reduce the gas temperatures from about 880 C by 150 C," but going down to 150 C, well it would put out the catalytic converter.

As for elimination of the exhaust VVi, well that is often a decision driven by things having nothing to do with vehicle efficiency. That the 2010 Prius has intake and exhaust VVi and EGR works for me.

Bob Wilson

 

Bob, the 2010 has only VVTi on the inlet cam and the gas from the EGR is cooled not all the exhaust gas. The EGR gas is picked up after the cat so would be very hot, it is cooled to 150 degrees before being introduced to the inlet air passage.
I am a little concerned about condensation and the build up of soot and sludge in the EGR passages. In days of old a major problem was the EGR system being blocked by carbon and other contaminants which were trapped by condensed water on the inside of EGR valves and pipes.

 

Well that is weird. I remember taking this photo at the auto show in the Toyota Prius area:

I could be wrong but I think the press release on the 2010 also mentions dual, VVi valves. The only single VVi I found was the Ford Fusion.

Ahhhhh! I see the problem. I was reading that statement as the exhaust port gas temperature change, not the degree that the exhaust gas was cooled.

Thanks!

In mechanical engineering, we study engine heat cycles and the ratio of the combustion temperature to exhaust port is the prime determent of engine efficiency. What I was looking for was the degree the 880C original exhaust temperature was reduced because the exhaust gas recirculation. Still this is a good number suggesting the original exhaust temperature must have been somewhat over 880C.

I agree! I'm thinking if the exhaust gas were tapped after the catalytic converter, the suspended carbon load would be significantly reduced. When I go out to my Prius and run my finger around the rim of the tail pipe (after it COOLS!), I get a very fine, carbon powder. It is my hope the EGR results in a leaner mixture and even lower carbon footprint out of the exhaust stacks ... we will see.

Bob Wilson

 

I think the Prius Team issued a correction about the VVTi saying it was only on the inlet, the EGR removes the need for VVTi on exhaust.

 

In 3-4 months we should be able to download the maintenance manuals from Toyota. I'm patient and in the big scheme of things, this is not a 'deal breaker' for me. <grins>

Bob Wilson