Consumer Reports tests speed vs MPG & comes to false conclusion about Honda Insight 2

[Old Tele man]

...the Insight goes "...furthest..." on a gallon is way too simple for unsophisticated readers (duh) to read or understand. What?



...it's simple, really: you accentuate the POSITIVE and they'll accentuate the NEGATIVE. So, which is it, poor representation of the facts or biased writing, or both?

[2000mc]

on the upside... people like pictures charts and graphs. anyone that should be allowed on the road should be smart enough to see that the insight gets the best mileage at each given speed vs. the competitors listed.

the few who thoroughly read the article will almost undoubtedly come to the conclusion that the writer is a fool.

[bwilson4web]

Edmunds ran a mileage test and got these results:


Then Consumer Reports gave us the Honda Insight mph vs MPG for ranges that I'd already been tracking for the Prius NHW11, NHW20 and ZVW30:

Note that I do not consider Consumer Reports conclusions terribly helpful; not when we have three Prius models to compare to the Insight.

An Australian magazine also ran a head-to-head mileage test:


Finally, there are the EPA results from individuals:


What I'm seeing is the speed range, 70-75 mph, is key to a higher EPA mileage rating. The ZVW30 and NHW20 Prius do and they have an excellent EPA rating. But the NHW11 does not and it came in pretty low. So too did the Honda Insight.

I am fairly certain that BSFC at high power settings is the single most important aspect of highway performance. This is something the diesels share, a high BSFC at high power settings. Of course the diesels fall down in the city but that is something they will have to address.

Bob Wilson

[dcb]

Originally Posted by bwilson4web

...the diesels fall down in the city but that is something they will have to address...

I can address that, any driver can address that, more efficiently than a hybrid even, with just their brain

Oh, wait, U.S. Consumers, nevermind...

[Old Tele man]

...uh, how many KILOMETERS to a MILE? or was that LITERS-PER-FURLONG?


...my (YMMV) simplistic summary:

A) hybrids do better in CITY than on HIGHWAY, while...
B) IC-vehicles do better on HIGHWAYS than in CITY.

...and, predominately IC-vehicles don't "...run out of steam..." at >65 mph as small-engined hybrids do (notice the current, larger engined Prius doesn't follow the same downward trend of its two predecessors).

[some_other_dave]

Originally Posted by bwilson4web

I am fairly certain that BSFC at high power settings is the single most important aspect of highway performance.

Why would high throttle settings have any impact on highway FE? When you're at a steady speed on a flat highway, your engine is only generating about 10-15 HP. That says a very low throttle setting to me.

High throttle settings would be useful in getting up to a given speed, so they would be used more frequently in stop-and-go driving. Like in a city with lots of stop signs and traffic lights.

-soD

[bwilson4web]

Originally Posted by some_other_dave

Why would high throttle settings have any impact on highway FE? When you're at a steady speed on a flat highway, your engine is only generating about 10-15 HP. That says a very low throttle setting to me. . . .

This graph includes the power curve for my NHW11 and is not far off from the NHW20 and ZVW30:


You'll notice that:

70 mph -> 25 hp
75 mph -> 30 hp

But that assumes flat land and most roads, even on river bottom, have small dips and rises. These variations push the power requirement up quickly and that is where the inefficiencies come it.

At 10-15 hp, I'll be in the 45-55 mph range, which is great for performance but not what the EPA nor the most reviewers are actually driving. In fact, there are dead stops in the Euro, 'intra-urban' cycle, and though I don't have the EPA profile handy, I thought it had at least one dead stop.

Originally Posted by some_other_dave

High throttle settings would be useful in getting up to a given speed, so they would be used more frequently in stop-and-go driving. Like in a city with lots of stop signs and traffic lights.

A good theory, it seldom works out in practice. Too much of the energy goes to heating the brake pads.

Bob Wilson

[Old Tele man]

...the same reason that parachutes "work" is why going faster takes more "energy" (HP).

...similarly, air resistance approaches 'solidity' (incompressability), ie: going "faster" requires exponentially more HP as you approach Mach 1.0 at sea level.

...the fact that the FE of four of the cars remained almost linear between 55 and 75 mph means their losses were FAR less than typical.

[tjts1]

Looks like the misinformation campaign hit its stride with the nitwit online media.
Consumer Reports tests fuel efficiency vs. speed; Honda Insight biggest loser — Autoblog

[MetroMPG]

Bob - thanks for posting that info-fest. Good stuff.

tjts1 - yes, I've seen the headline & skewed Insight conclusion spreading as well. Here's another random example: Consumer Reports tests fuel efficiency vs. speed; Honda Insight biggest loser - GupShup Forums

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