Subject: Prius aerodynamics.
From: rotaryeng
Date: 4/12/2014, 9:45 AM
To: AAA-rotaryeng




-------- Original Message --------
Subject:     Re: Why Car Makers are NOT pursuing Turbocompound
Date:     Wed, 20 Feb 2008 16:16:50 -0800
From:     Rotary Engine <rotaryeng@earthlink.net>


A main problem was the longevity of the battery, which needed to be between 7 to 10 years.
The solution the engineers came up with was to keep the battery pack between 60% and
40% charged, proving to be the "sweet spot" for extending the battery life to roughly
that of the other car components.[

The break-even date is uncertain, but according to the head of the Prius team,
the company initially lost money on the Prius.


For any car, aerodynamic losses, which vary roughly as the velocity squared
due to air drag are much greater on the highway than in low speed city driving.
The Prius hybrid has less of an advantage in higher speed open road driving,
typical of intercity driving and LA.

The environmental impact of the car's batteries has been questioned.

Its more aerodynamic body resulted in a drag coefficient of 0.26.

0.04 lower than almost any other car. The weight reduction and the hard, low rolling
friction tires, if applied to any car would reduce the fuel consumption.


The The New York Times in July 2007[99] published an article using data
from CNW Marketing Research that found that just 36% of Prius buyers cited
fuel economy as a prime motivator, while 57% said their main reason was that
"it makes a statement about me." Shortly afterwards Washington Post columnist
Robert Samuelson coined the term "Prius politics" to describe a situation where
the driver's desire to "show off" is a stronger motivator than the desire to curb
greenhouse gas emissions.


Lifetime energy cost

A 2006 study by CNW Marketing Research, Inc. calculated the overall
energy cost of a Prius at US$3.25 per mile and a Chevrolet Tahoe SUV at
US$2.94 per mile. It concluded that 2005 hybrids cost "significantly more in
overall energy costs than conventional Internal Combustion Engine (ICE) vehicles."

Dust to Dust: The Energy Cost of New Vehicles
from Concept to Disposal. CNW Marketing Research, Inc.
(December 2006). Retrieved on 2007-07-27

http://cnwmr.com/nss-folder/automotiveenergy/


Older used Prius's are down to $8,000 and that is just the tip of
the ice burg. Wait until they all need new batteries just like your notebook
computer. At the head of all traffic jams is a Prius. There are a lot
of wackos in Calif.

Hydrogen must come from somewhere. The cheapest is getting it from oil.

You need to put more electricity in than you get out in energy.

Another stupid idea. Hydrogen cars are pure PR for the wackos and the
idiots that believe they can burn water.

The rotary is unique for turbo compound. There are no exhaust valves.
Read this chart again if you are able.

I told you that over and over and over again but it goes in one
ear and out the the other because you are so emotionally involved in electricity.


They ought to electrocute all you  electric over weight  car wackos :)

The future is lighter weight cars with better power to weight ratio
IC engines like the twice as good turbo compound rotary.

Paul




From the web:

The relatively small frontal area of Prius, as well as the small upper grille aperture, minimizes the initial impact of air, directing its passage over and around the rest of the body rather than attempting to pass through it. A subtle chin spoiler at the bottom of the bumper slices the air heading around the car from that passing underneath, while the flat, vertical surface of the front bumper corners serve to correct the airflow as it passes over the front wheels, minimizing turbulence in the wheel arches. Spats are fitted at the front of each wheel arch to further suppress airflow changes around the tires, which themselves feature a low rolling resistance compound.

Minimal disruption smooths air passage across the rest of the vehicle, thereby reducing drag and improving high-speed stability. The A-pillars are pushed forward to increase the rake of the windscreen, panel gaps are narrow, and the glazing seals are flush with the body. Necessary additions such as the door mirrors, handles, light lenses and rear spoiler are carefully designed to be aerodynamically efficient.

Side skirts are used to carve a clear aero demarcation between the outside and underside of the car, directing air to flat vertical surfaces on the rear bumper corners that once again correct airflow and reduce turbulence. Meanwhile, the underside of Prius is comprehensively covered with flat panels to prevent air getting trapped and causing turbulence within pocket-like elements such as the bottom of the engine bay and load space floor.

Finally, the distinctive, extended roof line of Prius ends rather abruptly with an upright ‘Kamm effect’ design for the rear end – one of the most efficient means of reducing the low-pressure area of trailing wake pulling on the back of the car. This feature converges the vehicle’s contours into the beginnings of an aero-efficient teardrop shape but abbreviates it at an intermediate point to avoid unnecessary body structure adding to the length and weight of the vehicle. Aerodynamicists have discovered that passing air needs only an initial suggestion of this teardrop shape in order to deliver a large proportion of the turbulence-reducing effect of a full ‘Kammback’ or ‘Kamm tail’ design.

It slips through the air with a remarkable drag coefficient of just Cd 0.25, which has secured its position as the world’s most aerodynamic hatchback.

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