October
5, 1998 Design News
Technology Bulletin
Late developments that shape
engineering
by Gary Chamberlain, Senior Editor
Are night-lighting measurements misleading?
Students racing over curving roads in a video-game
simulation hope to help scientists at Rensselaer Polytechnic
Institute's Lighting Research Center (LRC) answer a
serious question: Do current lighting standards mislead
us about the efficiency of roadway, parking lot, and
security lighting? Lighting efficiency is widely calculated
as lumens per watt of energy, explains Mark Rea, LRC
director. The lumen, a measurement defined in the 1920s,
is based on the response in bright light of the fovea,
the part of the retina that contains cone photoreceptors.
It's responsible for central, high-acuity vision. However,
parts of the retina containing rod-shaped photoreceptors
also are important in low-light conditions and for peripheral
vision. As a result, lumens per watt delivers an accurate
efficiency measure for tasks done in bright light, but
is less accurate for such tasks as night driving, which
requires good peripheral vision in low light. In research
sponsored jointly by General Electric, OSRAM Sylvania,
Philips, and the Department of Energy, the LRC is conducting
experiments with the driving simulator to measure the
reaction of the participants under varying lighting
conditions. The information gained could help industry
produce new lighting systems that are more efficient,
Rea believes, since they would take into account the
complex responses of the human eye. Phone Rea at (518)
276-8701 (E)
New-generation motor powers electric-car race winner
An electric-powered, Indy-style race car from Bowling
Green State University (OH) won the 1998 Arizona Public
Service Electrics Race. Powered by a third-generation,
liquid-cooled motor made by the Lincoln Electric Motor
Div. (Cleveland), the car set a new event speed record
of 29.44.774 minutes for the 30.8-mile course. Average
speed was 62.126 mph, although the car can reach 140
mph on the straightaway. The "Electric Falcon's"
power plant: an inverter-duty NEMA 256 frame motor that
generates 160 hp at 10,000 rpm. "Winning the race
is a strong sign that our new motor technology is paying
off," states Gary Schuster, Lincoln Electric Co.
vice president. "Many of the same technologies
we've developed for racing are being applied to our
industrial electric motors, with exciting results."
The race, part of the ABB University Spec Series race,
organized by Electric Vehicle Technology Competitions
Ltd., featured cars from 13 universities. FAX Greg Myers
at (216) 383-4730 (P)
Programmable 'vehicle' emulates driver-to-component
layout
To the prospective owner who tries out current models
at several dealerships, small changes in the location
of controls, parking brake, seat position or contour,
or instrument panel position often tip the scale in
favor of one car over another. To help automotive development
engineers capture "the right feel," Prefix
Corp. (Rochester Hills, MI) has patented an adjustable
prototype development device called a Programmable Vehicle
Model (PVM). The PVM is outfitted to appear like a vehicle.
Each functional element (seat, roof pillar, steering
wheel, etc.) can be moved to emulate different trial
designs within ±1/2 mm. Positions of all the elements
are monitored and updated with Prefix's control software.
Individual elements are mounted on bearing rails using
ball screws to move them, via stepper motors, in two
or three dimensions. Thus, spatial relationships of,
say, the seat to the instrument panel, can be adjusted
so that visibility or knee room can be changed. A computerized
measuring device, known as the FaroArm, made by Faro
Technologies Inc. (Lake Mary, FL), confirms the ergonomics.
The arm scans the previously positioned interior and
creates a drawing of the desired interior package. FAX
Stefanie L. Curylo at (407) 333-4181 (T)
Truck technology simplifies transmission shifting
Meritor Automotive has introduced the "shift-by-wire"
system--the SureShiftTM transmission--that
it claims will "dramatically increase the ease
and comfort of safely shifting a non-synchronized manual
transmission" for truckers. The new system offers
the ease of an automatic transmission, but keeps manual
control at the driver's fingertips. The technology prevents
improper shifting by making it virtually impossible
for drivers to make a shift that would over-rev or excessively
jug the engine. To operate, the driver simply pushes
a joystick forward for upshifts and pulls it back for
downshifts. Clutch actuation is only required for starts
and stops, which further reduces the driver's workload.
The module is integral to the seat, ensuring that it's
always comfortably within the driver's reach. The design
also allows drivers to fold the module down and out
of the way when not in use for easy access to the rest
of the cab. Phone (800) 535-5560 (P)
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