to 200+ mpg
Enterprises Press Release) The XR-3 Hybrid is a
super-fuel-efficient two-passenger plug-in hybrid that achieves 125
mpg on diesel power alone, 225 mpg on combined diesel and electric
power, and performance like a conventional automobile. The design of
the XR-3 Hybrid focuses on existing technologies and a vehicle
“personality” that makes conserving energy a fun driving experience.
It showcases the design ideas explored in Robert Q. Riley’s book,
Alternative Cars in the 21st Century.
At just 1300 pounds,
this high-performance design combines lightening-fast acceleration,
a maximum speed of 85 mph, and fuel economy of 125- to over 200-mpg.
Its clam-shell canopy
and three-wheel platform boldly differentiates the XR-3 from
conventional passenger cars. The vehicle’s hybrid power system,
diesel engine, and low curb weight are the main ingredients of its
super-high fuel economy and excellent performance. Acceleration
equal to that of a conventional car and a maximum speed of 85 mph
make the XR-3 Hybrid equally at home on freeways and surface
Advanced safety features
of a production XR-3 Hybrid will include occupant protection and
crash avoidance systems. Enabling technologies already exist, and
nothing new has to be invented.
Plans will be available so readers can build a duplicate of the XR-3
Hybrid prototype, or convert their own car into a significantly more
fuel-efficient vehicle. Readers will understand the factors that
influence fuel economy, and learn how to make any car achieve
greater fuel economy. The XR-3 Hybrid gives enthusiasts and
experimenters the opportunity to significantly reduce their
transportation expenses and have fun doing it. On a broader level,
the vehicle is a highly visible example of the kinds of vehicles
that could help reduce personal mobility energy on a global scale.
Styling Makes an Implied Promise
The driving experience
is defined by the vehicle’s layout and styling – it's “theme" or
"personality.” The vehicle theme says: “This is what I am and this
is what I do." It’s a statement that’s on a visual level, and it’s
maintained throughout the ambiance of the vehicle. Mechanical design
simply supports that statement. “Once we decide on the basic
architecture of the vehicle, styling is the first thing that’s
done,” says Riley. “It’s the most intangible quality of the design,
but it provides a visual marker for what we are trying to achieve
through mechanical design. Styling makes an implied promise, and
then it’s up to the mechanical designers to deliver on that
The Technology of Fuel Economy
performance and fuel economy comes from a combination of two
fundamental design factors. First, it’s essential to keep the
vehicle as light as possible in order to reduce the amount of
mechanical "work" that has to be done. The method of getting rid of
unwanted mass while still keeping the car’s mechanical benefits
demands good design and modern materials. Once the amount of "work"
has been minimized, then the other part of the equation is to do the
remaining "work" as efficiently as possible. And that’s where the
hybrid power system comes in. So the fundamental approach is very
simple. The key is in the execution.
New types of products
that rely more on vehicle packaging and market positioning could
play an important role in reducing global energy demand.
Significantly downsized vehicles - smaller, lighter, highly
fuel-efficient personal mobility products - could help turn the tide
against escalating energy demand and open new markets in the
Consumer Perceptions and Choices
that small, super-efficient cars would help the environment and
reduce imported oil. But industry has been slow to see marketing
opportunities and create products of this category that capture the
imagination of consumers. The XR-3 Hybrid is designed to explore
vehicle packaging and styling, with an eye toward creating a new
design theme and market positioning for alternative personal
transportation products. We call it a “Personal Mobility Vehicle.”
To paraphrase the lead
quote from John Locke, the ideas and images in the minds of
designers invisibly guide them toward particular design options. A
product’s “character” naturally emerges from the collective mind-set
of its designers. Consumer appeal of any alternative mobility
product depends on the ideas and images in the minds of its
creators, not on the core idea of saving energy and emissions
through size/mass reduction. In order to enjoy success in a consumer
market, significantly different vehicle types - Personal Mobility
Vehicles - must be rendered in ways that create new appeals of their
own. And energy savings and emissions reduction must be positioned
as secondary benefits. Or stated differently, a consumer vehicle’s
environmental benefits can be an effective motivator only in terms
of providing a rationale for a purchase that is, in fact, based
largely on the product’s emotional appeal.
The XR-3 focuses on the
power of “design” to influence consumer perceptions and choices. It
points to a new category of personal mobility products that are
neither automobiles nor motorcycles.
The Power of Design
The idea that vehicle
theme or personality - vehicle “design” - has the power to influence
global energy demand goes against conventional thinking. Consider,
however, that in the 1990s vehicle personality influenced automobile
energy intensity in the negative with lifestyle vehicles that pushed
energy use upward. The popularity of SUVs is a good example of how
an "image" can influence choices, and those choices can lead to
significantly higher fuel consumption.** Hardly anyone buys an SUV
to go trailblazing. Consumers are turned on to the personality of
SUVs, the vehicle theme, and they buy them to drive around the city.
New-car average fuel economy has plunged in recent years, mainly
because of the power of design to shift purchasing choices toward
trucks. As of year 2000, light trucks accounted for roughly half of
all new car sales. This same dynamic can work in the reverse.
**It might be argued that greater utility, rather than vehicle
design, is responsible for the popularity of SUVs. But consider that
station wagons and panel trucks have been around almost since the
inception of the automobile. And it was only when carmakers
connected with consumers through “design” that trucks began to
replace family sedans in the personal mobility market.
Advanced Safety Systems
Extremely small and
lightweight vehicles operating in an environment with high-mass
vehicles present inherent safety challenges due to the large
transfer of energy to the smaller vehicle during a crash. Although
small-car occupant protection is technically feasible, crash
avoidance is the superior approach. According to NHTSA, the emphasis
in highway safety is expected to shift away from crash survival and
toward crash avoidance by year 2020. But the technology for crash
avoidance already exists. Crash avoidance capability will become
standard equipment on production vehicles like the XR-3.
Plug-In Hybrid Architecture
The XR-3 is designed as
a “plug-in hybrid.” This makes it possible to drive on battery power
alone on trips of about 40 miles. In other words, on short trips you
never have to turn on the diesel engine. And when both the diesel
and the battery-electric systems are used together, and the car is
driven conservatively, fuel economy increases to over 200-mpg. Fuel
economy is about 125-mpg on diesel power alone.
Today’s hybrids are
called “mild hybrids” or “charge-maintaining hybrids”. They use the
electric system to help with acceleration. You can drive on battery
power alone, but only for a short distance – around the block, for
example. The battery pack is typically used to provide bursts of
power for brief periods of acceleration. The combustion engine then
recharges the battery between periods of acceleration. But fuel
economy suffers while the battery is being recharged. That’s why
today’s hybrids do not provide much advantage in fuel economy over a
well-designed conventional car.
In order to get the full
benefits of a hybrid power system, you have to switch to a plug-in
hybrid architecture like the XR-3. Plug-ins will be the next
generation of hybrid vehicles. A plug-in hybrid simply means that
part or all of the vehicle’s energy is taken from the grid system
where it is cleaner and less costly to produce. Most of the world’s
automakers are now working on plug-in hybrids.
Virtually Unlimited Options for
The plug-in power system
architecture also allows much greater flexibility in power system
choices. With a mild hybrid, like the Honda Insight and the Toyota
Prius (also called “charge-maintaining hybrids”), proper control of
the power system depends on the fact that the subsystems - the
internal combustion engine (ICE) and electric systems - are selected
in advance and controlled by a computer. The computer, however, has
to be programmed for the specific output characteristics of the two
systems. Any modification in either of the power systems (electric
or ICE) causes a mismatch with the control system. The computer
control system cannot, on its own, account for changes in the power
system. So whenever a change is made, the computer has to be
reprogrammed to account for the change.
With a plug-in hybrid
system, configured like the system in the XR-3, you are free to add
a larger or smaller ICE, or even switch to a gasoline engine,
without having to reprogram the control system. You can also build
the car as a conventional ICE-powered car, or a full
battery-electric car. So the options are greatly expanded with the
plug-in hybrid power system.
With the XR-3, the two
front wheels are powered by the ICE engine, and the single rear
wheel is electric powered. The two power systems are not integrated
within the vehicle. The connection between the ICE and the electric
power systems is provided by the ground. Proper phase-in between the
two power systems is handled by a simple throttle mechanism, and a
dash-mounted switch to select between ICE power, electric power, and
dual power modes. In the dual power mode, the XR-3 will have lots of
burst power for outstanding acceleration. If you were to use this
acceleration potential to its fullest, fuel economy would be reduced
to something on the order of 150 mpg over a 70 mile trip. Fuel
economy will vary according the particular components chosen for the
power system, and how heavy you are on the throttle pedal.
Performance figures quoted here are for a system configured just
like the prototype. Plans will provide the information necessary for
you to select different components if you want to.
The XR-3 is being
developed as a plans-built vehicle. Body and chassis kits are slated
to follow along after the release of the plans.
A kit, however, will be
unnecessary. The XR-3 will be constructed using the same techniques
used to build Tri-Magnum. Click on FRP/foam composite for a document
that shows the composite system used to build the body for
Tri-Magnum. The XR-3 body may be built of carbon fiber over foam or
conventional fiberglass over foam. Both systems are designed for the
home craftsman using virtually identical techniques.
About the Designer
Robert Q. Riley consults
for corporate and private clients on new product design and product
strategies. He promotes environmentally friendly technologies, and
writes and speaks on the subject of alternative automobile design.
He has chaired conference workshops and spoken at industry,
scientific, and academic events, including the Global Energy Future
symposium (Columbia University), the World Car Conference, and the
Northwest Alternative Fuels Conference. He consulted on the
Different Roads automobile exhibit at New York’s Museum of Modern
Art, and was a panelist on the museum’s daylong symposium on the
future of the automobile. He was one of the two U.S. technical
consultants selected by Delcan Corporation to assist with Transport
Canada’s Sustainable Transportation Technology Forecast.
Mr. Riley is the author
of Alternative Cars in the 21st Century: A New Personal
Transportation Paradigm (Society of Automotive Engineers, 1994), and
Alternative Fuels for Spark-Ignition Engines (for a volume on Motor
Gasoline in the series, Critical Reports on Applied Chemistry, Royal
Society of Chemistry & Society of Chemical Industry, U.K., 1995).
The Second Edition of Alternative Cars in the 21st Century, with a
Forward by Dr. Paul MacCready, was published in 2003.