125 MPG Diesel-Electric Three-Wheeled Car Headed For Production

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For all you nerdlingers who need to brag about fuel economy around the water cooler, soon you'll be able to buy a factory-built 125 MPG XR3 diesel-electric hybrid straight out of the box.


The XR3 plug-in hybrid has been around since about 2006 as a kit vehicle, requiring the DIYer to do all the wrenching, assembling the T-shaped chassis, installing the lithium-ion batteries, the 23 HP diesel, the electric motor, suspension, body, etc. Think of the XR3 as a super simplified Chevy Volt, it has a 40 mile all-electric range, but the diesel engine and electric motor are completely decoupled and the driver controls selection of drive system instead of a computer.


Now, according to company owner Robert Q. Riley (which totally sounds like a made up name) the vehicle is going to be available with most of the work completed direct from the factory. The complete details aren't available yet, but some degree of assembly is slated to take place at the companies Cleveland manufacturing facility, we're assuming everything will be assembled except the installation of the diesel and electric motor, in order to avoid costly Federal certification.

XR3 Plug-In Hybrid Heads for Production

In June, 2008, Robert Q. Riley introduced the 125-mpg XR3 plug-in hybrid, a stylish three-wheeled "personal transit vehicle" (PTV) that home craftsmen could build from plans. Now the design is headed for production, which was the goal Riley had in mind all along. If he's successful, it could establish an entirely new category of vehicles and change the landscape of personal mobility.

Riley's design approach is simple. Try walking a block and then try pushing your car a block and you'll quickly understand where all the energy goes. In reality, most of a car's energy goes to getting itself around town and you come along for free. So when your car goes out for a drive, you simply "hop the freight-train" and ride for nothing. If we could get rid of the massive hardware overhead we'd slash personal mobility energy and greenhouse emissions to the bone.

Mass reduction is the fundamental idea behind Riley's super-fuel-economy design philosophy. Reducing vehicle mass facilitates many other alternative technologies, but the core idea is to move less mass around the city. It's a concept that has driven his alternative car designs over the last 30 years, it's the core idea in his book, "Alternative Cars in the 21st Century" (SAE 1993 and 2004), and it's the philosophy that drove the design of the XR3. In urban driving, roughly 80 percent of a car's energy is directly related to mass. Overweight mobility machines take much more energy than lean machines. And according to Riley, "with enough market penetration, super-efficient personal transit vehicles like the XR3 could forever put an end to imported oil, and do it with affordable technology that already exists."

The XR3 plug-in hybrid combines low mass with simplified state-of-the-art technology to achieve 125mpg while cruising on its 23hp diesel engine, and up to 40 miles range while running only on its Li-Ion battery pack. It's an all-wheel-drive, ground-connected parallel hybrid, which means there's no mechanical transmission between the two power systems. Instead, it relies on the ground to provide the connection. When the two systems are used in series, with half the miles driven on battery power and half on diesel power, average fuel economy shoots past 200mpge.* For local trips of up to 40 miles, the XR3 can run on battery power alone and never burn a drop of fuel.

The choice of operating mode – diesel-only, battery-electric-only, or hybrid - is operator selectable by flipping a pair of switches. And there's not a single computer in the power system. According to Riley, "we needed a simple way to integrate two very different power systems, and I wanted to avoid computer controls and costly transmissions that are common to today's hybrids. So I designed a $10 throttle integrator mechanism. But I spent several sleepless nights pondering whether it was too simple to actually work. Amazingly, it works better than my wildest dreams!"

Power system integration is handled by a simple electromechanical 'throttle integrator'; one of the many features for which patents are pending. In the hybrid mode, the throttle integrator is designed to blend the two power systems in a way that uses the electric propulsion motor as a "supercharger" for the burst acceleration needed to safely merge into freeway traffic - and do it by simply pressing down on the accelerator pedal. "It's a very simple and reliable system, and it works beautifully," said Riley.

Construction Plans for DIYers

With the release of XR3 construction plans, skilled individuals can create their own XR3 using the basic shop tools normally found in a home workshop. These inventive early-adopters often include their own customized touch by using different engines and new styling elements. Riley's plans also introduced high-level 3D CAD to the average home craftsman, where they can zoom, pan, and rotate parts and assemblies in 3D on any home PC. High-tech construction-plans are available from his website (www.rqriley.com). As the XR3 moves toward mass production, complete knockdown kits will become available prior to the release of fully-manufactured turnkey vehicles. The original construction plans could ultimately morph into something more along the lines of an assembly manual. So the existing plans could become a collector's item over the long term.

Customizable Performance

In addition to its light weight and superb handling, another innovation made possible by avoiding on-board mechanical power-system connections and computers is the ability to quickly and easily reconfigure the chassis for different markets. It can accept far more powerful engines. Even a 100hp engine, small by automotive standards, will result in lightening-fast acceleration and a plug-in hybrid vehicle that can also drive efficiently and economically on battery power alone. Or the electric power train can simply be left off. By sticking with the small 0.9L engine and eliminating the electric power system, production costs can be cut nearly in half without reducing its 125-mpg fuel economy. Or the combustion power train can be left off and extra batteries can be installed in its place to produce a battery-electric vehicle with a range of up to 100 miles. The modular design provides almost unlimited power train choices. And the simplified hybrid power system allows for significant changes without having to reprogram a computer to account for the differences in power characteristics.


The manufacturing entity, XR3 Motors LLC, has prototype facilities located on the outskirts of Cleveland. Under the leadership of veteran racecar builder and manufacturing expert, Phillip A. Lane, XR3 Motors has been forming alliances and pulling in new talent since the decision to move ahead was made late in 2008. In contrast to Riley's low-key manner, Lane has an infectious enthusiasm that's almost impossible to resist. Even if you arrive tired and wishing you were somewhere else, you'll leave a meeting with Lane full of energy and feeling as though you've just witnessed the genesis of something big.

Lane has years of experience with alternative fuels such as bio-diesel and ethanol, and he pioneered environmentally sustainable methods and materials in his vintage restoration and racecar fabrication business. He is now parlaying his eco-friendly background into XR3 manufacturing. Lane, for example, is responsible for the company's focus on corrosion prevention technologies to prevent the maintenance problems typical of conventional vehicles in regions like the Northeastern U.S.

Through Lane's networking and life-long associations in the region, the prototype is now headed to one of Ohio's top automotive research universities where power train analysis and optimization will be carried out. Although the vehicle is fundamentally a diesel-electric hybrid, another Ohio university is slated to install an advanced fuel cell in a pre-production prototype for testing and evaluation. Noise, vibration, and harshness (NVH) engineering, as well as a new technology that cancels out noise by using artificially generated sounds, are on the agenda. It seems counter-intuitive, but vehicle noise can be significantly reduced by adding artificially generated sounds tuned to the vehicle's natural sounds.

So why would an Arizona-based vehicle designer decide to locate manufacturing facilities in Cleveland? "The region has a strong and underutilized manufacturing base that is ideally suited for this type of venture", said Riley. "It was actually the seat of the automotive industry when it began in the early 1900s. The White Steamer, the Baker Electric, and Alexander Winton's record-making Winton Bullet racers, all came from Cleveland and surrounding regions," he continued. "With its industrial and workforce assets it has the potential to become a big player in sustainable mobility, renewable energy, and advanced manufacturing."

XR3 Motors is attracting a powerful team of advisors, designers, and directors. "We are fortunate to have Ron Will on our team," Riley said. Ron Will was formerly Manager of Product Planning & Design at Subaru of America and is perhaps most well known for developing the Subaru Outback. According to Riley, "I asked Ron to join our team because of his extensive automotive experience and his forward thinking views on alternative vehicle design. Ron also designed the high-performance three-wheel Turbo Phantom back in the 1980s, and so he understands three-wheel vehicle design," Riley explained.

One of his first tasks will be to design a new front clip for the large-engine high-performance model. He will also design a motorcycle based on the XR3's electric power train, which is a self-contained unit that bolts to the rear of the XR3's tunnel-frame. When you consider that the XR3's electric power module can deliver over 500 foot-pounds of torque to the single rear wheel, it is easy to get a sense of the performance of a motorcycle built around the system.

Riley also has a remarkable track-record of his own. He is responsible for a long line of alternative car designs dating back to the mid-1970s, including three and four wheelers of electric, hybrid, and conventional power systems. He is also the author of "Alternative Cars in the 21st Century" (SAE 1993, and 2004), a book that anticipated today's push for new transportation solutions more than a decade in advance. Riley literally "wrote the book" on where we are today.

Conservation and sustainability have been key considerations throughout the XR3's design. Many of the vehicle's cut-and-weld components will be switched to aluminum castings or stampings. The company is working with a number of vendors on advanced materials and processes. A new type of recycled aluminum that costs one-third the price of new aluminum is slated for several structures that make up the chassis. Advanced foam-core composites are used throughout the body, both for strength and reduced weight.

Design Philosophy

To understand the XR3's blend of motorcycle and automotive styling elements, it helps to understand Riley's mindset on marketing and low-energy-demand vehicles.

Everyone knows that driving little econobox cars would help save fuel. But those are not the kinds of vehicles that consumers want to own. No one wants to drive a dorky little car - even if it costs less - in order to save the planet or help ease the transfer of wealth to the folks who own all the oil. So we end up stuck on the horns of a dilemma – spend lots of money on advanced technology vehicles or continue to buy oil for as long as we can pay for it.

According to Riley's vision, "one way around this dilemma is to design a new type of vehicle – a 'personal transit vehicle', for example - that people do want to own. The XR3's styling and layout is intended to differentiate it from a conventional automobile and give it a personality captures the imagination of consumers. If we are successful, we'll end up promoting the idea that families need one type of super-efficient vehicle for those everyday, single- or double-occupant trips to work and to the market, and another type (the big vehicle) for family outings and long-distance trips," he continued.

If you carry out the numbers, dependence on foreign oil could be ended through nothing more than vehicle packaging and personality, plus a little help from advanced technology and alternative fuels. Vehicles that demand less energy make alternative fuels more feasible. For example, natural gas vehicles that are refueled at home become more practical when the storage tanks do not have to match the energy content of an SUV's tank-full of gasoline. Fuel cells become more practical and less costly when energy demand is reduced. Domestically-produced biofuels become more feasible when less fuel is needed to do the same amount of driving. Consider that the XR3's small three-gallon tank carries enough fuel for nearly 400 miles of driving.


But is a small, lightweight vehicle safe?

In terms of raw physics, when a big thing runs into a little thing the little thing receives the biggest blow. But several studies have shown that mass is not necessarily a safety feature. Over the past three decades, cars have become much lighter and safety has significantly increased. And today, many SUVs have a poorer safety record than smaller and lighter vehicles. The big difference is "design." It's important to design for occupant protection, which in the industry is called "crash survival." And the vehicle has to stay upright in an out-of-control situation, which is a safety shortfall of high-profile vehicles.

The XR3 has a rollover threshold of 1.2g, which is about the same as a conventional compact car. SUVs typically have a rollover threshold on the order of 0.8g to 1.2g. In layman's terms, that means most four-wheeled SUVs are more likely to roll over than the three-wheeled XR3.

In terms of occupant protection, the XR3's canopy is equipped with a steel roll cage. The rear wall of the cabin serves as a foam-filled composite roll bar, and the sides along the occupant zone are filled with crushable foam for side intrusion protection. Rear impacts are taken by the exposed rear tire, and frontal impacts are taken by the foam-filled nose.

The occupant zone is entirely open and free of the nearby structures that tend to cause injury in conventional cars. And the centrally-mounted steering column is designed to yield at the connection near the front wall of the cabin while still providing steering control. In other words, there is no steering column in front of the driver. The actual steering column is located over the tunnel in the center of the cabin. And, of course, seat belts are essential.

Much attention has been given to design-for-safety features in the XR3.

End to Oil Dependence

We will not wake up one Tuesday to find that the earth's oil tank has been pumped dry. But even if we wanted to remain dependent on petroleum, at some point it has to come to an end. It's really about economic health. And the real economic impact of oil is partially hidden because it does not show up in the price of motor fuel. When military, environmental, and health costs are combined with the economic impact of the transfer of wealth to oil-rich regions, the real price of petroleum ends up double or triple the price of the oil itself.

Riley became interested in alternative vehicle design while sitting in a half-mile-long line waiting to buy gasoline during the '73-'74 oil crisis. He has been developing prototype vehicles since then. In an upcoming episode in Discovery Channel's Next World series entitled "Radical Vehicles", Riley makes the statement: "Imagine a world in which petroleum is irrelevant. Imagine how unhooked we would be from political difficulties in certain areas of the world if petroleum was just irrelevant."

* mpge = miles per gallon equivalent. In order to compare electrical energy to diesel or gasoline energy, an equivalency factor must be assumed for the electrical energy. Once the onboard efficiencies are accounted for, it has been assumed that wall-plug electrical energy costs about 25 to 35 percent of the cost of diesel or gasoline energy. But this will vary between different regions and the source-fuels used to produce the electrical energy.