Car-biz geek-squad gathers to share latest wonders
The Society of Automotive Engineers’ annual World Congress—WCX18 in abbrev-speak—aims to be the SXSW of the car-biz’s nerd-illuminati. “Better mousetraps” for accomplishing nearly anything mechanical or electronic onboard a vehicle are displayed every year. The best of these answer questions mere automotive enthusiasts have yet to imagine asking. Let’s take a look at a baker’s dozen of them.
The SAE Show always includes a fresh new twist on the combustion engine. This year’s is described as “an inside-out Wankel.” Where the Wankel fits a triangular rotor in a peanut-shaped housing, the X1 rotates a peanut-shaped rotor inside a vaguely triangular housing. All four strokes happen in each corner of the triangle every revolution. One benefit of the inside-out design is that the apex seals are mounted to the stationary block, not the rotating rotor, so they can be easily lubricated, resulting in vastly less oil consumption. Another key difference: intake air and exhaust gasses enter and leave via ports in the rotating rotor through openings in the end plates.
Bloomfield, CT-based LiquidPiston Inc. CEO Alexander Shkolnik claims that the circular ends of the rotor seal off the combustion chamber for about 12 degrees of crankshaft rotation during which spark or compression ignition (depending on compression ratio) can be completed at constant volume. This is followed by an expansion phase that, thanks to port timing, is longer than the compression phase for an efficiency-enhancing Atkinson effect and greatly reduced exhaust noise at the port (perhaps negating the need for a muffler). Thermal efficiency of up to 45 percent has been measured. Size and weight are major strengths of the design. A 4-hp 70cc spark-ignition version of the engine measures just 6 x 6 x 5 inches and weighs 3.5 pounds (1.6 kg). The design can be scaled up in diameter, in rotor thickness, or by compounding multiple rotors. Sikorsky has LiquidPiston working on a 1,000-hp version, and the Defense Advanced Research Projects Agency (DARPA) has awarded a grant to develop the X1 for use powering a generator. Shkolnik says a diesel-powered hybrid range-extender version would likely weigh 40 pounds (18 kg) and produce 40 hp. Of course, much work has yet to be done on the emissions compliance front. Watch this space.
In-Wheel Electric Motors
Among the news being made this week in the wheel-motor space, Chinese pump-manufacturer SLPT showed off a 49-lb 20-hp, 258-lb-ft wheel motor destined for a tiny (A00-class) 2020-model Chinese city car. Perhaps the best-established name in this space, Protean Electric announced it’s teaming with the additive-manufacturing automotive disruptors at Local Motors to provide propulsion for its Olli self-driving electric and shuttle.
But the biggest news came from Silicon Valley startup Orbis Wheels, which introduced its Ring-Drive product. The concept seeks to eliminate the unsprung-weight disadvantage of wheel motors by two means: Eliminating the wheel’s hefty hub and spoke structure, and drastically lightening the motor by selecting a high-speed low-torque design that powers the wheel rim via a pinion gear. Orbis claims that high-speed, low-torque skateboard/drone-copter type motors rated at the same power as a high-torque hub motor require far less copper, so they weigh 1/20th as much and cost far less. The hub-less wheel mounts to the vehicle suspension via a stationary carrier that supports the motor, brake caliper, and a triangular bearing arrangement of three pairs of rollers. Orbis claims its 9.5 x 20-inch Ring-Drive wheel designed for the rear of a Honda Civic Type R and fitted with a 70-hp/300-lb-ft motor weighs the same as the Civic’s original wheel while demonstrating one-fifth the dynamic friction and 13-percent less rotational inertia. CEO Marcus Hays further believes his setup could cost 25 percent less than a conventional EV powertrain. The company seeks to license the technology and assist interested clients with prototype development. Military and civilian applications are currently under development with no forecast production date.
Messaging on Glass
Sekisui Luminous PVB—Japan’s Sekisui Chemical has developed a laminated glass inner layer with phosphorescent molecules that glow in green, blue, or red when illuminated by an ultraviolet projector. Unlike reflected head-up display images visible only to the driver, messages projected on glass by this method are visible to all. A large portion of the windshield could be equipped with Luminous PVB to indicate impending hazards (pedestrians, animals, etc.) so that fellow occupants could also be aware. The messages can also be read outside the vehicle, so that autonomous or shared/hailed ride vehicles could signal availability, pricing, etc. on their windows. Look for this technology to hit the market in the 2021-2022 timeframe.
AGP eGlass Display Plus—American Glass Products, supplier of the jumbo Tesla windshields, is also getting in on the glass messaging action with its Display Plus product. This one uses a directly powered matrix display with pixels of 1mm-square proportions. When switched off it’s a bit less transparent than the Luminous PVB, and for now it has a maximum size limitation of 3.5 x 11.5 inches. It is ready for production but no customers have been announced as yet.
Eaton Diesel Cylinder-Shutoff
Diesel engines are so efficient when cruising at light load that it’s never occurred to anybody to shut off cylinders the way we do in gas engines. But Eaton has discovered a duty cycle for which this technology makes a lot of sense: at idle and when creeping. Diesels are exceptionally efficient idlers—unless you need to keep the exhaust aftertreatment system above 480 degrees F to pass emissions. Accomplishing this today typically requires over-dosing the fuel so it burns in the exhaust and/or constricting the variable-nozzle turbine geometry. Both approaches waste fuel. Eaton has demonstrated that shutting half the cylinders of an inline-six diesel off at idle and slightly overdosing the remaining three can maintain the optimal temperature at a savings of 3 percent or more on the Heavy Duty Federal Test Procedure (HD-FTP). These fuel savings jump to as high as 35 percent in port drayage duty, which involves copious idling and creeping in queues. This technology was just unveiled at SAE and will require considerable development, but could eventually benefit pickup truck diesels.
This Lake Forest, CA-based company’s name—“LiquidMetal”—didn’t rouse much interest initially. Duh, all metal is liquid at some temperature. But this peculiar manganese-zirconium alloy’s party trick is that it can be injected into the type of highly detailed mold you might use for plastic materials and rapidly cooled. What you end up with is a part shaped to exceptionally tight tolerances that retains an amorphous solid crystalline structure (like glass) with no heat treating or secondary operations necessary. That gives it a plasticity that’s unusual in a metal, and permits consolidation of what might have been multiple parts (a housing and spring, for example) into a single part. Limitations? Large parts are not possible (11 ounces is about the max), and parts can’t get very hot without crystalizing and changing their properties. The car biz is interested in it for things like key fobs that convey the cool touch, heft, and machined quality of metal in a one-step operation. Another bonus—electromagnetic signals of all sorts pass right through LiquidMetal parts.
When last we checked in with the Nautilus folks two years ago, their four-stroke, six-cycle Dynamic Multiphasic Combustion engine had only run in the computer. Well, the company has modified a Briggs & Stratton single-cylinder engine with its unique tiny-piston-atop-normal-piston inside tiny-chamber-atop-combustion-chamber cylinder head design and now has results to discuss. Let’s start with the nomenclature: “Dynamic Multiphasic” refers to the engine’s ability to switch on the fly between different ignition and fuel injection modes during different conditions of operation. For example, upon startup the primary (small) chamber can spark-ignite a port-injected mixture or glow-plug-ignite a direct-injected mixture, with the secondary chamber igniting via compression ignition.
Then, primary combustion can occur without spark or glow plug under acceleration or warm cruising, leading to secondary compression ignition. A big difference in the design of the test engine is placement of the valves. Instead of four overhead valves, it riffs on the old flat-head or side-valve concept, placing the exhaust valve closest to the piston and the intake valve outboard of that. This means the intake air is warmed by (and cools) the exhaust valve. Because homogeneous compression ignition happens more or less all at once everywhere, there’s no need to worry about a flame front reaching the far end of this passage. The test engine is validating claims of 30 percent fuel efficiency and ultra-low engine-out emissions running on 87-octane pump gas. Next step: Scale the design up to four cylinders. Nautilus anticipates the primary automotive use for its DMC engine will be as a range-extender.
A square ball?! Yes. Imagine starting with a cube, then machining said cube round (cylindrical) along just two axes, leaving it square along the third. Now use this to replace the X member in the center of most universal joints. Instead of the U-shaped yokes that would connect to that X member via roller bearings, the yokes in this design are machined to almost the same cylindrical dimension, sliding onto the “square” ball. A single pin engages a channel machined around the circumference of the two round sides to keep the yokes from sliding back off. The resulting design transmits all the torque via the remaining “square” corners of the ball. The design can function at shaft angles as great as 40-45 degrees, but this is envisioned for use in steering shafts, not axle half-shafts, and 25 degrees is about as tight as those ever go. This new concept has no announced takers yet, but its mechanical simplicity (eight parts instead of 100) is sure to attract customers.
We’ve seen sparkly starlight baked into the opaque headliners of spectacularly expensive cars like Rolls-Royces, but American Glass Products showed off a clear glass roof featuring tiny LED “stars” and a crescent-moon-shaped brighter LED dome or reading lamp. Talk about a “moon roof…” It also features the company’s Vario Plus electro tinting, which dims the glass’ light transmissibility from 12 percent to 3 percent. The “stars” are all connected by faintly visible wire traces, which slightly diminishes their wow factor. Using Corning Gorilla Glass for the laminated panel’s inner surface ensures the resulting roof still weighs less than a conventional all-glass one would. No production plans have been announced as yet.
Laser-sintered metals are enabling additive manufacturing of parts that were unheard of a few years ago. IAV showed piston and wrist-pin designs for diesel and gas engines that utilize complex shapes with strategically designed voids in them that improve both rigidity and thermal management while reducing mass. The material consists of ceramic particles and an aluminum matrix (Al MMC). The diesel piston also includes a crown with an insanely complex shape designed to perfectly mimic the shape of the fuel injector spray pattern, including deep undercuts that would be impossible to die-cast or forge. Thermal management is improved by the ability to provide liquid sodium channels and/or oil-jet cooling passages in areas that might otherwise be susceptible to knock-inducing hot spots or to the ring lands to keep them from overheating and deteriorating. Pistons weigh as much as 18 to 23 percent less, they are stronger than cast or forged parts, and because they expand less when hot, their skirts create less friction. Cost is still prohibitive for anything but very low volume and racing applications.
The Clemson University International Center for Automotive Research (CU-ICAR) displayed its vision of a Mini for the year 2025, with funding from BMW corporate and design help from ArtCenter College of Design in Pasadena, California. Envisioned as a modular concept propelled by combustion, hybrid, plug-in hybrid, or pure electric drivetrains, the car rides on a stretched wheelbase within the length of the current Mini hardtop. Innovative features include locating the cooling modules in the vehicle rocker panels, a windshield hatch to access cargo space in front freed up by electrifying the front axle, a holographic gesture-controlled user interface, and a “Parking Marshal” that uses the Mini’s exterior lights to guide other drivers parking in front of or behind it, illuminating incrementally as the vehicle approaches.
IAV Phase-Change Cooling System
The coolant in most vehicle radiators is designed to remain a liquid. Something has usually gone wrong if it changes phase from liquid to gas (steam). IAV proposes a water-ethanol coolant that is designed to boil in certain areas of the engine, leveraging the liquid-to-gas phase change to remove a bunch of heat from the engine. In this system, instead of a thermostat, a pressure regulator is used to vary the liquid’s boiling point. A big bonus: this steam can power a generator as it cools, recovering heat as electricity. The system is said to improve performance enough to shrink the amount of air-cooling required by the radiator, further improving the vehicle’s aerodynamic efficiency.
OK, this one hit my inbox well before SAE, but it’s worthy of inclusion here. The exhaust experts at Borla sought to allow customers upgrading cars with variable exhaust systems to retain the variability feature while enhancing performance. Their patented solution: Improve upon the flow properties of the typical butterfly valve. When open, to allow for the greatest airflow (and noise) through the exhaust, a butterfly valve leaves an obstruction in the pipe that results in some backpressure. Borla’s new pocket valve pivots the closure valve up into a pocket recess above the main pipe, leaving the flow unimpeded. This technology is available now.
Another SAE-week release (in Germany) not at the show but worthy of inclusion here is this sensor-fusion application that detects the moment when a vehicle’s tires are about to become water skis. It uses the around-view cameras mounted on the mirrors and grille to detect water-splash patterns associated with hydroplaning, then it consults special sensors in the tire tread that measure instantaneous acceleration rates. The behavior of a tire making solid contact with the road is enough different from one under which a wedge of water is building up that Continental’s system can warn the driver to slow down. It may even be possible to use the rear brakes (which generally retain sufficient grip, riding as they do, in the wake of the fronts) to do some torque vectoring to help maintain control.