Drivers of Progress

Robot Convoy: Among the questions that the engineers of the SARTRE road-train project had to answer: How should a car signal that it wants to join the convoy? How many cars should be allowed in? Should a convoy be allowed to pass other cars?  Graham Murdoch

4. CAR-TO-CAR COMMUNICATION

Today’s high-end cars can correct your steering when you veer out of a lane, brake automatically to keep you from hitting other vehicles, and determine when you’re about to fall asleep. Cadillac is even expected to unveil hands-free cruise control in the next two years. For networks of autonomous or semiautonomous cars to work, however, vehicles must be able to communicate with and react to one another. The technology that will enable them to do so could soon be ready for production.

One afternoon in May members of a European Union–funded research project called SARTRE dispatched a convoy consisting of a tractor-trailer followed by three Volvo automobiles on a public highway in Spain. The vehicles, which were separated by just 20 feet, traveled together at 50 miles per hour; only the truck had a driver.

SARTRE is the first real-world test of a “road train”— a convoy of cars autonomously following a ­human-operated lead vehicle (most likely a truck or bus) driven by a professional. (See a trial run of it in the video below.) The trailing automobiles could be passenger cars on a long journey. By reducing wind resistance and traveling at a steady speed, these convoys could improve fuel economy and reduce tailpipe emissions by 20 percent. They could also make road trips vastly more pleasant. Once in the convoy, explains Eric Chan, the project’s chief engineer, the “drivers” of the following cars “could relax and read a book.”

The Volvos in the SARTRE test detect lane markers and other vehicles using the same cameras and radar/lidar sensors already available in production vehicles. Engineers added custom software to fuse together the data gathered by those sensors (and a processor to run it) as well as antennas that allow the cars to communicate via Wi-Fi. But SARTRE engineers stress that all of the technology involved is available off the shelf today. In fact, the biggest remaining challenges are legal and psychological. Regulators will have to change traffic laws to account for driverless vehicles. Carmakers will have to equip those vehicles with the software necessary for joining road trains. Finally, drivers will have to be convinced that the system is safe. (SARTRE engineers say that road trains could actually reduce traffic fatalities.) Those three steps are great enough that road trains realistically won’t be deployed for another decade.

5. TINY INTERNAL COMBUSTION

Fuel economy standards are set to rise to 54.5 mpg by 2025. That prospect has carmakers adding turbochargers and computer-controlled direct injection to ever-smaller engines in order to wring every last mile out of a gallon of gas. The 2012 BMW 328i, for example, runs on a turbocharged four-cylinder engine (the first four-cylinder from BMW since 1999) that is more efficient and produces more torque than the six-cylinder it replaced. Ford is expected to put a turbocharged three-cylinder in the Fiesta in the near future. But turbochargers and direct injection can only do so much: To approach triple-digit mileage, engineers will have to fundamentally rethink internal combustion. Plenty of them have already started.

The Scuderi Group, a company in Massachusetts, is testing a prototype engine that devotes separate pistons to the compression and the power strokes, setting in motion a series of changes that increase mileage by up to 50 percent. The Michigan-based firm EcoMotors is perfecting an opposed-piston, opposed-cycle (OPOC) engine, in which a pair of pistons moving horizontally share a combustion chamber. The added efficiency could push a compact car to 100 mpg. EcoMotors says they could have their engine in production in five to seven years.