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Cadillac tops Tesla in Consumer Reports semi-automated driving test

General Motors' Cadillac outscored Tesla in a new ranking of partially automated driving systems tested by Consumer Reports and released on Thursday. The highly influential nonprofit organization, which tests and rates a variety of consumer products from appliances to vehicles, said it compared Cadillac's Super Cruise and Tesla's Autopilot with similar systems from Nissan and Volvo. Nissan's ProPilot Assist was ranked third and Volvo's Pilot Assist fourth. Consumer Reports said it has been testing partially automated driving systems for several years but elected to conduct a formal study intended for publication, because "we are at a tipping point where they are now going mainstream," according to Jake Fisher, director of auto testing. The organization said its tests, conducted on a private track and on public roads in Connecticut, were designed to measure the systems' ability to automatically control steering and speed in certain situations, while helping drivers pay attention and regain manual control of the vehicle when required. CR noted that any of these systems can increase driving risk if used in inappropriate situations, or if drivers become inattentive or over-reliant on them. While they can help relieve driver stress and fatigue, Consumer Reports said, the partially automated systems are "not intended to be self-driving features." The systems typically use cameras, radar and other sensors, as well as mapping data, to monitor location and traffic conditions and help keep a vehicle centered in the lane at a safe distance behind other cars. Each system has limitations. Cadillac's Super Cruise, for instance, only functions on divided highways that have been mapped by GM. In contrast, Tesla's Autopilot can be used even on small, curvy roads with poor lane markings, but "operates erratically in those situations," Consumer Reports said.The organization tested Super Cruise on the Cadillac CT6; Autopilot on the Tesla Model 3, Model X and Model S; ProPilot Assist on the Nissan Leaf and Infiniti QX50; and Pilot Assist on the Volvo XC40 and XC60. Consumer Reports said Cadillac's Super Cruise did "the best job of balancing high-tech capabilities with ensuring the car is operated safely and the driver is paying attention." Tesla's Autopilot was cited for its capability and ease of use, while Nissan's ProPilot Assist did a better job than Autopilot or Volvo's Pilot Assist in keeping drivers engaged.

Infiniti's new VC-T changes the rules of small turbocharged engines

The upcoming Infiniti QX50 crossover does not get our pulse racing, no matter how shapely the QX Sport Inspiration concept that previews it may be. No midsize SUV does, to be fair. But it has something special under the hood – the world's first production variable-compression-ratio engine. That means the QX50's 2.0-liter turbo four, which makes 268 horsepower and 288 pound-feet of torque, will have up to 27 percent better fuel economy. Here's how it works. The trend of moving to smaller, turbocharged engines carries with it one big falsehood. Under low load when the turbo isn't needed, these engines are less efficient than an equivalent engine without a turbo because of the low compression ratio the turbo requires. That is, if you never need the extra power, you're wasting fuel. Turbocharged (and supercharged) engines use a lower compression ratio to prevent detonation. When you force extra air in a cylinder and mix it with fuel, it's more likely to prematurely go boom. Lowering the compression ratio prevents this problem, but it's less efficient. Infiniti's VC-T promises the best of both worlds, with a compression ratio that ranges from 8.0:1 for high-power turbo needs to a 14.0:1 ratio for fuel-sipping efficiency. At its heart the VC-T engine is a simple idea, but it's complicated to explain. Consider yourself warned. The photo below from Infiniti serves as a good visual overview. For the truly nerdy, this patent application covers the mechanical concept. Instead of having the pistons connected to the crankshaft, Infiniti's engine has a pivot arm with a connection on each end. One end connects to the piston, the other connects to a second lower shaft, which is controlled by an actuator arm. At any given time the engine's pistons move up and down according to the lobes on the crankshaft. But the actuator arm can change the angle of the pivot arm up and down. That is, the pistons still move in the same motion with the same stroke, but phase the entire stroke up or down. Move the pivot up and there's less room at the top, which means a higher compression ratio. Move the pivot down and the compression ratio goes down, too. As an added bonus, the lower shaft eliminates the need for counter-rotating balance shafts. Infiniti says this system works constantly and can vary the compression ratio to any number between 8:1 and 14:1. It also uses electronic variable valve timing on the intake valves to switch into Atkinson-cycle combustion for greater efficiency.

Nissan working on unspecified improvements to Carwings in Leaf EV

Fly a little higher, Carwings. Nissan has been using the communication system as a way for drivers of the battery-electric Leaf to do things like use a smartphone start the charging process remotely, check the charging status or find nearby charging stations. The service was one of the tools Nissan was offering to newbie drivers of the first US mass-produced electric vehicle to better familiarize themselves with ideas like recharging your car from miles away. Now, three-plus years into the model's lifetime, Nissan is looking to get more out of Carwings, Wards Auto says, citing Nissan North America executive Robyn Williams. Specifically, Nissan is hoping Carwings will eventually be able to communicate information about the battery's health, or lack thereof (i.e. degradation) to the driver. That issue was made clear a couple of years ago when Leaf drivers in hot-weather locales such as Arizona said their batteries were losing capacity at a faster rate than advertised. Nissan North America spokesman Brian Brockman, in an e-mail to AutoblogGreen, would only say that the automaker "is always working to determine ways to offer more value to customers via telematics systems like Carwings," but declined to be more specific about any particular technological advancements. Nissan debuted Carwings in late 2010, and, among other things, the concept was novel because it let Leaf drivers compare driving efficiency with other Leaf drivers (think of it as a real silent hypermiling contest). The feature had been used as a telecommunications system on a number of Nissan models in Japan for years before being introduced on the Leaf.