Gadgetory

well after years of hemming and hawing the u.s. finally has a law that says all new cars have to have one of those a backup camera here's how it's gonna work the camera must show an area at least ten feet wide and 20 feet back the image has to linger on the screen for four to eight seconds after you shift back out of reverse that screen may be in - or it could just be a portion of your rear-view mirror in a car that doesn't have a dash LCD by May 2016 10 percent of all new cars must have cameras by May 2017 40 percent and by May 2018 all of them but even without this law the feds predict some 73% of new cars would have cameras in them voluntarily by 2018 so we're talking about working the last 27% or so with this regulation now the cost if a vehicle just needs this little camera installed and already has a screen somewhere to show it on it adds maybe 40 bucks to the price of a car if the vehicle also needs a screen installed and the camera it's more like a hundred and forty dollars ballpark now if you watch many of our videos you know that an increasing number of cars have these cameras in already standard and many offer them optionally so we're talking about moving the margin to full compliance by 2018 210 people died in backover accidents each year but these cams are only expected to save maybe a third of those lives a recent visibility study by the IIHS shows the unparalleled coverage of a camera compared to any of your three mirrors or a glance over the shoulder or those beeping bumper sensors the camera handily beats them all generally speaking little cars like this on defit have less of a need for rear cameras than big cars like a big truck or SUV but there are exceptions the IIHS found that a Hyundai nada had 42% more of a blind spot where you could totally lose an infant that a Ford f-150 pickup so there are some weird anomalies out there I think every car can use a rear camera and it's not overkill even a little car at this Honda Fit you've always got a backseat you've got a bumper you've got a rear transom piece of sheet metal you can't see through that stuff Superman so there's always a significant place where especially little kids and pets can get lost like that I don't think rear cams are a luxury anymore the future rearview mirrors that are actually rear camera displays such as what Nissan's developing that virtually erases the pillars rear seats and even backseat passengers from your view bottom line it really pays to double check what's behind you before you backup and that there's a rear camera in your next car coming up variable valve timing it's a big deal and we demystify it when CNET on cars rolls on when McLaren re-entered the road car game in 2009 everybody got a little bit excited because McLaren had come along and said bring it to that effects they've launched to fix the 650s you know I think this car is about I think this is a big carbon-fiber extended in the middle finger straits at Ferrari find more from the ex car team of seen at UK at cnet.com slash welcome back to see net on cars coming to you from our home at the marine Club House of cars de witte AK just north of the Golden Gate Bridge you know one of the most ubiquitous revolutions under the hood in the last few years has been variable valve timing just about every car maker brags about it but Elmo's never tell you what it does or how it does it that's our job and a great car tech 101 first a quick lesson in engine valves and what they do on this big ol cutaway for its Shelby motor you can see them clearly the intake valves open to let the air and gas into the cylinder the exhaust valves open later to let the burned air and gas out of the cylinder and into the exhaust valves are operated by camshafts you see these guys up here they turn with the engine and these off-center lobes that are mounted on them push the valves open or not as they turn around these are dual overhead cams there's one cam four exhaust valves a separate one for intake valves also notice this engine has four valves per cylinder like many do these days you've got more area to let the engine breathe in and out but here's the problem a strictly mechanical system operates the same way at all rpms and all engine loads that's not ideal for mpg horsepower or emissions you want to vary this behavior at different points of the engines rev range that's why we have variable valve timing and it changes three parameters valve timing at what points in the engines rotation do the valves open and close valve duration how long the valve stays open once it is and valve lift how far a valve moves off its seat when it opens so varying all those valve events as they're called allows this engine and most importantly it's electronic control unit can constantly make a call to get the most power the best mpg and the lowest emissions all at once now I could do an hour on why that works but here just a couple simple examples if you leave this exhaust valve open longer on one stroke you get all the exhaust blown out of there that leaves a fully open and clean cylinder to take in the maximum gas and air on the next gulp and that could give you more power on the other hand if you close that exhaust valve a little sooner you leave some exhaust in here that fills part of the cylinder and therefore you take in less air and fuel the next time that kind of creates a virtually smaller engine for a moment that could give you better mpg now the mechanisms that allow these valves to change their behavior are almost as numerous as there are manufacturers of engines here just a few examples first of all some cars have multiple sets of lobes on their camshafts and different lobes of different shapes are used at different points in the engines operation here's another example some times you will change the relationship between the rotation of the crank and the rotation of the camshafts so they aren't always locked one-to-one another technology is what's called an eccentric cam drive so the engines turning at a certain rpm but eccentric drives here on the ends of the cams allow them to accelerate and decelerate their rotation that gives you a degree of control as well now who invented all this variable valve timing stuff interestingly Fiat is often given credit as having the first mainstream production-ready system dating back to a 1969 patent application but today you know it as MultiAir we saw it recently in the new Jeep Cherokee now owned by Fiat of course it's their version of changing valve events using hydraulic pressure out of the oil systems the most famous kind of valve timing yes valve timing can be famous is Honda's VTEC the source of one of the biggest memes ever on the Internet and just about every car maker has their own brand of variable valve timing and they push it hard which is weird considering how few car buyers have any idea what it is but now at least you've got a pretty good idea of how this one technology has dramatically improved how engines raise mpg increase horsepower and lower emissions it's one of the great revolutions and engineering in cars in the last few days