 2011 Ford Mustang 3.7-litre V6. Click image to enlarge |
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2011 Ford Mustang
It used to be that you could have either economy or power but not both. Ford’s 2011 Mustang proves that wrong with its new V6 engine: it is both powerful and economical on fuel.
The 3.7-litre V6 is new but has ties to the 3.5-litre Duratec V6 found in the Ford Edge and other recent Ford vehicles. Some of the block’s basic design was carried over: it has the same distance between cylinders and bearing bores which allows the new engine to be manufactured on the same machining line, reducing tooling costs and car prices for consumers. However, the block is a new design for rear-wheel drive applications, with a belt driven water pump on the front and a long-runner intake manifold designed to feed sufficient air to produce 305 horsepower.
  2011 Ford Mustang 3.7-litre V6. Click image to enlarge |
The big news for this 24-valve engine is in the cylinder heads: each cylinder head has Twin Independent Variable Camshaft Timing (Ti-VCT) allowing a unique balance of high performance and fuel economy. Many engines with variable camshaft timing vary only the timing of one cam. The Mustang V6 can change the timing of each camshaft independently. To do this, each camshaft drive sprocket has a spring-loaded mechanism that allows the camshaft to rotate in relation to the position of the sprocket. The engine computer operates solenoids that direct oil pressure to chambers inside the sprocket, moving the position of the cam. For the really technically inclined, the camshafts can be advanced as much as 88 degrees and the cam timing can be instantly varied by over 50 degrees as the engine operates. This may not mean much to most of us, but think of it this way: the computer can tune this engine so the cam timing is comparable to an extremely high performance race engine when full power is demanded but it can also move the cams so the engine idles smoothly and provides good fuel mileage like an economy car. While driving, the computer continuously varies the camshaft timing to provide the best economy and performance for any engine speed and load.
To drive the camshafts, a roller chain, similar to a bicycle chain but much stronger runs from the steel crankshaft inside the front engine cover to the top of the cylinder heads where it loops around to drive each intake camshaft. Another small chain from each intake camshaft drives the exhaust camshafts. Guides and hydraulic tensioners keep everything in place.
  2011 Ford Mustang 3.7-litre V6. Click image to enlarge |
Changing camshaft timing only a few degrees can have a significant effect on engine operation. The Mustang V6 can change each cam timing independently and over a wide range. Besides power and economy, the variable camshaft timing reduces exhaust emissions too. The camshafts can be positioned so that exhaust valve operation keeps some exhaust gases in the cylinder during light throttle operation. This may sound counterproductive to engine operation, but that is exactly what Exhaust Gas Recirculation does on other engines to reduce exhaust emissions. By trapping a small amount of exhaust gases in the cylinder, less fuel and air enter, so cylinder pressures and temperatures are lower. This reduces NOx emissions, but if power is needed, the cam timing changes instantly so maximum power is produced.
With cylinder heads that flow lots of air and an intake manifold to match, Ford engineers added a matched dual exhaust to help the engine produce that 305 horsepower. Internal changes were made as well, such as low resistance cam followers to improve engine efficiency and oil spray nozzles that direct oil at the bottom of each piston to cool it during high load conditions. The Mustang V6 is capable of revving to 7,000 r.p.m., and quickly. What is amazing is that when driven economically, it has a fuel economy rating of just 6.4 L/100 km (highway) when matched with the six speed automatic transmission. That’s fuel economy as good as many compact and mid size sedans! The Ti-VCT dual cam timing alone accounts for a 4.5 per cent fuel economy improvement over a non-variable cam timing equipped engine.
This new lightweight aluminum V6 drives like a performance engine and sips fuel sparingly. Barb Samardzich, vice president, Ford Global Powertrain Development said that by 2013, “you can expect to see this advancement available on 90 per cent of our nameplates.”
Ford appears to be on a roll.
