First things first, behold the harbinger of all that urge. It’s a Touareg, sure, and looks much like the five-pot oil-burning models you see every day at the school gates. Some special styling touches set this one apart though; sporty bumpers front and rear, side skirts, a rear roof spoiler and 18in alloy wheels. Inside, there’s piano black trim, some big, comfortable leather chairs, and a basic cabin layout that will be familiar to anyone who’s driven a Porsche Cayenne, VW Phaeton or Bentley Continental GT, but none the worse for the comparison. Stir the sleeping behemoth under the bonnet into life, and it quickly adopts a tappety, chugging idle. The Touareg V10’s engine sounds very much like a marine diesel, in fact; all that’s missing is the swoosh of propellers and the bubble of churned up water. It all seems very incongruous from a brand-new, £60k SUV. But does it feel so weird out on the road?
A hollow chamber within the valve contains sodium that is cooled by the exhaust port cooling jacket. Since the chamber reaches close to the valve head, the sodium helps to cool the entire valve. Since the valve is internally cooled, it doesn't need the enriched fuel mixture that was generally used in turbo engines to help cool the exhaust valve. The resultant leaner mixture reduces emissions, increases fuel efficiency and helps increase power. The cylinder head includes small 12-millimeter (M12) sparkplugs, down from the more common 14-millimeter (M14) size, to save space and weight. The head also includes direct-injection multi-hole fuel injectors with a small diameter bore. Higher-pressure direct injection optimizes fuel atomization, allowing for more efficient combustion. To provide a high-tumble intake charge that further enhances combustion efficiency, both the intake port and piston crown have special designs. The 1.5-liter DOHC 16-valve VTEC Turbo engine uses an advanced valve control system to combine high power output with high fuel efficiency and low emissions.
The system combines intake and exhaust Variable Timing Control (dual VTC), which continuously adjusts the intake and exhaust camshaft phase, with Variable Valve Timing and Lift Electronic Control (VTEC), which changes valve lift, timing and duration of the exhaust valves. In this application, the increased valve lift from VTEC operation varies to improve gas scavenging at low speed, part throttle conditions, as well as higher speed, full throttle operation, helping to improve performance across the engine speed range. The cam timing is varied based on input from sensors that monitor rpm, timing, throttle opening, cam position and exhaust air-fuel ratio. The result is increased fuel efficiency and lower emissions. With 33-percent greater displacement than the Accord's standard 1.5-liter turbocharged engine, the 2.0-liter powerplant delivers a maximum increase of 60 horsepower and 81 lb.-ft. Compared to the 3.5-liter normally aspirated V6 it replaces, the 2.0-liter engine has less peak horsepower (252 vs.
273 lb.-ft. of torque from 1,500 to 4,000 rpm, vs. With peak torque available at a much lower engine rpm, responsiveness and acceleration are notably enhanced. The 2.0-liter turbo also offers much broader power delivery, holding a torque advantage over the V6 that spans the entire operating range between 1200 and 4800 rpm - the engine rpm range that is typically used the most. The turbocharged Accord 2.0-liter turbo is designed to operate on Regular unleaded fuel. EPA fuel economy ratings are pending at this writing. The direct-injected Accord 2.0-liter 4-cylinder VTEC Turbo engine has a lightweight, low-pressure die-cast aluminum alloy DOHC cylinder head. With exhaust ports cast directly into the cylinder head, the use of a separate exhaust manifold is eliminated, reducing engine weight and simplifying assembly. The manifold is also liquid cooled to help keep heat in check and has a "4-into-1" design for improved fuel efficiency and responsiveness.
