Engine type M 291
Spark plugs 2 per cylinder
In 1921 Thomas Midgley, Jr. and T.A. Boyd in the United States discovered the effectiveness of tetraethyl lead (TEL) as an
"antiknock additive." The addition of TEL to the fuel reduced the knock, permitted higher compression ratios, and resulted in higher efficiencies.
Anti-Knock Index (AKI) or Pump Octane Number (PON), which is equal to the average of the Research Octane Number and the Motor Octane Number. The octane in the gasoline increases the activation energy needed for auto-ignition of the gasoline. The higher activation energy means less knocking of the engine.
RON (Research Octane Number) is determined in a single cylinder variable compression ratio engine that operates at 600 rpm with a 65.6 ºC inlet air temperature at standard barometric pressure.
MON (Motor Octane Number) is determined at engine speed of 900 rpm and 148.9 ºC inlet air temperature.
Anti Knock Index (AKI) = (RON+MON)/2
Anti Knock Index (AKI) also referred to as Road Octane Number (RdON) or Pump Octane Number (PON)
When paired with quattro all-wheel drive, the 4.0 TFSI now accelerates the A8 from 0 to 100 km/h (62.14 mph) in 4.5 seconds. Under partial load, the Audi cylinder on demand (COD) system deactivates four of the eight cylinders.
Cylinder deactivation (ACT)
The first three engines from the two-litre, four-cylinder Drive-E powertrain family will be launched in autumn 2013. The most powerful petrol version comes with a class-leading combination of a compressor and a turbocharger.
Using the supercharger to fill in the bottom end torque gives the petrol engine a big, naturally aspirated feel. The mechanically linked compressor starts to function immediately at low revs, while the turbocharger kicks in when the airflow builds up.
An automotive publication entitled "Auto Notizie", published by the Cizeta Moroder Company of Italy, in May 1989. That publication describes a V-16 engine with two independent crankshafts arranged end-to-end. The adjacent ends of the crankshafts are connected at their ends to a drive gear, and engine crankshaft torque is delivered through an idler to a bevel gear which serves as a torque input shaft for a multiple ratio transmission having an axis disposed perpendicularly with respect to the crankshaft axis.
A/R (Area/Radius) describes a geometric characteristic of all compressor and turbine housings.
The turbine's A/R (area/radius) ratio basically determines where the turbo starts to accelerate.
VFT (Variable Flow Turbocharger)