|The A4 2.0 TDIe. Click to enlarge.|
Audi has introduced its fuel-consumption optimized version of the A4 mid-size sedan, the A4 2.0L TDIe, in Europe. Noted by Rupert Stadler, Chairman of the Board of Management in his talk at the 120th Annual General Meeting of Audi AG in May, the A4 TDIe consumes an average 4.6 liters of diesel per 100 kilometers (51.13 miles per gallon US gallon) and consequently emits 120 g CO2/km.
The A4 Saloon TDIe adopts the 100 kW (134 hp) 2.0-liter TDI engine first seen in A6 TDIe. (Earlier post.) The turbocharged diesel features high pressure common rail injection and incorporates stop/start and energy recuperation systems. Further fuel savings come from grille and under-body modifications to enhance aerodynamics.
The A4 2.0 TDIe delivers peak power at 4,200rpm and 320 N·m (236 lb-ft) of torque from 1,750 rpm. Equipped with a six-speed manual transmission, the car reaches 62 mph from rest in 9.5 seconds and continues to a top speed of 143 mph (230 km/h).
The start-stop system cuts engine power at idle when the clutch pedal is released and the gear lever is in its neutral position, and then restarts in two-tenths of a second—more rapidly than comparable systems—when the clutch is depressed. With the system’s help, economy is boosted and CO2 is reduced by approximately 5g/km, but if required it can be deactivated at the touch of a button.
Recuperation technology provides further fuel and CO2 savings by recycling a proportion of the wasted kinetic energy which is generated under normal braking and normally dissipated as heat, and storing this temporarily in the vehicle battery to reduce the engine load when the car subsequently accelerates again.
The achievement of ‘e’ status in the A4 has also been helped by a 5% increase in the six-speed manual transmission’s final drive ratio, by the installation of a power steering pump which operates only on demand and by the use of low rolling resistance tires.
An additional streamlining underbody trim panel, extra enclosure for the radiator grille and sports suspension settings which help to reduce drag through a 20mm ride height reduction.
The TDIe also features a special instrument cluster with an efficiency-focused version of the Driver’s Information System (DIS) which recommends gear shift points and gives situation-specific driver advice on how to optimize fuel efficiency based on sensor analysis of driving conditions and driving style. The recommendations provided by the system, incorporated into the dashboard, have been shown to improve fuel economy by as much as 30%.