Audis latest experimental Audi A4 2.0 TDIe shown off at the Paris Auto show has a number of improvements to increase its fuel efficiency to just over 71 MPG (UK) just under 4liters /100km and 58 Mpg (US) they also managed to shave 5g off the CO2/Km figure.

Fortitude (an Audi news site) commented in their Paris round up:

“Foregoing fitting the ultra-efficient engine into a swoopy and far-from-production concept car, Audi went with their top-selling Audi A4. The result looks just like a car you can buy today, but nets a hair shy of 60 mpg (USA Gallons). You might miss seeing it, but it’s hard to miss the significance of this new engine tech”

A number of innovative energy saving and carbon reduction technologies where used to hit these impressive fuel and co2 figures

The Audi 2.0 TDI engine also features a comprehensive list of efficiency tweaks. The oil cooler, the oil nozzles for cooling the piston crowns, the oil pump and the water pump have been designed so that they can be switched off – when inactive they do not require any power.

A new design of piston rings resulted in lower tangential forces, the spring pressure on the intake valves was reduced slightly, and the vacuum pump for the brake booster received a new actuator. These measures as a whole reduced emissions by 5 grams of CO2/km.

This Audi A4 uses a thermostatically controlled cooling circuit with an internal heat exchanger for the automatic air conditioning system – this system uses 20 percent less fuel than its predecessor. The A4 TDI concept e uses a new controller: the engine disconnects the air conditioning system’s compressor from its drive whenever possible.

The Audi transmission is coupled to a start-stop system that switches the engine off whenever the car comes to a standstill. The engine is deactivated whenever the Audi A4 TDI concept e comes to a standstill,  It starts up again as soon as the driver steps on the clutch.

Audi Aerodynamics

The A4 TDI concept e has had changes to its aero package to improve its fuel efficiency A new boot lid with a restrained separating edge improves the already excellent aerodynamics. The partially closed grid in the single-frame grille and improved underbody fairings ; also contribute to the excellent drag coefficient of 0.25 for the model (the production model Audi A4 is 0.27).

Audi Energy recovery

The A4 TDIe concept uses a energy recovery system that converts the energy generated during deceleration into usable electrical energy. In the deceleration and braking phases the A4 TDI stores energy  temporality in a glass mat battery, which is a robust battery with a long life. Whenever the car accelerates again, the battery feeds the energy back in – this is similar in concept to the systems that Formula 1 cars will be using from next year.

With the credit crunch all businesses are looking to reduce the cost of their company car fleets, this ‘e’ version of the Audi A4 shows that Audi’s engineers are always looking to improve the efficiency of Audi cars with sacrificing the performance and style Audi is known for.

Audi plans to expand its ‘e’ model line in the near future and start putting further technologies from its modular efficiency assembly into production.