Showing posts with label tdi. Show all posts
Showing posts with label tdi. Show all posts
Tuesday, April 28, 2015
2014 Audi A6 TDI Concept
Electric biturbo and hybridization
The TDI engine gets its power from the boost pressure developed by the turbocharger, which is dependent on the energy of the exhaust. The electric biturbo breaks this dependency. Its supplemental electric compressor enables a rapid buildup of boost pressure and high torque even at low engine speeds. 25 years after the invention of the TDI, Audi is now taking the next big step and making the diesel engine even more emotional and sporty.
In addition to the classic exhaust gas turbocharger, the electric biturbo has a second charger arranged in series. Instead of a turbine wheel, it contains a small electric motor that applies a maximum drive power of seven kW to accelerate the compressor wheel to maximum speed within 250 milliseconds.
The electric compressor is downstream of the intercooler. At very low engine speeds and thus correspondingly low exhaust gas energy at the turbocharger, the bypass valve closes and the air is routed to the electric compressor. This can be flexibly and compactly integrated into a variety of forced induction concepts.
Audi has built two technology studies with the electric biturbo: The Audi A6 TDI concept is equipped with the new 3.0 TDI monoturbo; the Audi RS 5 TDI concept with the 3.0 TDI biturbo. In steady-state – no additional impetus – the monoturbo produces a constant 240 kW (326 hp) and 650 Nm (479.4 lb-ft) of torque, the latter between 1,500 and 3,500 rpm. The electric compressor fills the gap in the torque curve below this range and provides for fast response and excellent elasticity. Acceleration from 60 to 120 km/h (37.3 to 74.6 mph) in sixth gear is reduced from 13.7 to 8.3 seconds.
The modified V6 biturbo in the Audi RS 5 TDI concept is even more impressive. It produces 283 kW (385 hp), and peak torque of 750 Nm (553.2 lb-ft) is available between 1,250 and 2,000 rpm. The electric compressor provides for tremendous power when starting off. If the driver stays on the accelerator, 100 km/h (62.1 mph) is reached in roughly four seconds. Boost pressure is available immediately after each change of gears thanks to the intelligent interplay between the two turbochargers.
The most impressive aspect of both technology studies, however, is the rapid, nearly seamless development of power even at low engine speeds. The strengths of the electric biturbo lie exactly where they make the most sense in everyday driving. It eliminates the need for constant downshifting, keeping engine speeds low. Sporty drivers will really appreciate the passing power and immediate delivery of power when exiting a curve. The electric biturbo is suitable for use in many Audi model series as well as with gasoline engines, in principle. It will soon enter series production in the TDI sector.
The energy required to drive the electric compressor is largely generated by recuperation during coasting phases, so that the end effect is essentially neutral with regard to energy consumption. It is supplied with power via a separate 48-volt electrical system, complete with its own compact lithium-ion battery in the trunk and power electronics. A DC/DC converter provides the connection to the 12-volt electrical system.
The new 48-volt subsystem offers major advantages. It can supply the high-performance electrical consumers of the future – thermoelectric heating elements, electromechanical rear brakes or engine auxiliaries such as oil and water pumps – with more energy than the 12-volt electrical system. Higher voltage means lower currents, allowing for smaller cable cross-sections and thus reduced weight. Audi plans to introduce the 48-volt electrical subsystem to multiple model series shortly.
In parallel to this, the Audi engineers are also working to electrify the drivetrain. There will be a tailored solution for each customer. The hybrid platform offers numerous solutions, from the electric biturbo to the TDI with plug-in technology. The combination with the electric motor opens up new possibilities. It enables targeted shifting of the load points to the benefit of both fuel consumption and emissions behavior. In urban traffic, the electric motor provides for zero-emissions power.
Another interesting electrification option is the electric quattro drive, the e-quattro. Audi has shown this in many of its show cars. The TDI and an electric motor drive the front wheels, while a second electric motor in the rear drives the rear wheels. The battery can be installed in part in the floor tunnel.
Source:Audi Press
Monday, April 27, 2015
2014 Audi RS5 TDI Concept
The RS5 TDI concept technology study is powered by an enhanced-output V6 3.0 TDI biturbo boosted by an electrically driven turbocharger. This new development makes the diesel engine sportier and more efficient.
"25 years ago, Audi launched the first TDI on the market, writing the first chapter of an enduring success story," says Prof. Dr. Ulrich Hackenberg, Board Member for Technical Development. "Our latest innovation is the electric turbocharger, which further improves not just sprint times and pulling power, but also efficiency. This technology illustrates the possibilities harbored by 48-volt electrical systems, which we are currently developing for use in production vehicles."
The V6 biturbo in the Audi RS5 TDI concept produces 283 kW (385 hp); from 1,250 to 2,000 rpm it transfers 750 Nm (553.2 lb-ft) of torque to the crankshaft. The red-line is at 5,500 rpm. The supplemental electric turbocharger provides for staggering power when starting off. An electric motor replaces the turbine wheel and accelerates the compressor wheel to over 70,000 rpm in a few hundredths of a second. The exhaust turbochargers also provide as much as 2.4 bar of relative boost pressure.
This combination enables the Audi RS5 TDI concept to sprint from 0 to 100 km/h (62.1 mph) in just four seconds. The 200 km/h (124.3 mph) mark is reached in less than 16 seconds, and top speed is 280 km/h (174.0 mph). The average fuel consumption of less than 5.3 liters of diesel per 100 kilometers (less than 140 grams CO2 per kilometer) (44.4 US mpg/225.3 g/mi) documents the outstanding efficiency.
Recuperation is the primary source of the drive energy for the electric turbocharger. To transmit this energy, the RS5 TDI concept uses a separate 48-volt electrical system that is connected to the conventional 12-volt electrical system via a DC/DC converter. The energy is stored in a compact lithium-ion battery. The advantage of 48-volt electrical systems is that they enable the transmission of larger amounts of energy. This makes them an important milestone in the Audi electrification strategy.
Source:Audi press
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