Audi has revealed the details on the newest engine in the company's portfolio. The 1.8-liter, direct-injection, turbocharged gasoline four-cylinder produces an impressive 170 horsepower and 236 pound-feet of torque while returning 41.27 mpg in the A5 on the U.S. scale. That's a reduction in fuel consumption of as much as 21 percent compared to the outgoing engine, thanks in part to the clever use of both direct and indirect injection. In part-load range, fuel is injected into the intake runners where it's swirled with air just like in the good old days. Audi says that the design reduces fuel consumption and particulate emissions.

The direct-injection system handles fuel duty at low and high loads, and as a result, the 1.8 TFSI already conforms to the Euro 6 standard, which isn't set to take effect until 2015. In addition, a full electronic coolant regulation system reduces parasitic drag and adjusts coolant flow to accommodate a range of air temperatures. Audi engineers also managed to reduce internal friction for additional efficiency. Hit the jump for the full press release.
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Innovation engine: The new 1.8 TFSI

- Ample power and minimal consumption: 125 kW (170 hp) and
320 Nm (236.02 lb-ft) torque, but just 5.7 liters per 100 km (41.27 US mpg)

- New solutions in fuel injection and other fields of technology

- Fully electronic coolant regulation system

The engines in the updated A5 family set new standards for sportiness and efficiency. Even the base engine, the completely redesigned 1.8 TFSI, showcases the full extent of Audi's technological competence. The engineers have developed innovative solutions in numerous fields of technology to achieve surprisingly strong performance with minimal fuel consumption.

The high-end four-cylinder engine displaces 1,798 cm3 and delivers a brawny and constant 320 Nm (236.02 lb-ft) to the crankshaft between 1,400 and 3,700 rpm. Peak output of 125 kW (170 hp) is achieved at 3,800 rpm. With a manual transmission, the 1.8 TFSI accelerates the Audi A5 Coupé from zero to 100 km/h (62.14 mph) in 7.9 seconds on its way to a top speed of 230 km/h (142.92 mph). Despite all this power, it consumes just 5.7 liters of fuel per 100 km (41.27 US mpg) on average, which corresponds to best-in-segment emissions of 134 grams of CO2/km (215.65 g/mile). Consumption has been reduced by 21 percent compared with the previous model engine.

Combustion behavior was a particular focus of the development work. In addition to FSI direct injection, the 1.8 TFSI also uses indirect injection. This system injects the fuel at the end of the intake manifold near the tumble valves, where it is swirled intensively with the air. Indirect injection is used in the part-load range. It reduces fuel consumption and particulate emissions to such an extent that the four-cylinder engine already complies with the limits of the future Euro 6 standard, which does not enter into force until 2015.

The rail pressure of the FSI system has been increased from 150 to 200 bar. The direct injection system is active when starting off and at higher loads. It can perform two or three individual injection operations per work cycle. To further optimize gas exchange, the valve control system has been given greater operating freedom. The Audi valvelift system, which adjusts the lift of the valves in two stages, is active on the exhaust side. The two camshafts can be adjusted through 30 or 60 degrees of crankshaft angle.

Fully electronic coolant regulation system
The innovative thermal management of the four-cylinder engine features a new fully electronic coolant regulation system. Two fast-switching, rotating cores, which are consolidated in a module and driven by an electric motor via a screw drive, control the flow of coolant. One of their primary objectives is to bring the motor oil up to operating temperature as quickly as possible following a cold start. This is done by keeping the coolant in the crankcase for a relatively long time. The cabin heating runs off of a separate loop in the cylinder head. The main radiator, which dissipates the heat to the environment, does not come into play until the latest possible moment.

The new rotating core module can set the water temperature between 85 and 107 degrees Celsius as a function of load and rpm to always achieve the best compromise between minimal internal friction and thermodynamic efficiency. Switchable valves throughout the cooling system manage heat flows between the engine, the heat exchanger for the transmission and the cabin. All together, the thermal management system reduces the CO2 emissions of the 1.8 TFSI by around 2.5 g per 100 km (4.02 g/mile).

This concept benefited from the integration of the exhaust manifold into the water-cooled cylinder head. Because this also reduces the exhaust gas temperature, it is not necessary with the 1.8 TFSI to enrich the mixture at full load, which reduces fuel consumption significantly when driving sportily.

The turbocharger in the 1.8 TFSI is also an all-new design that develops the high relative boost pressure of up to 1.3 bar very systematically. Key features include a turbine wheel made from a new alloy that can withstand exhaust temperatures of up to 980 degrees Celsius, the oxygen sensor mounted directly upstream of the turbine wheel, a pulsation damper, a compressor wheel machined from a solid blank and an electric wastegate actuator that adjusts the boost pressure particularly quickly and precisely to further reduce fuel consumption.

Engine weight has been reduced from 135 to 131.5 kilograms (297.62 to 289.91 lb). The new turbocharger/cylinder head module, a new casting process for the gray cast iron crankcase that reduces wall thickness to roughly three millimeters (0.12 in) and the crankshaft with four rather than eight counterweights and reduced main bearing diameters all contributed to this weight reduction. The pistons are made of new, high-strength alloy. Lightweight polymers are used for the oil pan, and many screws are made of aluminum.

Internal friction has also been drastically reduced by the use of an innovative coating on the piston skirts and by mounting the two balance shafts that counteract the second-order inertial forces in roller bearings. The regulated oil pump requires little energy itself, and the oil-jet cooling for the piston heads is controlled via a high-precision electric system.


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    • 1 Second Ago
  • 105 Comments
      EB110Americana
      • 3 Years Ago
      This sounds like a diesel. 236Tq.>170HP. Peak horsepower is at 3,800 RPM. Peak torque is at 1,400-3,700 RPM. Fuel economy is over 40 MPG. Fuel pressure is 200 bar. The 1.8L engine block weighs 290 Lbs. True, there are direct injected gasoline engines out there, even turbocharged ones, with some of these characteristics, but I've never seen one with the RPM ranges this 1.8 seems to live in.
        Krishan Mistry
        • 3 Years Ago
        @EB110Americana
        That's what I thought. Max torque 1400-3700rpm? A turbo petrol could do that fine. But I have yet to see a small turbocharged petrol engine who maxes power at 3800rpm, that figure screams DIESEL!!! even more than the abundance of torque.
          NissanGTR
          • 3 Years Ago
          @Krishan Mistry
          Different cam profiles, longer stroke smaller bore, different exhaust design, a small turbo, and a low rpm limit will do that.
          Krishan Mistry
          • 3 Years Ago
          @Krishan Mistry
          @NissanGTR, you're probably right, but if you are going to put a 4000rpm limit and aim for torque and economy, why would you not make it a turbodiesel TDI? The result is more fuel economy and even more torque. But maybe calling it a diesel means that by default Audi will assume North Americans will disregard it, and they will not bring it over. But a 4000rpm petrol engine makes very little more sense than an 8000rpm diesel.
      Daz
      • 3 Years Ago
      Once upon a time Honda would have been inventing engines like this... oh how i miss those days.
      NipponEngine
      • 3 Years Ago
      me likie
      Ryth
      • 3 Years Ago
      Probably going in the A3 Sedan I bet.
      Jonathan Arena
      • 3 Years Ago
      Thats sick... now I wish they would put it in a smaller car.
      Hazdaz
      • 3 Years Ago
      Those are some impressive figures. I am especially surprised to see its torque rating is higher than its HP, especially on such a small displacement design. Wonder if VW will get a version of it.
      Slappy
      • 3 Years Ago
      Wonder if this will show up on a VW platform..
      donnieorama
      • 3 Years Ago
      This thing will never see the light day in an A5 over here...
      Joe
      • 3 Years Ago
      I'd love to see this in a Golf with a 6-speed manual. Near TDI economy at $0.25 less per gallon.
        Joe
        • 3 Years Ago
        @Joe
        Or an Audi A3 with AWD would be cool too.
      JP Chow
      • 3 Years Ago
      pleeease replace the VW 2.5L mill with this. Equivalent HP, more torque, better mileage, less weight.
        icharlie
        • 3 Years Ago
        @JP Chow
        This motor is expected to replace the 2.5L unit in Vws as well. Autoblog had a similar story to this up not too too long ago. Said Vw but this time it says audi
      Felix
      • 3 Years Ago
      Huh? Its 170 hp is 45 hp less than the 225 hp the 4-cylinder turbocharged engine of the same size (1.8L) in my 2001 Audi TT Quattro puts out! But at least the gas mileage is really impressive (15 mpg more than the EPA highway rating of 26 mpg for my engine).
        Christopher Meyer
        • 3 Years Ago
        @Felix
        welcome to reality, you can only keep the horsepower numbers so high if you want to build an engine for efficiency.
        TruthHertz
        • 3 Years Ago
        @Felix
        An then there's the fact that this one probably won't be a sludge monster unlike the longitudinally mounted 1.8T that found its way under the hood of many Audi's and the Passat. This engine is probably running a higher compression ratio to improve efficiency. The old 1.8T wasn't exactly setting the world on fire for efficiency when it was out there requiring mid grade fuel or higher.
        Krishan Mistry
        • 3 Years Ago
        @Felix
        I really believe this engine is a diesel. Maybe it will replace the 2.0TDI? And although the article clearly states TFSI (turbo direct injection gasoline), with the torque figure of 236lbft arriving so early (1400rpm-3700rpm), and max
          Krishan Mistry
          • 3 Years Ago
          @Krishan Mistry
          *got cut off anyways.... max power at 3800rpm is a clear indication that this is a diesel engine. That would explain the impressive mileage aswell. If this was a gasoline engine, it would max out at 5K or higher, especially for something so small and turbocharged.
        Bruce Wayne
        • 3 Years Ago
        @Felix
        if you own a tt 225 you probably are fully aware of why your 1.8 is different from the standard 1.8. you should've got a 3.2 dsg if you want power. 1.8 in any form is humdrum entry level.
      rty
      • 3 Years Ago
      Good job Audi.
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