Porsche Engineeringdriving technologies

Fuel consumption improvement on highly charged gasoline

engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

European GT-SUITE Conference Frankfurt am Main, 20. October 2014

Porsche Engineeringdriving technologies

20.10.2014 - 3 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

> Benchmark: state-of-the-art gasoline engines

> Boundaries of turbocharging

> Base model

> Cooling concepts

> Conclusions

Content Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction

Porsche Engineeringdriving technologies

20.10.2014 - 4 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Benchmark: state-of-the-art gasoline engines

> Benchmark: state-of-

the-art gasoline engines

> Boundaries of

turbocharging

> Base model

> Cooling concepts

> Conclusions

> Downsizing by the use of turbocharging has well established. > In future, the electrification of the powertrain offers a new degree of freedom.

Porsche Engineeringdriving technologies

20.10.2014 - 5 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Benchmark: state-of-the-art gasoline engines

> Downsizing concepts need to fulfil the trade-off between high specific power and early low end torque.

> Benchmark: state-of-

the-art gasoline engines

> Boundaries of

turbocharging

> Base model

> Cooling concepts

> Conclusions

Porsche Engineeringdriving technologies

20.10.2014 - 6 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Low engine speed area

Boundaries of turbocharging

> BMEP – 15-20 bar Possible to realise

even with increasing backpressure.

> BMEP – 25-30 bar Intake air temperature

is the major limitation in order to increase BMEP.

Higher downsizing level requires an efficient cooling system.

BMEP : 25 bar

BMEP: 15 bar BMEP : 20 bar

BMEP : 30 bar

Instable combustion

Instable combustion

> Benchmark: state-of-the-

art gasoline engines

> Boundaries of

turbocharging

> Base model

> Cooling concepts

> Conclusions

Porsche Engineeringdriving technologies

20.10.2014 - 7 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

High engine speed area

Boundaries of turbocharging

> BMEP – 15 bar Nearly no enrichment. Fuel consumption

depends little on the intake air temperature.

> BMEP – 30 bar Enrichment due to high back pressure.

Depends on the intake air temperature.

BMEP : 15 bar

BMEP : 15 bar BMEP : 30 bar

BMEP : 30 bar

> Benchmark: state-of-the-

art gasoline engines

> Boundaries of

turbocharging

> Base model

> Cooling concepts

> Conclusions

Porsche Engineeringdriving technologies

20.10.2014 - 8 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Base model

> Base model Max. BMEP [bar] 25 Engine speed area Tmax [U/min] 1800 - 6200 Charging system

> Turbo Charger > Mechanical Charger > 2 Charge Air Cooler

> Benchmark: state-of-the-

art gasoline engines

> Boundaries of

turbocharging

> Base model

> Cooling concepts

> Conclusions

Unit Value

Max BMEP [bar] 25

Max BMEP Range [rpm] 1800 - 6200

Charging System Turbocharger Mechanical Charger 2 Charge Air Cooler

Porsche Engineeringdriving technologies

20.10.2014 - 9 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Indirect charge air cooling Simulation model

Cooling concepts

> Additional cooling circuit necessary.

> Short air routes, low pressure losses and advantages in packaging.

> Benchmark: state-of-the-

art gasoline engines

> Boundaries of

turbocharging

> Base model

> Cooling concepts

> Conclusions

Porsche Engineeringdriving technologies

20.10.2014 - 10 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Direct charge air cooling Simulation model

Cooling concepts

> Reduction of intake air temperature between 10 and 20 °C.

> Improved anchor angle. > Lower boost pressure

demand and reduced enrichment.

> Fuel consumption decreases by nearly 5 %.

> Benchmark: state-of-the-

art gasoline engines

> Boundaries of

turbocharging

> Base model

> Cooling concepts

> Conclusions

Porsche Engineeringdriving technologies

20.10.2014 - 11 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Supercooling Simulation model

Cooling concepts

> Benchmark: state-of-the-

art gasoline engines

> Boundaries of

turbocharging

> Base model

> Cooling concepts

> Conclusions

> In order to increase the Cooling Power of the 2nd CAC, an addittional Turbocharger in the intake line is added

> The pressure losses through the Supercooling requires an increase of the Compression Ratio of the Exhaust Gas Driven Turbocharger by 50%

> Intake Manifold Temperature can be reduced by 29°C

53 °C 2,5 bar

53 °C 2,5 bar

156 °C 2,6 bar

25 °C 1,0 bar

32 °C 2,4 bar

950 °C 3,3 bar

850 °C 1,5 bar

106 °C 5,0 bar

68 °C 3,9 bar

69 °C 3,9 bar

223 °C 3,9 bar

25 °C 1,0 bar

43 °C 5,0 bar

3 °C 2,5 bar

950 °C 4,2 bar

801 °C 1,5 bar

+15°C +1,4 bar

+16 °C +1,4 bar

+67°C +1,3 bar

-29 °C +0,1 bar

+0,9 bar

- 49 °C

53 °C 2,5 bar

53 °C 2,5 bar

156 °C 2,6 bar

25 °C 1,0 bar

32 °C 2,4 bar

950 °C 3,3 bar

850 °C 1,5 bar

System patented by I. Kalmar and J. Antal in 1975 for Nox Reduction in CI Engines

Porsche Engineeringdriving technologies

20.10.2014 - 12 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Supercooling Simulation model

Cooling concepts

> Additional turbocharger in the air intake system.

> Reduced intake air temperature (below environment)

> Higher backpressure results in a minor advantage in fuel consumption and anchor angle compared to the direct charge air cooling.

> Turbocharger needs to be matched to the operating condition.

> Benchmark: state-of-the-

art gasoline engines

> Boundaries of

turbocharging

> Base model

> Cooling concepts

> Conclusions

Porsche Engineeringdriving technologies

20.10.2014 - 13 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Low temperature charge air cooling Simulation model

Cooling concepts

> Indirect charge air cooling combined with the cooling circuit of the air conditioning.

> Cooling power of the low temperature charge air cooling limited to 8 kW.

> Driving power of the ac-compressor is taken into account.

> Intake air temperature below ambient conditions.

> Improved anchor angle and lower enrichment.

> Reduced fuel consumption in full load of about 9 %.

> Benchmark: state-of-the-

art gasoline engines

> Boundaries of

turbocharging

> Base model

> Cooling concepts

> Conclusions

Porsche Engineeringdriving technologies

20.10.2014 - 14 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Indirect charge air cooling Simulation model

Cooling concepts

> Retarded anchor angle at higher load in the low engine speed area.

> Enrichment need increases with engine speed and load.

> Benchmark: state-of-the-

art gasoline engines

> Boundaries of

turbocharging

> Base model

> Cooling concepts

> Conclusions

Porsche Engineeringdriving technologies

20.10.2014 - 15 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Direct charge air cooling Simulation model

Cooling concepts

> Lower air intake temperature in full load conditions.

> Improved anchor angle.

> Lower enrichment in full load conditions.

> Benchmark: state-of-the-

art gasoline engines

> Boundaries of

turbocharging

> Base model

> Cooling concepts

> Conclusions

Porsche Engineeringdriving technologies

20.10.2014 - 16 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Supercooling Simulation model

Cooling concepts

> Increased backpressure due to higher compressor power.

> Slightly improvement of the anchor angle.

> Enrichment improves marginally compared to the direct charge air cooling.

> Worse package situation.

> Disadvantages in dynamic response need to be expected.

> Benchmark: state-of-the-

art gasoline engines

> Boundaries of

turbocharging

> Base model

> Cooling concepts

> Conclusions

Porsche Engineeringdriving technologies

20.10.2014 - 17 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Low temperature charge air cooling Simulation model

Cooling concepts

> Significant reduction of air intake temperature.

> Improved the anchor angle.

> Lower enrichment.

> Benchmark: state-of-the-

art gasoline engines

> Boundaries of

turbocharging

> Base model

> Cooling concepts

> Conclusions

Porsche Engineeringdriving technologies

20.10.2014 - 18 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Low temperature charge air cooling Simulation model – increased compression ratio

Cooling concepts

> Potential can be used to increase the compression ratio.

> Compression ratio is increased until an anchor angle, similar to basis version, is achieved.

> Fuel consumption reduces by further 2 %.

> Benchmark: state-of-the-

art gasoline engines

> Boundaries of

turbocharging

> Base model

> Cooling concepts

> Conclusions

Porsche Engineeringdriving technologies

20.10.2014 - 19 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Low temperature charge air cooling Simulation model – increased compression ratio

Cooling concepts

> Larger area of lower fuel consumption.

> Significant potential to improve fuel consumption for a wide range of operating conditions.

> Benchmark: state-of-the-

art gasoline engines

> Boundaries of

turbocharging

> Base model

> Cooling concepts

> Conclusions

Porsche Engineeringdriving technologies

20.10.2014 - 20 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Conclusions

Lower air intake air temperature allows to achieve a larger engine speed area with maximum torque, an higher power output or to increase the compression ratio for the reference engine. Indirect charge air cooling > Advantages in packaging and shorter air routes. Direct charge air cooling > Reduced air intake temperature in full load fuel consumption improvement of approx. 5

%. > Disadvantage in packaging and longer air routes. Supercooling > Potential to reduce fuel consumption for moderately charged engines. > High backpressure of highly charged engines avoids large fuel consumptions improvements. > Disadvantages in dynamic response could be expected. Low temperature cooling > Offers a large potential already at a cooling power of 8 kW. > Combined with an increased compression ratio, the system offers a fuel consumption

advantage of approx. 11 %. > Dynamic behaviour of the cooling circuit needs to be kept under control.

> Benchmark: state-of-the-

art gasoline engines

> Boundaries of

turbocharging

> Base model

> Cooling concepts

> Conclusions

Porsche Engineeringdriving technologies

Thank you very much for your attention!

Porsche Engineeringdriving technologies

20.10.2014 - 22 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Supercooling

Pressure loss

Pressure loss Principle

Porsche Engineeringdriving technologies

20.10.2014 - 23 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Low temperature charge air cooling

Cooling power

Air – low temperature Water – low temperature

Porsche Engineeringdriving technologies

20.10.2014 - 24 -

Fuel consumption improvement on highly charged gasoline engines through intake air temperature reduction V. Bevilacqua, E. Jacobs, K. Fuoss

Low temperature charge air cooling

Coefficient of performance

> 𝐶𝑂𝑃 =𝐶𝑜𝑜𝑙𝑖𝑛𝑔 𝑝𝑜𝑤𝑒𝑟

𝐷𝑟𝑖𝑣𝑖𝑛𝑔 𝑝𝑜𝑤𝑒𝑟 𝐴𝐶 𝑐𝑜𝑚𝑝𝑟𝑒𝑠𝑠𝑜𝑟

> The cooling power, but mainly the Evaporation temperature is responsible for the required driving power of the AC compressor.

> At high engine speed the same cooling power can be achieved with the same driving power due to the higher air mass flow and the higher air temperature.

Example [1/min] 2250 6200

Cooling power [kW] 5 5

Tevaporator [°C] -10 30

COP 1,0 3,1

Driving power AC compressor [kW] 5,0 1,6