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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