Combustion Features of Gasoline in CI Engines

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Combustion Features of Gasoline in CI Engines
Vittorio Manente
Department of Energy Sciences Division of
Combustion Engines
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Outline

• Experimental Set-Up
• Newly developed combustion concept
• Chronological steps towards this target
• Injection strategy concept development for the
  whole operating range
• Conclusions

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Outline

• Experimental Set-Up
• Newly developed combustion concept
• Chronological steps towards this target
• Injection strategy concept development for the
  whole operating range
• Conclusions

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Experimental setup

• Specifications of single cylinder engine

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Outline

• Experimental Set-Up
• Newly developed combustion concept
• Chronological steps towards this target
• Injection strategy concept development for the
  whole operating range
• Conclusions

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High Load Gasoline
Gasoline 98 ON
Homogeneous Mixture
Stratification for autoignition
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High Load Diesel
Swedish MK 1 54 CN
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Emissions
Rail Pressure1000 bar S.R. 1.7 -
0.17
0.12
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Efficiency Fuel Consumption
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EGR Sweep _at_ 12 bar IMEP
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Advantages of the concept
Gasoline Type of Fuels
More mixing trough longer natural ignition delay
Mostly kinetically controlled combustion (fast)
Very high boost
High rc
Low specific fuel consumption
NOx reduction with EGR Soot reduction with
injection pressure swirl relative homogeneity
of the mixture
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Outline

• Experimental Set-Up
• Newly developed combustion concept
• Chronological steps towards this target
• Injection strategy concept development for the
  whole operating range
• Conclusions

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Separation between EOI SOC, how much to boost?
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Pressure, RoHR Injection Traces
Double Injection
Single Injection, 1.8 ms
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Emissions Efficiency
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Losses Analysis
Thermal Boundary Layer breaks ? Higher Heat
Losses
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Losses Analysis
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Double Injection, where to place the pilot?
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Double Injection _at_ 14 bar IMEP

• Gasoline Diesel
• Pilot -20 TDC, 0.45 ms
• Main 1.8 ms
• Ethanol
• Pilot -20 TDC, 1 ms
• Main -1 TDC, 1.8 ms

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Emissions Fuel Consumption
IMEP 14 bar
Mostly kinetically controlled combustion
EGR 25 ? ?1.56
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Probable combution mode
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New combustion concept
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Energy Losses Analysis
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Outline

• Experimental Set-Up
• Newly developed combustion concept
• Chronological steps towards this target
• Injection strategy concept development for the
  whole operating range
• Conclusions

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Injection strategy concept
Load CA50
Stratification mf const
Stratification Load
Inlet Temperature has to increase
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Outline

• Experimental Set-Up
• Newly developed combustion concept
• Chronological steps towards this target
• Injection strategy concept development for the
  whole operating range
• Conclusions

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Conclusions

• PPC with high ON fuels is a feasible concept but
  the logic on how to operate the engine is
  different.
• Low fuel consumption, low emissions and low noise
  can be achieved at the same time.
• Gasoline PPC is able to run at much higher loads
  than Diesel and its power density is not
  penalyzed by a huge amount of EGR.

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Conclusions

• The concept might be applied to production if
  efforts are put in partially redesign the
  classical engine layout, i.e.
• More robust engines, Pmax gt 200 bar
• Electrical compressors
• New aftertreatment systems
• etc.

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Thanks for the Attention!
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Idle
IMEP 1.5 bar Tinlet Gasoline 105 C, Ethanol
135 C Pinlet atm