MSU Rapid Compression Machine and Turbulent Jet Ignition Testing

Dr. Elisa ToulsonAssistant Professor Department of Mechanical Engineering, Michigan State University

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Turbulent Jet Igniter

Fuel and Air Inlet /Exhaust Gas Outlet

Hydraulic Reservoir

Pneumatic Piston assembly

Hydraulic Piston

RCM Optical Head

Combustion Cylinder Piston

High Speed Camera

A rapid compression machine uses a single mechanical stroke of a piston to compress a charge of fuel and air to an elevated temperature and pressure suitable for combustion

Key FeaturesPneumatically driven and hydraulically stoppedVariable compression ratioControlled Chamber Wall TemperatureOptical Access for combustion visualizationEffective Compression Time: 7 ms Compressed Conditions

• Pressure= 10-30 bar (optical) and up to 50 bar (metal)

• Temperature= 600-1000 K

Rapid Compression Machine

RCM Direct Test Chamber (DTC) Charge Preparation

Compression and ignition of fuel

Introduction of oxidizer/diluent gases @ T0, p0

Metered injection of test fuel

Evaporation of fuel inside the chamber (~2 min)

(4)(1) (2) (3)

Fuel Injector

First stage ignition delay due to low temperature heat release

Overall ignition delay

End of RCM compression stroke

Pressure increase due to RCM compression

JP-8 sampled at t = 2 min after injection

S

S

+ t for evaporation

Samples drawn through septum witha syringe and analyzed in GC/MS

Gas Chromatography/Mass Spectrometry (GC/MS)

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1.2 Volatilized JP-8 Samples from RCM JP-8 Reference

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1.2 Volatilized JP-8 Samples from RCM JP-8 Reference

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7/29/20164

TJI is a pre-chamber ignition enhancement concept that produces a distributed ignition source through the use of a jet undergoing combustion

1.13 ms 1.25 ms 1.38 ms 1.63 ms 2.00 ms 2.25 ms 4.38 ms 10.00 ms

Advantages•Fast burning rates•Knock mitigation•Facilitates lean combustion and ignition of highly dilute mixtures

Turbulent Jet Ignition

Turbulent Jet Ignition Spark Ignition

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No Auxiliary Fueling PW=1.0 ms

No auxiliary fuel injection

Auxiliary fuel injection 1ms pulse

Pre-chamber visualization

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RANS Modeling of the TJI Process in the RCM

• RCM Schlieren Imaging• RCM testing and optical

imaging of a natural gas TJI system for large bore truck engines

• RANS modeling of TJI system in large bore truck engine

• Autoignition and spray testing of ethanol gasoline blends in RCM

• Construction of Optical Constant Volume Combustion Chamber (CVCC) for laminar flame speed measurements

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Plans for Future WorkRCM Schlieren Head Spray imaging in RCM

Initial Converge Modeling of Large Bore Truck Engine

Preliminary CVCC Design