150306 -- Reducing the Time of the Racing Engine Development Cycle at ECR Engines
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Transcript of 150306 -- Reducing the Time of the Racing Engine Development Cycle at ECR Engines
Reducing the Time of the Racing Engine Development Cycle at ECR Engines
Brian Kurn – Lead Engine Analyst, ECR Engines 2015
Introduction
• During this discussion we will demonstrate how we use virtual tools to shorten the time of the Development Cycle
• These tools allow us to answer critical questions needed for making quick decisions that have long-term effects
2014 Daytona Prototype Engine
Problem Description
• New Rule – Sonic Restrictor Mandatory in Airbox
• Displacement increased from 5 liters to 5.5 liters
• Parts not available for months
– Intake manifold
– Airbox w/Restrictor
• Engine configuration frozen at beginning of season and performance adjusted with restrictor diameter increase/decrease
Questions we need answered FAST
• Performance Optimization
– What will be the new operating RPM range?
– How can we shape the power curve to our advantage?
Drivability Fuel Economy Endurance
Questions we need answered FAST
• Valvetrain
– How will increased displacement and changes in manifold tuning affect valve timing?
– Will Limit Speed be higher or lower?
– Will last years components meet these new requirements or will we need to purchase new inventory and validate new designs?
Engine Simulation Challenges
• Simple 1D model requires calibration of trumpet lengths - Why?
– Unknown Pressure drop from Restrictors
– Trumpet length “end correction”
Restrictors
Dyno Assembly
Trumpets
Engine Simulation Provides Direction
• Use 3D CFD models of Restrictor, Airbox and Manifold to couple with 1D Engine Simulation code
Engine Simulation provides Direction• Establish behavior of Restrictor
– Couple Restrictors with 1D Airbox and Manifold to understand Restrictor Pressure Drop
Engine Simulation provides Direction• Establish behavior of Airbox and Manifold
– Couple Airbox and Manifold with simple 1D Restrictors to characterize tuning characteristics
Manifold w/Equal Length Trumpets
Engine Simulation provides Direction• Establish baseline behavior of
Restrictor, Airbox and Manifold
– Model equal trumpet lengths to determine the tuning behavior
Intake Pressure-Time Histories
Engine Simulation provides Direction
• Characterize 3D behavior in 1D model
– Correlate 1D model to replicate 1D-3D port pressure-time histories and observe peaks and valleys in individual cylinder Torque
Intake Port Pressure-Time Histories IMEP vs. RPM of 1D model
1D Engine Simulation Study
• Conduct Design of Experiment to Improve Initial Design– Trumpet Lengths
• Trumpet geometry dominant mechanism for shape of Torque curve
– Valve Event Timing• Maximize efficiency of induction system with
optimized valve events
• Improve fuel economy and drivability
– Header Geometry• Fill in any “holes” in the Torque curve with exhaust
tuning
Engine Simulation Study Results
• Recommended Changes
– Improved Trumpet Lengths
• Smooth Torque curve for improved Drivability
• Maintained average Torque
Average TQ identical between the two trumpet
configurations
Engine Simulation Study Results
• Recommended Changes
– Improved Valve Event Timing
• Higher Valve lift
• Wider Lobe Separation, 105.5 110
DoE: Lobe Centerline vs. Lobe Separation Valve Events – 2013 vs. 2014
Engine Simulation Study Results
• Recommended Changes
– Improved Header Geometry
Primaries
Secondaries
Collectors
Engine Simulation Study Results
• Recommended Changes
– Improved Header Geometry
• Shorter primaries
• Longer Secondaries
• Header pairing options
• 180/540 favors high-speed• 270/450 better for low-speed
Validation• Ensure predicted performance captured
accurately
– Intake port tuning and Individual Cylinder Torque accurately predicted
Measured vs. Converge-Lite Measured vs. Converge-Lite
Summary
• 1D Simulation inadequate by itself to characterize induction system tuning behavior without correlation to measured data
• Converge CFD was coupled with 1D model to characterize tuning behavior with sufficient accuracy to evaluate multiple design iterations
• Simulation allows critical decisions to be made with confidence months before physical testing is possible
Questions?