Lightweight Fuel Efficient Engine Package Brittany Borella, Chris Jones, John Scanlon, Stanley Fofano, Taylor Hattori, and Evan See

Project Overview

Customer Needs Customer Need # ImportanceDescription Engine CN11 The engine must reduce fuel consumption when compared to the previous engine package CN21The engine must provide sufficient power output and acceleration Control System CN112The control system must provide accurate fuel delivery and measurement Cooling System CN141 The cooling system must be able to allow the engine to operate in high ambient temperatures under race conditions Documentation and Testing CN171Documented theoretical test plan and anticipated results CN181Must provide a CFD analysis of the intake manifold, restrictor, and throttle CN192Must provide an accurate model of the engine in GT-suite

Engineering Specifications Spec. #ImportanceSource Specification (metric) Unit of Measure Marginal Value Ideal Value Comments/Status S11CN1 Fuel Consumption km/l Want to use ~0.7 gal for the 22km run S31CN2Power OutputHP4555 S41CN2Torqueft-lbs3135 S61CN4,15Reliabilitykm50100 Should be able to perform in all Formula SAE events and testing before major overhaul S81CN6Weightlbs7568Engine weight S91CN8Fuel TypeN/A E85 Ethanol-Gasoline Blend or 100 Octane Gasoline S121CN14Temperature°F Cooling system must keep the engine under 200 degrees in ambient temperatures up to 100 degrees

Engine Model

 Air/Fuel Ratio: 0.86 Lambda  Simplified tubular geometry used for initial induction and exhaust models  CRF250R valve flow scaled until WR450F data is measured  Wiebe combustion model parameters currently estimated until cylinder pressure data is obtained  Ignore effects of muffler  Surface roughness values estimated  Wall heat transfer properties estimated for steel exhaust sections  Intake and exhaust valve lift estimated from YZ400F until actual measurements can be made  Assume constant operating temperature and component temperatures—to be correlated with dyno data  Assume ambient conditions of 14.7 psia and 80°F Overall Assumptions

 Finalized intake/throttle/restrictor geometry  Finalized injector placement(s)  Injector flow data  Intake/exhaust valve inflow and outflow loss coefficients  Intake/exhaust cam profiles  Base cam timing  General cranktrain dimensions  Surface area ratios for head and pistons  P-V Diagrams to validate Wiebe model assumptions  Various temperature measurements Required Parameters

Theoretical Engine Model

Live Simulation of Engine Parameters

Dynamometer Test Stand

Cylinder Head Removed for Measurement

Photo Courtesy of DUT Racing Bore Tube Production Flow Testing of Cylinder Head

System Test Plan

 Engine Characterization  Torque  P-V Diagrams  Brake Specific Fuel Consumption  Cooling System  Sensors  Cylinder Pressure  Crank angle  Thermocouples  Fuel Flow  Coolant Flow  Basic Engine Diagnostics  Wideband Lambda Engine Testing

 FT-210 Series  Gems Sensors & Control  gal/min  ± 3% Accuracy Fuel Flow Sensor

 PCB Piezotronics  Transducer 112B10  422E In-Line Charge Converter Cylinder Pressure Sensor

 AM bit rotary  Measure Angular Position  Outputs  Incremental  Series SSI  Linear Voltage  Analogue Sinusoidal Magnetic Encoder

 Load Simulation  Power Characterization  Fuel/Spark Mapping Dynamometer

 Dynamometer Controller  Data Input Improvement  NI PCI-6024E  200 kS/s  12-Bit  16-Analog-Input DAQ Data Acquisition

CFD Analysis

 20 mm inlet diameter (19 mm for E85) creates choked flow conditions, limiting total mass airflow to engine  Required by competition rules  Keeps engine power at a safe level for competition  Design goal is to minimize loss coefficient through restrictor geometry to allow maximum airflow into engine  Supersonic Converging – Diverging Nozzle Geometry  Expand out diverging section to allow for proper shock development to minimize loss coefficient  Keep diffuser angle low enough to avoid potential flow separation  Keep overall length low to reduce viscous losses due to surface friction and boundary layer growth Intake Restrictor

 2 -Dimensional Axis-Symmetric analysis allows for fast solving time with refined mesh in areas of shock development Intake Restrictor

 Air flows from throttle to engine intake port through intake manifold  Intake Plenum  Acts as air reservoir for engine to draw air from during intake stroke  Primary purpose is to damp out pressure pulses from intake stroke to create steady flow conditions at the restrictor  Intake Runner  Path through which engine pulls air from the plenum into the combustion chamber during intake stroke  Length decided by harmonic frequency at various engine operating speeds, can be used to create a resonant “tuning point” Intake Manifold

 Transient Pressure Boundary Condition used to simulate pressure pulses within manifold from intake stroke  Piecewise-Linear Approximation used for initial analysis trouble-shooting  End analysis will use pressure trace measured during Dynamometer Testing Intake Manifold

 Component Simulation  Shroud structure analyzed to ensure uniform airflow distribution across radiator face and verify proper mass airflow through radiator  Radiator modeled as a material resistance with heat addition and flow re-direction to properly simulate airflow through core Cooling System Airflow

 Full Car Simulation to verify shroud is receiving adequate airflow  Simulation model still in progress, needs additional geometry and refinement Cooling System Airflow

Cooling System

Cooling System Schematic Surge Tank Overflow Tank Steam from Cylinder Head Engine Block Water Pump Fan Radiator Thermostat

 Rule of thumb: 1.1 in 2 radiator surface area needed per hp produced  Therefore need approx. 66 in 2  Radiator from YFZ450R Yamaha ATV  7.5” H x 11.5” W x 7/8” D  Surface Area in 2  Inlet and Outlet ¾” ID tubing to connect to water pump Radiator Outlet to Water Pump Inlet from Engine Modify for bleed line to Surge Tank

 Coolant naturally builds to approximately psi  Normal production cars run psi, high performance cars run psi, and racing systems run psi  Pressurizing the water allows for the water to reach a higher temperature before boiling (therefore vaporizing)  Part# T30R Radiator Cap PSI Pressure (PSI)Boiling Point (° F) 0 PSI 212° F 10 PSI 239° F 20 PSI 259° F 30 PSI273° F 40 PSI 286° F 50 PSI 297° F Radiator Cap

 Typically a 1 quart container  Need to modify the part of the Radiator that currently has the cap and overflow line to run a ¼”- 3 / 8 ” bleed line from radiator to top of surge tank  ½” – ¾” Refill line from bottom of surge tank to inlet of water pump  Benefits – de-aeration  2% air in the system leads to an 8% decrease in cooling efficiency  4% air in the system leads to a 38% decrease in cooling efficiency! Surge Tank Bleed line inlet from radiator and cylinder head Outlet to overflow tank Refill line back to water pump 30 PSI Pressurized Radiator Cap

 Comes stock on engine  No internal bypass system. Thermostat will have to regulate continual water flow through engine  ¾” ID inlet and outlet tubing to connect to radiator Water Pump Flow Rate vs. RPM from R6 water pump Need to test flow rate once we have the cylinder head again

 Placed at the outlet of the engine, a thermostat allows water to circulate through the block, but doesn’t allow this water to circulate through the radiator until it has reached proper operating temperature  This temperature (195°F) melts the “wax motor”, which forces the thermostat piston to open and allows the water to flow through.  If the engine’s temperature is lowered too much, the piston closes until it has reached proper operating temperature once again Thermostat  Stewart/Robert Shaw Thermostats – 302  Augments bypass system  $14.95

Cooling System Data  Reviewed three sets of autocross runs with different drivers

 Verify radiator is receiving adequate airflow at low speeds  SPAL Axial Fan  11” Dia.  CFM  Based on predicted power require minimum 450 CFM  Based on airflow at speed available require minimum 500 CFM  Maximum 7” Dia. to fit radiator  Yamaha R6 Fan  5.5” Dia.  Est. >500 CFM Fan

Risk Assessment

Risk Assessment - Technical IDRisk ItemEffectCauseLSIAction to Minimize RiskOwner Technical Risks 1 Engine Dynamometer not reliable Unable to characterize engine torque Dynamometer control system not reliable 224 Be familiarized with the Dynamometer control programs. Attempt to characterize the Dynamometer and create an accurate control system in case the original is inefficient. Stanley Fofano 3 Insufficient Cooling of the Engine Engine Overheats/damag e to engine Cooling system undersized or inefficient 236 Correctly analyze cooling system to maximize efficiency Evan See, Brittany Borella 4 Unable to accuractly predict airflow through the intake manifold, restrictor, and throttle Inaccurate theoretical model of engine Improper CFD analysis 224 Accurately control initial assumptions and conditions in order to create the most accurate model possible Taylor Hattori 5 Unable to accurately predict fuel consumption and power output Inefficiencies in the engine package Improper Engine Modeling 236 Verify engine model with dynamometer testing in correlation with fuel flow sensors. John Scanlon 8Air:Fuel Ratio too lean Damage to engine Ratio leaned out too far in order to increase fuel economy 236 Slowly change the air fuel mixture in order to realize effects before another change is made Chris Jones, John Scanlon

Risk Assessment - Management IDRisk ItemEffectCauseLSIAction to Minimize RiskOwner Project Management Risks 10 Insufficient funding Outside contracted work won't be able to be paid for Outside Contracting work is expensive 111 Use funds wisely and try to do as much in house testing as possible. When outside testing is necessary, try to take advantage of sponsorships. Brittany Borella 11 Inconsistant Team Priorities Actual Senior Design deliverables do not get met Actual engineering in the project given more priority than Senior design paperwork and deliverables 111 Project Manager(s) in charge of keeping track of all deliverables, for the class and the actual engine design, and making sure they are being taken care of by everyone on the team Evan See, Britttany Borella 12 Project not completed on time Formula team does not have a complete engine package Poor time management and planning 133 Lead engineer will make sure that sufficient time is put into all engine systems so that all components are properly tested and prepared for the final engine package John Scanlon 13 Parts are ordered too late Engine Dyno testing and on car testing cannot be completed on time long lead parts not identified and ordered on time 122 Long lead time parts ordered as soon as identified - early in MSD1 John Scanlon