Detailed Design Review

KGCOE MSD

P13222: FSAE Turbocharger Integration

MSD I: Detailed Design Review

Thursday, November 8th, 2012

4:00-6:00pm

Kelly Conference Room

Team members:

-Kevin Ferraro

-Phillip Vars

-Aaron League

-Ian McCune

-Brian Guenther

-Tyler Peterson

Faculty Guide: Dr. Alan Nye

Primary Customer: RIT Formula SAE Racing Team

Contents

Tables

Figures

Table 1: Project Information

Project Description

Project Background

Problem Statement

Objectives/Scope

Deliverables

Expected Project Benefits

Core Team Members:

Assumptions & Constraints

Issues and Risks

Customer Needs Review

Table 2: Customer Needs

Specifications Overview

Table 3: Specifications Review

Table 4: Specifications, Continued

System Architecture

Figure 1: Simplified Block Diagram

Compliance with Requirements

Induction

Table 5: Induction System Compliance

Throttle/Restrictor

Figure 2: Spike Geometry Comparison

Figure 3: CFD Analysis of Spike/Restrictor

Figure 4: Restrictor Geometry

Intercooler

Table 6: Intercooler Compliance

Turbocharger

Table 7: Turbocharger Compliance

Figure 5: GT Power Simulation Schematic

Figure 6: GT Power, Efficiency Results

Exhaust System

Figure 7: GT-Power: Power and Efficiency results, Screen shot of header design #2 (green)

Boost Control

Table 8:Boost Control System Compliance

Figure 8: Boost Control Block Diagram

Figure 7: Solenoid Details

Figure 8: Solenoid Cross Section

Engine

Mounting System

Risk Assessment

Table 9: Risk Items

Table 10: Risk Items, Continued

Testing Plans

Bill of Materials

Timeline/Schedule

Tables

Table 1: Project Information

Table 2: Customer Needs

Table 3: Specifications Review

Table 4: Specifications, Continued

Table 5: Induction System Compliance

Table 6: Intercooler Compliance

Table 7: Turbocharger Compliance

Table 8:Boost Control System Compliance

Table 9: Risk Items

Table 10: Risk Items, Continued

Figures

Figure 1: Simplified Block Diagram

Figure 2: Spike Geometry Comparison

Figure 3: CFD Analysis of Spike/Restrictor

Figure 4: Restrictor Geometry

Figure 5: GT Power Simulation Schematic

Figure 6: GT Power, Efficiency Results

Figure 7: Solenoid Details

Figure 8: Solenoid Cross Section

Page 1 of 25

Detailed Design Review

KGCOE MSD

P13222: FSAE Turbocharger Integration

Table 1: Project Information

Project # / Project Name / Project Track / Project Family
P13222 / FSAE Turbocharger Integration / Vehicle Systems and Technologies
Start Term / Team Guide / Project Sponsor / Doc. Revision
20121 / Dr. Nye / RIT Formula SAE Team

Page 1 of 25

Detailed Design Review

KGCOE MSD

P13222: FSAE Turbocharger Integration

Project Description

Project Background

Group of students that design and build a small open wheeled racecar
Vehicle must satisfies the safety requirements
Limitations: 20 mm diameter, maximum displacement of 610 cubic centimeters.
Fuel economy emphasis: 10% of total points
Best balance between power and fuel efficiency with significant physical limitations

Problem Statement

Successfully integrate a turbocharger into the Yamaha WR450F engine package on the Formula SAE race car.

Objectives/Scope

Develop accurate engine simulation
Increase generated horsepower to 60 HP and torque to 45 ft*lbs
Electronic boost control to maximize power and fuel efficiency
Package components into vehicle using 3D CAD software
Correlate simulation results to dynamometer performance
Robust mounting to withstand extreme vibration and thermal environment

Deliverables

Engine Simulation, Dyno Data
Induction/Exhaust System
Turbocharger/Mounting System
Boost Control System

Expected Project Benefits

Increase power output of the lightweight single cylinder engine without excessive fuel economy penalty. Increased power will allow for faster acceleration, higher top speed, and the ability to use additional aerodynamic downforce.

Core Team Members:

Kevin Ferraro
Phil Vars
Tyler Peterson
Aaron League
Brian Guenther
Ian McCune

Assumptions & Constraints

Single cylinder engine: 2010 Yamaha WR450F
Complies with all Formula SAE rules
20mm restrictor
Throttle->restrictor->compressor
Maximum weight gain: 15 lbs

Issues and Risks

Increased power generation will negatively affect fuel economy of engine if not properly tuned
Improperly operating turbocharger can either be inefficient or damaging to engine
High exhaust temperature and severe vibration will require robust mounting scheme

Page 1 of 25

Detailed Design Review

KGCOE MSD

P13222: FSAE Turbocharger Integration

Customer Needs Review

The following shows the customer needs for the implemented turbocharger package.

Table 2: Customer Needs

Customer Need # / Importance / Description
CN1 / 5 / Overall Horsepower and Torque Gains:
CN2 / 5 / Optimized ECU Map for Best Performance
CN3 / 5 / Consistent Engine Performance
CN4 / 5 / Necessary Engine Internals are Included with System
CN5 / 4 / Adequate System Cooling
CN6 / 4 / Sufficient Dyno Testing and Validation
CN7 / 4 / Optimized Turbo Size for Application
CN8 / 4 / Meet FSAE Noise Regulations
CN9 / 3 / Quick Throttle Response
CN10 / 3 / Easy to Access in Car
CN11 / 3 / Compact Design in Car
CN12 / 3 / Fit Within Constraints of Current Chassis
CN13 / 2 / Easy to Drive
CN14 / 2 / Drivetrain Components Designed for Power Increase
CN15 / 2 / Design for Intercooler Location (if required)
CN16 / 1 / Readily Available Replacement Parts
CN17 / 1 / Simple Interface with Current Engine
CN18 / 1 / Maximized Use of Composite Material

Page 1 of 25

Detailed Design Review

KGCOE MSD

P13222: FSAE Turbocharger Integration

Specifications Overview

Table 3: Specifications Review

Source / Function / Specification (metric) / Unit of Measure / Ideal Value / Comments/Status
S1 / CN1 / Engine / Peak Power Output / Hp and ft-lbs / >= 60hp 45 ft-lbs / General increase overall can also compensate
S2 / CN1, 2 / Intake / Mass Air Flow / g/s / >=40 / Maximize for restrictor, based on restrictor geometry
S3 / CN1, 2, 9, 13 / Intake / Plenum Volume / cc / >=1000 / Proper plenum size required for acceptable throttle response and resolution
S4 / CN3 / Sensors / Sensor Voltage / V / 5 / Proper voltage and grounding provided to each sensor for proper measurement and signal
S5 / CN1, 5, 15 / Intercooler / Air Temperature Reduction / Deg F / >=20 / Increase density of air
S6 / CN1, 2, 5 / Intake / Manifold Air Temperature / Deg F / <=100
S7 / CN1, 7, 9 / Turbo / Turbine Shaft RPM / rpm / ~100,000 / Depending on turbo chosen
S8 / CN1, 7, 9 / Turbo / Intake Manifold Pressure / psi / >=20 / Amount of "Boost": Map of boost pressure vs. load/throttle position determined through engine simulation
S9 / CN7, 9, 13 / Turbo / Peak Compression by RPM (specified) / rpm / <=6000
S10 / CN1,2, 3, / Sensors / Air Fuel Ratio Range / 12.6<x<17.6 / Controlled by ECU, necessary for proper engine operation, possible through wideband lambda sensor

Table 4: Specifications, Continued

Source / Function / Specification (metric) / Unit of Measure / Ideal Value / Comments/Status
S11 / CN1, 3 / Sensors / Manifold Air Pressure Range / psi / 0-30 / Sensor operates across expected pressure range
S12 / CN3,4,13, 17 / Turbo / Pressure to Actuate Wastegate / psi / >=20 / Determines minimum boost pressure level
S13 / C3,C4 / Turbo / Supplied oil pressure / kPa / >=170 / Manufacturer specification
S14 / CN1,11,17 / Exhaust / Flow Rate / g/s / >=100
S15 / CN8 / Exhaust / Noise Level / dBa / <110 / Based on FSAE regulation
S16 / CN3,5,7,16 / Turbo / Max Temperature of Turbo / Deg F / <800 / Manfr's recommendations
S17 / CN7,11,18 / System / Overall Maximum Weight Increase / lbs / <=15 / Maximum acceptable weight gain, based on laptime simulation
S18 / CN1,3,4,6 / Engine / Compression Ratio / ~10:1 / Max achievable without engine knock
S19 / CN1,13 / Engine / Max Power Design RPM / rpm / ~9000
S20 / CN1,13 / Engine / Max Torque Design RPM / rpm / ~7000
S21 / CN1,3,13 / Engine / Max Spark Advance / deg / 40-45 / Exact value determined through empirical testing
S22 / CN4,16,18 / Funding / Cost to Formula Team / $$$ / <100 / Funding/Sponsorship will be required

Page 1 of 25

Detailed Design Review

KGCOE MSD

P13222: FSAE Turbocharger Integration

System Architecture

The following shows a simplified block diagram for the components of the system:

Figure 1: Simplified Block Diagram

Page 1 of 25

Detailed Design Review

KGCOE MSD

P13222: FSAE Turbocharger Integration

Compliance with Requirements

Induction

The induction system is composed of the throttle body, restrictor, compressor and intercooler.

The following table shows the specifications relevant to the induction system.

Table 5: Induction System Compliance

Specification / Value / Compliance / Verification
Mass air flow / >= 50 g/s / CFD / Pressure measurements
Restrictor Diameter / <=20 mm / Design / Measure
Plenum Volume / >=1000cc / CAD, 3D modeling / Volume measurement
Air temperature reduction / >= 50°F / CFD, heat transfer analysis / Thermocouple measurement
Intake manifold pressure range / 0-30 psi / Design, component selection / Component pressure capacity will be tested during dyno data collection
Throttle Modulation / Near linear, Throttle position vs flow / CFD analysis / Dynamometer measurement

Throttle/Restrictor

The throttle modulates the airflow into the engine. The throttle assembly consists of a spike-shaped plug that controls the size of the opening into the restrictor. A cable connected to the gas pedal of the car pulls the spike away from the opening to increase the flow rate of air. A spring returns the spike to the rest position against the opening of the restrictor. This plugs the restrictor for the engine to idle.

The spike geometry has significant influence on the nature of the throttle modulation. As the spike is pulled away from the restrictor, the area open for air flow changes. It is critical for the driver to have accurate and predictable feedback for the throttle inputs from the gas pedal. There must be a linear response between the throttle position and the flowrate of air into the engine. The diameter along the spike can be varied to tune the response of the airflow. In addition, the throttle/spike assembly must allow for proper pressure recovery after the restriction. This is necessary in order for the engine to make the maximum amount of power. CFD analysis was performed to determine a suitable geometry that would allow for a linear response to flow rate and complete outlet pressure recovery.

The following graph compares CFD results from two different spike profiles. The response of mass flow rate and outlet pressure is plotted against throttle position. Perfectly linear modulation would result in a linear line extending from minimum flow rate at 0% throttle position to maximum flow rate at 100% throttle position.

Figure 2: Spike Geometry Comparison

The new spike (blue and red lines) show a relationship that is closer to linear than the original spike.

The following figure shows an example screen shot of the CFD analysis that was performed on the assembly. The inlet boundary condition was air at atmospheric pressure and the outlet boundary condition is a flow rate based on engine displacement and speed.

Figure 3: CFD Analysis of Spike/Restrictor

The following figure shows a drawing of the profile of the restrictor. The minimum diameter, 20 mm, is specified in the Formula SAE rules document.

Figure 4: Restrictor Geometry

Intercooler

The intercooler component increases the efficiency of the turbocharger by cooling the incoming air. The energy density of the incoming air increases as it cools.

The following table shows the relevant specifications for the intercooler.

Table 6: Intercooler Compliance

Specification / Value / Compliance / Verification
Air Temperature reduction / >=50°F / Thermal analysis / Thermocouple measurement
Manifold air temperature / <=100°F / Thermal analysis / Thermocouple measurement

The intercooler will be manufactured from purchased intercooler stock. There are three dimensions of the intercooler: thickness, width, and length . The induction stream into the engine passes through the plane made by the thickness and width dimension, and the cooling stream passes through the plane made by the length and width dimensions.

Intercooler stock is only commercially available in a limited number of thicknesses. The intercooler width and thickness dimensions control the amount of warm, compressed flow that can pass through. The length of the intercooler controls the amount of cooling that occurs. Longer sections result in additional cooling.

Turbocharger

The turbo charge that will be used is manufactured by Honeywell. It is a model GT06 which was originally designed for a small displacement 2 cylinder diesel engine. The relevant specifications for the turbocharger are listed below.

Table 7: Turbocharger Compliance

Specification / Value / Compliance / Verification
Peak Power Output / 60 hp, 45 ft*lbs / GT Power simulation / DC Dynamometer measurement
Peak efficiency / Efficiency maps,
GT Power simulation / DC Dynamometer measurement: Fuel consumption vs. power
Pressure to Actuate Wastegate / 20 psi / Purchased part / Test stand measurement
Max Temperature of Turbo / <800°F / Assumption: no modification from production part / Thermocouple measurement
Supplied Oil Pressure / 170 kPa (24.7 psi) / Tapping into oil return line of engine / Oil pressure sensor, tapped into oil return line
Mass flow rate, compressor / >=40 g/s / Compressor efficiency map / DC Dynamometer measurement
Mass flow rate, turbine / >=100 g/s / Turbine efficiency map / DC Dynamometer measurement

The selection of this turbocharger is primarily based on engine simulation using the software package "GT Power". This is a 1-D simulation of the performance of an engine and its associated flow system. The simulation was used to compare the performance of 2 different models of turbochargers offered by Honeywell. The following figure shows the schematic of the engine simulation.

Figure 5: GT Power Simulation Schematic

Each component of the engine system is represented through its own module. The schematic follows the flow through each component and shows connections between components. The software simulates engine performance at several discrete operating conditions and can show a variety of performance characteristics. When comparing turbochargers it is very useful to compare the efficiency map of the compressor with the load points of the engine shown.

Figure 6: GT Power, Efficiency Results

Exhaust System

The design of the exhaust system will optimize the efficiency of the turbine. This will in turn increase the overall efficiency of the turbocharger and improve engine performance. The shape of the header and exhaust will have a large effect on the performance of the turbocharger. The highly pulsed flow of the single cylinder exhaust is far from an ideal steady flow. There are however, several constraints that limit the design. The exhaust must fit in the car with all of the other components, the shape must be possible to fabricate, and the heat from the exhaust must not cause damage.

Specification / Value / Compliance / Verification
Fit in the Car / 1 / Creo / Solid modeling
Efficiency of turbine / >40% / GT-Power / Dyno Testing
External Temperature / <800 °F / GT-Power / Dyno Testing
Bend Radius / 3 in / Creo / Solid Modeling

Several iterations of exhaust design have been modeled in Creo and simulated in GT-Power. The initial (red line) design simulated in GT-power was similar to what was used on F20 and would not actually fit in F21. The design #1(blue line) was the first iteration of a header that would fit in F21 but an arbitrary exhaust after the turbo. Design #2 (green line) had a revised header geometry and a more reasonable geometry after the turbo.

Figure 7: GT-Power: Power and Efficiency results, Screen shot of header design #2 (green)

It is clear from the initial simulation that the performance of the turbocharger, and therefore the engine, is very sensitive to the exhaust design. It is evident that further analysis is required to optimize the performance of the system.

Boost Control

Electronic boost control will be accomplished through the MoTec M400 engine control unit (ECU). The ECU will vary the level of boost delivered to the engine by actuating a solenoid that controls the pressure applied to the wastegate. Boost control is critical to the performance of the system by allowing the boost to be reduced to increase efficiency where needed.

The following table shows the relevant specifications for the boost control system.

Table 8:Boost Control System Compliance

Specification / Value / Compliance / Verification
Peak Power / 60 hp, 45 ft*lbs / GT Power / DC Dynamometer measurement
Pressure to actuate wastegate / 20 psi / Purchased part / Bench-top testing

Boost control is achieved through the wastegate and solenoid control valve. The wastegate is a valve that can open to allow exhaust gas to bypass the turbine of the turbocharger. The wastegate is held closed through the force of a spring. The spring is attached to a diaphragm that is connected to the pressure of the plenum. When the pressure in the plenum builds to a certain level, the force on the diaphragm overcomes the force of the spring and the wastegate is pushed open. Exhaust gas bypases the turbine through the wastegate, slowing the turbine. The boost pressure falls, reducing the pressure on the diaphragm, and the wastegate closes.

The boost control level will be electronically controlled by positioning a three-way solenoid in-line between the plenum pressure and the diaphragm. This three-way solenoid connects the diaphragm volume, the plenum volume, and a vent to atmosphere.

To increase the boost level, the solenoid will open so that pressure is routed away from the diaphragm and vented to atmosphere. The boost pressure is not exerted on the diaphragm so the wastegate remains in the closed position, and the exhaust gasses are routed through the turbine.

To decrease the boost pressure, the solenoid closes so that pressure is routed to the diaphragm. The boost pressure is applied to the diaphragm, which opens the wastegate. Exhaust gasses are routed through the wastegate to bypass the turbine.

The figure below is a simplified block diagram of the system.

Figure 8: Boost Control Block Diagram

In order to accurately control the level of boost, the ECU will control the solenoid through pulse width modulation (PWM). The controller will vary the duty cycle of the solenoid according to a PID control algorithm to achieve the desired boost level. The target boost level will depend on the desired operating characteristics of the engine. When maximum power is needed, the boost level will be increased to

generate extra power. When fuel efficiency is a priority, the boost level will be decreased so that the engine burns less fuel.

A solenoid from MAC Valves has been selected for use in the boost control system. The part number is 35A-AAA-DDBA-1BA. It is a miniature 3-way valve with 1/8" NPT fittings. The solenoid accepts PWM control signal from the ECU. The following figure is a page from the MAC catalogue with additional details on the valve.

Figure 7: Solenoid Details