Lightweight Fuel Efficient
Engine Package
Brittany Borella, Chris Jones,
John Scanlon, Stanley Fofano,
Taylor Hattori, and Evan See
Project Overview
Customer Needs
Customer Need
#
Importance
Description
Engine
CN1
1
The engine must reduce fuel consumption when compared to the previous
engine package
CN2
1
The engine must provide sufficient power output and acceleration
Control System
CN11
2
The control system must provide accurate fuel delivery and measurement
Cooling System
CN14
1
The cooling system must be able to allow the engine to operate in high
ambient temperatures under race conditions
Documentation and Testing
CN17
1
Documented theoretical test plan and anticipated results
CN18
1
Must provide a CFD analysis of the intake manifold, restrictor, and throttle
CN19
2
Must provide an accurate model of the engine in GT-suite
Engineering Specifications
Spec. # Importance
Source
Specification Unit of Marginal
(metric)
Measure
Value
Fuel
km/l
6.9
Consumption
Ideal
Value
Comments/Status
8.3
Want to use ~0.7 gal for the
22km run
S1
1
CN1
S3
1
CN2
Power Output
HP
45
55
S4
1
CN2
Torque
ft-lbs
31
35
S6
1
CN4,15
Reliability
km
50
100
Should be able to perform in
all Formula SAE events and
testing before major overhaul
S8
1
CN6
Weight
lbs
75
68
Engine weight
S9
1
CN8
Fuel Type
N/A
S12
1
CN14
Temperature
°F
220
200
E85 Ethanol-Gasoline Blend
or 100 Octane Gasoline
Cooling system must keep the
engine under 200 degrees in
ambient temperatures up to
100 degrees
Engine Model
Overall Assumptions

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
Required Parameters
 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
Theoretical Engine Model
Live Simulation of Engine
Parameters
Dynamometer Test Stand
Cylinder Head Removed for
Measurement
Flow Testing of Cylinder Head
Bore Tube Production
Photo Courtesy of DUT Racing
System Test Plan
Engine Testing
 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
Fuel Flow Sensor
 FT-210 Series
 Gems Sensors & Control
 0.026 - 0.65 gal/min
 ± 3% Accuracy
Cylinder Pressure Sensor
 PCB Piezotronics
 Transducer 112B10
 422E In-Line Charge Converter
Magnetic Encoder
 AM4096 - 12 bit rotary
 Measure Angular Position
 Outputs
 Incremental
 Series SSI
 Linear Voltage
 Analogue Sinusoidal
Dynamometer
 Load Simulation
 Power Characterization
 Fuel/Spark Mapping
Data Acquisition
 Dynamometer Controller
 Data Input Improvement
 NI PCI-6024E
 200 kS/s
 12-Bit
 16-Analog-Input DAQ
CFD Analysis
Intake Restrictor
 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 Manifold
 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
Cooling System Airflow
 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
Cooling System Schematic
Overflow Tank
Surge Tank
Steam from Cylinder Head
Thermostat
Water Pump
Radiator
Fan
Engine Block
Radiator
in2
 Rule of thumb: 1.1
radiator surface
area needed per hp produced
 Therefore need approx. 66 in2
Modify for
bleed line
to Surge
Tank
Inlet from Engine
 Radiator from YFZ450R Yamaha ATV
 7.5” H x 11.5” W x 7/8” D
 Surface Area 86.25 in2
 Inlet and Outlet ¾” ID tubing to
connect to water pump
Outlet to
Water Pump
Radiator Cap
 Coolant naturally builds to approximately 16-18 psi
 Normal production cars run 16-18 psi, high performance cars run
22-24 psi , and racing systems run 29-31 psi
 Pressurizing the water allows for the water to reach a higher
temperature before boiling (therefore vaporizing)
 Part# T30R Radiator Cap 29-31 PSI
Pressure (PSI)
Boiling Point (° F)
0 PSI
212° F
10 PSI
239° F
20 PSI
259° F
30 PSI
273° F
40 PSI
286° F
50 PSI
297° F
Surge Tank
30 PSI
Pressurized
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
Bleed line
inlet from
radiator
and
cylinder
head
Outlet to
overflow
tank
 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!
Refill line
back to water
pump
Water Pump
 Comes stock on engine
Need to test flow rate once we
have the cylinder head again
 No internal bypass system.
Thermostat will have to regulate
continual water flow through
engine
 ¾” ID inlet and outlet tubing to
connect to radiator
Flow Rate vs. RPM from R6 water pump
Thermostat
 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
 Stewart/Robert Shaw Thermostats – 302
 Augments bypass system
 $14.95
Cooling System Data
 Reviewed three
sets of autocross
runs with different
drivers
Fan


Verify radiator is receiving
adequate airflow at low speeds
11” Dia.

755.0 CFM

Based on predicted power require
minimum 450 CFM

Based on airflow at speed available
require minimum 500 CFM


mph
0
5
10
15
20
25
30
35
40
SPAL Axial Fan

Maximum 7” Dia. to fit radiator
Yamaha R6 Fan
F19
ft^3/m
0
213
426
639
853
1066
1279
1492
1705
F20
ft^3/m5
0
130
260
391
521
651
781
912
1042
 𝑞 = 𝑚 × ∆𝑇 × 𝑐𝑝
𝑄
 𝑐𝑓𝑚𝑟 = ∆𝑇

5.5” Dia.

𝑐𝑓𝑚𝑟 = 𝑟𝑒𝑞𝑢𝑖𝑟𝑒𝑑 𝑎𝑖𝑟𝑓𝑙𝑜𝑤 𝑓𝑟𝑜𝑚 𝑓𝑎𝑛

Est. >500 CFM

Q = required heat rejected into air
Risk Assessment
Risk Assessment - Technical
ID
Risk Item
Effect
Cause
L
S
I
Action to Minimize Risk
Owner
Technical Risks
1
Engine Dynamometer
not reliable
Dynamometer
control system
not reliable
2
2
4
3
Engine
Cooling system
Insufficient Cooling of
Overheats/damag undersized or
the Engine
e to engine
inefficient
2
3
6
Unable to accuractly
Inaccurate
predict airflow through
Improper CFD
4
theoretical model
the intake manifold,
analysis
of engine
restrictor, and throttle
2
2
4
2
3
6
5
Unable to accurately
predict fuel
consumption and
power output
8 Air:Fuel Ratio too lean
Unable to
characterize
engine torque
Inefficiencies in
the engine
package
Improper
Engine
Modeling
Damage to
engine
Ratio leaned
out too far in
order to
increase fuel
economy
2
3
6
Be familiarized with the
Dynamometer control
programs. Attempt to
characterize the
Dynamometer and create
an accurate control system
in case the original is
inefficient.
Correctly analyze cooling
system to maximize
efficiency
Accurately control initial
assumptions and
conditions in order to
create the most accurate
model possible
Verify engine model with
dynamometer testing in
correlation with fuel flow
sensors.
Slowly change the air fuel
mixture in order to realize
effects before another
change is made
Stanley Fofano
Evan See,
Brittany Borella
Taylor Hattori
John Scanlon
Chris Jones,
John Scanlon
Risk Assessment - Management
ID
Risk Item
Effect
Cause
L
S
I
Action to Minimize Risk
Owner
Project Management Risks
10
Outside contracted
Insufficient
Outside Contracting
work won't be able
funding
work is expensive
to be paid for
11
Actual engineering in
Actual Senior
Inconsistant
the project given more
Design
Team
priority than Senior
deliverables do not
Priorities
design paperwork and
get met
deliverables
1
1
Formula team
Project not
does not have a Poor time management
12 completed on
1
complete engine
and planning
time
package
13
Engine Dyno
Parts are
long lead parts not
testing and on car
ordered too
identified and ordered
testing cannot be
late
on time
completed on time
1
1
Use funds wisely and try to do as
much in house testing as possible.
When outside testing is necessary, Brittany Borella
try to take advantage of
sponsorships.
1
1
Project Manager(s) in charge of
keeping track of all deliverables, for
the class and the actual engine
Evan See,
design, and making sure they are Britttany Borella
being taken care of by everyone on
the team
3
Lead engineer will make sure that
sufficient time is put into all engine
3 systems so that all components are John Scanlon
properly tested and prepared for the
final engine package
2
2
1
Long lead time parts ordered as
soon as identified - early in MSD1
John Scanlon