1. Diesel Fuel Filter Heater
Assembly
Group IX
Justin Brewer, Abanoub Riyad, Ethan Smelcer
Benjamin Rogers, Mohanad Al-Mokhadm
ME 4444
Dr. M. Sundaram

2. Diesel Clouding:
● Temperature at which dissolved wax
comes out of solution -28°C (-18°F) to -
7°C (+20°F)
● Wax Coats Filter Medium Blocking Fuel
Flow (Starves Engine)
● Primary Issue: Cold Start-Ups
Background Information

3. Background Information
Single Dual
● Korean Forklift Customer:
- Needed additional heater performance
for cold start-ups
● Cummins’ Solution:
- “Dual Sandwich” 24V PTC Heater
Configuration
● Lab Tests Conducted:
- Compared Heater Performance With
Other available Heater Solutions

4. Background Information
“Dual Sandwich” Heater Configuration
Cummins’ Lab Test Data:
● Outlet Temperature
-Fastest Rise-Time

5. Background Information
● Cummins uses Positive Temperature Coefficient
(PTC’s) stones as heating elements.
Cummins Fuel HeaterA typical configuration of PTC stones

6. Background Information
Resistance versus Temperature for PTC Stones
PTC’s 2 Stages:
● Self Regulating: Voltage passes
through allows the PTC to heat which
decreases the resistance and allows
more current to flow.
● Self Protecting: When temperature
reaches the switch temperature, the
resistance increases exponentially
and no more current passes through.

7. Need Statement
Leak Path
Project Deliverables:
1. Eliminate the additional Leak
Path between the 2 heaters.
1. Decrease the cost of
additionally machined parts
required for added length.
1. Decrease the moment arm
that is created due to dual
heaters.
1. Decrease cost of 2 heaters.

8. Project Constraints
● Only one more disc heater will be added.
● Heater testing takes place using diesel fuel with a cloud point of -12 0C.
● Heater testing takes place using a pump flow of at least 4 liters per
minute.
● Heater testing takes place after turning them for 15 seconds before
pump operation.
● Heater testing takes place for 20 minutes.
● Mounting of heater has to match with the currently-used head
● peak Current of 25 Amps MAX

9. Design Concepts
Concept 1:
● 2 PTC Stone arrays in a single circuit in housing

10. Design Concepts
Concept 2:
● 1 PTC Stone array in housing and 1 PTC Stone array on top of
housing set in the head of the filter both on separate circuits

11. Concept 3:
● 2 PTC Stone arrays two separate circuits in housing
Design Concepts

12. Concept 1:
● Single circuit would not produce
enough heat based on circuit
analysis.
Concept 2:
● Unable to build due lack of access
to different PTC stones.
Concept 3:
● Showed good results from initial
analysis.
● Access to material for
manufacturing.
● Continued on to simulation phase.
Design Concepts
Selection Criteria Baseline Weight Concept
#1
Concept
# 2
Concept
# 3
Max Power
Consumption
0 5 + - +
Easy Assembly 0 5 - - +
Size(thickness) 0 1 S S +
Number of Plugs 0 1 + + -
Number of
Thermostat
0 1 + + -
# of Pluses 7 2 11
# of Minuses 5 10 2

13. Single and Dual Simulation
Single
● Inlet Pressure: 0.3448 psi
● Out Temperature: -6.84 ºC
Dual
● Inlet Pressure: 0.6047 psi
● Out Temperature: 3.66 ºC
Simulation Results

14. Prototype Simulation
● Inlet Pressure: 0.1502 psi
● Outlet Temperature: 1.33 ºC
Simulation Results
Heater Inlet Pressure
(psi)
Outlet Pressure
(psi)
Press Diff.
(psi)
Outlet Temperature
(ºC)
Inlet Temperature
(ºC)
Temp Diff
(ºC)
Single 0.3448 0 0.3448 -6.84 -17 10.16
Dual 0.6047 0 0.6047 3.66 -17 20.66
Prototype 0.1502 0 0.1502 1.33 -17 18.33
Overall Results

15. Prototype
Concept 3:
● CFD simulation as well as circuit analysis show good results.
● Continued on to the build and testing phase, comparing results
to the single and dual sandwich heaters test results.

16. ● Housing of prototypes were produced by
using a 3D Systems ProJet™ SD 3500
printer
● Printer is located at the STEM Center at
Tennessee Tech University
Manufacturing Prototypes

17. Plate Fabrication
● Four plates with different dimensions
were needed for the prototype
● 2024 aluminium alloy sheets with 0.5
mm thickness

18. ● Test Rig was needed to validate simulation
results
● Temperature and pressure, at the inlet and
outlet were measured as well as volumetric
flow rate
● Pump was used to circulate fuel through the
system.
● Fuel cycled through 12 gallon Diesel tank
● Power supply of two 12 Volt batteries in series
● Clamp on multimeter used to measure current
draw
Test Configuration

19. 1. Fuel cooled to 0ºC or lower
2. Reservoir was connected to assembly and the
system was primed at room temperature
3. Heater was turned on for 15 seconds
4. Pump was then turned on
5. Multiple group members assisted in collecting
data points
6. Each test was ran for 20 minutes
Testing Setup/Constraints

20. Simulation vs Testing
Simulation Test
Measurements were taken DIRECTLY at
inlet and outlet of the heaters themselves.
Measurements were taken before and after
filter assembly.
Variable viscosity / Density Not Modeled Variable viscosity affects overall
performance.
Inlet Flow Rate modeled as CONSTANT Flow rate measured as variable.
Heat Rate of PTC Elements modeled as
constant.
Heat Rate of PTC Elements is actually a
function of their own internal temperature.
Pressure drop neglects filter Pressure drop includes filter
*Test results CANNOT be compared DIRECTLY to Simulation Results

21. Test Results (Single Heater)

22. Test Results (“Dual-Sandwich”)

23. Test Results (Prototype)

24. Test Results (Comparison)
Test ∆P (psi) ∆T (ºC) Flow (L/min)
Single 5.629 5.033 4.101
“Dual-Sandwich” 5.138 6.298 6.149
Prototype 5.455 4.364 5.451
Average of last 10 minutes of each test’s results:

25. Test Results (Prototype)
Potential Prototype Issues:
1. Poor circuit connections
2. Thermal conductivity of aluminum used
3. Poor flow around PTC elements

26. Cost

27. Accomplishments
● Eliminated the leak path.
● 25% moment arm reduction
● Material Cost reduction
● From CFD simulations, the design concept is valid.

28. Recommendations
● Different type of PTC stones with different properties.
● Different metal for the plates with different thermal
conductivity.
● Use different thermostat with higher set point for the
bottom circuit.
● Different flow path for diesel.

29. Acknowledgments
● Cummins Filtration
● University of Tennessee- Center for Industrial Services
● Tennessee Technological University
ME Department
Dr. Meenakshi Sundaram
Chris Mills
Jeff Randolph
Robert Reab

30. Questions?