MECHANOLOGY, LLC 1

Development of a Toroidal Intersecting Vane Machine Air Management System for Automotive

Fuel Cell Systems

Sterling Bailey Ph.D., P.E. Mechanology, LLC

sterling@mechanology.com

The focus of this program is to develop the innovative TIVM concept into working compressor/expander/motor hardware that satisfies the FreedomCAR Guidelines – and is easily adaptable

to individual car system requirements – and to measure the TIVM air management system performance

MECHANOLOGY, LLC 2

Relevance and Objective of The TIVM Compressor/Expander/Motor Development Project

The Objective of Mechanology’s TIVM CEM Development and Demonstration project is to overcome the following Transportation Systems Technical Barrier identified in the Draft Fuel Cell R&D Plan:

“Compressors/Expanders. Automotive-type compressors/expanders that minimize parasitic power consumption and meet packaging and cost requirements are not available. To validate functionality in laboratory testing, current systems often use off-the-shelf compressors that are not specifically designed for fuel cell applications resulting in systems that are heavy, costly, and inefficient. Automotive-type compressors/expanders that meet the FreedomCAR program technical guidelines need to be engineered and integrated with the fuel cell and fuel processor so that the overall system meets packaging, cost, and performance requirements. “

MECHANOLOGY, LLC 3

The Toroidal Intersecting Vane Machine Concept

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Toroidal Intersecting Vane Machine Characteristics

Positive Displacement

- Compressor/Expander

- Compressor/Compressor

- Blower

High Flow

High or Low Pressure

Small Volume

Low Production Cost

Many Spin-off Products

TIVM Attributes Provide Efficient Operation as an

Integral Compressor/Expander for Automotive Fuel Cell

Applications With Very Good Performance at High Turndown

Ratios

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TIVM Development TimelineSoftware Developed

TIVM Concept Invented at

Stanford

DOE Contract AwardUS and Foreign

Patents Granted TIVM CEM Prototype Due

Generic Prototype Built

DOE Contract Start

Pressure and Flow Demonstrated

Single Vane Test Rig Operational

Fabricate TIVM CEM Prototype, Measure

Mathematics Developed

Friction, Sealing, and Porting Tech Solution

Performance, Deliver

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The Basic Viability of the TIVM Has Been Proven Through Hardware and Tests

Outlet Pressure vs Time, Generic Prototype

0

0.5

1

1.5

2

2.5

3

3.5

4

0 2 4 6 8 10 12

Time, sec.

Pre

ssu

re,

atm

.

DOE

0

0.5

1

1.5

0

20

40

60

80

100

130 140 150 160 170 180 190 200 210

440C Stainless Steel on PEEK 450FC30010806D

Friction Coefficient Linear Velocity (m/s)

Fric

tion

Coe

ffici

ent

Linear Velocity (m/s)

Time (s)

MECHANOLOGY, LLC

MECHANOLOGY, LLC 7

Requirements Compliance Matrix for TIVM Compressor/Expander

Expected to be acceptable

Cost estimates based on vendor quotesGive several $100’s in high volume

$400Cost

To Be Demonstrated

Use of polymer parts and compliant seals will mitigate

<70 dbNoise

16 kg – Acceptable (2005)

Acceptable to car makers and OEMs8-11 kgWeight

8 L – Acceptable(2005)

Acceptable to car makers and OEMs(Compressor, expander, and motor)

8-11 litersSize

6 kW - Remains to be Demonstrated

Key remaining performance issue –requires low friction effective seals

5.0 kWPower

Capability Demonstrated

3.5 atm pressure demonstrated with temporary seals - as expected for positive

displacement device

3.2 atm Pressure

Capability Demonstrated

Flow consistent with design flow demonstrated with temporary seals - as

expected for positive displacement device

76 g/s(135 cfm)

For 50 kWe

Flow

TIVM StatusCommentValueRequirement

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Three Key Performance Issues Needed to Satisfy the Power Requirement

• Seals to limit air leakage without adding excessive friction• Confirmation of coefficient of friction for meshing vane

interface – including high humidity environment• Porting to assure low pressure drop, and power loss, across

the compressor and expander inlet and discharge paths

These are not unusual engineering tasks that require inventions or new materials. Solid, disciplined engineering development

will provide the required solutions

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Requirements for Vane Seals(For 6 kW Shaft Power at 100% Power and Flow)

Limit air leakage from compressor and expander to < 5%

- leakage rate < 0.38 g/s for full power and flow

- leakage rate < 0.076 g/s for 20% power and flow

Friction < 1.5 lb drag per rotor

Accommodate dimensional changes from wear, thermal expansion, fabrication tolerances, tolerance stack up. Requires compliance of ~15 x 10^-3 inches

Manufacturable in large volume

Cost effective

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Single Vane Test Machine Features• Designed for Development of Vane Seals

• Preserves Dimensional Scale of 50 kW TIVM / CE

• Leverages Existing Test Stand Hardware and Instrumentation

• Fast Turn Around Time for Test Specimens

• Static Sealing

• Dynamic Sealing (to 15 m/s vane velocity)

• Gas Pressure and Temperature (4 kHz)

• Seal Friction via Load Cell

• Linear Servo Motor

Position feedback (5 micron)

Velocity control (0 to 15 m/s)

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Leakage Rate vs Compliance For Several Seal Options Screening Test Summary Results

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0.0000 0.0050 0.0100 0.0150 0.0200 0.0250 0.0300 0.0350 0.0400Compliance, in x 10^-3

Le

ak

Ra

te, g

/s

TARGET FOR 5% LEAKAGE AT FULL POWER

TARGET FOR 5% Leakage AT 20% POWER

SEVERAL CONCEPTS ELIMINATED

Two Seal Concepts Meet Full Power Requirements

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Friction vs Compliance for Candidate Seals

0

0.5

1

1.5

2

2.5

3

3.5

0.0000 0.0050 0.0100 0.0150 0.0200 0.0250 0.0300 0.0350 0.0400

Compliance, in x 10^-3

Fri

cti

on

, lb

s

TARGET VALUE

Two Seal Design Concepts Meet Friction Requirement

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Leakage vs Friction Tradeoff for 6 kW Shaft Power

0

0.5

1

1.5

2

2.5

3

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4

Leakage Mass Flow Rate, g/s

Co

mp

res

so

r S

ea

l F

ric

tio

n, lb

TARGET DESIGN

BETTER

WORSE

Two Seal Concepts Meet Leakage and Friction Requirements for 6 kW – Further Optimization Possible

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Friction Coefficient vs Speed, Most Recent ANL Data

0

0.05

0.1

0.15

0.2

0.25

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0

Speed, m/s

Fri

ctio

n C

oef

fici

ent

SS on PEEK 100% RH

SS on PEEK 18% RH

Brass on PEEK 34% RH

Brass on PEEK 100% RH

NFC on NFC 100% RH

NFC on NFC 30% RH

TARGET VALUE

Vane to vane coefficient of friction of <0.15 is achievable

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Shaft Power vs % Power and Flow, DOE Guidelines, Seal "B" Characteristics and 3.2 atm Pressure

0

1

2

3

4

5

6

7

0 20 40 60 80 100 120

Percent of Full Power and Flow

Sha

ft P

ower

, kW

mu=0.1Mu=0.15

Parasitic power load of <6 kW appears to be achievable

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Future Plans

Complete seal measurements for combined leakage and friction – confirm satisfactory performance of at least one design – August 2003

Perform porting feature measurements to confirm satisfactory performance – August 2003

Complete investigation of additional innovation with potential to reduce shaft power by > 1kW.

Build fully operational prototype with selected seals and ports – measure integral performance

With accelerated funding, August 2004 At planned funding rate, September 2005

Integrate high efficiency motor – measure performance, deliver to Argonne National Laboratory for testing

With accelerated funding, September 2004 At planned funding rate, September 2005