A Combined Pressure and Temperature Sensorwithout External Temperature Probe

2

Content

(1) Key P/T Sensor Specifications

(2) Patented Thin Film Technology

(3) Sensor Design for CO2 / R744 MACS

(4) Finite Element Modeling / Simulation

(5) Qualification Testing

(6) Other Thin Film Applications and Sensor products

3

(1) Key P/T Sensor Specifications

Ø Pressure:Measurement Range0 to 170 BarAccuracy < ± 1,0% (F.Sp.)Response time 4 ms (t63)

Ø Temperature:Media -40°C to +180°CAccuracy ~ ± 3 KResponse time < 10 sec (t63)Ambient Temperature up to 135°C

Ø Electrical Interface: 3-pin LIN2.0, 3-pin PWM,4-pin P/T analog

4

(2) Patented Thin Film Technology

Ø Thin Film Element on SST 1.4548.4Ø Sputtered Metal Strain GaugeØ TiON Strain Gauge with high K-Factor/ Gauge Factor:

K: TiON ~ 5 (CrNi ~ 1,1..2)K-Factor: dR/R= K * dl/l

Ø High Temperature Resistance (330°C)Ø Pressure Range: 25 to 3.000 Bar

6 mm

5

(3) Sensor Design for CO2 / R744 MACS

Digital output: LIN2.0 or PWM(Temperature output embedded in signal)

Integrated Temp. feature: Less part complexity, higher reliability, less flow restriction and reduced leakage risk.

Long term stability, Rugged Design.Smallest possible thread interface: M10x1mm

6

Exploded View / Cross Sectional

DV Chip

p,T

Connector

Flexwire

Component boardwith µC

Housing

Flexwire

Combined Sensor Assembly (p,T)

7

Kavlico DV Chip

Dual Frequency-Output ASIC for Thin-Film and PRT Resistive type sensors:

Ø Ratiometric multiplexed frequency (digital) output for Sensor (Pressure-) and Temperature-data.

Ø Coarse gain and offset calibration via serial-interface, allowing wide range of sensors.

Ø Fine calibration by µP ; calibration coefficients to be stored in memory of µP.

Ø Extreme temperature range ( -50ºC to +200ºC ). Ø Low-Power (sleep mode and 3mA operational current)Ø Self-diagnostics and failure analysis.

8

DV Chip placement on Thin Film Flexure

Accurate Temperature measurement independent fromambient temperature.Digital, non-susceptible output (temperature output embededin signal).

Solder or Conductive Epoxy Bumps on DV Chip

UnderfillAdhesive

Solder Conductive Epoxy Bumps or on Flexure Bridge Pads

Bridge pads

9

Schematic

Thin Film

Strain

Gauge

DV chip Flexwire

Inter-connection

Micro Controller

LIN2.0

Transceiver

Out

Sensing(Sensor assy)

Conditioning(PC Board)

p T

10

(4) Finite Element Modeling of P/T Sensor

11

Effect of Chip on Diaphragm Stress and Deflection

0.00E+00

1.00E-03

2.00E-03

3.00E-03

4.00E-03

0 0.25 0.5 0.75 1

r/R

Def

lect

ion

(m

m)

No Chip Chip loaded

The influence of DV chip on the stress distribution and deflection of diaphragm is small

Condition: 180ºC temperature, 150 bar pressure

Rr

12

Ambient Conditions: a) 25ºC still airb) 150ºC still air

150ºC air flow / 4.4 m/s

c) 135ºC still air

Thermal AnalysisImpact to electrical Components (PCB)

CO2 @ 200 kg/h and 180ºC or 165ºC

13

a) Temperature Distributions after 5 Min. (25ºC Ambient Temperature)

Printed Circuit Board112~140ºC

25°C, Voo = 0m/s

Initial Fluid Temperature: 25ºC; Transient to 180ºC

14

b) Temperature Distributions after 5 Min. (150ºC Ambient Temperature)

167~173ºC

Printed Circuit Board

166~172ºC

Initial Fluid Temperature: 25ºC; Transient to 180ºC

150°C, Voo = 0m/s 150°C, Voo = 4.4m/s

15

Replace PCB

Mount the circuit board to components with low thermal conductivity (plastics) away from the metal housing.

ULTEM 2310 PolyetherimidePlastic Connector

Circuit Board

Stainless Steel 304L

16

c) Design at 135ºC Ambient Temperature

141-144ºC

Printed Circuit Board Temperature

139-141ºC

CO2 Temperature

5 min of 180ºC

5 min of 165ºC

Initial Fluid Temperature: 135ºC; Transient to 180ºC and 165ºC

17

Conclusions

Ø DV chip has negligible influence on the performance of sensor diaphragm / pressure sensor functionality.

Ø By connecting the circuit board to plastics and away from the metal housing, the circuit board temperature can be reduced to around

~ 140ºC under 135ºC ambient Temperature

18

(5) Qualification Testing

ØLeackage test March 2008

Requirement <1,0 gram per year The test will be carried out at an external test lab, specialized on these kind of tests.

ØDesign validation test on sensor level

Start after sample build in July 2008Duration appr. 6 month.

19

(6) Other Thin Film Application and Sensor Products:

ØDirect Fuel Injection / Common RailØIn-Cylinder PressureØTransmission / Break PressureØCompressed Natural Gas (CNG)ØTraction ControlØ(Mobile) Hydraulic Pressure / ControlsØHVAC / Hydraulic Machinery

20

Thank you for your attention !

Contact:Mr. Markus ButenopDirector of Sales EuropeKAVLICO GmbH Potsdamer Str. 14D-32423 Minden (Ger.)Phone: +49 (0)571 3859 –171Fax.: +49 (0)571 3859 –119Email: mbutenop@kavlico.deWeb: www.kavlico.de / www.cst-sensors.com