Transcript A combined pressure and temperature sensor without

A Combined Pressure and
Temperature Sensor
without external temperature probe
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
(1) Key P/T Sensor Specifications
 Pressure:
Measurement Range
Accuracy
Response time
0 to 170 Bar
< ± 1,0%
(F.Sp.)
~4 ms
(t63)
 Temperature:
Media
Accuracy
Response time
Ambient Temperature
-40°C to +180°C
~±3K
< 10 sec
(t63)
up to 135°C
 Electrical Interface:
3-pin LIN2.0, 3-pin PWM,
4-pin P/T analog
(2) Patented Thin Film Technology
 Thin Film Element on SST
 Sputtered Metal Strain Gauge
 TiON Strain Gauge with high K-Factor/ Gauge Factor:
K: TiON ~ 5 (CrNi ~ 1,1..2)
K-Factor:
dR/R= K * dl/l
 High Temperature Resistance (330°C)
 Pressure Range: 10 to 3.000 Bar
6 mm
(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
Exploded View / Cross Sectional
Connector
Flexwire
Component board
with µC
Housing
Flexwire
DV
Chip
Combined Sensor Assembly (p,T)
p,T
Kavlico DV Chip
Dual Frequency-Output ASIC for Thin-Film and PRT
Resistive type sensors:
 Ratiometric multiplexed frequency (digital) output for
Sensor (Pressure-) and Temperature-data.
 Coarse gain and offset calibration via serial-interface,
allowing wide range of sensors.
 Fine calibration by µP ; calibration coefficients to be
stored in memory of µP.
 Extreme temperature range ( -50ºC to +200ºC ).
 Low-Power (sleep mode and 3mA operational current)
 Self-diagnostics and failure analysis.
DV Chip placement on Thin Film Flexure
 Accurate Temperature measurement independent
from ambient temperature.
 Digital, non-susceptible output (temperature output
embeded in signal).
Electrical
Contact
Bumps on
DV Chip
Underfill
Adhesive
Bridge pads
Schematic
Conditioning
(PC Board)
Sensing
(Sensor assy)
p
Thin Film
Strain
Gauge
T
DV chip
Flexwire
Interconnection
Micro
Controller
LIN2.0
Transceiver
Out
(4) Finite Element Modeling of P/T Sensor
Effect of Chip on Diaphragm Stress and
Deflection
R
No Chip
Chip loaded
4.00E-03
Deflection (mm)
r
The influence of DV chip on the
stress distribution and deflection
of diaphragm is small
3.00E-03
2.00E-03
1.00E-03
0.00E+00
0
0.25
0.5
0.75
1
r/R
Condition: 180ºC temperature, 150 bar pressure
Thermal Analysis
Impact to electrical Components (PCB)
Ambient Conditions:
a) 25ºC
still air
b) 150ºC
still air
150ºC
air flow /
4.4 m/s
c) 135ºC
still air
CO2 @ 200 kg/h and
180ºC or 165ºC
a) Temperature Distributions after 5 Min.
(25ºC Ambient Temperature)
25°C, Voo = 0m/s
Printed Circuit Board
112~140ºC
Initial Fluid Temperature: 25ºC; Transient to 180ºC
b) Temperature Distributions after 5 Min.
(150ºC Ambient Temperature)
150°C, Voo = 4.4m/s
150°C, Voo = 0m/s
167~173ºC
166~172ºC
Printed
Circuit Board
Initial Fluid Temperature: 25ºC; Transient to 180ºC
Replace PCB
ULTEM 2310 Polyetherimide
Plastic Connector
Circuit Board
Stainless Steel 304L
Mount the circuit board to components with low thermal conductivity (plastics)
away from the metal housing.
c) Design at 135ºC Ambient Temperature
CO2 Temperature
Printed
Circuit Board
Temperature
5 min of 180ºC
141-144ºC
5 min of 165ºC
139-141ºC
Initial Fluid Temperature: 135ºC; Transient to 180ºC and 165ºC
Conclusions
 DV chip has negligible influence on the performance of sensor
diaphragm / pressure sensor functionality.
 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
(5) Qualification Testing
Leackage test
Requirement <1,0 gram per year
The test is carried out at an external test lab,
specialized on these kind of tests.
Design validation test on sensor level
Start after sample build in July 2008
Duration appr. 6 month.
(6) Other Thin Film Application and Sensor
Products:
Direct Fuel Injection / Common Rail
In-Cylinder Pressure
Transmission / Break Pressure
Compressed Natural Gas (CNG)
Traction Control
(Mobile) Hydraulic Pressure / Controls
HVAC / Hydraulic Machinery
Contact:
Mr. Markus Butenop
Director of Sales
KAVLICO GmbH
Potsdamer Str. 14
32423 Minden
Germany
Phone:
Fax.:
Email:
Web:
+49 (0)571 3859 – 171
+49 (0)571 3859 – 119
[email protected]
www.kavlico.de / www.cst-sensors.com