Transcript Presentation

Self-Contained Particulate
Filter
Filter 3
Presenters: Ian Gray, Kyhia Bostic
Demo Given by: Nathan Sullivan
Unique Feature of System
• Sensor Checker
• Components of Sensor Checker:
– Controls bypass valve
– Monitors differential pressure of filter
– Checks instantaneous RPMs of engine
– Calculates engine revolutions elapsed
since previous cleaning cycle
What does Sensor Checker
support?
• Opens bypass valve
– Differential pressure exceeds 10 kPa
– Differential pressure equals zero
• Sensor checker finds the differential
pressure to be 11 kPa. It sets a variable
to indicate a pressure warning and then
opens the bypass valve.
Unique Feature of System
• Heater Elements
• Components of Heater Elements:
– Self-contained
– Monitors current
– Monitors temperature
– Mark itself not operational
– Knows operational status
What does Heater Element
support?
• Takes itself out of cleaning sequence
– Current reaches 40 Amps or above
– Temperature reaches 275° or above
• Controller tells Heater Element to
increase current. Heater Element
updates internal data value representing
current and then increases current to
actual heater element.
Two Key Models
• Sensor Checker State Diagram
• Class Diagram
Key Model
• Sensor Checker State Diagram
• Logic of system
– How the system reacts to sensor data
– Order of internal events of system
– Reflects state of system, i.e. values of
variables in system
Model
Key Model
• Class Diagram
• Highly detailed
– Details system operations
– Reflects topology of system
– Shows how real world objects are modeled
in the SCPF
Model
Critical Properties
• Safety Properties
– Messages are sent to the driver if high
pressure is detected
– High temperature will cause the element to
be taken out of the heating sequence
– An electrical short will cause the cleaning
process to terminate
Critical Properties (cont.)
• Liveliness Properties
– The cleaning process will begin when all
criteria are met
– The cleaning process gradually increases
and decreases the power supplied to an
element
– Every 1000ms a message is sent over the
CAN to the engine controller
Promela and XSpin
• Results of analysis
– Modeled the sensor checker
– Made sure appropriate action was taken
according to the sensor readings
• Our sensor checker performed well
• Learned the importance of sensors
Promela Testing
Bypass valve testing code
In the pressure
warning and fault
states the bypass
is opened by
setting the bypass
variable to true
Promela Testing (cont.)
Elapsed Revolutions & Instantaneous
RPMs testing code
Instantaneous RPMs
Check
– returns Low if < 700
– returns OK if > 700
Elapsed Revolutions
Check
– returns Low if <
10000
– returns OK if >
10000
sets revs = true to
start cleaning process
Demo of Prototype
• High-level features of User Interface:
– Start/Stop engine
– Control engine RPMs and filter pressure
– Control operational status of individual
heater elements
– Displays CAN communication information
– Displays driver display information
Scenarios
• Normal Scenario
– Turn on engine
– Increase RPMs to above 700
– Increase pressure to above 8 kPa
– All operational heaters will turn on and
ramp up/down in sequence
– When finished the system waits until
10,000 revolutions have occurred before
starting cleaning sequence again
Scenarios (cont.)
• Non-operational heaters are skipped
– Turn on engine
– Uncheck the Operational box of a heater
– Increase RPMs to above 700
– Increase pressure to above 8 kPa
– When a non-operational heater is reached,
it is skipped
– Cleaning process continues with next
operational heater
Scenarios (cont.)
• Excessive pressure causes a message
to be sent to the driver display
– Turn on engine
– Increase RPMs to above 700
– Increase pressure to 12 kPa
– A message appears in the driver display
box