Self-Contained Particulate Filter

1. Self-Contained Particulate Filter Filter 3 Presenters: Ian Gray, Kyhia Bostic Demo Given by: Nathan Sullivan

2. 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

3. 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.

4. Unique Feature of System • Heater Elements • Components of Heater Elements: • Self-contained • Monitors current • Monitors temperature • Mark itself not operational • Knows operational status

5. 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.

6. Two Key Models • Sensor Checker State Diagram • Class Diagram

7. 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

8. Model

9. Key Model • Class Diagram • Highly detailed • Details system operations • Reflects topology of system • Shows how real world objects are modeled in the SCPF

10. Model

11. 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

12. 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

13. 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

14. Promela Testing Bypass valve testing code In the pressure warning and fault states the bypass is opened by setting the bypass variable to true

15. 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

16. 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

17. 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

18. 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

19. 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