Method of testing an evaporative emission control system

• US 5,606,121 A
• Filed: 03/05/1996
• Issued: 02/25/1997
• Est. Priority Date: 03/05/1996
• Status: Expired due to Term

• Current Assignee: FCA US LLC (Stellantis NV)
• Original Assignee: Chrysler Corporation (Stellantis NV)
• Inventors: Hope, Mark E., Blomquist, William B., Dawson, Gary D., Richardson, Roland T., Tallarek, Glen, Letcher, John E.
• Primary Examiner(s): Chilcot, Richard
• Assistant Examiner(s): Dombroske, George M.
• Application Number:
  US08/611,137
• Time in Patent Office: 357 Days
• Field of Search: 73/115, 73/116, 73/117.2, 73/117.3, 73/118.1, 73/118.2, 73/23.31, 73/40, 73/49.2, 73/49.7, 73/49.5
• US Class Current: 73/114.39
• CPC Class Codes: G01M 3/3236 by monitoring the interior space of the containers

Abstract

A method of testing an evaporative emission control system to determine if the evaporative emission control system has reached a predetermined pressure includes the steps of pulsing a leak detection pump at a predetermined rate and determining if a last pump period is greater than or equal to a predetermined test mode period threshold. The method also includes the steps of pressurizing the evaporative emission control system if the last pump period is less than a test mode period threshold and continuing the method if the last pump period is equal to or greater than the test mode period threshold.

Claims

1. A method of testing an evaporative emission control system to determine if the evaporative emission control system has reached a predetermined pressure, said method comprising the steps of:

pulsing a leak detection pump at a predetermined rate;

determining if a last pump period is greater than or equal to a predetermined test mode period threshold;

pressurizing the evaporative emission control system if the last pump period is less than a test mode period threshold; and

continuing said method if the last pump period is equal to or greater than the test mode period threshold.

2. A method as set forth in claim 1 including the step of determining whether a general state indicator is less than a predetermined pump mode test limit prior to said step of determining.

3. A method as set forth in claim 2 including the step of continuing pulsing a leak detection pump if the general state indicator is less than the predetermined pump mode test limit.

4. A method as set forth in claim 1 including the step of:

continuously monitoring an engine vacuum level;

determining if the engine vacuum level is greater than or equal to a predetermined minimum engine vacuum level; and

continuing pulsing the leak detection pump until the engine vacuum level is greater than the minimum engine vacuum level.

5. A method of testing an evaporative emission control system to determine if the evaporative emission control system has reached a predetermined pressure, said method comprising the steps of:

pulsing a leak detection pump at a predetermined rate;

determining whether a general state indicator is less than a predetermined pump mode test limit;

continuing pulsing a leak detection pump if the general state indicator is less than the pump mode test limit;

determining whether a switch closure counter is less than a predetermined switch closure counter limit;

determining if a last pump period is greater than or equal to a predetermined test mode period threshold if the general state indicator is greater than or equal to a pump mode test limit or if a switch closure counter is greater than or equal to the switch closure counter limit;

continuing pressurizing the evaporative emission control system if the last pump period is less than a test mode period threshold; and

continuing said method if the last pump period is equal to or greater than the test mode period threshold.

6. A method as set forth in claim 5 including the step of:

continuously monitoring an engine vacuum level;

determining if the engine vacuum level is greater than or equal to a predetermined minimum engine vacuum level; and

continuing pulsing the leak detection pump until the engine vacuum level is greater than the minimum engine vacuum level.