Variable Vacuum Threshold for Evaporative Emissions Leak Testing

The patent applies dynamics by transitioning from a static, fixed vacuum threshold to a dynamic, variable threshold that adapts to changing ambient and fuel conditions. The electronic controller continuously adjusts the vacuum threshold based on real-time sensor inputs (temperature, pressure, humidity), allowing the leak test to remain reliable across varying environmental conditions. This dynamic adjustment resolves the contradiction by maintaining high reliability without requiring a complex mechanical system, as the electronic adaptation is achieved through software algorithms rather than mechanical complexity.

The patent implements parameter changes by modifying the vacuum threshold parameter from a constant value to a variable value that changes with ambient conditions and fuel properties. The electronic controller calculates the appropriate vacuum threshold based on temperature, pressure, and humidity parameters, then adjusts the test criterion accordingly. This parameter adaptation eliminates false test results caused by environmental variations while using a relatively simple electronic control system, thus resolving the contradiction between reliability and device complexity.

The patent applies periodic action by implementing an event-driven monitoring strategy where the electronic controller enters sleep mode during normal operation and only wakes up when specific trigger events occur (such as engine shutdown, vacuum threshold attainment, or diagnostic requests). This periodic activation pattern allows the system to maintain measurement precision when needed while dramatically reducing average power consumption during extended shutdown periods, effectively resolving the contradiction between continuous monitoring and energy efficiency.

The patent implements self-service through an autonomous wake-up mechanism where the system automatically activates the controller when vacuum levels reach predetermined thresholds or when diagnostic conditions are met, without requiring continuous power. The controller uses low-power wake-up inputs and event-triggered processing to maintain measurement capability while minimizing energy consumption, allowing the system to serve itself by intelligently activating only when necessary.

The patent applies universality by designing the electronic controller to perform multiple functions: it manages engine shutdown operations, monitors vacuum levels, processes sensor data from temperature and pressure sensors, calculates variable vacuum thresholds, and conducts leak testing. By consolidating these diverse functions into a single multi-functional controller, the system achieves high measurement precision through variable threshold adjustment without proportionally increasing overall device complexity, as the same processing unit handles all tasks.

The patent uses intermediary elements (temperature sensors, pressure sensors, and humidity sensors) that provide raw data to the electronic controller, which then processes this information to calculate the appropriate vacuum threshold. These intermediary sensors are relatively simple components that convert physical conditions into electrical signals, allowing the complex threshold calculation to be performed through software rather than requiring complex hardware, thus achieving high accuracy with moderate overall system complexity.