Purge Pump and HC Sensor for EVAP Cold Start Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional evaporative emissions (EVAP) control systems are ineffective during engine-off periods, such as cold starts, as they rely on engine vacuum to deliver fuel vapor, leading to increased hydrocarbon emissions and inefficient combustion due to unknown vapor composition.
Innovation Solution
An EVAP control system incorporating a purge pump to actively pump fuel vapor from a vapor canister to the engine, a hydrocarbon sensor to measure HC levels, and a controller to regulate the purge pump and purge valve to deliver a desired amount of fuel vapor, ensuring efficient combustion and emission reduction during engine-off periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If engine vacuum is used to deliver fuel vapor from the vapor canister to the engine, then the EVAP system can operate with simple passive components, but the system becomes ineffective during engine-off periods such as cold starts
Solution Approach 1:
The purge pump is activated before the engine starts (during engine-off periods) to deliver fuel vapor to the engine in advance, ensuring the engine receives combustible vapor during cold starts when natural vacuum cannot be generated
Solution Approach 2:
The system uses the trapped fuel vapor in the canister itself as the source of combustible material for engine cold starts, eliminating the need for external fuel delivery systems during engine-off periods
2Loss of information
If engine vacuum is relied upon to deliver fuel vapor, then no active pumping components are needed, but the composition and concentration of fuel vapor remains unknown
Solution Approach 1:
The hydrocarbon sensor provides real-time feedback on the concentration and composition of fuel vapor in the vapor line, allowing the controller to monitor and adjust purge pump operation to deliver optimal amounts of combustible vapor to the engine
3Object-generated harmful factors
If the purge pump is activated to deliver fuel vapor during engine-off periods, then hydrocarbon emissions are reduced, but additional active components and control systems are required
Solution Approach 1:
The controller adjusts the purge pump operational parameters (activation timing, duration, speed) based on sensor feedback and engine conditions to optimize vapor delivery while minimizing emissions during engine-off periods
Solution Approach 2:
The purge pump serves multiple functions: delivering fuel vapor during engine-off periods, providing combustible vapor for cold starts, and working in conjunction with the purge valve during normal engine operation to control vapor flow
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively reduces hydrocarbon emissions and warms engine components faster by delivering a controlled amount of combustible fuel vapor during cold starts, improving combustion efficiency and reducing emissions of HC, NOx, and CO.
Implementation Method 1
a purge pump configured to pump fuel vapor trapped in a vapor canister to an engine of the vehicle via a vapor line when engine vacuum is less than an appropriate level for delivering fuel vapor to the engine
Implementation Method 2
a hydrocarbon (HC) sensor disposed in the vapor line and configured to measure an amount of HC in the fuel vapor pumped by the purge pump to the engine via the vapor line
Implementation Method 3
a controller configured to, based on the measured amount of HC, control at least one of the purge pump and a purge valve to deliver a desired amount of fuel vapor to the engine
Implementation Method 4
the measured amount of HC in the fuel vapor is indicative of a portion of the fuel vapor that is combustible, and wherein the controller is configured to utilize the combustible portion of the fuel vapor in controlling at least one of the purge pump and the purge valve
Data Source
AI summary
An evaporative emissions (EVAP) control system for a vehicle includes a purge pump configured to pump fuel vapor trapped in a vapor canister to an engine of the vehicle via a vapor line when engine vacuum is less than an appropriate level for delivering fuel vapor to the engine, the fuel vapor resulting from evaporation of a liquid fuel stored in a fuel tank of the engine. The EVAP control system includes a hydrocarbon (HC) sensor disposed in the vapor line and configured to measure an amount of HC in the fuel vapor pumped by the purge pump to the engine via the vapor line. The EVAP control system also includes a controller configured to, based on the measured amount of MC, control at least one of the purge pump and a purge valve to deliver a desired amount of fuel vapor to the engine.