Adaptive Refueling to Prevent Canister Breakthrough Emissions
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Solution Overview
Problem
In vehicles with alternate engine technologies such as start/stop and mild hybrid-electric vehicles, the fuel vapor canister's reduced adsorption capacity due to high temperatures leads to breakthrough emissions during parking, as the engine operation after refueling is insufficient for complete purging, especially when the tank is full.
Innovation Solution
Implementing an adaptive refueling adjustment method that reduces the amount of fuel dispensed based on predicted canister purge events and loading capacity, using predictive data to anticipate parking conditions and engine operation, thereby reducing the likelihood of breakthrough emissions by managing fuel tank pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the fuel tank is filled to maximum capacity during refueling, then the fuel tank volume is maximized, but the fuel vapor canister loading capacity is exceeded causing breakthrough emissions
Solution Approach 1:
The system performs preliminary assessment of canister loading capacity and purge event timing before completing refueling. By evaluating whether a purge event will occur within a threshold time window and calculating the canister's available loading capacity, the system determines the maximum safe fuel volume in advance, preventing breakthrough emissions before they occur.
Solution Approach 2:
The refueling volume is made dynamic rather than fixed at maximum capacity. The system adjusts the refueling volume based on real-time conditions including predicted purge events, current canister loading, ambient temperature, and vehicle operation patterns, allowing the fuel tank to be filled to the optimal level that prevents emissions while maximizing storage.
2Reliability
If the engine operates for extended duration to purge the canister completely, then the canister loading capacity is restored, but the vehicle operation time is increased
Solution Approach 1:
The system predicts future purge events using learned vehicle operation patterns and route information before they naturally occur. By anticipating when the engine will run and purge the canister, the system can proactively limit refueling volume to match the predicted purge capacity, eliminating the need for extended engine operation solely for purge purposes.
Solution Approach 2:
The system continuously monitors actual purge performance and compares it with predictions, using this feedback to refine future predictions and adjustments. This closed-loop approach ensures that refueling volume limits are optimally set based on actual vehicle usage patterns, minimizing unnecessary engine runtime while maintaining effective canister management.
3Object-generated harmful factors
If the refueling volume is reduced to prevent canister overload, then breakthrough emissions are prevented, but the fuel tank utilization is decreased
Solution Approach 1:
The refueling volume limit is dynamically adjusted based on multiple factors including predicted purge events, ambient temperature, canister age and condition, and vehicle usage patterns. This dynamic approach maximizes fuel tank utilization at each refueling event while ensuring emissions are prevented, rather than using a fixed conservative limit.
Solution Approach 2:
The system changes the refueling volume parameter based on calculated canister loading capacity and predicted purge events. By continuously updating this parameter according to real-time conditions and predictions, the system optimizes the balance between fuel tank utilization and emissions prevention for each refueling event.
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
This approach effectively reduces the likelihood of fuel vapor breakthrough emissions by adjusting the refueling volume according to predicted conditions, ensuring the fuel vapor canister is not overloaded during refueling, thereby minimizing emissions during vehicle-off periods.
Implementation Method 1
vaporized hydrocarbons (HCs) from a fuel tank may be stored in a fuel vapor canister packed with an adsorbent which adsorbs and stores the vapors
Implementation Method 2
the EVAP system allows the vapors to be purged into the engine intake manifold for use as fuel
Implementation Method 3
the fuel vapor canister may be subjected to high temperatures due to heat rejection from exhaust gases, thermal radiation from road surfaces
Data Source
AI summary
Methods and systems are provided for an evaporative emission control system. In one example, a method may include halting a dispensing of fuel to a fuel tank during a refueling event by increasing a backpressure in the fuel tank. The halt to fuel dispensing may be executed based on one or more of an upcoming fuel vapor canister purge event and an estimated fuel vapor canister loading capacity to determine a predicted canister breakthrough. The predicted canister breakthrough may be compared to a threshold to regulate a refueling volume.