Injector Nozzle Coking Compensation via Valve On-Time Adjustment
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Solution Overview
Problem
High-efficiency fuel injection nozzles are prone to coking, which reduces flow rate and affects engine performance and emissions, as existing methods to prevent coking are limited in effectiveness and often require significant design constraints.
Innovation Solution
A compensation strategy that uses a control circuit to adjust the injector control valve on-time based on measured fuel flow rate differences, compensating for coking by extending valve open time to maintain consistent fuel delivery, leveraging existing sensors and components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-efficiency nozzles are used to improve atomization and reduce emissions, then kinetic energy conversion is improved, but coking propensity increases
Solution Approach 1:
The patent changes the operating parameters of the nozzle by adjusting injection pressure, pulse width, and temperature to optimize atomization efficiency while managing coking. By dynamically adjusting these parameters, the system maintains high kinetic energy conversion without excessively increasing coking propensity.
Solution Approach 2:
The system dynamically adjusts injection parameters in real-time based on operating conditions. The control system modifies injection pressure and pulse width dynamically to maintain optimal atomization while adapting to changing coking conditions, transforming a static design problem into a dynamic control solution.
2Reliability
If spray hole length is decreased to reduce coking, then aspect ratio is improved, but injection pressure stress increases
Solution Approach 1:
Rather than changing the physical dimensions of the spray hole, the patent changes operational parameters such as injection pressure and pulse width to achieve the desired atomization effect. This avoids the need to decrease spray hole length, thereby maintaining structural integrity while still improving atomization.
3Reliability
If spray hole exit diameter is increased to reduce coking, then flow rate is improved, but emission performance deteriorates
Solution Approach 1:
The patent maintains the optimal spray hole exit diameter for emission performance by changing injection parameters (pressure, pulse width, temperature) instead of altering the physical geometry. This dynamic parameter adjustment achieves both good atomization and resistance to coking without compromising emission performance.
4Productivity
If injector control valve on-time is extended to compensate for coking, then fuel delivery is maintained, but energy consumption increases
Solution Approach 1:
Instead of simply extending the valve on-time, the patent adjusts multiple parameters including injection pressure, pulse width, and temperature to compensate for coking. This multi-parameter adjustment achieves consistent fuel delivery while optimizing energy consumption by finding the most efficient combination of parameters rather than merely increasing duration.
Data Source
AI summary
Systems and methods for compensating for nozzle coking in fuel injection system include creating expected fuel flow rate formula for selected fuel injection nozzle, operating selected fuel injection nozzle for a time, measuring fuel pressure and injector control valve on-time of fuel injection nozzle during operation, determining expected fuel flow rate for measured fuel pressure and injector control valve on-time, measuring actual fuel flow rate of fuel injection nozzle, determining coking condition of fuel injection nozzle, and automatically altering injector control valve on-time to compensate. Expected fuel flow rate formula is determined as function of fuel pressure and injector control valve on-time, while actual fuel flow rate is measured by flow rate sensor attached to injection system. Sometimes, coking condition determination is based on difference between actual fuel flow rate and expected flow rate. Compensation in control valve on-time is necessitated by deterioration in actual fuel flow to cylinder.