Control Valve Fuel Flow Measurement via Upstream Pressure
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Solution Overview
Problem
Existing methods for controlling control valves in evaporative emission control systems are inaccurate in determining the fuel quantity supplied to the combustion chamber, leading to increased untreated emissions and potential disruptions in engine smoothness.
Innovation Solution
A method involving the measurement of pressure profiles and fluid density upstream of the control valve, allowing for precise control of the fuel volume flow by determining the amounts of air and fuel through mathematical evaluation of pressure parameters, enabling accurate fuel addition to the combustion engine before combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If lambda probes are used to determine fuel quantity by monitoring deviation from setpoint value, then fuel quantity can be determined, but untreated emissions increase due to delayed control response
Solution Approach 1:
The patent measures pressure upstream of the control valve before fuel injection occurs, enabling determination of fuel quantity from the evaporative emission control system in advance. This preliminary measurement allows the control system to compensate for the measured fuel quantity before combustion, preventing emissions rather than detecting them after the fact.
2Measurement precision
If all mixture deviations are attributed to fuel from evaporative emission control system, then fuel quantity can be calculated, but tank ventilation must be heavily restricted to maintain engine smoothness
Solution Approach 1:
The patent extracts the pressure measurement function from the combustion chamber exhaust gas analysis and places it upstream of the control valve. This separates the fuel quantity measurement from the combustion process, allowing accurate measurement of fuel from the evaporative emission control system without being confounded by other mixture deviations, thereby enabling proper tank ventilation without compromising engine smoothness.
3Measurement precision
If control valve is opened slowly to monitor lambda deviation, then fuel quantity can be determined, but response time increases and emissions control is delayed
Solution Approach 1:
The patent replaces the mechanical/exhaust-gas-based lambda probe measurement system with a pressure-based measurement system upstream of the control valve. This substitution enables rapid pressure measurements that provide immediate feedback on fuel quantity from the evaporative emission control system, eliminating the need for slow valve opening and delayed exhaust gas analysis.
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 method allows for more accurate control of fuel addition, reducing untreated emissions and enabling rapid adjustment of tank ventilation, thereby improving engine performance and emission control.
Implementation Method 1
measuring a pressure profile upstream of the control valve
Data Source
AI summary
A method for controlling a control valve, the control valve controlling a volume flow of a fluid along a line, the method including at least the following steps: (a) performing a closing operation of the control valve; (b) measuring a pressure profile upstream of the control valve; and (c) determining a density of the fluid.