Diesel Cetane Estimation via Pressure Wave Feedback Correction
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Solution Overview
Problem
Existing cetane number estimation methods for diesel engines are inaccurate due to variations in fuel properties like kinematic viscosity and bulk modulus of elasticity, which affect fuel injection amounts and pressures, leading to incorrect cetane number calculations.
Innovation Solution
A cetane number estimation apparatus that uses a pressure sensor and pressure correcting section to calculate actual operating characteristics of the fuel injection valve, correcting the target fuel injection amount based on differences between actual and reference operating characteristics, thereby isolating the cetane number from other fuel properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fuel injection amount is calculated based on pressure sensor detection, then fuel injection control is achieved, but measurement precision deteriorates due to influence from kinematic viscosity and bulk modulus of elasticity variations
Solution Approach 1:
The patent applies feedback by detecting the actual fuel injection amount through pressure sensor signals and comparing it with the target fuel injection amount. The ECU uses this feedback information to calculate correction amounts and adjust subsequent fuel injection control, thereby compensating for measurement errors caused by fuel property variations and improving overall measurement precision.
Solution Approach 2:
The patent changes the parameter of fuel injection amount calculation from direct pressure-based calculation to correction-based calculation. By introducing correction amounts that compensate for kinematic viscosity and bulk modulus of elasticity variations, the system adjusts the calculation parameters to maintain measurement precision despite fuel property changes.
2Measurement precision
If cetane number is estimated based on fuel injection amount and output torque relationship, then cetane number estimation is achieved, but measurement precision deteriorates due to fuel property variations
Solution Approach 1:
The patent uses feedback from actual fuel injection amount detection to improve cetane number estimation. By comparing detected fuel injection amount with target fuel injection amount and using the difference as correction information, the system enhances the reliability of cetane number estimation under varying fuel properties.
Solution Approach 2:
The patent changes the estimation approach by introducing correction amounts that account for kinematic viscosity and bulk modulus of elasticity. This parameter adjustment allows the cetane number estimation to remain reliable even when fuel properties vary, as the correction compensates for the indirect effects of these properties on measurement.
3Ease of operation
If pressure sensor is used to detect fuel pressure variation, then fuel injection amount calculation is enabled, but measurement precision deteriorates due to bulk modulus of elasticity influence on pressure wave transmission
Solution Approach 1:
The patent applies feedback by detecting pressure sensor signals that reflect actual fuel injection amount and using this information to calculate correction amounts. The system feeds back the difference between detected and target fuel injection amounts to improve subsequent measurements, compensating for bulk modulus of elasticity influence.
Solution Approach 2:
The patent introduces correction amount calculation as an intermediary process between pressure sensor detection and fuel injection amount determination. This intermediary step compensates for the distorting effect of bulk modulus of elasticity on pressure wave transmission, allowing accurate fuel injection amount measurement despite the physical interference.
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 allows for accurate cetane number estimation by minimizing errors caused by variations in kinematic viscosity and bulk modulus of elasticity, ensuring precise fuel injection and improved engine performance.
Implementation Method 1
when fuel pressure varies, the speed at which a variation wave transmits through fuel becomes greater as the bulk modulus of elasticity of the fuel becomes higher
Data Source
AI summary
A cetane number estimation apparatus injects fuel from a fuel injection valve in a diesel engine based on a target fuel injection amount, calculates an indicator of output torque of the diesel engine produced through fuel injection, and estimates the cetane number of the fuel using the calculated indicator. The cetane number estimation apparatus includes a pressure sensor for detecting fuel pressure varied by variation in actual fuel pressure in the fuel injection valve at the time of the fuel injection. The cetane number estimation apparatus also has a pressure correcting section that is adapted to calculate actual operating characteristics of the fuel injection valve based on a variation waveform of the detected fuel pressure and corrects the target fuel injection amount based on the difference between the calculated actual operating characteristics and prescribed reference operating characteristics.