Fuel Flow Rate Determination via Engine Deceleration
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Solution Overview
Problem
Diagnostic tests for vehicle engines face challenges in accurately determining the fuel flow rate due to sensor calibration issues, errors in flow rate evaluation, and the difficulty in tracing faults without removing components or using external instruments, leading to imprecise identification of problems.
Innovation Solution
A process to determine the true fuel flow rate by measuring deceleration and friction torque, comparing it to reference values, and using this value for diagnostic testing to identify faults within the engine management system, allowing for in-vehicle calibration and validation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensor calibration and flow rate evaluation methods are used, then diagnostic capability is provided, but measurement precision deteriorates due to sensor errors and calibration losses
Solution Approach 1:
The patent introduces an intermediary calculation method that uses easily measurable parameters (intake air flow rate, engine speed, volumetric efficiency) to compute the true fuel flow rate, bypassing the need for direct measurement with imprecise fuel flow sensors. This intermediary approach allows diagnostic testing without relying on faulty direct measurement devices.
2Loss of information
If direct fuel flow rate measurement is attempted, then diagnostic information is obtained, but device complexity increases due to additional sensors and calibration procedures
Solution Approach 1:
The patent extracts the essential information needed for fuel flow rate determination from existing, simpler measurements (intake air flow rate sensor, engine speed sensor, volumetric efficiency data) rather than adding complex direct fuel flow measurement systems. The true fuel flow rate is derived by taking out and processing information already available from less complex sources.
3Ease of operation
If existing sensor calibration methods are used, then system operation is maintained, but measurement precision deteriorates due to cumulative errors
Solution Approach 1:
The patent implements a feedback mechanism where the calculated true fuel flow rate is continuously compared with the fuel flow rate evaluated by existing sensors and calibration data. This feedback loop identifies discrepancies and enables correction of measurement errors, maintaining ease of operation while improving measurement precision through iterative validation.
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 process enhances the accuracy of fuel flow rate determination and fault identification, reducing the need for component removal and external instruments, thereby improving diagnostic reliability and efficiency.
Implementation Method 1
measuring a deceleration (Δn/Δt) of the engine from a first to a second rotation speed, in the absence of a fuel supply, corresponding to a load the engine is subjected to
Implementation Method 2
measuring a deceleration (Δn/Δt) of the engine from a first to a second rotation speed
Data Source
Figure 1
AI summary
A process for the evaluation of the true fuel flow rate supplied to a tested vehicle engine, in particular an industrial vehicle, the process including: the determination of a reference fuel flow rate, corresponding to the exact flow rate measured on a reference engine of the same type as the tested engine under various operation conditions as a function of a load the engine is subjected to; the measurement of the deceleration (An/At) of the tested engine from a first to a second rotation speed which are preset in the absence of fuel supply, corresponding to a load the engine is subjected to; the determination, based on said deceleration, and based on the actual operation conditions of the engine under similar load conditions, of the corresponding reference flow rate.