Engine Injector Lookup Table Adjustment for Fuel Injection Accuracy
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Solution Overview
Problem
Conventional combustion engine injector control systems using lookup tables for fuel injection quantities experience deviations over time, leading to uneven idling and lost pilot or post injections due to changes in injector characteristics, which existing methods fail to accurately address.
Innovation Solution
A method that adjusts the lookup table by determining the actual fuel injection quantity based on torque loss and combustion efficiency, comparing it with the applied on-time value, and modifying the table to align the injected fuel quantity with the expected value, thereby improving accuracy without requiring new hardware or sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If preset on-time values from a lookup table are used for injector control, then the fuel injection quantity can be controlled based on operating conditions, but the accuracy deteriorates over time due to changes in injector characteristics
Solution Approach 1:
The patent implements a feedback mechanism where the actual fuel injection quantity is continuously monitored and compared with the desired quantity from the lookup table. The difference (deviation) is used to adjust future injection commands, creating a closed-loop control system that compensates for injector drift over time without requiring manual recalibration or hardware changes.
Solution Approach 2:
The system dynamically adjusts the injection quantity parameter based on measured deviations. By calculating the difference between desired and actual injection quantities and applying correction factors to subsequent lookup table queries, the system adapts to changing injector characteristics while maintaining control simplicity.
2Measurement precision
If the lookup table is adjusted to compensate for injector drift, then the fuel injection accuracy is improved, but the system complexity increases
Solution Approach 1:
The control system performs self-adjustment by automatically monitoring its own performance and correcting deviations without external intervention. The ECU calculates injection deviations and autonomously modifies the lookup table or injection commands, eliminating the need for manual calibration procedures or additional adjustment mechanisms.
Solution Approach 2:
The existing ECU is made to perform multiple functions: it not only controls fuel injection based on the lookup table but also monitors actual injection quantities, calculates deviations, and adjusts future injections. This multi-functionality is achieved through software updates rather than hardware additions, keeping the physical system simple while enhancing capabilities.
3Measurement precision
If hardware modifications are made to improve injection accuracy, then the measurement precision is improved, but the manufacturing cost and complexity increase
Solution Approach 1:
The patent replaces potential mechanical/hardware solutions (such as additional sensors, flow meters, or manual calibration mechanisms) with a software-based control algorithm. The ECU uses mathematical calculations and lookup table adjustments to achieve accuracy improvements that would otherwise require physical hardware modifications, significantly reducing manufacturing costs and complexity.
Data Source
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AI summary
A method for adjusting a lookup table comprising preset on-time values for an injector (11) of an engine (2) linked to fuel injection quantity values (d). The following steps are executed in a situation when the output shaft of the engine is disconnected from the output shaft of the gearbox: - determining or receiving a torque loss value (Tloss) and a combustion efficiency value (eF); - calculating, based on the torque loss value and the combustion efficiency value, an actual fuel injection quantity value (dactual); - determining from said lookup table the on-time value (tg) linked to the actual fuel injection quantity value and comparing this on-time value with the presently applied on-time value (tb) established by the engine control means (20) with the aid of a regulator (22) and said lookup table; and - adjusting the lookup table in dependence on the result of said comparison.