Throttle Position Sensor Calibration for Transport Refrigeration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional transport refrigeration systems lack a closed-loop calibration method for the engine throttle position sensor, leading to inaccurate engine load monitoring, which results in inefficient balancing of refrigeration load with available engine power.
Innovation Solution
A method and system for calibrating the engine throttle position sensor by monitoring current RPM and throttle position signals, gradually increasing refrigeration load to determine a recalibrated throttle position signal when engine RPM drops to a preset limit, ensuring accurate representation of engine power output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the throttle position sensor is calibrated using conventional methods, then the calibration process is simple, but the measurement precision of engine load is inaccurate
Solution Approach 1:
The patent implements a closed-loop calibration method where the controller continuously monitors engine RPM and throttle position sensor signals, compares them against expected values, and automatically adjusts the throttle calibration until the sensed RPM matches the expected RPM at wide-open throttle. This feedback mechanism ensures high measurement precision for engine load monitoring.
Solution Approach 2:
The calibration process is performed automatically by the controller using the engine's own operational parameters (RPM and throttle position signals) without requiring external calibration equipment or manual intervention. The system calibrates itself during normal operation by identifying the condition where sensed RPM equals expected RPM at wide-open throttle.
2Measurement precision
If the refrigeration load is increased to calibrate the throttle, then the calibration accuracy improves, but the engine may become overloaded
Solution Approach 1:
The controller gradually increases the refrigeration load in incremental steps rather than applying full load immediately. This preliminary, progressive approach allows the engine to adapt to increasing loads safely while the calibration process identifies the true wide-open throttle position, preventing sudden overload conditions.
Solution Approach 2:
The calibration process dynamically adjusts the refrigeration load based on real-time engine RPM feedback. The controller continuously monitors whether the engine can sustain the increased load and adjusts the load increment size accordingly, ensuring the engine operates within safe parameters throughout the calibration process.
3Productivity
If the throttle position sensor signal is not accurately calibrated, then the system operation is simple, but the fuel flow control becomes inefficient
Solution Approach 1:
The system uses feedback from the throttle position sensor and engine RPM to continuously verify and adjust the calibration. The controller compares the actual throttle position signal against the expected signal at known engine loads and automatically corrects any deviations, ensuring optimal fuel flow control efficiency.
Solution Approach 2:
The patent replaces manual mechanical calibration procedures with an electronic control-based calibration system. The controller uses electronic sensors and software algorithms to automatically determine the correct throttle position mapping, eliminating the need for physical adjustment mechanisms and improving fuel flow control precision.
Data Source
Figure 1~4
Figure 2
Figure 3
AI summary
A method is provided for calibrating an engine throttle position sensor operation of a refrigeration system powered by a fuel fired engine.