Vehicle Torque Compensation for Cylinder Misfire Detection
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Solution Overview
Problem
Conventional engine control systems often misdiagnose engine misfires due to torque imbalances caused by unequal drive torque output from cylinders, leading to inaccurate detection of weak cylinders.
Innovation Solution
A control system that includes a crankshaft and engine speed sensor to estimate torque output based on air and fuel delivery, with a torque compensation module determining weak cylinders and adjusting the estimated torque output to compensate for misfires, using a fuel-to-torque conversion and torque correction module to improve misfire detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional engine control systems use torque output to detect engine misfire, then misfire detection can be performed, but detection accuracy deteriorates due to torque imbalance from weak cylinders
Solution Approach 1:
The system transitions from evaluating overall engine torque to evaluating individual cylinder torque output. By determining the torque output of each cylinder and comparing it against expected values, the system can locally identify weak cylinders and misfires, thereby improving detection accuracy while accounting for torque imbalances in specific cylinders.
Solution Approach 2:
The system continuously monitors cylinder torque output and uses this feedback to adjust misfire detection. By comparing actual cylinder torque against expected torque values and using this information to refine detection algorithms, the system improves both accuracy and reliability of misfire detection while adapting to varying engine conditions.
2Measurement precision
If the system determines weak cylinders based on torque output, then misfire detection can be improved, but system complexity increases due to additional calculation modules
Solution Approach 1:
The control module performs multiple functions using a unified approach: it estimates torque output, determines weak cylinders, calculates torque compensation values, and detects misfires. By making the control module multi-functional and eliminating the need for separate dedicated modules for each function, the system achieves improved weak cylinder identification without proportionally increasing overall system complexity.
Solution Approach 2:
The system changes the parameter used for analysis from overall engine torque to individual cylinder torque output. This parameter change enables more precise weak cylinder identification while the calculations are performed within the existing control module framework, minimizing the increase in system complexity through software-based solutions rather than hardware additions.
Data Source
AI summary
A control system configured to control an internal combustion engine includes a crankshaft and an engine speed sensor. The crankshaft is rotated in response to combusting a mixture of air and fuel delivered to at least one cylinder included in the internal combustion engine. The engine output speed sensor is configured to output an engine output speed signal indicating a rotational speed of the crankshaft. An engine control module controls an amount of air and fuel delivered to the at least one cylinder and estimates a torque output based on the amount of air and fuel. A torque compensation module is configured to determine at least one weak cylinder based on the engine output speed signal. The torque compensation module is further configured to determine a torque compensation value that adjusts the estimated torque output based on the weak cylinder.