Engine Torque Balancing via Cylinder Pressure Intermediary
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Solution Overview
Problem
Internal combustion engines face torque imbalances due to cylinder-to-cylinder variations in breathing conditions, leading to noise, vibration, and harshness, which existing feedback control techniques struggle to address effectively due to poor signal-to-noise ratios.
Innovation Solution
A system with a controller that interprets operating parameters to determine cylinder torque adjustments, providing a torque balancing response by calculating net torque outputs and adjusting spark timing or valve actuation to balance torque across cylinders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing feedback control techniques using speed signal are used to address torque imbalance, then torque balancing response is provided, but signal to noise ratio is poor
Solution Approach 1:
The patent introduces an intermediary measurement system that uses cylinder pressure sensors and operating parameters as intermediate variables to indirectly measure torque. Instead of directly measuring torque (which has poor signal-to-noise ratio), the system measures intermediate parameters (cylinder pressure, EGR fraction, air amount, spark timing) that are easier to measure with high precision and from which torque can be accurately derived through calculation.
2Productivity
If cylinder deactivation or dedicated EGR system is used, then engine performance is improved, but cylinder breathing imbalance and torque imbalance are created
Solution Approach 1:
The patent applies local quality by providing individualized torque balancing for each cylinder based on its specific operating conditions. The system calculates net torque for each cylinder separately using local parameters (cylinder pressure, EGR fraction, air amount, spark timing) and provides cylinder-specific torque adjustments through individualized spark timing modifications, allowing each cylinder to be optimized independently despite system-level constraints.
3Reliability
If cylinder-by-cylinder torque measurement and adjustment is implemented, then torque imbalance is reduced, but system complexity increases
Solution Approach 1:
The patent implements a feedback control system where cylinder torque is continuously measured (through intermediate parameters), compared against target values, and adjustments are made via spark timing modifications. The controller receives real-time operating parameters, calculates net torque for each cylinder, determines torque adjustments, and applies corrections in a closed-loop manner, enabling accurate torque balancing through systematic feedback control.
Data Source
AI summary
An internal combustion engine includes a number of cylinders and a controller operably connected to interpret operating parameters related to the operation of the number of cylinders. A cylinder torque adjustment for each cylinder is determined from the operating parameters to provide a torque balancing response that reduces noise, vibration and/or harshness in engine operation.