Valve-Lift Changeover Torque Neutrality Correction
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Solution Overview
Problem
The existing valve-lift changeover process in spark-ignition engines often results in torque neutrality issues during the transition from small to large valve lift, leading to jerky vehicle operation due to inaccuracies in engine models and manufacturing tolerances, which complicates data processing and increases costs.
Innovation Solution
A method that involves acquiring engine operating data during valve-lift changeover, evaluating acceleration and lambda characteristics to detect irregularities, and correcting cylinder charging and torque calculations to ensure torque neutrality, with correction values stored in a database for future reference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate models are stored for each valve-lift configuration with identical data content, then manufacturing costs are reduced, but torque accuracy deteriorates due to manufacturing tolerances and system individuality
Solution Approach 1:
The system performs preliminary characterization of the actual engine behavior during valve-lift changeover and stores correction values in advance. By pre-measuring the actual torque behavior and comparing it with model predictions, the system creates individualized correction factors that compensate for manufacturing tolerances and system-specific variations, thereby improving torque accuracy without requiring expensive custom models for each engine.
Solution Approach 2:
The system implements feedback by measuring actual torque during valve-lift changeover, comparing it with model-predicted torque, and using the difference to determine correction values. This feedback loop allows the system to continuously refine and adapt the correction factors stored in memory, improving accuracy over time while maintaining the use of standard, cost-effective engine models.
2Measurement precision
If model calculation accuracy is increased to compensate for tolerances, then torque accuracy improves, but data processing complexity increases rapidly
Solution Approach 1:
The system extracts only the essential correction information needed for torque accuracy from complex model calculations. Instead of using overly complex models that process all possible parameters, the system isolates and stores only the specific correction values related to valve-lift changeover behavior, thereby maintaining accuracy while significantly reducing data processing complexity and storage requirements.
Solution Approach 2:
The system changes the approach from using complex models with many parameters to using simple models with targeted correction parameters. By transforming the problem from one requiring high-complexity real-time calculations to one using pre-calculated correction factors stored in memory, the system achieves the same accuracy goal with much lower computational complexity.
3Measurement precision
If sensors with higher accuracy are used to reduce tolerances, then measurement precision improves, but manufacturing costs increase
Solution Approach 1:
The system uses the existing, cost-effective sensors already present in the engine to measure torque and lambda during valve-lift changeover. Instead of requiring additional high-precision sensors, the system leverages the self-service capability of available sensors combined with intelligent processing to achieve the needed accuracy through correction factor calculation and storage.
4Productivity
If valve-lift changeover is performed quickly, then productivity improves, but torque neutrality deteriorates due to model inaccuracies
Solution Approach 1:
The system performs preliminary measurement and characterization of torque behavior during valve-lift changeover and stores correction values in advance. This allows the system to execute rapid changeovers while maintaining torque neutrality, as the pre-calculated correction factors can be applied instantly without requiring complex real-time calculations that would slow down the process.
Data Source
AI summary
This invention describes a method for optimizing a valve-lift changeover on spark-ignition engines with lambda control. On the basis of the evaluation of an acceleration characteristic and a lambda characteristic during the valve-lift changeover, it is determined whether cylinder charging errors and/or torque errors that require correction are present in the spark-ignition engine.