Dynamic Cylinder Firing Patterns for Engine Torsional Vibration Control
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Solution Overview
Problem
Existing engine firing pattern selection strategies for dynamic cylinder activation (DCA) require extensive calibration and are not applicable to different engine families, often necessitating energy storage/release devices or active mounts for driveline vibration management, which are not universally present.
Innovation Solution
A physics-based algorithm using mixed-integer programming to design firing patterns that minimize torsional vibration content over a user-defined frequency range, applicable to various engine configurations, by optimizing firing sequences through phase-angle approaches and cost functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If physics-based algorithm with mixed-integer programming is used to design firing patterns, then torsional vibration content is minimized and forcing frequencies are shifted away from drivetrain resonances, but device complexity increases due to implementation of optimization algorithm
Solution Approach 1:
The patent replaces complex mechanical vibration control devices (energy storage/release devices, active mounts) with a computational approach - a physics-based algorithm using mixed-integer programming that calculates optimal firing patterns. This substitutes mechanical complexity with algorithmic complexity, achieving vibration minimization through mathematical optimization rather than physical components.
Solution Approach 2:
The algorithm dynamically changes firing pattern parameters (which cylinders fire, when they fire, and in what sequence) based on optimization criteria. By varying these operational parameters through the optimization algorithm, the system minimizes torsional vibration content and shifts forcing frequencies without requiring physical modifications to the engine or additional mechanical components.
2Adaptability or versatility
If physics-based algorithm is used to design firing patterns, then adaptability to different engine configurations is improved, but manufacturing precision requirements increase for accurate implementation
Solution Approach 1:
The optimization algorithm is designed as a universal tool that can be applied to different engine configurations (different numbers of cylinders, different firing orders, different engine types). The same mathematical framework adapts to various engine families by inputting their specific parameters, eliminating the need for separate calibration procedures for each engine type and enhancing versatility.
Solution Approach 2:
The patent uses a physics-based model that replicates the dynamic behavior of different engine configurations through mathematical equations. Rather than requiring physical prototypes or extensive experimental calibration for each engine type, the algorithm creates a virtual copy of the engine's dynamic characteristics and optimizes firing patterns in silico, reducing manufacturing and calibration precision requirements.
3Use of energy by moving object
If dynamic cylinder activation is implemented to achieve fuel savings and aftertreatment thermal management, then fuel economy improves, but driveline torsional vibration increases
Solution Approach 1:
The patent implements dynamic cylinder activation where the firing pattern is not fixed but dynamically optimized based on operating conditions. The algorithm determines which cylinders should fire and when, creating a dynamic firing schedule that adapts to minimize vibration while maintaining fuel economy benefits. This dynamic approach allows real-time adjustment of vibration characteristics without sacrificing the fuel savings achieved through cylinder deactivation.
Solution Approach 2:
The optimization algorithm incorporates feedback from the engine's operating state and vibration characteristics to adjust firing patterns. By continuously evaluating the effects of different firing sequences on torsional vibration and fuel consumption, the system provides feedback-driven optimization that balances fuel economy improvements with vibration control, selecting firing patterns that achieve both objectives simultaneously.
Data Source
AI summary
A system and method for dynamically deactivating engine cylinders of an engine equipped with a cylinder deactivation system, where the system and method control torsional vibration in the engine while deactivating cylinders using a computer programed with a desired firing density and a controlled range of engine vibration frequencies. The computer dynamically determines a cylinder firing pattern that provides the desired firing density while optimizing a cost function norm in the controlled range of engine vibration frequencies. The cylinder deactivation system in the engine is then controlled using the determined cylinder firing pattern.