Engine Valve Timing Estimation via Cylinder Pressure
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Solution Overview
Problem
Existing engine systems face challenges in accurately determining and adjusting intake and exhaust valve timing due to valve position sensor errors, which can lead to increased emissions and reduced engine output, and are costly and complex to maintain.
Innovation Solution
A method using a controller to estimate intake and exhaust valve opening timings from cylinder pressure data, eliminating the need for direct valve position sensors by applying feedforward adjustments based on estimated timings, thereby reducing feedback errors and system complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If valve position sensors are used to determine intake and exhaust valve timings, then valve timing control accuracy is improved, but system cost and complexity increase
Solution Approach 1:
The patent replaces mechanical valve position sensors with a computational approach that uses cylinder pressure sensor data and mechanical motion models to determine valve timing. This substitution eliminates the need for complex mechanical sensing systems while maintaining timing determination capability through software-based estimation algorithms.
Solution Approach 2:
The patent introduces cylinder pressure as an intermediary parameter to indirectly determine valve timing. Instead of directly measuring valve position, the system uses pressure changes in the cylinder during the combustion cycle to infer valve opening and closing events, thereby avoiding direct mechanical measurement complexity.
2Measurement precision
If valve position sensors are used to determine intake and exhaust valve timings, then valve timing control accuracy is improved, but system cost increases
Solution Approach 1:
The patent replaces expensive, specialized valve position sensors with a low-cost approach using standard cylinder pressure sensors that are already present in the engine system. This substitution significantly reduces component cost while maintaining functional capability through computational analysis of pressure data.
Solution Approach 2:
The patent makes the cylinder pressure sensor multi-functional by using it for both combustion monitoring and valve timing determination. This universal use of existing components eliminates the need for separate dedicated valve position sensors, thereby reducing overall system cost.
3Measurement precision
If valve position sensors are used to determine intake and exhaust valve timings, then valve timing control accuracy is improved, but reliability decreases due to sensor failure risk
Solution Approach 1:
The patent extracts the vulnerability associated with valve position sensors by completely removing them from the system. The timing determination function is extracted from the mechanical sensing domain and relocated to the computational domain, eliminating the reliability issues inherent in mechanical sensor failures.
Solution Approach 2:
The patent implements a feedback mechanism where cylinder pressure data continuously informs the valve timing estimation. This feedback loop allows the system to adapt to varying operating conditions and compensate for potential measurement inaccuracies, thereby improving overall system reliability.
4Ease of manufacture
If mechanical motion-based valve position measurement is used, then system cost is reduced, but measurement precision deteriorates due to tolerance stack-up errors
Solution Approach 1:
The patent replaces mechanical motion-based measurement with a pressure-based computational approach. This substitution eliminates the tolerance stack-up errors inherent in mechanical linkages by using fluid pressure measurements that are not subject to mechanical tolerance accumulation.
Solution Approach 2:
The patent uses cylinder pressure as an intermediary that bridges the gap between mechanical valve motion and electrical sensing. The pressure signal serves as a robust mediator that reflects valve timing without being directly coupled to mechanical tolerances, thereby achieving both cost reduction and maintained precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves engine emissions by reducing valve timing errors, lowers system costs by eliminating sensors, and enhances robustness by using mechanical motion-based valve position measurement.
Implementation Method 1
estimating intake valve opening timing and estimating exhaust valve opening timing of a cylinder from output of a pressure sensor in the cylinder
Data Source
AI summary
Methods and systems are provided for controlling and monitoring intake and exhaust poppet valves of an internal combustion engine. In one example, the methods and system include feedback control that estimates intake and exhaust valve timing based on output of an in cylinder pressure sensor. In another example, the methods and system include compensation for feedforward control of intake and exhaust valves based on output of the in cylinder pressure sensor.