Variable Geometry Turbocharger Flow Rate Adjustment Method
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Solution Overview
Problem
Variable geometry turbochargers face challenges due to dimensional and mounting errors in power transmission members, leading to inaccuracies in nozzle opening adjustments, which can result in torque level differences and inefficiencies.
Innovation Solution
A flow rate adjustment method for variable geometry turbochargers that includes an actuator, power transmission member, stopper, and opening detection sensor, allowing for precise adjustment of nozzle openings by acquiring and storing abutment and temporary control position data, and using adjustment gas to measure and correct flow rates, thereby canceling combined errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a variable nozzle is driven by an actuator through multiple power transmission members to adjust the opening of the flow path, then the turbocharger can maintain appropriate supercharging pressure across different engine conditions, but dimensional errors and mounting errors of the power transmission members accumulate, leading to inaccuracies in the nozzle opening position
Solution Approach 1:
The patent employs a feedback mechanism where a learning means detects the actual supercharging pressure and compares it with the target pressure. Based on this comparison, the system calculates a correction value that compensates for errors in the power transmission members, thereby accurately controlling the nozzle opening position despite manufacturing tolerances.
Solution Approach 2:
The patent replaces direct mechanical precision requirements with an electronic control system. Instead of relying solely on precise mechanical dimensions and assembly of power transmission members, the system uses sensors, processors, and actuators to electronically adjust and compensate for mechanical errors, substituting mechanical precision requirements with electronic control accuracy.
2Reliability
If learning means is used to compensate for turbocharger individual differences by detecting supercharging pressure changes, then torque level consistency can be achieved, but the learning process takes time to complete, and torque level differences may occur during the transient stage before learning is finished
Solution Approach 1:
The patent performs preliminary characterization of the turbocharger's flow rate characteristics during the manufacturing process. By pre-measuring and storing the relationship between nozzle opening and flow rate for each individual turbocharger, the system eliminates the need for time-consuming learning during vehicle operation, providing immediate accurate torque control from startup.
Solution Approach 2:
The patent pre-compensates for individual turbocharger variations by characterizing each unit's specific flow rate characteristics before delivery to the customer. This beforehand cushioning ensures that torque level consistency is maintained from the first use, preventing torque fluctuations that would otherwise occur during the learning phase.
3Ease of manufacture
If the number of power transmission members is reduced to minimize dimensional and mounting errors, then manufacturing simplicity increases, but the ability to accurately control and adjust the nozzle opening across various flow rate requirements decreases
Solution Approach 1:
The patent employs a dynamically adjustable nozzle system where the opening position can be continuously varied based on real-time sensor feedback and pre-stored flow rate characteristics. This dynamic control allows a simple mechanical structure to achieve versatile adaptation to different operating conditions through electronic actuation and control algorithms.
Solution Approach 2:
The patent controls the nozzle opening by changing the actuator's drive signal parameters based on pre-measured flow rate characteristics and real-time operating conditions. By varying electrical control parameters rather than mechanical design parameters, the system achieves high adaptability with a simplified mechanical structure.
Data Source
AI summary
A flow rate adjustment method for a variable geometry turbocharger may include steps as follows. An adjustment apparatus drives an actuator to an abutment position where a power transmission member abuts a stopper. The apparatus acquires the abutment position opening amount based on an opening detection sensor's signal. The apparatus drives the actuator until the detection amount attains a pre-set amount, moving the power transmission member to a temporary control position. The apparatus acquires a temporary control position flow rate. It is acquired when an adjustment gas inflow apparatus causes the adjustment gas to flow into an exhaust turbine, and a flow rate measurement sensor measures the flow rate of the adjustment gas. The apparatus obtains a correction amount based on a difference between the temporary control position flow rate and a real control position flow rate, which is a proper flow rate corresponding to the pre-set amount.