Turbocharger Variable Speed Control via Planetary Gear Brake
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Solution Overview
Problem
Turbochargers face responsiveness issues at lower engine speeds and exhaust temperatures, where the exhaust gas torque is insufficient to power the compressor wheel, leading to reduced engine efficiency and increased pollutant emissions.
Innovation Solution
A turbocharger variable speed control mechanism using a planetary gear set and a brake actuator mechanism, allowing the engine output shaft to drive the turbocharger shaft through a non-braking or full braking state, ensuring the turbocharger operates effectively even at low exhaust gas conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a turbocharger is powered solely by exhaust gas turbine wheel, then it can rotate at high speeds and be more efficient, but it becomes less responsive at lower engine speeds and lower exhaust temperatures and pressures
Solution Approach 1:
The system dynamically switches between two operating modes: at low engine speeds, the clutch engages to mechanically couple the turbocharger to the engine output shaft for direct drive; at higher speeds, the clutch disengages to allow exhaust gas-driven operation. This dynamic transition resolves the contradiction by adapting the power transmission mode to current operating conditions.
Solution Approach 2:
A one-way overrunning clutch acts as an intermediary mechanism between the engine output shaft and the turbocharger shaft. It allows the engine to drive the turbocharger when needed while permitting the turbocharger to operate independently when exhaust energy is sufficient, thus mediating between mechanical drive and exhaust-driven operation.
2Speed
If a one-way overrunning clutch is used to allow engine output shaft to drive the turbocharger, then responsiveness improves at low engine speeds, but the system becomes more complex
Solution Approach 1:
The one-way overrunning clutch is a passive device that automatically engages and disengages based on rotational speed differential without requiring external control signals or active components. This self-regulating behavior adds minimal complexity while achieving the desired responsiveness improvement.
3Productivity
If the turbocharger is mechanically driven by the engine through a belt or gear train, then it provides air pump capability at low engine horsepower output, but it cannot rotate at speeds as high as exhaust-driven turbochargers
Solution Approach 1:
The system dynamically transitions from mechanical drive at low speeds to exhaust gas drive at high speeds. The clutch mechanism enables this dynamic reconfiguration, allowing the turbocharger to achieve high rotation speeds when exhaust energy is available while providing mechanical drive assistance when engine output is low.
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
Enhances turbocharger responsiveness and efficiency by enabling direct drive from the engine at low speeds, reducing pollutant emissions and improving engine performance across a range of operating conditions.
Implementation Method 1
a brake actuator mechanism disposed proximate the brake disk and mounted to a turbocharger housing of the turbocharger to remain stationary relative to the turbocharger housing. The brake actuator mechanism may be selectively actuatable between a non-braking state where the brake actuator mechanism does not apply a braking force to the brake disk... and a full braking state where the brake actuator mechanism applies a full braking force to the brake disk such that the ring gear is held stationary relative to the turbocharger housing
Data Source
AI summary
A turbocharger variable speed control mechanism for a turbocharger for an engine includes a sun gear of a planetary gear set coupled to a turbocharger shaft, a planet carrier operatively connected to an engine output shaft of the engine, a brake disk coupled to and rotatable with a ring gear, and a brake actuator mechanism proximate the brake disk and mounted to a turbocharger housing. The brake actuator mechanism is selectively actuatable between a non-braking state where no braking force is applied to the brake disk so that the ring gear is free to rotate relative to the turbocharger housing, and a full braking state where a full braking force is applied to the brake disk such that the ring gear is held stationary relative to the turbocharger housing and rotation of the planet carrier is transmitted through the planetary gear set to cause rotation of the turbocharger shaft.