Variable Geometry Turbocharger Engine Braking Control
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Solution Overview
Problem
Internal combustion engines, such as diesel engines, face limitations in engine braking power and exhaust gas temperature during engine braking procedures, leading to inefficient operation of exhaust aftertreatment systems and increased wear on wheel brakes.
Innovation Solution
A controller adjusts the components of a variable geometry turbocharger (VGT) and throttle valve based on the requested engine braking power and exhaust gas temperature to enhance braking power and temperature, ensuring efficient operation of the exhaust aftertreatment system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If engine braking is used to reduce wheel brake wear, then wheel brake wear is reduced, but braking power is limited and exhaust gas temperature decreases
Solution Approach 1:
The patent applies dynamics by making the turbocharger geometry adjustable during engine braking. The VGT turbine vane position is dynamically changed from a first position during power mode to a second position during engine braking mode, allowing the system to optimize exhaust gas flow and temperature dynamically rather than being fixed. This enables the system to adapt to different operating conditions and maintain high exhaust temperatures during braking.
Solution Approach 2:
The patent changes physical parameters of the exhaust system during engine braking. The EGR valve position is adjusted to increase exhaust gas recirculation, and the VGT turbine vane position is changed to optimize exhaust flow. These parameter changes increase both the exhaust gas temperature and the braking power, resolving the contradiction between limited braking power and the need to reduce wheel brake wear.
2Power
If gas is released to exhaust system during engine braking, then engine braking power is generated, but exhaust gas temperature decreases and aftertreatment system operates poorly
Solution Approach 1:
The VGT system dynamically adjusts the turbine vane position during engine braking to optimize exhaust gas temperature. By changing the vane angle, the system controls exhaust gas flow velocity and pressure, maintaining higher temperatures in the aftertreatment system even during braking when power is being generated.
Solution Approach 2:
The EGR system acts as an intermediary to manage exhaust gas temperature during engine braking. By recirculating exhaust gas back to the intake manifold and controlling the EGR valve position, the system maintains thermal energy in the exhaust stream, ensuring the aftertreatment system receives sufficiently hot gas for effective operation while still generating braking power.
3Temperature
If additional systems are added to heat exhaust gas and aftertreatment system, then exhaust gas temperature increases, but device complexity increases
Solution Approach 1:
The VGT and EGR systems perform multiple functions: they optimize engine performance during power mode, enable engine braking, and maintain exhaust gas temperature for aftertreatment. By making these existing components adjustable and controllable during engine braking, the patent avoids adding separate heating systems while achieving the same temperature maintenance goal, thereby reducing device complexity.
Solution Approach 2:
The exhaust system serves itself by using the existing VGT and EGR mechanisms to maintain exhaust gas temperature during engine braking. Rather than requiring external heating systems, the system uses its own components to regulate and maintain the necessary thermal conditions for aftertreatment operation, eliminating the need for additional heating equipment.
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 solution increases engine braking power and exhaust gas temperature, reducing the need for additional heating systems and minimizing wheel brake wear, while maintaining effective emissions control.
Implementation Method 1
causing, by the controller, one or more components of a variable geometry turbocharger (VGT) of the engine to adjust
Implementation Method 2
a throttle valve of the engine to adjust
Data Source
AI summary
A controller may identify an indication to initiate an engine braking procedure associated with an engine of a machine. The controller may obtain, based on identifying the indication to initiate the engine braking procedure, information relating to a requested amount of engine braking power of the engine. The controller may cause one or more components of a variable geometry turbocharger (VGT) of the engine to adjust, and a throttle valve of the engine to adjust, based on the information relating to the requested amount of engine braking power of the engine.