Hybrid Compressor Boost Pressure Distribution Control
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Solution Overview
Problem
Internal combustion engines face challenges in efficiently managing the compression of combustion air during transient vehicle operating conditions, as existing systems struggle to optimally distribute the boost pressure between electric driven compressors and exhaust driven turbochargers, leading to suboptimal performance and emissions.
Innovation Solution
A method and system that control the engine by defining a total pressure ratio target and a distribution factor to calculate and adjust the contributions of both the electric driven compressor and the exhaust driven turbocharger, ensuring optimal boost pressure distribution through equations and a combustion air control module, allowing for continuous recalibration during transient conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If only an exhaust driven turbocharger is used to compress combustion air, then the system is simpler, but the response during transient vehicle operating conditions is slow due to turbo lag
Solution Approach 1:
The patent combines an electric driven compressor and an exhaust driven turbocharger into a hybrid compressor system. The electric compressor provides immediate response during transient conditions, while the turbocharger handles steady-state operation, merging the advantages of both systems to eliminate turbo lag while maintaining manageable complexity.
Solution Approach 2:
The system dynamically switches between electric compressor and turbocharger based on operating conditions. During transient vehicle operating conditions, the electric compressor is activated to provide immediate boost pressure, while during steady-state conditions, the turbocharger takes over. This dynamic operation optimizes response speed across different driving scenarios.
2Productivity
If both electric driven compressor and exhaust driven turbocharger are used, then the boost pressure distribution can be optimized, but the control system complexity increases
Solution Approach 1:
The control system uses a distribution factor (a controllable parameter) to dynamically adjust the pressure ratio contribution of each compressor. By changing this parameter based on operating conditions, the system optimizes boost pressure efficiency without requiring complex multi-variable control algorithms, thus managing control system complexity.
Solution Approach 2:
The system continuously monitors actual boost pressure and compares it with target values, then adjusts the distribution factor accordingly. This feedback mechanism enables automatic optimization of the pressure ratio distribution between the electric compressor and turbocharger, achieving high productivity while keeping the control logic relatively simple through iterative adjustment.
3Speed
If the electric driven compressor provides all the pressure ratio, then the response to transient conditions is immediate, but the energy consumption increases
Solution Approach 1:
Instead of using the electric compressor at full capacity continuously, the system applies partial action by using it only when necessary (during transient conditions) and at the minimum required level to achieve the target pressure ratio. The distribution factor controls the electric compressor to provide only the necessary portion of pressure ratio, reducing energy consumption while maintaining responsive performance.
Solution Approach 2:
The system uses the vehicle's own exhaust energy to drive the turbocharger, which handles the majority of compression work during steady-state operation. This self-service approach converts waste exhaust energy into useful mechanical work, reducing the burden on the electric compressor and thereby reducing electrical energy consumption.
4Measurement precision
If the distribution factor is continuously adjusted during transient conditions, then the boost pressure control precision is improved, but the computational load increases
Solution Approach 1:
The system focuses computational effort on adjusting a single key parameter (the distribution factor) rather than simultaneously controlling multiple independent variables. This parameter reduction approach maintains pressure ratio control precision during transient conditions while significantly reducing the computational load compared to full-state control algorithms.
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 enables the engine system to provide consistent boost pressure across both transient and steady-state conditions, optimizing performance, reducing turbo lag, and minimizing CO2 emissions by effectively allocating the boost pressure between the electric compressor and the turbocharger based on real-time conditions.
Implementation Method 1
An electric driven compressor uses an electric device, such as an electric motor, to drive a compressor to compress the flow of combustion air
Implementation Method 2
An exhaust driven turbocharger uses the flow of exhaust gas from the internal combustion engine to drive a turbine, which in turn drives a compressor to compress the flow of combustion air
Data Source
AI summary
A method of controlling an engine system, having both an electric driven compressor and an exhaust driven turbocharger for compressing a flow of combustion air for an internal combustion engine, includes defining a total pressure ratio target for the flow of combustion air, and defining a distribution factor to calculate a first portion of the total pressure ratio target and a second portion of the total pressure ratio target. The sum of the first portion of the total pressure ratio target and the second portion of the total pressure ratio target is equal to the total pressure ratio target. The electric driven compressor is controlled to provide the first portion of the total pressure ratio target, and the exhaust driven turbocharger is controlled to provide the second portion of the total pressure ratio target.