Engine Intake Air System with CAC Bypass and Heater
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Solution Overview
Problem
Internal combustion engines optimized for gasoline or diesel fuel struggle to efficiently operate with alternative fuels like propane and natural gas due to issues such as condensation in intake air systems and limitations in compression ratios, leading to suboptimal performance and increased emissions.
Innovation Solution
A hybrid intake air system with a charge air cooler, bypass line, and bypass heater, controlled by a system that adjusts intake air flow based on engine load and ambient temperature to prevent condensation and minimize airflow restrictions, allowing operation at higher compression ratios and improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a charge air cooler is used to cool intake air, then combustion efficiency is improved, but condensation occurs in the intake air system
Solution Approach 1:
The intake air cooling system is segmented into multiple parallel paths: a primary cooling path through the charge air cooler, and secondary bypass paths (including heated bypass and unheated bypass) that can be independently controlled. This segmentation allows selective routing of intake air to prevent condensation while maintaining cooling efficiency.
Solution Approach 2:
The system dynamically changes the temperature parameter of the bypass air by introducing a heater in one of the bypass paths. By controlling the heater activation, the system can raise bypass air temperature above dew point to prevent condensation when needed, while maintaining overall system efficiency.
2Object-affected harmful factors
If bypass lines are added to prevent condensation, then condensation is reduced, but airflow restrictions increase
Solution Approach 1:
Multiple bypass paths (heated bypass and unheated bypass) are merged into a single integrated system with common inlet and outlet connections to the charge air cooler. This merging allows the system to achieve condensation prevention functionality while minimizing overall airflow resistance through parallel flow paths.
Solution Approach 2:
The bypass system incorporates dynamic control through electronically controlled valves that can open or close different bypass paths based on operating conditions. This dynamic adjustment allows the system to minimize airflow restrictions by opening unheated bypass during conditions where heating is unnecessary, while maintaining condensation prevention when required.
3Ease of operation
If multiple valves are used to control intake air flow paths, then flow path control is improved, but system complexity increases
Solution Approach 1:
The electronically controlled valves are designed to perform multiple functions: controlling flow to the charge air cooler, directing flow to heated bypass, directing flow to unheated bypass, and coordinating with the heater control. This multi-functionality reduces the need for separate dedicated control components for each function.
Solution Approach 2:
The system incorporates feedback control where the controller monitors operating conditions (such as temperature, load, and condensation risk) and automatically adjusts valve positions and heater activation accordingly. This feedback mechanism simplifies operation by eliminating manual intervention while maintaining optimal performance across varying conditions.
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
The system effectively prevents condensation and reduces airflow restrictions, enabling engines to operate efficiently at higher compression ratios, improving performance and reducing emissions, while maintaining optimal power output and fuel efficiency.
Implementation Method 1
a charge air cooler positioned along the intake air circuit
Implementation Method 2
a bypass heater positioned along the intake air circuit in parallel with each of the charge air cooler and the bypass line
Implementation Method 3
a turbocharger that includes a compressor
Data Source
AI summary
An intake air circuit is structured to transmit intake air from a turbocharger compressor to an intake manifold of an engine. A charge air cooler (“CAC”), a bypass line, and a bypass heater are each positioned along the intake air circuit in parallel with each other. A first control valve is structured to controllably divert the intake air around the CAC. A second control valve is structured to controllably divert the intake air around at least one of the bypass line and the bypass heater. A controller operatively coupled to each of the engine, and the first and second control valves is structured to control each of the first and second control valves to cause the intake air to flow along a determined desired flow path based on each of measured ambient temperature and measured engine load.