Exhaust Pressure Governor Bypass for Engine Brake Control
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Solution Overview
Problem
Existing engine brake systems face challenges in accurately controlling exhaust backpressure over a wide range, particularly in combining a Variable Geometry Turbine (VGT) with an Exhaust Pressure Governor (EPG) to achieve efficient engine braking while maintaining a compact design and minimizing interference with engine operation.
Innovation Solution
The system incorporates an EPG located in a bypass conduit connected upstream of the turbo arrangement, with a valve arrangement allowing for stepless control of backpressure, and a VGT in the main exhaust conduit to manage backpressure levels, enabling efficient engine braking and heating functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an EPG is integrated with a VGT to control exhaust backpressure, then engine braking performance is improved, but the system complexity and difficulty of controlling the VGT for accurate backpressure regulation increase
Solution Approach 1:
The exhaust system is segmented into a main exhaust conduit and a bypass conduit. The EPG is placed in the bypass conduit to create backpressure when needed, while the main conduit remains open for normal exhaust flow. This segmentation allows independent control of backpressure generation without complicating the overall system architecture.
Solution Approach 2:
The backpressure control function is extracted from the VGT and placed in a separate EPG device located in the bypass conduit. This extraction allows the EPG to handle backpressure regulation independently, simplifying the control requirements for each component and improving overall system reliability.
2Reliability
If the EPG is placed in the main exhaust conduit, then backpressure control is achieved, but the system size increases and interference with normal engine operation occurs
Solution Approach 1:
The exhaust system is divided into main and bypass conduits. The EPG is installed only in the bypass conduit, which has smaller dimensions than the main exhaust conduit. This segmentation reduces the overall system size while maintaining backpressure control capability when the bypass is activated.
Solution Approach 2:
The bypass conduit acts as an intermediary pathway that allows the EPG to influence exhaust backpressure without being directly in the main exhaust flow path. This intermediary approach minimizes interference with normal engine operation while enabling backpressure control when needed.
3Volume of stationary object
If the EPG exhaust conduit size is reduced, then system size is minimized, but the ability to provide desired backpressure over a wide range is limited
Solution Approach 1:
The system uses dynamic switching between the main exhaust conduit and the bypass conduit with EPG. The bypass conduit with EPG is activated when backpressure is needed (engine braking), while the main conduit handles normal exhaust flow. This dynamic configuration allows a small EPG to provide the required backpressure range without needing to handle the full exhaust flow capacity.
Solution Approach 2:
The bypass conduit with EPG serves multiple functions: it provides backpressure control for engine braking, and can be integrated with the VGT system to work across a wide pressure range. The EPG's smaller size is sufficient because it only needs to regulate backpressure, not handle the complete exhaust flow.
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 configuration allows for precise control of backpressure, reducing system size and minimizing backpressure when not needed, while ensuring efficient engine operation and compact design, effectively addressing the limitations of previous systems.
Implementation Method 1
An Exhaust Pressure Governor (EPG) located in a bypass conduit which is connected to said main exhaust conduit upstream the connection to the turbine of the turbo arrangement... the EPG being controllable to provide a desired backpressure
Implementation Method 2
A bypass conduit (9) connected to said main exhaust conduit (4) upstream the turbo arrangement (5)... a Variable Geometry Turbine (VGT), having its turbine connected to the main exhaust conduit
Data Source
Figure 1~2
AI summary
The invention relates to an engine brake system and a method for controlling the exhaust gas pressure of an exhaust system for a vehicle provided with an engine (1). The system comprising a main exhaust gas conduit (4) connected to the turbine (6) of a turbo arrangement (5) and an Exhaust Pressure Governor (EPG) (10) which is used to create a backpressure in the exhaust system so as to function as an engine brake. The turbo arrangement (5) comprises a Variable Geometry Turbine (VGT). The system is characterised in that the Exhaust Pressure Governor (10) is located in a bypass conduit (9) which is connected to said main exhaust conduit (4) upstream the connection to the turbine (6) of the turbo arrangement (5) and that the main exhaust conduit comprises a valve arrangement (6, 10, 13, 14) downstream the bypass conduit (9) connection for closing the main exhaust conduit (4). According to the method for controlling the system, the flow passage through the main conduit (4) is open and the flow through the bypass conduit (9) is closed in response to an output control indicating that no engine braking is desired. In case there is an output control indicating that engine braking is desired, the flow passage through the main conduit (4) is closed and the flow through the bypass conduit (9) is open whereby the EPG (10) is controlled to provide a 0 desired backpressure according to the control signals from the control system (12).