Engine Braking Device Using Exhaust Bypass Nozzles
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Solution Overview
Problem
Existing engine braking systems for multi-cylinder internal combustion engines face limitations in increasing braking power without requiring complex and costly modifications to the exhaust gas turbocharger, such as those involving variable turbine geometry or specialized turbines.
Innovation Solution
A device that allows complete shutdown of each exhaust gas collection line during engine braking, with a bypass line branching off to nozzle bores in the turbine housing, directing high-pressure exhaust gas jets tangentially onto the turbine wheel to enhance turbocharger acceleration and boost pressure, thereby increasing braking performance without complex installations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If variable turbine geometry (VTG) is used to increase braking performance, then braking power is improved, but device complexity and cost increase significantly
Solution Approach 1:
The exhaust gas flow is segmented into two separate paths: a main exhaust gas collection line and a bypass line. The bypass line branches off before the shut-off valve and directs a portion of exhaust gas through nozzle bores onto the turbine wheel, while the main line can be completely shut off. This segmentation allows independent control of exhaust gas flow for braking enhancement without complex turbine geometry changes.
Solution Approach 2:
Nozzle bores are introduced as intermediary elements in the bypass line to direct exhaust gas jets onto the turbine wheel at specific angles. These nozzle bores serve as a simple mechanical intermediary that achieves the desired flow direction and pressure distribution without requiring variable turbine geometry or complex internal turbine modifications.
2Power
If shut-off flaps are used to block exhaust gas collection lines, then braking performance is improved, but device complexity increases
Solution Approach 1:
The exhaust system is divided into two independent collection lines, each with its own shut-off valve. This segmentation allows one line to be completely blocked while the other maintains flow through the bypass, enabling effective braking without requiring complex multi-stage shut-off mechanisms in a single line.
Solution Approach 2:
Instead of requiring complete shutdown of all exhaust lines, the invention uses partial action by allowing one exhaust collection line to remain open with flow through the bypass, while the other line is completely shut off. This partial approach achieves sufficient braking performance with simpler valve requirements.
3Power
If turbine-internal modifications are implemented to increase braking performance, then braking power is improved, but manufacturing cost increases
Solution Approach 1:
The braking enhancement function is extracted from the turbine internal geometry and relocated to the external bypass line with nozzle bores. This extraction allows the turbine itself to remain a conventional, easily manufactured component, while the braking enhancement is achieved through externally added bypass piping and simple nozzle openings in the turbine housing.
Solution Approach 2:
The bypass line with nozzle bores serves as a simple, inexpensive addition that achieves the braking enhancement function without requiring expensive custom turbine manufacturing. The solution uses readily available piping and simple drilling operations rather than complex turbine blade geometries.
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 significantly increases braking performance by accelerating the turbocharger and introducing compressed air into the combustion chambers, allowing for a simpler design of service brakes and retarders, while maintaining a conventional turbocharger structure.
Implementation Method 1
directing high-pressure exhaust gas jets tangentially onto the turbine wheel
Implementation Method 2
high-pressure exhaust gas jets
Implementation Method 3
exhaust gas turbine and a charge air compressor
Implementation Method 4
charge air compressor
Data Source
Figure 1~2
Figure 3~4
Figure 5~8
AI summary
The combustion chambers of the internal combustion engine (1) has two exhaust gas header pipes (5,6), each connected to an inlet of a single flow exhaust gas turbine (9) of a turbosupercharger (4) though the nozzle bores. The supply of exhaust gas streams from the header pipes to the turbine is controlled using throttle valves (10,11).