Turbocharged Two-Stroke Exhaust Bypass for Low Back Pressure
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Solution Overview
Problem
Two-stroke engines with turbochargers face inefficiencies due to increased back pressure, leading to performance hindrances and turbo lag.
Innovation Solution
An exhaust system with a valve that controls the flow of exhaust gas, allowing it to bypass the turbocharger, minimizing back pressure and optimizing air charging for improved engine performance, while also enabling rapid turbocharger spool-up.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a turbocharger is added to compress air for improved combustion efficiency, then air charging and power are improved, but back pressure increases causing performance hindrance and turbo lag
Solution Approach 1:
The exhaust system incorporates a variable geometry design with movable diverters that dynamically adjust the exhaust flow path based on operating conditions. This allows the system to optimize between turbocharger engagement and bypass modes, reducing back pressure when the turbo is not spooled while maintaining air charging when needed
Solution Approach 2:
The exhaust system is segmented into multiple independent flow paths including a primary exhaust path through the turbocharger and alternative bypass paths. This segmentation allows selective routing of exhaust gases to either drive the turbocharger or bypass it, eliminating the need to choose between power and low back pressure
2Power
If exhaust gas is directed through the turbocharger to compress intake air, then air charging is improved, but turbo lag occurs due to delayed turbocharger spool-up
Solution Approach 1:
The system maintains exhaust flow through the turbocharger pathway even when full power is not required, keeping the turbocharger partially spooled and ready. This preliminary action reduces the time needed for turbo spool-up when sudden power demands occur, eliminating turbo lag while maintaining the capability for effective air charging
3Speed
If a bypass conduit is added to reduce back pressure, then engine response is improved, but system complexity increases
Solution Approach 1:
The bypass conduits and diverters are integrated into the existing exhaust system architecture rather than being added as separate external components. The diverters are positioned within the exhaust collector and routing channels, merging the bypass functionality with the primary exhaust path to minimize additional complexity while maximizing performance benefits
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 enhances engine response time and power by reducing turbo lag and back pressure impact, providing optimal air charging and rapid turbocharger activation.
Implementation Method 1
The compression of the air by the turbocharger may be of particular importance when the internal combustion engine is operated in environments where atmospheric pressure is low or when the air gets thinner.
Implementation Method 2
The back pressure flowing into the turbocharger is generally higher than the pressure for entry of the exhaust gas entering the bypass such that the exhaust will generally flow into the bypass, bypassing the turbocharger, when the valve is opened.
Data Source
AI summary
A vehicle and a method of supplying a fuel-air mixture in an engine thereof. The vehicle includes a frame; at least one ground-engaging member connected to the frame; an engine supported by the frame, the engine having an engine air inlet and an exhaust outlet; a plurality of fuel injectors operatively connected to the engine for injecting fuel thereinto; and a system controller for controlling the plurality of fuel injectors. The method includes determining a pressure differential between an intake air pressure of air flowing toward the engine and an exhaust gas pressure of exhaust gas flowing out of the engine; determining, based on at least the pressure differential, an amount of fuel to be injected into the engine; and injecting the amount of fuel into the engine.