Internal Combustion Engine Air Bypass Valve Pressure Release
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Solution Overview
Problem
Existing internal combustion engines face challenges in quickly reducing pressure inside the intake system when switching from a lean combustion mode to a stoichiometric combustion mode, leading to low response and temporary torque variation due to the inability to efficiently release excess compressed air.
Innovation Solution
The engine employs a strategy where the throttle valve's opening degree is reduced, and an air bypass valve is temporarily opened to bypass supercharged intake air from the downstream side of the throttle valve to the upstream side of the compressor, facilitating the quick reduction of pressure inside the collector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the throttle valve is closed to reduce intake air amount when switching from lean combustion mode to stoichiometric combustion mode, then the target air-fuel ratio is achieved, but the response is slow and temporary torque variation occurs due to inability to quickly release pressure in the closed space downstream of the throttle valve
Solution Approach 1:
A pressure release valve is introduced as an intermediary component between the throttle valve and the engine cylinder. This valve temporarily opens to release excess pressure from the closed space downstream of the throttle valve, enabling quick pressure reduction without compromising the air-fuel ratio control. The pressure release valve acts as a mediator that resolves the conflict between maintaining precise air-fuel ratio and achieving fast response during mode transition.
2Productivity
If the air bypass valve is positioned upstream of the throttle valve, then compressed air can be bypassed, but the pressure in the closed space downstream of the throttle valve cannot be released
Solution Approach 1:
The air bypass system is segmented into two distinct functional parts: (1) an upstream bypass valve that handles normal bypass operations, and (2) a downstream pressure release valve that specifically addresses pressure release in the closed space. This segmentation allows each component to perform its specialized function effectively, ensuring both bypass efficiency and pressure control reliability during mode transitions.
3Adaptability or versatility
If the throttle valve is located downstream of the compressor, then the engine can be switched between combustion modes, but the region downstream of the throttle valve becomes a closed space that cannot release pressure through the air bypass valve
Solution Approach 1:
A pressure release valve is positioned downstream of the throttle valve to act as a mediator for releasing pressure from the closed space. This additional component enables the system to maintain the beneficial arrangement of having the throttle valve downstream of the compressor while resolving the pressure release issue, thereby preserving combustion mode switchability without excessive complexity.
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 enhances the response to the reduction in intake air amount during mode switching, suppressing torque variation by rapidly releasing pressure and ensuring a smooth transition between combustion modes.
Implementation Method 1
an air bypass valve communicating with a position more on a downstream side than the throttle valve is temporarily opened to bypass intake air inside a collector to the upstream side of the compressor
Data Source
Figure 1
Figure 2
Figure 3(a)~3(i)
AI summary
An internal combustion engine (1) is provided with a turbocharger (2), and is configured to be switchable between a stoichiometric combustion mode having a theoretical air-fuel ratio as a target air-fuel ratio and a lean combustion mode having a lean air-fuel ratio as a target air-fuel ratio. An air bypass valve (20) is provided in an air bypass passage (19) communicating a collector (11a) on the downstream of a throttle valve (12) with the upstream side of a compressor (2b) in an intake passage (11). At the time of the shifting from the lean combustion mode to the stoichiometric mode, the throttle valve (12) is closed and the air bypass valve (20) is temporarily opened to decrease the pressure inside the collector (11a) quickly.