Air Intake Nozzle L>D Ratio Prevents Blow-by Gas Backflow
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Solution Overview
Problem
The existing air intake apparatus for internal combustion engines experiences a decrease in performance due to backflow of air into the external gas passage, leading to reduced engine efficiency and variability in gas distribution.
Innovation Solution
The air intake apparatus features external gas introduction nozzles with a length greater than their equivalent diameter, a tapered inner surface, and a rounded entrance, which increases pressure loss and prevents backflow, while being easily integrally molded with the apparatus, reducing size and component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a short path cutout is used to introduce blow-by gas into the air intake pipe, then the gas introduction efficiency is improved, but air backflow into the distribution passage occurs due to pulsation
Solution Approach 1:
The invention inverts the conventional short-path cutout design by using a long-path nozzle structure. Instead of minimizing the path length from distribution passage to air intake pipe, the patent deliberately extends the path length to L>D ratio to prevent backflow, transforming the harmful pulsation effect into a beneficial flow control mechanism.
Solution Approach 2:
The invention changes the geometric parameters of the gas introduction structure by specifying that the nozzle length L must be greater than its equivalent diameter D (L>D ratio). This parameter change fundamentally alters the flow characteristics, increasing pressure loss in the reverse direction and preventing air backflow into the distribution passage while maintaining effective gas introduction.
2Reliability
If air flows back from the air intake pipe to the distribution passage, then the engine performance decreases, but preventing backflow requires additional structural complexity
Solution Approach 1:
The long-path nozzle structure serves multiple functions simultaneously: it introduces blow-by gas into the air intake pipe, prevents air backflow into the distribution passage through its L>D geometry, and maintains simple integration with the existing air intake manifold structure. This multi-functionality avoids the need for additional separate components.
Solution Approach 2:
By changing the geometric parameters of the nozzle (length L greater than equivalent diameter D), the invention achieves backflow prevention through flow dynamics rather than mechanical barriers. This parameter-based solution maintains structural simplicity while reliably preventing air backflow and protecting engine performance.
3Object-generated harmful factors
If the external gas introduction nozzle has a long length relative to its diameter, then pressure loss increases to prevent backflow, but the nozzle size increases
Solution Approach 1:
The invention applies local quality by concentrating the length increase specifically at the nozzle section where flow control is needed, rather than increasing the overall system size. The L>D ratio requirement ensures that the extended length is localized to the critical gas introduction path, creating high pressure loss only where needed to prevent backflow while keeping the rest of the system compact.
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 design effectively prevents backflow, maintains engine performance, improves fuel economy, and enhances gas distribution uniformity, while reducing the size and complexity of the air intake system.
Implementation Method 1
the length of each of the external gas introduction nozzles in a direction in which the external gas introduction nozzles extend is larger than an equivalent diameter of an exit of each of the external gas introduction nozzles. Thus, the length of each of the external gas introduction nozzles is relatively large, and hence the pressure loss increases when air flows back from the air intake pipes to the external gas introduction nozzles.
Data Source
AI summary
In this air intake apparatus for an internal combustion engine, an external gas passage includes external gas introduction nozzles that introduce external gas into air intake pipes, and a length of each of the external gas introduction nozzles in a direction in which the external gas introduction nozzles extend is larger than an equivalent diameter of an exit of each of the external gas introduction nozzles.