Crank Chamber Vent Layout for Hydrogen Blow-By Discharge
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In engine systems using gaseous fuels with a specific gravity less than 1, such as hydrogen, blow-by gas tends to accumulate above the crank chamber, and there is a risk of backfire due to easy ignition, making efficient discharge and backfire countermeasures challenging.
Innovation Solution
The engine system incorporates a ventilation passage extending straight from the ventilation port along the up/down direction, efficiently discharging blow-by gas from the crank chamber, and includes a fuel supply unit to supply gaseous fuel to the intake port, with a dual-fuel capability for premix and diffusion combustion methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ventilation port is placed at the lower part of the crank chamber to facilitate blow-by gas discharge, then the discharge efficiency is improved, but liquid fuel accumulates at the lower part causing backfire
Solution Approach 1:
The ventilation port is positioned at a specific location (above center C1 in the up/down direction) where blow-by gas concentration is high but liquid fuel accumulation is minimized. This local optimization allows efficient gas discharge while avoiding the harmful effect of liquid fuel accumulation that causes backfire.
Solution Approach 2:
The ventilation port is oriented to communicate with the interior space Sp1 through a specific spatial arrangement. By considering the three-dimensional position and orientation of the port relative to the crank chamber geometry, the system achieves effective gas removal without creating conditions for liquid fuel pooling at the discharge location.
2Reliability
If the ventilation port is placed at the upper part of the crank chamber to avoid liquid fuel accumulation, then backfire is prevented, but blow-by gas discharge efficiency is reduced
Solution Approach 1:
The ventilation port is positioned at an optimized location (above center C1) that balances two competing requirements: it is high enough to avoid liquid fuel accumulation zones but low enough to remain in the path of rising blow-by gases. This local optimization resolves the contradiction between backfire prevention and gas discharge efficiency.
3Device complexity
If the ventilation port is placed at center C1 of the crank chamber, then structural symmetry is maintained, but blow-by gas discharge efficiency is insufficient
Solution Approach 1:
The ventilation port is deliberately positioned asymmetrically relative to center C1 (specifically above it in the up/down direction). This asymmetric placement optimizes the port's effectiveness in discharging blow-by gases by positioning it in a region where gas concentration and upward flow are maximized, sacrificing structural symmetry for functional performance.
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 effectively discharges blow-by gas and provides a robust backfire countermeasure, ensuring efficient operation and safety in hydrogen-fueled engines.
Implementation Method 1
blow-by gas with a specific gravity less than 1 with reference to air is generatable
Data Source
Figure 1
Figure 2
Figure 3
AI summary
[Problem] To provide an engine system that efficiently discharges blow-by gas from a crank chamber with ease, and that is capable of providing a further backfire countermeasure. [Solution] An engine system in which blow-by gas with a specific gravity less than 1 with reference to air is generatable includes a cylinder block 5. The cylinder block 5 includes a cylinder 51 and a crank chamber 52 which are arranged in an up/down direction D2, the crank chamber 52 being positioned below the cylinder 51. An internal peripheral face 501 of the cylinder block 5 has a ventilation port 502 that connects to a ventilation passage 503 that connects an internal space Sp1 of the crank chamber 52 with an external space out of the cylinder block 5, and that is open. The ventilation port 502 is placed above a center C1 in the up/down direction D2 in the crank chamber 52.