Hydrogen Engine Blow-By Control for Crankcase Pressure Spikes
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Solution Overview
Problem
In hydrogen engines, blow-by gas containing moisture accumulates in the crankcase during cold operation, leading to abrupt pressure increases when moisture evaporates, potentially causing oil to be jetted into the intake passage.
Innovation Solution
A control device that includes a blow-by gas passage recirculating blow-by gas to the intake passage and limits engine power when the oil temperature exceeds a threshold temperature and crankcase pressure exceeds a threshold pressure, preventing oil ejection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the blow-by gas passage recirculates blow-by gas to the intake passage, then the blow-by gas is effectively recirculated, but the oil may be jetted into the intake passage when pressure rises abruptly
Solution Approach 1:
The control device applies preliminary anti-action by detecting the rising crankcase pressure caused by moisture evaporation and proactively limiting engine power before the pressure reaches a level that would cause oil ejection. This preventive measure counteracts the harmful effect of oil being jetted into the intake passage while maintaining the beneficial blow-by gas recirculation function.
2Object-affected harmful factors
If engine power is limited to prevent oil ejection, then oil jetting is suppressed, but engine performance is reduced
Solution Approach 1:
The control device implements dynamic power management by continuously monitoring crankcase pressure and oil temperature, and adjusting engine power output in real-time. The power limitation is applied only when moisture evaporation causes abnormal pressure rises, and is released when the conditions normalize, thereby dynamically balancing oil ejection prevention with engine performance maintenance.
Solution Approach 2:
The control device changes the operating parameters by limiting engine power specifically when the crankcase pressure exceeds a predetermined threshold and oil temperature is above a predetermined value. This parameter-based control allows the engine to operate at full power under normal conditions while preventing oil ejection only when moisture evaporation causes abnormal pressure conditions.
3Adaptability or versatility
If moisture accumulates in the crankcase during cold operation, then the engine can operate in cold conditions, but abrupt pressure increases occur when moisture evaporates
Solution Approach 1:
The control device employs feedback control by continuously monitoring crankcase pressure and oil temperature, and adjusting engine power output based on these measurements. When moisture evaporation causes pressure rises, the system detects this feedback and responds by limiting power to maintain pressure stability, thereby enabling cold operation while preventing abrupt pressure changes.
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
Suppresses the abrupt pressure increase and prevents oil from being ejected into the intake passage by controlling engine output, thereby maintaining engine performance and reducing potential damage.
Implementation Method 1
When the oil temperature rises along with continuation of the engine operation from this state, the moisture accumulated in the oil due to the blow-by gas starts to evaporate. Therefore, the pressure inside the crankcase rises abruptly.
Data Source
AI summary
The hydrogen engine includes a blow-by gas passage that recirculates the blow-by gas leaked from the combustion chamber to the crankcase from the crankcase to the intake passage. The threshold temperature is set in advance based on the temperature at which the water contained in the oil stored in the crankcase starts evaporation in the crankcase. The control device limits the output of the hydrogen engine from when the oil temperature, which is the temperature of the oil, exceeds the threshold temperature for a predetermined period of time.