PCV Valve Failure Detection Using Intake Pressure Changes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing failure detection device for blow-by gas recirculation apparatuses in engines cannot effectively detect failures of the PCV valve without increasing the number of components, leading to higher size and cost.
Innovation Solution
A failure detection device that uses an intake pressure changing unit and an intake amount detecting unit to determine the operating condition of the engine, allowing for the detection of PCV valve failures during deceleration operations without additional dedicated sensors or components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated gas pressure sensor is provided in the blow-by gas recirculation passage to detect pressure, then gas leakage and gas clogging can be detected, but the number of components increases, resulting in increased device size and cost
Solution Approach 1:
The patent reuses existing components (intake amount detecting unit and intake pressure changing unit) for their original engine control functions while simultaneously enabling PCV valve failure detection. The intake amount detecting unit detects both intake air flow for engine control and blow-by gas recirculation abnormalities, while the intake pressure changing unit controls intake pressure for engine operation and creates detection conditions for PCV valve status. This multi-functionality eliminates the need for dedicated failure detection components.
2Reliability
If a cutoff valve is added to the blow-by gas recirculation passage to detect PCV valve failure, then PCV valve failure can be detected, but the number of components increases further, increasing device size and cost
Solution Approach 1:
The system uses the engine's own operating conditions and existing sensors to detect PCV valve failure. During deceleration operation with fuel supply cutoff, the engine naturally creates negative pressure in the intake passage, and the intake amount detecting unit measures the resulting air flow. This self-service approach eliminates the need for external cutoff valves or additional active components to create detection conditions.
3Reliability
If additional components are added for failure detection, then detection accuracy improves, but device cost increases
Solution Approach 1:
The patent makes existing components serve dual purposes: the intake amount detecting unit performs both engine air flow measurement and PCV valve failure detection, while the intake pressure changing unit performs both engine intake pressure control and creates detection conditions. This eliminates the need for additional expensive sensors and actuators, maintaining cost-effectiveness while achieving reliable failure detection.
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
Enables effective detection of PCV valve failures without increasing the number of components, thus maintaining device size and cost efficiency.
Implementation Method 1
a PCV valve configured to be operated in response to negative pressure to regulate a flow rate of blow-by gas in the blow-by gas recirculation passage
Implementation Method 2
an intake pressure changing unit to change intake pressure in the intake passage downstream of the intake regulating valve
Data Source
AI summary
An engine includes a EGR valve to regulate a EGR flow rate. A blow-by gas recirculation passage allows blow-by gas generated in the engine to flow in a surge tank to return to the engine. A PCV valve operates in response to negative pressure to regulate a blow-by gas flow rate in the recirculation passage. During deceleration fuel cutoff of the engine, an ECU holds a throttle valve at a predetermined slight opening degree and controls the EGR valve to be forcibly opened from a valve-closed state to change intake pressure (negative pressure) in the surge tank and determines whether or not the PCV valve is in sticking failure based on changes in intake amount detected by an air flow meter before and after the negative pressure changes.