Inlet Valve Blockage Detection via Exhaust Oxygen Monitoring
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Solution Overview
Problem
The existing methods for detecting blockages in intake valves of indirect injection systems in motor vehicles are inadequate, leading to fuel accumulation and potential catalyst degradation due to unburned fuel being sent to the exhaust, especially when the cylinder disconnection system fails, causing reliability issues and increased emissions.
Innovation Solution
A method involving fuel injection into a cylinder to detect combustion in the engine or catalyst using probes placed upstream and downstream of the catalyst, measuring mixture richness to diagnose valve blockages and ensure reliable cylinder disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If cylinder disconnection is deployed to reduce pumping losses and meet CO2 emission targets, then fuel economy is improved, but reliability deteriorates due to potential valve blockage detection failure
Solution Approach 1:
The patent performs a diagnostic test before normal operation by injecting fuel and attempting to initiate combustion. This preliminary action reveals valve blockage issues before they cause harmful fuel accumulation and catalyst damage during actual engine operation.
Solution Approach 2:
The patent uses oxygen sensors to monitor exhaust gas composition and provide feedback on combustion status. By analyzing oxygen levels upstream and downstream of the catalyst, the system can detect whether fuel is burning in the engine or accumulating and burning in the catalyst, thereby identifying valve blockages.
2Productivity
If fuel injection is performed in cylinders supposed to produce torque, then combustion should occur, but fuel accumulates in intake ducts when inlet valves are blocked in closed position
Solution Approach 1:
The patent performs a diagnostic fuel injection test to detect valve blockages before normal fuel injection begins. By attempting to ignite a small amount of fuel and monitoring combustion, the system identifies blocked valves that would otherwise cause harmful fuel accumulation during productivity-critical operation.
Solution Approach 2:
The patent takes preliminary diagnostic action to prevent the harmful effect of fuel accumulation. By detecting valve blockages before normal operation, the system prevents the scenario where fuel injection for torque production would lead to fuel trapping and subsequent catalyst damage.
3Ease of operation
If accumulated fuel is re-sucked from active cylinders when injection is cut off, then fuel is distributed to other cylinders, but combustion cannot be initiated due to exceeding lower flammability limit
Solution Approach 1:
The patent uses oxygen sensors to provide feedback on the composition of exhaust gases. By monitoring oxygen levels, the system can detect when fuel is not burning in the engine (indicating valve blockage) and is instead being sent to the exhaust, where it would cause harmful catalyst temperature increases.
Solution Approach 2:
The patent converts the harmful effect of unburned fuel reaching the exhaust into a useful diagnostic signal. By monitoring oxygen levels downstream of the catalyst, the system detects when fuel accumulates and burns in the catalyst rather than the engine, thereby identifying valve blockages that would otherwise cause undetected harmful emissions.
4Reliability
If catalyst combustion occurs due to unburned fuel, then temperature increases rapidly, but this causes degradation of the post-treatment system
Solution Approach 1:
The patent performs a preliminary combustion test by injecting and igniting fuel under controlled conditions. This diagnostic action verifies that the combustion system is functioning properly before normal operation, preventing scenarios where unburned fuel would later cause harmful catalyst temperature spikes and degradation.
Solution Approach 2:
The patent uses oxygen sensors to monitor combustion completeness and provide feedback on engine health. By detecting abnormal oxygen levels that indicate fuel is not burning in the engine, the system can identify valve blockages before they cause harmful fuel accumulation and catalyst damage during normal operation.
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 method effectively detects blockages in intake valves, preventing fuel accumulation and catalyst degradation by accurately identifying combustion events, thereby enhancing the reliability of the cylinder disconnection system and reducing emissions.
Implementation Method 1
The first and the second probe can be capable of measuring the oxygen content of the mixture passing through the exhaust line
Implementation Method 2
In the catalyst, the thermodynamic conditions will be met (accumulation of fuel, presence of air and strong thermal exhaust) to initiate combustion
Data Source
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AI summary
The subject matter of the invention is a method for detecting the blocking of at least one inlet valve in the closed position in an indirect injection system of a motor vehicle, the vehicle being provided with an internal combustion engine comprising cylinders each fitted with an inlet valve and an exhaust line provided with a catalyst, characterised in that the method comprises: - an injection of fuel into at least one cylinder of the engine by the opening of the inlet valve of the cylinder, said injection resulting in the combustion of the fuel if the inlet valve is open, - stopping of the injection in all the cylinders, - after the stopping of the injection, a step to detect if combustion is taking place in the engine or in the catalyst, - detecting the blocking of at least one inlet valve in the closed position if combustion is detected in the engine and/or in the catalyst.