Engine Control System for Hydrocarbon Accumulation Detection
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Solution Overview
Problem
Existing engine control systems fail to effectively address cylinder torque imbalances caused by hydrocarbon accumulation, which can lead to engine degradation, as increasing internal EGR may not reduce hydrocarbon accumulation and can exacerbate imbalances, especially in engines with specific intake system configurations.
Innovation Solution
An engine control system that uses crankshaft acceleration differences and exhaust exotherm data to identify hydrocarbon accumulation at the intake, limiting engine speed and load to reduce further accumulation, and elevating engine temperatures to release accumulated hydrocarbons, thereby distinguishing and mitigating hydrocarbon-induced imbalances from other causes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If internal EGR is increased to address cylinder torque imbalances, then ignitability of the mixture is improved, but hydrocarbon accumulation is not reduced and may be exacerbated
Solution Approach 1:
The patent extracts the harmful hydrocarbons from the intake system by inducing a controlled reverse flow through the throttle body using negative manifold pressure, physically removing the accumulated hydrocarbons rather than attempting to burn them in place
Solution Approach 2:
The patent inverts the normal airflow direction by creating negative manifold pressure that causes reverse flow through the intake system, forcing hydrocarbons out through the air filter rather than allowing them to accumulate and burn in the cylinders
2Speed
If internal EGR is increased to address cylinder torque imbalances, then engine speed can be adjusted, but cylinder imbalances caused by hydrocarbon accumulation are not reduced
Solution Approach 1:
The patent extracts the root cause of cylinder imbalance by removing accumulated hydrocarbons from the intake system through reverse flow, rather than attempting to compensate for the imbalance through EGR adjustments
3Power
If internal EGR is increased during tip-in, then power control is achieved, but hydrocarbon release from charge air cooler is not improved
Solution Approach 1:
The patent performs preliminary action by clearing hydrocarbons from the charge air cooler and intake system before they can be forced into the engine during tip-in, preventing the problem rather than reacting to it
Solution Approach 2:
The patent extracts hydrocarbons from the charge air cooler using reverse flow induced by negative manifold pressure, removing them before they can enter the cylinders during transient conditions
4Productivity
If engine operation continues without addressing hydrocarbon accumulation, then engine runs normally, but hydrocarbons spread from affected cylinder to remaining cylinders causing further imbalances
Solution Approach 1:
The patent applies preliminary anti-action by detecting hydrocarbon accumulation early and inducing reverse flow to clear it before it can spread to other cylinders, preventing the propagation of the problem
Solution Approach 2:
The patent uses feedback from crankshaft acceleration monitoring to detect cylinder imbalances and trigger the hydrocarbon clearing process, creating a closed-loop control system that responds to actual engine conditions
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 approach effectively reduces primary and secondary engine degradation by accurately identifying hydrocarbon accumulation and limiting its impact, preventing further imbalance and component damage.
Implementation Method 1
cylinder imbalances are identified based on deviations in cylinder pressure peak timings from a predetermined timing range
Implementation Method 2
elevating engine temperatures to release accumulated hydrocarbons
Implementation Method 3
elevating engine temperatures to release accumulated hydrocarbons
Implementation Method 4
limiting engine speed and load to reduce hydrocarbon accumulation at an engine intake
Implementation Method 5
an elevated engine exhaust exotherm indicative of hydrocarbon oxidation
Data Source
AI summary
Methods and systems are provided for detecting hydrocarbon ingestion into an engine based on the simultaneous monitoring of cylinder imbalance and an elevated exhaust exotherm. Crankshaft acceleration data is monitored during steady-state and transient engine conditions while exhaust temperatures are estimated during non-regeneration conditions. Engine speed and load is limited to reduce further hydrocarbon ingestion.