Skip Fire Engine Induction Fault Detection
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Solution Overview
Problem
Current methods for diagnosing induction faults in internal combustion engines, particularly in skip fire and dynamic firing level modulation modes, are inadequate in detecting failures of intake valves and cam adjustments, leading to issues like unburnt hydrocarbons, increased engine roughness, and emission problems.
Innovation Solution
The use of intake manifold pressure monitoring and crankshaft angular acceleration measurements to detect induction faults, with diagnostic filters processing these signals to identify deviations from commanded operations, allowing for real-time fault detection and identification of specific cylinder issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If skip fire engine control is used to vary effective displacement, then fuel efficiency is improved, but induction faults are not detected leading to increased emissions
Solution Approach 1:
The patent implements a diagnostic system that continuously monitors intake manifold pressure and crankshaft angular acceleration to detect induction faults in real-time. When a fault is detected, the system provides feedback to the engine control unit, which can then adjust engine operation to prevent harmful emissions while maintaining fuel efficiency benefits of skip fire control.
Solution Approach 2:
The patent replaces traditional mechanical diagnostic methods with electronic sensing and signal processing. Intake manifold pressure sensors and crankshaft position sensors provide electrical signals that are processed by the engine control unit to detect induction faults, substituting mechanical inspection with electronic detection to enable real-time fault identification without compromising fuel efficiency.
2Adaptability or versatility
If complex valve control is used for dynamic skip fire, then finer displacement control is achieved, but device complexity increases
Solution Approach 1:
The patent employs a universal diagnostic approach that monitors multiple engine parameters (intake manifold pressure, crankshaft angular acceleration) using a single integrated system. The engine control unit processes signals from various sensors to detect multiple types of induction faults, providing multi-functional capability that manages complex valve control without requiring separate diagnostic systems for each parameter.
Solution Approach 2:
The patent introduces the engine control unit as an intermediary that coordinates complex valve control operations and diagnostic monitoring. The ECU receives signals from multiple sensors, processes them through diagnostic algorithms, and controls valve actuation based on detected conditions, simplifying the overall system architecture while enabling fine displacement control through centralized management.
3Object-generated harmful factors
If real-time fault detection is implemented, then emissions are reduced, but measurement precision requirements increase
Solution Approach 1:
The patent detects induction faults by analyzing multiple dimensions of engine operation simultaneously - intake manifold pressure variations and crankshaft angular acceleration changes. By monitoring faults across different operational dimensions rather than relying on a single measurement, the system achieves accurate fault detection with moderate precision requirements for each individual sensor.
Solution Approach 2:
The patent establishes baseline values for intake manifold pressure and crankshaft angular acceleration under normal operating conditions. The diagnostic system compares real-time measurements against these pre-established baselines to detect deviations indicating induction faults, allowing for real-time emission reduction without requiring extreme measurement precision by using relative rather than absolute threshold 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
This approach enhances engine efficiency, reduces emissions, and prevents component degradation by accurately detecting induction faults during the same engine cycle, improving the reliability of engine operation and compliance with regulatory standards.
Implementation Method 1
An air induction event generates a fluctuation in the intake manifold pressure, which is recorded.
Implementation Method 2
The measured angular acceleration is compared with a reference angular acceleration.
Data Source
AI summary
A variety of methods and arrangements for detecting failure of the commanded air induction in an internal combustion engine are described. In some embodiments, the intake manifold pressure is monitored. An air induction event generates a fluctuation in the intake manifold pressure, which is recorded. The signal is processed through a diagnostic filter to help determine whether the actual induction matched the commanded induction. In other embodiments, measured crankshaft acceleration is compared with estimated crankshaft acceleration. If the two quantities differ by a threshold amount an induction fault is detected. The two detection methods may also be combined. The describe approaches are particularly well suited for use in engines operating in a skip fire mode with cylinder deactivation and/or a dynamic firing level modulation mode.