Fuel Cutoff Transition Control for Engine Torque Stability
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Solution Overview
Problem
Traditional engine control systems for internal combustion engines lack precision in controlling engine output torque and fail to provide rapid responses to control signals, leading to inefficient engine operation and potential engine shutdowns due to faults.
Innovation Solution
An engine control system comprising a fuel cutoff module, a fuel control module, and a spark control module that determines a feed-forward number of cylinders to offset fuel supply delays and maintains a predetermined torque request, along with fully retarded spark timing to minimize vibration and maintain engine performance during fuel cutoff events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional engine control systems transition to engine shutdown when faults are diagnosed, then engine reliability is improved, but engine productivity deteriorates due to complete shutdown
Solution Approach 1:
The engine control system segments the engine into multiple independently controllable cylinders. When a fault is detected, the system can selectively disable only the affected cylinder( s) while maintaining operation of other cylinders, rather than shutting down the entire engine. This allows the engine to continue producing power at reduced capacity, balancing reliability with productivity.
Solution Approach 2:
The control system dynamically adjusts the number of active cylinders based on real-time fault conditions and operational requirements. The system can transition between different operating modes (full power, reduced power, shutdown) and selectively activate/deactivate cylinders to optimize the balance between reliability and productivity based on current conditions.
2Measurement precision
If fuel supply delay is not compensated, then device complexity is reduced, but torque control precision deteriorates
Solution Approach 1:
The control system performs preliminary actions by calculating and compensating for the known fuel supply delay before it affects torque output. When a cylinder is deactivated or activated, the system anticipates the delay in fuel injection and adjusts the timing and amount of fuel supply to other cylinders accordingly, maintaining precise torque control without requiring complex real-time adjustment mechanisms.
3Ease of operation
If spark timing is not retarded, then engine power is improved, but vibration increases during fuel cutoff transition
Solution Approach 1:
The control system applies preliminary anti-action by retarding spark timing in advance during the transition out of fuel cutoff mode. This preemptive spark timing adjustment counteracts the potential for excessive vibration and rough operation that would occur if normal spark timing were restored immediately, ensuring a smooth transition while minimizing harmful vibrations before they can manifest.
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
The system enables precise control of engine torque output, reduces vibration, and allows for efficient transition out of fuel cutoff events, enhancing engine performance and fuel efficiency by rapidly adjusting fuel supply and spark timing.
Implementation Method 1
commanding fuel be supplied to the FF number of cylinders of the engine
Implementation Method 2
maintaining a spark timing of the FF number of cylinders at a fully retarded spark timing
Implementation Method 3
combust an air and fuel mixture within cylinders to drive pistons, which produces drive torque
Data Source
AI summary
An engine control system includes a fuel cutoff (FCO) module, a fuel control module, and a spark control module. The FCO module, when a FCO event is disabled, determines a feed-forward (FF) number of cylinders to offset a delay period associated with supplying fuel to the cylinders of an engine and selectively maintains a FCO torque request at a predetermined torque. The fuel control module commands fuel be supplied to the FF number of cylinders of the engine when the FCO event is disabled. The spark control module maintains a spark timing of the FF number of cylinders at a fully retarded spark timing based on the FCO torque request.