Cylinder Deactivation Ignition Timing Control
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Solution Overview
Problem
Cylinder deactivation systems in internal combustion engines often result in noticeable torque shock and engine speed fluctuations during cylinder deactivation and activation events, leading to inefficiencies and discomfort for vehicle occupants.
Innovation Solution
The implementation of a cylinder deactivation control system that adjusts ignition timing and throttle control using predicted valve deactivation timing and an inverse servo throttle model to minimize torque shock, by advancing ignition timing for cylinders not to be deactivated and retarding it for those to be activated, and using inverse servo control to compensate for mechanical delays in the throttle system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If cylinder deactivation is implemented to reduce fuel consumption and emissions, then fuel efficiency and emissions are improved, but torque shock and engine speed fluctuations occur during deactivation and activation events
Solution Approach 1:
The system performs preliminary actions by advancing ignition timing for cylinders that will remain active and retarding ignition timing for cylinders that will be deactivated, before the actual deactivation event. This preliminary timing adjustment ensures that torque production is maintained or increased in active cylinders to compensate for the upcoming cylinder deactivation, thereby preventing torque shock when the deactivation occurs.
Solution Approach 2:
The system applies preliminary anti-action by anticipating the torque deficit that will result from cylinder deactivation and counteracting it in advance. By advancing ignition timing in active cylinders before deactivation, the system pre-compensates for the torque loss, effectively neutralizing the harmful torque shock effect before it can occur.
2Stability of the object's composition
If ignition timing is advanced for cylinders not to be deactivated to maintain torque, then torque stability is improved, but ignition system complexity increases
Solution Approach 1:
The system implements dynamic ignition timing adjustment based on real-time operating conditions. The control algorithm continuously monitors engine parameters such as load, speed, and temperature to determine the optimal ignition timing advance or retard for each cylinder, allowing the system to adapt to changing conditions while maintaining torque stability without requiring overly complex hardware.
Solution Approach 2:
The system changes ignition timing parameters dynamically based on the deactivation strategy and operating conditions. By adjusting ignition timing as a controllable parameter rather than using complex mechanical modifications, the system achieves torque stability through software-based control, reducing hardware complexity while maintaining performance.
3Stability of the object's composition
If throttle control is adjusted in advance of cylinder deactivation to compensate for mechanical delays, then transition smoothness is improved, but control system complexity increases
Solution Approach 1:
The system applies preliminary action to throttle control by calculating and implementing the required throttle position adjustment in advance of the cylinder deactivation event. By predicting the timing of the deactivation and pre-positioning the throttle, the system compensates for mechanical delays in the throttle actuator, ensuring smooth transition without requiring complex additional hardware.
Solution Approach 2:
The system uses feedback control to monitor actual throttle response and adjust the timing and magnitude of throttle commands accordingly. By continuously monitoring the throttle's actual position and response characteristics, the system fine-tunes the advance timing to compensate for mechanical delays, achieving smooth transitions through adaptive feedback rather than complex predetermined mechanisms.
Data Source
AI summary
A method of managing a number of active cylinders of an engine can be provided. The method comprises: determining for a current engine operating condition a number of active cylinders required for the current engine operating condition; if the determined number of active cylinders is different than a current number of active cylinders, selecting one or more cylinder which is to be activated or deactivated in order to provide the determined number of active cylinders; where one or more cylinders is to be activated, retarding ignition timing for a cylinder preceding in firing order the first firing of a first activated cylinder; and where one or more cylinders is to be deactivated, advancing ignition timing for a cylinder that is not to be deactivated and which precedes in firing order a first cylinder which is to be deactivated.