Cylinder Deactivation Timing Coordination for Engine Busyness Reduction
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Solution Overview
Problem
Existing engine technologies experience frequent and noticeable cylinder mode changes, leading to increased fuel consumption and discomfort for drivers due to the frequent deactivation and reactivation of engine cylinders, especially when driver demand torque varies with traffic conditions.
Innovation Solution
A method is developed to manage cylinder mode changes by adjusting the deactivation time of one cylinder based on the deactivation time of another, allowing for smoother transitions and reducing the frequency of mode changes by delaying or accelerating deactivation based on the likelihood of cylinder inactivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If cylinder deactivation is implemented to improve fuel economy, then fuel consumption is reduced, but frequent mode changes increase busyness and may still consume more fuel
Solution Approach 1:
The system performs preliminary action by predicting future cylinder deactivation needs based on current deactivation duration and driver behavior patterns. When a cylinder is currently deactivated, the system proactively adjusts the deactivation timing of other cylinders to coincide with the expected reactivation time, rather than waiting for torque changes to occur. This advance planning prevents frequent mode changes and reduces busyness.
Solution Approach 2:
The system implements dynamics by making the deactivation timing flexible and adaptive rather than fixed. The deactivation time for each cylinder is dynamically adjusted based on real-time conditions including current deactivation duration, predicted driver torque requests, and traffic conditions. This dynamic approach allows the system to optimize fuel economy while minimizing mode change frequency.
2Ease of operation
If cylinder deactivation timing is adjusted based on driver torque requests, then mode changes can be reduced, but large torque changes still cause frequent mode switching
Solution Approach 1:
The system uses preliminary action by predicting driver torque requests based on current traffic conditions and accelerator pedal position trends. Rather than reactively responding to torque changes, the system proactively schedules cylinder deactivations to occur when torque demand is predicted to remain stable, preventing frequent mode changes while maintaining adaptability to actual driver needs.
Solution Approach 2:
The system implements feedback by continuously monitoring actual driver torque requests and comparing them with predicted values. This feedback loop allows the system to learn from driver behavior patterns and refine its predictions, ensuring that deactivation scheduling remains adaptive to actual driving conditions while minimizing unnecessary mode changes.
3Ease of operation
If cylinders are locked out of deactivation modes to reduce busyness, then mode change frequency decreases, but fuel economy opportunities are lost
Solution Approach 1:
Instead of locking cylinders out of deactivation modes, the system uses preliminary action to predict when deactivation will occur and schedules other cylinder deactivations accordingly. This predictive approach maintains all fuel economy opportunities while reducing busyness by coordinating mode changes to occur at optimal times when torque demand is stable.
Solution Approach 2:
The system replaces the static lockout mechanism with a dynamic scheduling approach. Rather than preventing deactivation outright, the system dynamically determines the optimal timing for each cylinder deactivation based on current and predicted operating conditions. This dynamic scheduling maintains fuel economy benefits while coordinating mode changes to reduce busyness.
Data Source
AI summary
Systems and methods for operating an engine with deactivating and non-deactivating valves are presented. In one example, mode changes between deactivating cylinders is based on an amount of time a valve is deactivated, and the longer the valve is deactivated the sooner cylinder valves may be deactivated. If the amount of time the valve is deactivated is short, the time that valves may be deactivated may be delayed.