Variable Active Fuel Management Delay Hybrid Start-Stop
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In hybrid vehicles with cylinder deactivation, the fixed time period for purging the hydraulic control system before deactivating cylinders results in a significant loss of fuel-saving opportunities, as it assumes worst-case conditions and does not account for varying engine temperatures and crankshaft states.
Innovation Solution
A control system that determines an engine time off value and estimates a re-purge time based on engine temperature and crankshaft states to allow earlier cylinder deactivation by using a re-purge determining module, which characterizes drain-back and purge times at different temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed time period is used to purge the hydraulic control system before cylinder deactivation, then the system ensures complete air purging under worst-case conditions, but it causes significant fuel loss due to unnecessary delay in cylinder deactivation
Solution Approach 1:
The patent applies dynamics by transitioning from a static fixed time delay to a dynamic variable delay that adapts to real-time engine conditions. The control system monitors engine temperature, crankshaft position, and hydraulic pressure to dynamically adjust the purge time, allowing cylinder deactivation to occur as soon as conditions permit rather than waiting for a predetermined fixed period to expire.
Solution Approach 2:
The patent implements parameter changes by using multiple sensor inputs (engine temperature, crankshaft position, hydraulic pressure) to vary the purge time parameter based on actual system state. When sensors indicate favorable conditions (e.g., engine already warm, crankshaft in appropriate position), the system reduces the purge delay parameter, enabling earlier cylinder deactivation and reducing fuel loss.
2Device complexity
If a fixed time period is used for hydraulic system purging, then the system maintains simplicity in control logic, but it fails to optimize fuel economy by not accounting for varying engine temperatures and crankshaft states
Solution Approach 1:
The patent applies universality by using a single control module that performs multiple functions: monitoring engine temperature, tracking crankshaft position, measuring hydraulic pressure, calculating optimal purge time, and controlling cylinder deactivation timing. This multi-functional approach avoids the need for separate dedicated systems for each monitoring and control task, maintaining reasonable system complexity while achieving optimized fuel economy.
Solution Approach 2:
The patent implements feedback by continuously monitoring engine conditions (temperature, crankshaft position, hydraulic pressure) and using this information to adjust the purge time in real-time. The system receives feedback from sensors and modifies its control strategy accordingly, creating a closed-loop control system that optimizes fuel economy while ensuring proper hydraulic purging.
Data Source
AI summary
A control system for a hybrid vehicle including an engine with cylinder deactivation comprises an engine time off module that determines an engine time off value. A re-purge determining module estimates a re-purge time required to purge a hydraulic control system of the engine of air before initiating cylinder deactivation. The re-purge time is estimated based on the engine time off value and an engine temperature.