Hybrid Vehicle Engine Control via Power Demand Filtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hybrid electric vehicles experience unintentional engine pull-up and pull-down due to rapid fluctuations in driver power demands, leading to inefficient fuel usage and reduced drivability.
Innovation Solution
A power distribution control system that calculates a filtered power demand to differentiate between intended and unintended power changes, preventing engine activation and deactivation based on a threshold difference, thereby inhibiting unnecessary engine starts and stops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the engine is activated or deactivated in response to power demand changes, then the vehicle can meet power demands efficiently, but unintended engine on/offs occur during rapid power demand fluctuations
Solution Approach 1:
The control system performs preliminary filtering of the power demand signal to predict the driver's true intent before making engine on/off decisions. By calculating a filtered power demand signal that smooths out rapid fluctuations, the system anticipates genuine power demand changes while ignoring transient noise, thereby preventing unintended engine activations or deactivations during rapid pedal movements
Solution Approach 2:
The system continuously monitors both the raw power demand signal and the filtered power demand signal, comparing them to detect when rapid fluctuations occur. This feedback mechanism allows the control system to identify unintended driver inputs and adjust engine operation accordingly, maintaining reliability while preserving responsiveness to genuine power demand changes
2Loss of energy
If the engine is frequently activated and deactivated to match power demand, then fuel economy can be improved, but drivability deteriorates due to unintended engine on/offs
Solution Approach 1:
By pre-filtering the power demand signal before it reaches the engine control logic, the system eliminates the need for frequent corrective engine on/off cycles that would result from reacting to transient fluctuations. This preliminary signal processing ensures that the engine operates continuously when genuinely needed while avoiding unnecessary shutdowns and restarts that would harm drivability
Solution Approach 2:
The continuous comparison between raw and filtered power demand signals creates a feedback loop that prevents unintended engine on/offs from occurring in the first place. This feedback mechanism maintains smooth drivability by ensuring engine state changes only occur when the filtered signal confirms a genuine, sustained power demand change
3Speed
If the engine control system responds quickly to power demand changes, then vehicle performance is maintained, but unintended engine on/offs increase during rapid pedal movements
Solution Approach 1:
The system performs preliminary filtering of the power demand signal at a rate that preserves genuine response speed while eliminating transient noise. By calculating the filtered power demand in advance and comparing it with the current power demand, the system maintains fast response to true driver intent while preventing reactions to momentary fluctuations during rapid pedal movements
Data Source
AI summary
A system and method for controlling a hybrid electric vehicle powertrain having an engine defining one power source, and a traction motor and electrical storage device defining another power source include inhibiting a stopping and a starting of the engine based upon an unintended tip-out event and an unintended tip-in event, respectively. The total power demand and the available electric power are determined. The total power demand is filtered. The engine is prevented from being pulled-up or pulled-down based upon a difference between the total power demand and the filtered power demand being exceeding a threshold. However, if the difference exceeds the threshold, and if the available electric power exceeds the total power demand, then the engine is permitted to pull-up or pull-down.