Hybrid Powertrain Engine State Transition Path Planning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hybrid powertrain systems face challenges in efficiently managing engine states and torque transitions to optimize fuel economy, emissions, and performance, particularly in responding to operator torque requests and varying driving conditions.
Innovation Solution
A method for operating a hybrid powertrain system that involves monitoring operator torque requests, determining preferred engine states and torque levels, planning an engine state transition path, and adjusting engine torque to achieve optimal engine states and torque levels, utilizing a multi-cylinder engine coupled with a hybrid transmission and electric machines to manage torque and rotational speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the engine operates in a limited number of main states to simplify control, then the device complexity is reduced, but the ability to optimize fuel economy and emissions across varying driving conditions deteriorates
Solution Approach 1:
The engine operation is segmented into discrete main states (e.g., idle, part-load, full-load states) with specific torque ranges. By dividing the continuous operating range into segmented states, the control system achieves simplicity while still providing multiple optimized operating points for different driving conditions, resolving the contradiction between control simplicity and adaptability.
Solution Approach 2:
The system dynamically transitions between discrete main states based on real-time operator torque requests and driving conditions. This dynamic state switching allows the engine to adapt to varying conditions while maintaining the simplicity of discrete state control, balancing device complexity with optimization capability.
2Speed
If the engine transitions directly between main states to respond quickly to torque requests, then the response speed is improved, but torque ripple and transient emissions increase
Solution Approach 1:
The system determines an engine state transition path that includes intermediate engine transition states before reaching the preferred main state. This preliminary action of planning a multi-step transition path allows the engine to prepare for state changes in advance, reducing abrupt torque changes and emissions while maintaining responsive overall transition speed.
Solution Approach 2:
Intermediate engine transition states act as mediators between main engine states. These transition states serve as buffer zones that smooth the torque transition, reducing torque ripple and emissions during state changes while still enabling quick response to operator torque requests through efficient transition path planning.
3Power
If the engine adjusts torque rapidly to meet operator requests, then the performance and acceleration are improved, but fuel consumption and emissions during transient operation increase
Solution Approach 1:
The control system preliminarily determines an optimal transition path that includes intermediate states before executing torque adjustments. This advance planning allows the engine to transition through fuel-efficient intermediate states, reducing transient fuel consumption while still achieving rapid overall torque response for vehicle acceleration.
Solution Approach 2:
The system changes engine operating parameters (torque, speed, air-fuel ratio) in controlled steps through intermediate transition states rather than abrupt changes. This staged parameter adjustment reduces energy loss during transients while maintaining the ability to deliver high power when needed for acceleration, balancing performance with fuel efficiency.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A powertrain system includes a multi-cylinder engine (14) coupled to a hybrid transmission (10). The engine (14) is selectively operative in one of a plurality of main engine states to transfer engine torque to the hybrid transmission (10). A method for operating a powertrain system (10) includes monitoring an operator torque request, determining a preferred main engine state and a preferred engine torque associated with the preferred engine state, determining an engine state transition path from a present main engine state to the preferred main engine state including an engine transition state, and executing the engine state transition path between the present main engine state and the preferred main engine state and adjusting engine torque to the preferred engine torque.