Multi-mode Powertrain Engine State Selection
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Solution Overview
Problem
Current powertrain systems face challenges in optimizing engine operating states between all-cylinder and cylinder deactivation modes to balance fuel economy, emissions, and drivability, as they lack efficient methods to determine the preferred operating points based on output torque requests and system costs.
Innovation Solution
A method is implemented to execute searches for determining engine operating points in both all-cylinder and cylinder deactivation states, using a search scheme to converge on preferred engine speeds and loads, and an analytic framework to calculate powertrain system operating costs, allowing the system to select the most cost-effective state for operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the engine operates in all-cylinder state to meet output torque requests, then power output and drivability are improved, but fuel economy deteriorates
Solution Approach 1:
The system dynamically switches between all-cylinder and cylinder deactivation states based on real-time operating conditions, torque requests, and search results. The engine operating state is not fixed but adapts continuously to optimize the trade-off between power output and fuel consumption.
Solution Approach 2:
The system changes the operational parameters of the engine by deactivating specific cylinders under certain conditions. This parameter change allows the engine to reduce fuel consumption during low-load operations while maintaining the capability to operate in all-cylinder mode when high power is required.
2Use of energy by moving object
If the engine operates in cylinder deactivation state to improve fuel economy, then fuel consumption is reduced, but power output and drivability deteriorate
Solution Approach 1:
The system dynamically transitions between cylinder deactivation and all-cylinder states based on changing torque requests and operating conditions. When power demand increases, the system quickly switches to all-cylinder mode to maintain drivability and power output.
Solution Approach 2:
The system performs preliminary searches in both all-cylinder and cylinder deactivation state spaces before making a state selection. This preliminary action ensures that when the system needs to switch states, it can do so efficiently with pre-calculated operating points available.
3Use of energy by moving object
If frequent switching between all-cylinder and cylinder deactivation states occurs to optimize fuel economy, then fuel consumption improves, but system reliability and drivability deteriorate
Solution Approach 1:
The system performs searches in both possible state spaces (all-cylinder and cylinder deactivation) beforehand and compares results. This cushioning approach prevents abrupt or unnecessary state transitions by having pre-evaluated options ready, ensuring smoother transitions and more reliable operation.
Solution Approach 2:
The system uses feedback from operating cost calculations and search results to determine when state transitions are beneficial. By continuously monitoring operating conditions and comparing costs of different states, the system avoids unnecessary switching and maintains stability while optimizing fuel consumption.
4Use of energy by moving object
If the system performs comprehensive searches in both all-cylinder and cylinder deactivation state spaces to select optimal operating points, then operating cost optimization improves, but computational complexity increases
Solution Approach 1:
The search space is segmented into two distinct state spaces: all-cylinder state space and cylinder deactivation state space. Each space is searched independently, allowing the system to manage complexity by dividing the overall optimization problem into manageable segments.
Solution Approach 2:
The search process is dynamic and adaptive. The system adjusts its search strategy based on current operating conditions, torque requests, and preliminary results. This dynamic approach allows comprehensive optimization without requiring exhaustive searches in all possible states.
Data Source
AI summary
A method for operating a powertrain system including a multi-mode transmission configured to transfer torque among an engine, torque machines, and a driveline, includes executing a first search to determine a first engine operating point within an all-cylinder state and a corresponding operating cost for operating the powertrain system in response to an output torque request. A second search is executed to determine a second engine operating point within a cylinder deactivation state and a corresponding operating cost for operating the powertrain system in response to the output torque request. One of the first and second engine operating points is selected as a preferred engine operating point based upon the operating costs and the engine is controlled at the preferred engine operating point in the corresponding one of the all-cylinder state and the cylinder deactivation state.