Hybrid Powertrain Neutral Torque Error Mitigation
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Solution Overview
Problem
Hybrid powertrain systems face challenges in maintaining neutral operation without mechanical decoupling, leading to undesirable vehicle motion due to torque errors, which results in lost functionality and inefficient energy management.
Innovation Solution
A powertrain system with an internal combustion engine, electric machines, and an electro-mechanical transmission that enables neutral operation by coordinating torque commands between the engine and electric machines to establish a net zero output torque condition, using a first clutch to dissipate excess torque through slippage when a torque error is detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hybrid powertrain system is shutdown after a short period during neutral operation to prevent undesirable vehicle motion, then vehicle safety is improved, but lost functionality of auxiliary components occurs
Solution Approach 1:
A clutch device is introduced as an intermediary component between the transmission and driveline to mechanically decouple them during neutral operation. This allows the powertrain to remain running (maintaining auxiliary component functionality) while the clutch prevents torque transmission that would cause undesirable vehicle motion, thus resolving the contradiction between safety and functionality.
2Adaptability or versatility
If the powertrain system maintains continuous operation during neutral operation, then auxiliary components remain functional, but undesirable vehicle motion occurs due to torque error
Solution Approach 1:
The clutch acts as a mechanical intermediary that can be engaged to disconnect the driveline from the transmission during neutral operation. This allows continuous powertrain operation (maintaining auxiliary functionality) while preventing torque errors from causing vehicle motion, as the clutch physically interrupts the torque path to the wheels.
3Object-affected harmful factors
If a clutch is activated to mechanically decouple the driveline from the transmission during neutral operation, then undesirable vehicle motion is prevented, but device complexity increases
Solution Approach 1:
The clutch is designed to serve multiple functions: it enables neutral operation by mechanical decoupling, facilitates gear shifting operations, and supports various transmission modes. By making the clutch multi-functional rather than dedicated solely to neutral operation, the added complexity is justified by the versatility it provides across multiple operational scenarios.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows the powertrain to maintain neutral operation without mechanical decoupling, preventing undesirable vehicle motion and enabling efficient energy management by allowing slippage in the clutch to dissipate excess torque, thus maintaining vehicle functionality and supporting auxiliary components during engine idle operation.
Implementation Method 1
slippage of the first clutch is allowed to dissipate net output torque from reacting with the driveline of the powertrain system
Data Source
AI summary
A powertrain system includes an internal combustion engine, at least one electric machine and an electro-mechanical transmission operative to transmit torque to a driveline. A method for controlling the powertrain system includes enabling neutral operation of the transmission in response to an operator input, activating a first clutch coupled to a first planetary gear set, the first planetary gear set which includes a first element, a second element and a third element. Torque commands are coordinated between the engine and a first electric machine to establish a net zero output torque condition. If a violation of the net zero output torque condition is present, slippage of the first clutch is allowed to dissipate net output torque from reacting with the driveline of the powertrain system.