Hybrid Vehicle ISGM Launch Control With Clutch-Coupled Engine Start
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Solution Overview
Problem
Hybrid electric vehicles face challenges in efficiently managing engine starting during vehicle launch, particularly in single machine parallel hybrid vehicles where the electric machine must provide starting torque while propelling the vehicle.
Innovation Solution
The system employs an integrated starter/generator/motor (ISGM) coupled to the internal combustion engine via a clutch assembly, allowing the ISGM to operate as a starter, generator, and traction motor. During vehicle launch, the ISGM provides initial torque through the torque converter, and the engine is coupled to the ISGM once it reaches a predetermined speed, with the lock-up clutch engaged later based on speed and efficiency considerations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the electric machine provides starting torque for the engine while simultaneously propelling the vehicle during launch, then the vehicle can achieve movement, but the energy efficiency deteriorates
Solution Approach 1:
The patent segments the launch process into distinct phases: initial launch phase where the electric machine provides torque through the torque converter, and subsequent phase where the engine is engaged. This temporal segmentation allows optimization of energy efficiency at different stages while maintaining launch capability.
Solution Approach 2:
The engine is pre-started by the electric machine before the vehicle launch begins. This preliminary action ensures the engine is already running and can immediately contribute torque when engaged, avoiding the inefficiency of starting the engine during the launch process itself.
2Use of energy by moving object
If the lock-up clutch is engaged early to transmit torque, then the torque transmission efficiency is improved, but the engine speed control flexibility deteriorates
Solution Approach 1:
The lock-up clutch engagement is made dynamic and conditional rather than fixed. The control system monitors multiple parameters (engine speed, vehicle speed, throttle position) and adjusts clutch engagement timing accordingly, allowing the system to optimize between torque efficiency and speed control flexibility based on real-time conditions.
Solution Approach 2:
The system changes the operational parameters of the lock-up clutch based on engine speed thresholds. The clutch is engaged only when engine speed exceeds a predetermined threshold, transforming the clutch state from a static component to a dynamically controlled element that adapts to changing operational parameters.
3Use of energy by moving object
If the engine is coupled to the electric machine at high speed, then the engine efficiency is improved, but the vehicle acceleration performance deteriorates
Solution Approach 1:
The engine is pre-started by the electric machine before the vehicle launch begins. This preliminary action ensures the engine is already running and can immediately contribute torque when engaged, avoiding the inefficiency of starting the engine during the launch process itself.
Solution Approach 2:
The torque converter serves as an intermediary between the electric machine and the engine during the transition phase. It allows smooth torque transfer and speed matching, enabling the engine to be coupled at optimal speeds without compromising acceleration performance through abrupt connections.
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 enables efficient engine starting and vehicle propulsion during launch, optimizing energy usage and improving fuel efficiency by leveraging the multi-functional capabilities of the ISGM and precise control of the clutch and torque converter.
Implementation Method 1
the ISGM provides initial torque through the torque converter
Data Source
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Figure 2A
Figure 2B
AI summary
A method for operating an engine and an integrated starter/generator/motor (ISGM) disposed in a hybrid electric vehicle, which includes launch and deceleration processes. The ISGM is used to both launch the vehicle and start the engine. The deceleration process includes operating a first clutch to disengage the engine from the ISGM during an initial phase, and engaging a second clutch during the initial phase to direct substantially all regenerative energy to provide the only source of electrical energy to recharge the energy storage device.