Front-End Motor-Generator with Switchable Coupling
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Solution Overview
Problem
Existing hybrid electric vehicle systems face challenges in scaling up to handle high-torque outputs of large engines, particularly commercial diesel engines, due to engineering difficulties and inefficiencies in energy management, leading to increased weight, cost, and complexity, as well as the need for auxiliary power units that are costly and hazardous.
Innovation Solution
A hybrid electric vehicle system with a front-end motor-generator arrangement that includes a switchable coupling and torque transfer segment, allowing for flexible torque exchange between the engine crankshaft and motor-generator, enabling independent operation of engine accessories and reducing parasitic loads, and utilizing a combination of batteries and supercapacitors for energy storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional belt-driven alternator and starter motor are used, then the system is simple and reliable, but the weight and cost increase due to duplicate components
Solution Approach 1:
The patent combines the alternator and starter motor functions into a single integrated motor-generator unit. This unit can operate as a generator during braking to recover energy and as a motor to assist propulsion or start the engine, eliminating the need for separate alternator and starter components while maintaining system reliability
Solution Approach 2:
The motor-generator unit performs multiple functions: it acts as a generator during regenerative braking, as a motor for propulsion assistance, and as a starter motor for engine ignition. This multi-functionality reduces component count and weight while improving overall system efficiency
2Power
If the motor-generator is positioned behind the engine, then torque can be delivered directly to the driveline, but the system complexity and weight increase when scaling to commercial vehicle engines
Solution Approach 1:
The patent employs a switchable coupling mechanism that dynamically connects or disconnects the motor-generator from the engine crankshaft based on operating conditions. This allows the system to adapt between different operational modes (engine-driven generator mode, motor-assist mode, independent accessory mode) without increasing structural complexity
Solution Approach 2:
The system is divided into independent functional segments: the engine, the motor-generator unit, and the accessory drive system. Each can operate independently or in coordination through the switchable coupling, allowing flexible configuration and reducing overall system complexity
3Device complexity
If engine accessories are always connected to the crankshaft, then the system is simple, but parasitic loads increase fuel consumption
Solution Approach 1:
The accessory drive system uses switchable couplings that dynamically connect or disconnect accessories from the engine crankshaft based on operational needs. When an accessory is not required, it is disconnected to eliminate parasitic loading on the engine, thereby reducing fuel consumption
Solution Approach 2:
The system automatically manages accessory operation based on real-time conditions. The control system monitors engine load, vehicle speed, and accessory requirements to determine when accessories should be engaged or disengaged, optimizing fuel efficiency without manual intervention
4Power
If auxiliary power units are used to provide additional power, then the power availability increases, but the weight, cost, and safety hazards increase
Solution Approach 1:
The patent integrates the motor-generator unit directly with the engine's accessory drive system, combining multiple functions (generation, motor assist, starting) into a single compact unit. This eliminates the need for separate auxiliary power units while maintaining power availability
Solution Approach 2:
The motor-generator unit serves multiple purposes: it generates electricity during braking, provides propulsion assistance, and can start the engine. This multi-functionality provides sufficient power availability across different operating conditions without requiring heavy auxiliary power units
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 configuration minimizes engine accessory energy consumption, recovers wasted energy, and extends component life by allowing accessories to operate only when needed, reducing brake wear and fuel consumption, while eliminating the need for heavy auxiliary power units and conventional alternators.
Implementation Method 1
A dynamic heat generator, preferably shaft-driven hydrokinetic device in which a fluid is sheared to generate heat in the fluid
Implementation Method 2
The hydrokinetic device may be a shaft-driven device in which a fluid is forced through a valve or orifice to generate hydraulic power
Data Source
AI summary
A system and method are provided for hybrid electric internal combustion engine applications in which a motor-generator, a narrow switchable coupling and a torque transfer unit therebetween are arranged and positioned in the constrained environment at the front of an engine in applications such as commercial vehicles, off-road vehicles and stationary engine installations. The motor-generator is preferably positioned laterally offset from the switchable coupling, which is co-axially-arranged with the front end of the engine crankshaft. The switchable coupling is an integrated unit in which a crankshaft vibration damper, an engine accessory drive pulley and a disengageable clutch overlap such that the axial depth of the clutch-pulley-damper unit is nearly the same as a conventional belt drive pulley and engine damper. The front end motor-generator system includes an electrical energy store that receives electrical energy generated by the motor-generator when the coupling is engaged. When the coupling is disengaged, the motor-generator may drive the pulley portion of the clutch-pulley-damper to drive the engine accessories using energy returned from the energy store, independent of the engine crankshaft.