Front-End Motor-Generator Coupling for Independent Accessory Drive
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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 vehicle diesel engines, due to engineering difficulties and inefficiencies in energy management, leading to increased weight, cost, and complexity, as well as limitations in independently meeting accessory power demands without 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, while using a combination of batteries and supercapacitors for energy storage to optimize energy management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional belt-driven alternator and starter motor are used, then the engine can start and generate electrical power, but the system requires duplicate heavy components increasing weight and cost
Solution Approach 1:
The patent combines the starter motor and alternator functions into a single integrated motor-generator unit. This unit can operate as a motor to start the engine and as a generator to produce electrical power, eliminating the need for separate starter and alternator components, thereby reducing weight and cost while maintaining both functions
2Force
If starter-generators are mounted at the front end of large commercial vehicle engines, then the electric motor can handle high torque demands, but the belt drive becomes prohibitively large and heavy
Solution Approach 1:
The patent extracts the belt drive from the torque transmission path by directly coupling the motor-generator unit to the engine crankshaft. This direct coupling eliminates the need for a heavy-duty belt drive system that would be required to handle high commercial vehicle engine torques, significantly reducing weight while maintaining torque handling capacity
Solution Approach 2:
The patent introduces a fluid coupling as an intermediary between the motor-generator unit and the engine crankshaft. This fluid coupling allows for flexible torque exchange without requiring a rigid mechanical connection or heavy belt drive, enabling the system to handle high torque demands while keeping the belt drive system small and lightweight
3Power
If the motor-generator is directly coupled to the engine crankshaft, then torque can be efficiently transferred, but the system lacks flexibility in independently managing engine accessories
Solution Approach 1:
The patent segments the torque transmission system by introducing a switchable coupling between the motor-generator unit and the engine accessories. This allows the system to operate in different modes: directly coupled for efficient torque transfer, or decoupled for independent accessory management, providing both torque efficiency and operational flexibility
4Power
If the engine runs continuously to power accessories during idling, then accessory power demands are met, but fuel consumption and emissions increase
Solution Approach 1:
The patent enables the motor-generator unit to serve the engine accessories independently during idle conditions. When the engine is shut off, the motor-generator can draw power from the battery to operate essential accessories, eliminating the need for continuous engine operation and thereby reducing fuel consumption and emissions while still meeting accessory power demands
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
The system efficiently manages energy, reduces fuel consumption and emissions, and eliminates the need for heavy starter motors and auxiliary power units, providing improved vehicle performance and reduced weight and cost by allowing the engine to be shut off during idling, while also enabling regenerative braking and supplemental propulsion torque.
Implementation Method 1
a motor-generator (3) arranged in a front end region of the engine (8)... capable of being directly driven by the driveline (102) of the vehicle (100), with the clutch-pulley-damper unit (19) allowing for flexible torque exchange between the engine crankshaft (47) and the motor-generator (3)
Implementation Method 2
The controller (13) is programmed to control the operation of the motor-generator (3) and clutch-pulley-damper unit (19) to maximize the generation of electrical energy during braking, deceleration, or negative torque events
Data Source
AI summary
A system and method for integrated electrification of vehicle accessories conventionally driven by an internal combustion engine includes an electric motor coupled to a common accessory drive that drive a plurality of accessories, such as a power steering pump, an air conditioning compressor, an air compressor, a thermodynamic heater and/or a coolant pump. The integrated electrified accessory unit preferably has the electric motor, accessory drive and accessories arranged in a common housing which is configured to be mounted to a chassis frame rail of the vehicle, the common housing including wall penetrations which facilitate rapid connection of the accessories to external lines of the vehicle.