Front-End Motor-Generator System for High-Torque Hybrid Engines
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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 torque transfer segment and a switchable coupling, allowing for flexible torque exchange between the engine crankshaft and motor-generator, enabling independent operation of engine accessories and supplemental propulsion, while minimizing space and weight requirements, using a combination of batteries and supercapacitors for energy storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If starter-generators are mounted at the front end of large commercial vehicle engines, then the system can serve both as engine starter and alternator, but the electric motor must be much larger to handle high torque demands, increasing weight, size, and cost
Solution Approach 1:
The system segments the starter and alternator functions into separate motor-generators (front-end motor-generator and rear-end motor-generator) rather than requiring one oversized motor to perform both functions. Each motor-generator is sized appropriately for its specific function, reducing overall weight and complexity.
Solution Approach 2:
The front-end motor-generator serves multiple functions including engine starting, alternator operation, and accessory drive, while the rear-end motor-generator handles propulsion assistance and regenerative braking. This distributed multi-functionality approach allows each component to be optimized for its specific roles.
2Force
If belt drive systems are enlarged to transfer high torque levels, then torque capacity increases, but the belts and pulleys become much larger and heavier, becoming weight, size, and cost prohibitive
Solution Approach 1:
The system replaces mechanical belt drive connections with direct mechanical couplings between the motor-generators and the engine crankshaft. This eliminates the need for oversized belts and pulleys, reducing weight and complexity while maintaining high torque transfer capacity through direct drive mechanisms.
3Adaptability or versatility
If multiple individual electric motors are used to drive engine accessories, then accessory power demands are met independently, but vehicle weight and system complexity increase significantly
Solution Approach 1:
The front-end motor-generator serves as a universal power source for multiple engine accessories (alternator, air compressor, coolant pump, etc.) through a single unified drive system. This reduces the number of separate electric motors needed while maintaining independent control capability through electronic modulation of the motor-generator output.
Solution Approach 2:
The system merges multiple accessory drive functions into a single front-end motor-generator unit that can independently control power delivery to various accessories. This consolidation reduces overall system complexity and weight compared to using separate electric motors for each accessory.
4Power
If auxiliary power units are used to meet accessory power demands, then power requirements are satisfied, but the units are costly and hazardous
Solution Approach 1:
The hybrid electric system enables the vehicle to serve its own power needs through the front-end motor-generator, which can independently generate electrical power for accessories without requiring external auxiliary power units. This self-sufficiency eliminates the cost and safety hazards associated with traditional 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 solution enhances fuel efficiency, reduces emissions, and eliminates the need for heavy auxiliary power units by allowing the motor-generator to operate as both a generator and motor, providing supplemental torque and power to the engine and accessories, thereby improving overall system efficiency and reducing parasitic loads on the engine.
Implementation Method 1
a motor-generator (3) arranged in front of the engine, away from the crankshaft end of the engine
Implementation Method 2
using a combination of batteries and supercapacitors for energy storage
Implementation Method 3
using a combination of batteries and supercapacitors for energy storage
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.