Front-End Motor-Generator System for High-Torque Hybrid Vehicles
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Solution Overview
Problem
Existing hybrid electric vehicle systems face challenges in scaling up to handle high-torque output engines, particularly commercial 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, which pose safety hazards and inefficiencies.
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 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
1Weight of stationary object
If starter-generators are mounted at the front end of the engine to reduce weight and cost, then weight and cost are reduced, but the system becomes difficult to adapt to large commercial vehicle diesel engines with high torque demands
Solution Approach 1:
The system is divided into two separate motor-generators: a first motor-generator coupled to the front end of the engine for starting and accessory driving, and a second motor-generator coupled to the rear end for regenerative braking and supplemental propulsion. This segmentation allows each motor-generator to be optimized for its specific function and engine size, with the front motor-generator remaining compact while the rear motor-generator handles high torque recovery.
Solution Approach 2:
The patent transitions from a single front-mounted motor-generator to a dual motor-generator arrangement utilizing both front and rear engine ends. This spatial dimensionality change enables the system to handle high torque demands of commercial vehicles while maintaining the benefits of front-mounted starting capability.
2Force
If belt drives are enlarged to handle high torque demands of commercial vehicles, then torque capacity is increased, but the drive belts and pulleys become so much larger and heavier that they are weight, size and cost prohibitive
Solution Approach 1:
The patent replaces the mechanical belt drive system with direct mechanical coupling of motor-generators to the engine crankshaft at both front and rear ends. This eliminates the need for enlarged belts and pulleys, as the motor-generators directly transfer torque through rigid connections to the driveline, achieving high torque capacity without proportional increases in belt and pulley size and weight.
3Use of energy by moving object
If multiple individual electric motors are used to drive engine accessories to reduce fuel consumption, then fuel consumption is reduced, but vehicle weight, cost, and wiring harness complexity significantly increase
Solution Approach 1:
The first motor-generator mounted at the front end of the engine is designed to perform multiple functions: engine starting, driving accessory components during engine operation, and providing supplemental propulsion. This multi-functionality eliminates the need for separate electric motors for each accessory, reducing wiring harness complexity and control system requirements while maintaining fuel consumption benefits.
4Adaptability or versatility
If auxiliary power units are used to meet accessory power demands independently, then independent operation is achieved, but safety hazards and inefficiencies are introduced
Solution Approach 1:
The dual motor-generator system enables the vehicle to service its own power needs through regenerative braking (second motor-generator) and front-mounted motor-generator assistance. The first motor-generator can drive accessories independently when needed, while the second motor-generator recovers energy during braking, eliminating the need for separate auxiliary power units and their associated safety hazards.
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 and an electrical energy storage system have been the focus of considerable attention in the automotive field
Implementation Method 2
recapture energy which would otherwise be wasted (such as mechanical energy from braking that would otherwise be dissipated as thermal energy to the environment) and return of the captured energy at another time when needed
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.