Eco-design and Validation of In-Wheel Concept for Electric Vehicles
Background & policy context
Promotion of Electric Vehicles is strategic for the European Community, but nowadays battery performance is still poor and all forecasts for near future transport electrification suggest that A-B class EV cars with limited range are the first step to develop. Even in the actual economic crisis, global demand of A-B class cars is expected to grow by about 5.3% in 2010, with a positive sale scenario in the next years. In-wheel electric motor architecture holds major advantages for these A-B class, allowing high modularisation of the vehicle architecture, increased interior space and improved driveability. However, current existing solutions for in-wheel motor are still in prototype phases, resulting in non-existence of A-B class EV car commercialized and equipped with in-wheel motor, even though the predicted market for this technology is 100K vehicles for 2015.
The main objective of this proposal is the design, development and validation of a complete in wheel motor assembly prototype (electric motor, power electronics, reduction gear, structural parts and wheel), based on a McPherson corner suspension topology, to meet the defined car top level specifications.
The main technical risks associated with the use of an in-wheel concept are the thermal stress under extreme operation conditions, vehicle dynamics, driveability, safety and durability. The proposed baseline concept will be based on an air cooled motor in wheel concept, with conventional airflow driven by vehicle, and forced airflow provided by an innovative wheel design. Detailed specifications of extreme operation conditions will be defined and validated by the OEM, during the project, including the hot day-cold day conditions, representative of vehicle extreme use. During the assembly and testing phase, the aspects related to vehicle dynamics, driveability, safety, user acceptance, reliability, previously defined, will be validated with the motor in wheel prototypes installed in a test vehicle. In addition, aspects as eco-design, LCA of the concept and components, dismantling and recyclability of key materials and rare earths will be considered during the in-wheel concept design.
Motor efficiency map improvement based on real representative driving cycle (mix of USA-FTP75 – USA Highway – NEDC, total 100 Km) not on peak efficiency.
Air cooling, integration simplicity. Air cooling is a very challenging target, and offers market penetration competitive advantages.
Power electronics integrated in the motor cover with cooling capabilities
Rotor. Polymeric composite with assembled magnets able to withstand high rotation velocity.
Effective integration of gearbox oil circuit to remove heat generated in the motor stator.
WP1: E-CORNER SPECIFICATIONS
The preliminary requirements and specifications of the DoW, used during the preparation of the proposal, will be defined in detail by PIN, in order to establish the required performance of the EUNICE solution and the acceptance criteria for different aspects. The baseline E-corner option is air cooled with wheel integrated power electronics and motor, proposed in order to develop a solution that would meet the above stated performance requirements while responding to the proposal objectives. The mentioned baseline is to be assessed and evaluated during this WP, using multi domain simulation and optimization tools (theoretical assessment). If the optimisation of the baseline concept is not able to meet the requirements, a series of alternatives will be evaluated, until an acceptable motor in wheel solution is achieved, taking into account performance, vehicle dynamics-driveability, safety, endurance and user acceptance. To summarize, the main objectives of this WP are:
- To define in detail the specifications and performance of the EUNICE solution, oriented to a B-segment type vehicle.
- To perform a functional analysis of each of the sub-modules that will integrate the e-corner, in order to define the basic requirements for their design.
- To analyze the EUNICE proposed baseline design and alternatives, based in their performance and their fulfilment of the proposal objectives.
- To select the best concept which will be developed in the following WP´s.
- To continue the patent study, covering all the components that will be developed within the project.
WP2: ELECTRICAL COMPONENTS
This work-package is committed to the development and manufacturing of the electrical components of the e-corner, the e-motor, and power electronics, together with their related sub-systems such as cooling system and safety system. These components will be designed, manufactured and evaluated. Their design will follow the eco-design guidelines, from WP1. Also, LCA, material benchmarking and dismantling/recycling of the rare earths, will be analysed when designing the e-motor. In detail, the objectives of this work-package are:
- To design the e-motor and power electronics, following an effective eco-design guidelines.
- To develop the cooling system, specific for the e-motor and power electronics.
- To develop the optimum motor control strategy for the E-corner application.
- To manufacture the e-motor and power electronic components.
- To assemble the sub-system, and to carry on performance and functionality tests, ensuring that the manufactured components meet the specifications and objectives.
- To define the safety systems related to the operation of the e-corner.
WP3: ACTIVE WHEEL
- To optimize the weight of the wheel and to provide a wheel design that allows enough space to accommodate the components of the e-corner.
- To enable air cooling capacity of the wheel, so that it can be used to cool down the e-corner components.
- To produce and effective eco-design of the wheel, that would meet the performance requirements for the e-corner.
- To manufacture the wheel prototypes which will be used during the wheel testing, e-corner dynamic tests and vehicle testing. These prototypes will be manufactured in a cost effective way.
- Carry on performance and functionality tests, to evaluate the validity of the wheel design.
- To perform a dismantling and recycling assessment of the wheel.
WP4: MECHANICAL COMPONENTS
- To analyze how the heat generated by the e-motor, power electronics, brake system and tyre is transmitted to other e-corner mechanical components. This will enable to set the operational thermo mechanical cycles, for the detail mechanical design of those components.
- To produce an effective eco-design of the mechanical components, in order to meet the performance requirements while ensuring a low cost and large scale production capability.
- To provide a manufacturing process analysis for each one of the mechanical components.
- To perform an eco-design assessment of the manufacturing processes involved.
- To manufacture the mechanical components.
- To assemble the mechanical components, and to carry on performance and functionality tests.
- To perform a dismantling and recycling assessment of each one of the mechanical components.
WP5: ASSEMBLY, VALIDATION AND DEMONSTRATION
The main purpose of this WP is to provide the experimental evidences which will ensure that the developed e-corner fulfils the defined specifications concerning mainly the aspects related to vehicle dynamics and driveability. Other WP sub-objectives are:
- To integrate the EUNICE solution into a functional vehicle. This will enable the execution of the necessary tests in order to demonstrate the feasibility of the solution.
- To perform dynamic, electrical performance and functionality tests. These validation tests are representative and will cover the most important operational aspects that the EUNICE solution will address, once operating as the power drive of a vehicle.
- To correlate the results of the validation tests with the EUNICE solution specifications and targets in terms of vehicle efficiency, validating the models used during the research phase.
- To obtain valuable driving impressions which will yield in optimized specifications for the future distributed tractions concepts.
- To suggest further design improvements, resulting from the validation tests conclusions.
WP6: EXPLOITATION AND IMPACT
- To generate an exploitation plan to define the industrialization of the project results.
- To assess the technological impact of the project developments on the participant partners, on the European Community EV automotive industry and on the Green Car initiative.
- To conclude the patent study, aimed at exploring the possible patents and IPR resulting from the project outcomes.
- To make stakeholders aware of the project and to disseminate the project results.
- To generate plans for the use and dissemination of the knowledge.
- Support of the specifications by more than one OEM will be established through a series of user workshops, which should continue at regular intervals during the project to assist in dissemination and exploitation.
The aim of this WP is to perform the administrative management of the EUNICE project.