The Electric Evolution

The Electric Evolution

The challenges remain the same regarding the electrification of the automotive industry. A majority of the CTI Symposium USA event in Novi, Michigan focused on areas like battery life, battery range, cost issues, buyer needs, buyer incentives and charging stations. The focus in 2019 appears to be on bringing competitors and product families together in order to provide a connected eco-system for electrification.

While the industry continues to plan and prepare for major changes regarding e-mobility, ride-sharing, autonomous vehicles, electric commercial bus and freight fleets and the future of the transmission itself, the audience of this very magazine (the suppliers) will be thrilled to learn that almost every panel expert or market analyst at CTI shared a similar, unified voice regarding component suppliers. The word in question: Opportunity.

“The integration that is occurring in the automotive segment will create many new opportunities for suppliers,” said Mayank Agochiya, managing director at FEV Consulting, Inc., USA. “These will include sensor integration, software packages and mobility as a service.”

In the coming years, the automotive industry also will rely heavily on new product developments and technologies in areas like bearings, drives, motors, pumps, clutches, brakes, etc. Here’s what we learned during the symposium:

The future of vehicle electrification was discussed at great lengths during CTI Symposium USA.

NVH in Electric Drive Units

Thomas Wellerman, department manager, transmission and driveline systems at FEV, Inc., examined NVH issues in electric drive units during a presentation at CTI.

Wellerman said that with powertrain electrification as one of the megatrends in the automotive industry, corresponding market forecasts expect significant increase of shares of electrified powertrains. Pure electric vehicles (EV) and hybrid electric vehicles (HEV) are the most popular types of vehicles utilizing electrified powertrains. For achieving CO2 fleet targets for passenger vehicles, high growth rates for both EV and HEV are expected, resulting in a strong demand for electric drive units (EDUs).

“The transition from combustion engines towards electric propulsion systems is accompanied by a reduction in vehicle exterior and interior noise levels, in particular during low vehicle speed operation. Without masking effects, objectionable sound content from EDUs in the vehicle interior can become crucial for customer acceptance. Further, electric drive units usually have a very tonal and high frequency content, which often result in an unpleasant sound quality. Therefore, it is important to include NVH considerations throughout the entire EDU development phase,” Wellerman said.

An important aspect of electric vehicle development is the change in the vehicle’s interior noise behavior. Noise components in the internal combustion engine such as combustion noise, induction and exhaust are no longer present. While these noise levels are reduced, wind and road induced noise become the main contributors to electric vehicle interior noise levels. The noise contribution of an electric drive unit is much lower from a sound pressure level perspective, and has a different noise and frequency content compared to the noise of an internal combustion engine. The tonal noise and high frequency noise character of an EDU is related to both the gear train and the electric motor. This is often subjectively rated as annoying which reduces vehicle pleasantness and ultimately impacts customer satisfaction.

To refine the electric vehicle interior noise level and character, continuous NVH support is needed during the development of the EDU system and its vehicle integration throughout the development process. This includes optimization of the overall EDU system, its individual subcomponents such as the gear drive, electric motor, inverter, and EDU mounting, and their corresponding noise transfer paths into the vehicle. The following areas need to be addressed during the NVH development process for an EDU: Gear train geometry, dynamic gear forces related to EDU drivetrain torsionals, electromagnetic excitation at the rotor/stator interface, stator stiffness, EDU housing stiffness, and power electronics (inverter).

In addition to the optimization of the EDU itself, Wellerman believes that the integration of the unit into the vehicle plays a vital role in influencing the vehicle’s NVH characteristics and ultimately the customer’s perception of the vehicle. (www.fev.com)

From Industrial to Automotive Applications

A prime example of taking knowledge from one industry and transferring that knowledge to another occurred in the case of Marzocchi Pompe S.P.A. The Italian company produced a gear pump specifically for automotive applications based on their expertise in the industrial segment.

North American Product Engineer, Dr. Andrea Rimondi, spoke about how company used its knowledge and engineering expertise from industrial pumps to build one from the ground up for high-volume automotive applications.

“Today, Marzocchi Pompe supplies the automotive market not only with pumps, but also integrated solutions, complete with motor and manifold with valves, actuator systems, and complete power units with reservoir,” Rimondi said. “On one side, a range of products with very high performances and on the other side an enviable product know how that allows our engineers to develop new products in smaller sizes, at reliable and affordable cost as well as micro systems integrated into the gear pump.”

Marzocchi Pompe consolidated the production of pumps for the automotive industry in a new plant built in 2016 in Zola Predosa, Bologna. It is divided into two divisions: one takes care of the manufacturing of all the gears for the entire Marzocchi’s pump and motor range; the other takes care of the assembly and testing of pumps for automotive applications, on specifically designed lines.

These gear pumps have been specifically designed in order to be integrated into assemblies of automatic transmissions, semi-automatic clutches, electro-hydraulics power steering, AWD systems, assistance in hybrid-type of propulsion, etc. (www.marzocchipompe.com)

A Look at Coating Technology

Surface coatings can be applied to components to provide unprecedented protection, as well as additional highly desirable features and benefits. Dr. Mahdi Amiriyan, surface engineer/coating expert, surface technology, Schaeffler Group USA,  discussed some of the state-of-the-art approaches that Schaeffler takes to improve performance and add value to standard components.

Surface technology is a design element for leading products with added value. Since many coatings in the Schaeffler toolbox are categorized in thin films, there is no need for changing in part/component dimensions. The Schaeffler coating toolbox is categorized in five main families, namely Corrotect, Durotect, Triondur, Insutect and Sensotect.

It is possible to coat every single component in a plain or rolling bearing. This can include corrosion protection coatings on bearing races to thin films for lower friction and maximum wear protection on rolling elements and cages. Zinc and zinc alloy coatings are the most common ones for corrosion protection and DLC (diamond like carbon) coatings are common coatings for friction and wear applications.

Amiriyan discussed four of the five coating families during CTI:

Corrotect: Machine components that come into contact with humidity, salt water, or other corrosive media can undergo corrosion. Corrotect engineered coating systems are used to provide protection against a wide variety of corrosive elements. Corrotect coatings can be applied using a range of techniques, including electroplating (an electrochemical process used, for example, for zinc alloys), electroless plating (such as nickel-phosphorous coatings), or by spraying or dipping (such as paint systems).

Durotect: These coatings are specifically developed to provide wear protection and increased durability for components under high tribological stress. Because high surface hardness is necessary for protection against abrasive wear, the hardness of the coating is essential. Adhesive wear occurs principally in contact partners with similar chemical bonding characteristics, such as steel on steel. With a suitable coating, both abrasive and adhesive wear can be postponed or even prevented. Accordingly, Durotect coatings are well-suited for emergency running conditions with minimal to no lubrication.

Triondur: The unceasing need for greater energy efficiency in modern machines and equipment is accompanied by ever-increasing demands on the tribological load-carrying capacity of their components. Accordingly, friction-reducing Triondur coating systems utilize sophisticated coating processes to achieve significant increases in the performance capability of components subjected to high tribological stresses.

Insutect: Under certain conditions, stray electrical current can pass through rolling bearings in electric motors or generators. This can damage and degrade the lubricant inside the bearing, which can cause the entire motor to fail prematurely. Current-insulated bearings, which feature ceramic-coated inner or outer rings, offer cost-effective protection against electrical arcing damage—especially when they are specified at the design stage. (www.schaeffler.com)

Deep Groove Ball Bearings for EV Motor Support

Motors used in hybrid electric vehicles (HEV), electric vehicles (EV), and similar drives are required to be small and have high-output. The downsizing of the motor brings demands for higher motor speeds to maintain power output. This in turn requires higher bearing performance. Standard steel and polymer cage designs have limiting speeds below what is needed for the faster drives.

Standard steel and polymer cage designs ring have limiting speeds below what is expected to become common for the electric motors driving vehicles of the future. A presentation by Mike Johns, consultant, advanced engineering, at JTEKT, reviewed the development of a two piece symmetrical dual support cage which increases the limiting speed to about 2 million dmn bearing pitch diameter (mm) x rotational speed (rpm) without the aid of more expensive bearing features like ceramic balls.

When using a steel cage, the contact between the ball and cage pocket intensifies with high shaft speeds due to the eccentric motion of the cage and marginal lubrication at the points of contact between each ball and its cage pocket. This can lead to seizure between the balls and cage.

The more standard crown type polymer cage has pocket claws. These asymmetrical claws deform unevenly when subject to high speed centrifugal loads. A more rigid reinforced crown type cage has excellent high speed performance, but also deforms unevenly at high speeds potentially compromising the ball cage contact. These two types of single piece cages generate more heat at higher speeds and are more prone to lubrication failure and seizure.

In addition to the cage, applying tighter tolerances, special lubrication, roundness, roughness, raceway curvature adjustments all contribute to the bearing speed limit. Special materials like ceramic balls can also be applied, but this presentation focused on the cage which provides the greatest performance gains relative to the cost.

It was confirmed during the analysis that the developed cage has a high speed performance over 1.3 times that of existing cages (standard and highly rigid cage). Even after heat shock and durability tests, it was confirmed that the developed cage was free of abnormalities and displayed satisfactory durability. In line with the future growth of the HEV and EV markets, it is predicted that motors will have increasingly higher speeds. It is expected that specialized features like this dual support two piece cage will become more common as the electric motor supports the bearings. (jtekt-na.com)

Electric Opportunity

In summary, the panel discussions and Q&A sessions during CTI Symposium USA covered everything from sensors and simulation software to hybrid vehicle analysis and the electrification of trucks here in the United States. Experts debated these subjects as they attempted to look into the crystal ball and determine what the automotive industry will really look like 20 years down the road.

For component suppliers, the opportunity is going to be there no matter how the electrification of the industry pans out. Mechatronic systems, component upgrades and more powerful software tools will play a vital role in the coming years in automotive applications in all formats, ICE, EVs, BEVS, hybrids and more. Working closely with your partners and suppliers today will no doubt benefit product innovation and advancement in the future (win-win no matter what the inside of an automotive vehicle looks like).

For more information:

Car Training Institute (CTI)

Phone: +49 211 88743-3333

www.car-training-institute.com

 

Categories: Editors Choice

About Author

Matthew Jaster

Matthew Jaster, Senior Editor, has a B.A. in journalism from Columbia College Chicago and has 15+ years of writing and editing experience in automotive, manufacturing, engineering, law and arts and entertainment.

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