{"id":13034,"date":"2022-01-16T10:29:28","date_gmt":"2022-01-16T09:29:28","guid":{"rendered":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/?p=13034"},"modified":"2022-01-16T10:29:28","modified_gmt":"2022-01-16T09:29:28","slug":"maintenance-45","status":"publish","type":"post","link":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/2022\/01\/16\/maintenance-45\/","title":{"rendered":"Understanding e-axle maintenance"},"content":{"rendered":"

What the maintenance sector should know about the next evolution in driveline technology.<\/span><\/p>\n

With the increase of hybrid and battery-electric tractors on the road, it\u2019s time for the commercial vehicle maintenance sector to get up to speed on electric axles, or e-axles, and what to expect in terms of maintenance.<\/span><\/p>\n

The first thing to know is what an e-axle is. This drivetrain system consolidates several of an ICE vehicle\u2019s major systems into one, including the motor, transmission, power electronics, and brakes. The motors also serve as regenerative brakes, which assist with stopping, as well as redirect that kinetic energy to the battery.<\/span><\/p>\n

\u201cYou\u2019ve got a lot of content that\u2019s being condensed into a small package, and replacing a diesel engine and conventional transmission and driveshaft opens up all sorts of opportunities,\u201d explained Jeremy Freznick, senior director of commercial vehicle engineering at\u00a0Dana Inc.<\/a>, one of the more active OE\u2019s developing and manufacturing e-axles, with options for medium- and heavy-duty trucks, vans, and buses. \u201cThat\u2019s whether you want to use that [space] for additional payload or to package additional batteries in that space to get extended range.\u201d\u00a0<\/span><\/p>\n

Dana\u2019s eS9000r e-axle<\/a>\u00a0for medium-duty hybrids and EVs weighs 815 lbs. Its standard battery pack setup allows Classes 4-6 trucks and buses to run for up to 170 miles between charges. The first of Dana\u2019s Spicer Electrified Zero-6 e-axles line will also be used as the drivetrain for the Freightliner Custom Chassis Corp. (FCCC<\/a>) all-electric MT50e medium-duty last-mile delivery vehicle. According to\u00a0Hyliion<\/a>, the Hybrid eX will also use Dana’s e-axle propulsion system.<\/span><\/p>\n

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The Hyliion Hybrid eX will use Dana’s e-axle powertrain.<\/span><\/figcaption><\/figure>\n<\/div>\n<\/div>\n<\/div>\n

Automatic transmission manufacturer\u00a0Allison Transmission<\/a>\u00a0also has thrown its engineering prowess into the EV sector. The Indianapolis-based company now offers the\u00a0eGen Power 100D e-Axle<\/a>\u00a0for 6×2 tractors and eGen Power 100S for 6×4\u2019s and heavy-duty straight trucks, along with buses and medium-duty trucks. Like their burly fossil fuel-guzzling cousins, Allison\u2019s leaner e-axles boast plenty of muscle.<\/span><\/p>\n

\u201cThe eGen 100D features two electric motors, each capable of generating greater than 200 kW of continuous power, with peak combined power of 648 kW,\u201d Allison CTO Michael Foster noted. \u201cThis is similar power to a 15L engine paired with a 4000 Series Allison transmission, but packaged in the space claim of a traditional axle. The eGen Power 100D also integrates a two-speed gearbox in the central housing, optimizing the e-axle to enable the high starting gradeability to get heavy loads moving, while also offering the benefit of superior efficiency at cruise speed.\u201d<\/span><\/p>\n

Hino Trucks<\/a>\u00a0will be the first OEM to use Allison\u2019s eGen Power 100S e-axles, which will be spec\u2019d on Hino\u2019s Classes 6-8 battery-electric trucks.<\/span><\/p>\n

These are just two examples. Others include Bosch, Detroit, Eaton, and Meritor, though even that list is not exhaustive.<\/span><\/p>\n

Say goodbye to maintenance?<\/span><\/h3>\n

What\u2019s\u00a0not\u00a0<\/i>exhaustive is the list of preventive maintenance items: no oil changes, fuel injector replacements, diesel exhaust fluid, nor cleaning of the diesel particulate filter, a maintenance bane of many a diesel technician.<\/span><\/p>\n

Some OEs are claiming certain products can be virtually maintenance-free under the right conditions, but for most, there are at least a few infrequent lube changes in terms of preventive maintenance. According to the OEs, any PMs for the e-axle are more than offset by the elimination of the aftertreatment system in diesel trucks.<\/span><\/p>\n

\u201cTechnicians can expect reduced maintenance from an e-axle when compared to a traditional powertrain,\u201d Foster asserted. \u201cThere are less moving mechanical components in an e-axle, which results in less friction and less wear and tear, leading to increased durability and a longer axle life.\u201d<\/span><\/p>\n

Allison\u2019s regenerative braking system and gear layout \u201callows for maximum efficiency and 100% regeneration torque capability,\u201d which does reduce brake wear, but Foster noted the actual brake components, such as roots and pads, will still require periodic maintenance.<\/span><\/p>\n

All told, the benefits include reducing downtime, maintenance costs, and total cost of ownership, Foster surmised.<\/span><\/p>\n

The real work for fleets will be in spec\u2019ing the right e-axle, ensuring it provides the best performance and range. How to do that will be a bit more complicated than the maintenance.<\/span><\/p>\n

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\"Dana&apos;s<\/span><\/div>\n<\/div>
Dana’s Spicer Electrified e-Powertrain was awarded New Achievement of the Year at the 2021 Diesel Progress Summit and Awards. Pictured here is the eS9000r paired to a Sumo motor.<\/span><\/figcaption><\/figure>\n<\/div>\n<\/div>\n<\/div>\n

Everyone joining in<\/span><\/h3>\n

As far as spec\u2019ing, a fleet will have many different options from which to choose. Like Allison, fellow transmission maker Eaton has also diversified into e-axles.\u00a0Eaton\u2019s eMobility business<\/a>\u00a0announced a 4-speed heavy-duty transmission for EVs at the NACV show in 2019. Julie Marshaus, manager of new product introductions and systems, eMobility, for Eaton, said that the HD 4-speed transmission design is progressing well.<\/span><\/p>\n

\u201cIt is heading to B-samples shortly and is still targeting full production in 2023,\u201d Marshaus said. \u201cThe HD 4-speed is intended for the Classes 6-8 market, with the capability of 2,600Nm input torque at 5,000 rpm. The transmission is capable of the typical applications in this class of vehicle, with expected markets in drayage and regional haul. It will easily expand to linehaul when that application is more viable for the EV space.\u201d<\/span><\/p>\n

So how does an Eaton e-axle differ from say, the Eaton Cummins Endurant automated manual transmission?<\/span><\/p>\n

\u201cThe major difference is that the EV transmission only needs four gears, and because electric motors spin backwards, the reverse gear and idler assembly have been removed,\u201d Marshaus explained of Eaton\u2019s EV transmission design. \u201cThe torque curve for electric motors is peak torque at zero speed and is very flat.<\/span><\/p>\n

\u201cThis allows the transmission to use fewer gears because we do not have to shift to maintain a diesel engine in the peak torque range of 1,800 rpm as conventional transmissions are required to do for drivability and efficiency,\u201d she continued. \u201cRegarding efficiency, the electric motors have peak efficiency at the higher rpm bands. Therefore, the transmission holds the top input speed as long as possible before shifting to maximize the vehicle efficiency.\u201d<\/span><\/p>\n

The differences are found in of course the components and design, but also the efficiency and performance, as well as maintenance requirements.<\/span><\/p>\n

Meritor<\/a>\u00a0is currently developing\u00a0three different electric powertrain platforms<\/a>: the 12Xe, 14Xe, and 17Xe.<\/span><\/p>\n

\u201cThe bigger the number, the bigger the vehicle that it\u2019s intended to cover,\u201d explained John Bennett, VP and CTO at Meritor. \u201cA 12Xe has an integrated electric motor and two-speed transmission, focused on Class 4 and 5 vehicles. Our 14Xe\u2014Class 6, 7, and then can be used as a tandem for Class 8\u2014also has an integrated electric motor and a two or three speed transmission. The 17Xe is targeting heavy Class 8 as a single axle, so European applications which are predominantly 4×2 or 6×2, using a single driving axle. The 17Xe has a much larger motor and a larger integrated transmission available as both a two speed or a three speed.\u201d<\/span><\/p>\n

The 14xe is being used as the e-axle for\u00a0Hyliion\u2019s ERX truck<\/a>.<\/span><\/p>\n

Bennett noted that the transmission can also be configured as a single speed.<\/span><\/p>\n

\u201cRight off the bat you\u2019ll notice, compared to a diesel engine mounted to an automated manual transmission, that the number of speeds is significantly reduced,\u201d Bennett said. \u201cThe reason for that is an electric motor has a very wide speed range in comparison to diesel engine, and it\u2019s very efficient across the majority of that speed range. In our 17Xe, for example, the electric motor can run up to 5,500 rpm, and it\u2019s efficient; and by efficient, I\u2019d say over 92% efficient for about 80% of that range. So, it\u2019s highly efficient, as opposed to a diesel engine\u2026 That\u2019s a big difference with an electric powertrain\u2014you can get away with, in some cases, a single speed, but in most cases of the heavy-duty vehicle, two or three speeds, and that\u2019s it.\u201d<\/span><\/p>\n

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A diagram of Meritor’s 14Xe e-axle and related components.<\/span><\/figcaption><\/figure>\n<\/div>\n<\/div>\n<\/div>\n

Diagnostics<\/span><\/h3>\n

Utilizing diagnostic software will remain standard practice when servicing electric powertrains and e-axles. Bennett explained that a familiar process will still exist with diagnostics, as plugging in a diagnostic tool \u201cwill flash fault codes and indicate which areas are problematic or need to be serviced. That\u2019ll give a technician a pretty easy indication, very similar to today, of where to look and where to go, and what things to service, potentially.\u201d<\/span><\/p>\n

Understanding how the system functions lends to being able to accurately diagnose performance issues.<\/span><\/p>\n

\u201cThe controls themselves are a bit more complex,\u201d Bennett heeded. \u201cThe mechanical parts are simplified. The parts that are there are very conventional. There\u2019s no clutch in these systems. It\u2019s essentially gears, shafts, and bearings.\u201d<\/span><\/p>\n

Bennet said while the shift rail, shift collar, and actuator will be familiar to technicians, the controls, which are clutch-less, are more complex, similar to an AMT.<\/span><\/p>\n

\u201cYou\u2019re doing synchronization of the motor speed; you\u2019re essentially taking the motor and going into a speed mode, releasing the torque, shifting into a neutral position, then you either spin up or speed down the electric motor, depending on which way you\u2019re shifting, and re-engaging the shift collar,\u201d Bennet explained. \u201cSo, it\u2019s really coordinating and synchronizing the electric motor which is done through your motor controls. From a system standpoint, it\u2019s going to be very simple to diagnose and easy to service.\u201d<\/span><\/p>\n

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\"Meritor<\/span><\/div>\n<\/div>
Meritor is developing three different electric powertrain platforms: the 12Xe, 14Xe, and 17Xe. The 12Xe is focused on Class 4-5 vehicles; the 14Xe (pictured here) is for Class 6-7 vehicles, or Class 8 as a tandem; the 17Xe is for Class 8 single axle applications.<\/span><\/figcaption><\/figure>\n<\/div>\n<\/div>\n<\/div>\n

When dealing with Meritor\u2019s \u201cXe\u201d platform, especially because it will be connected to either a fuel-cell vehicle or EV, higher voltages must be considered. Proper safety training and personal protective equipment must be paramount. However, the transmission itself is not utilizing higher voltages.<\/span><\/p>\n

\u201cIt\u2019s only low-voltage connections to the actuator and the sensors,\u201d Bennett said of transmission service considerations. \u201cThe transmission on our ePowertrains can be removed without really touching any of the high voltage system whatsoever, so it\u2019s simple, from that standpoint\u2026 The electric motor is integrated into the axle itself, but the high voltage goes through the motor, the inverter in the battery pack. Our transmission mounts on as a self-contained sub assembly, and it can be removed that way. So, disconnecting the low-voltage sensors and cable, and then popping off the transmission as a sub assembly is the way to service it.\u201d<\/span><\/p>\n

Fleets need not expect any specialty tooling or equipment, beyond up-to-date diagnostic software, to service EV transmissions.<\/span><\/p>\n

\u201cOne key benefit of EV transmissions is that technicians and fleets already have all of the tools and knowledge required to service them,\u201d Marshaus said. \u201cThe EV transmission, with its four forward gears, no back box, no clutch, and no clutch actuator, has greatly simplified the overall drivetrain service strategy. The transmission will only need an oil change on a PM schedule and regular troubleshooting in case of a failure.\u201d<\/span><\/p>\n

\u201cThere are no unique tools that are required,\u201d Bennett agreed. \u201cA standard mechanic\u2019s toolkit would suffice. You need tools; you\u2019ll need wrenches, and sockets, and whatnot, to take it apart and disassemble it, but nothing out of the ordinary\u2026 A certain diagnostic tool will be required. In many cases, the service shop will have that tool, but in the event that they don\u2019t, that is a unique tool; but once you get into the transmission itself, it\u2019s the standard mechanical stock tools that everybody would have.\u201d<\/span><\/p>\n

Lubrication needs<\/span><\/h3>\n

With fewer moving parts, there\u2019s also less of an emphasis on lubricating them.<\/span><\/p>\n

\u201cElectrified transmissions will have fewer mechanical components and will require longer drain intervals compared to conventional transmissions,\u201d said Penney Do, product technology specialist at\u00a0Chevron<\/a>, who has been developing e-axle and electric powertrain lubricants. \u201cThose units will require less frequent and extensive services and will need less volume of fluids for servicing them during their effective lives.\u201d<\/span><\/p>\n

It is important to note electric powertrains and e-axles may require special lubrication fluids.<\/span><\/p>\n

\u201cAs electrification of driveline systems (including transmissions and axles) is getting more widely developed by OEMs at different parts of the world, Chevron is partnering with them to develop the right fluids for their evolving hardware in this space,\u201d Do said.<\/span><\/p>\n

Allison\u2019s will require longer drain intervals compared to conventional transmissions.<\/span><\/p>\n

\u201cDepending on the duty cycles and vocation, the fluid and filter of the e-axles may last for a vehicle\u2019s lifetime,\u201d Foster said of the eGen line.<\/span><\/p>\n

When it comes to the lubrication of the electric powertrain, and specifically the transmission, Meritor has simplified the design and runs the axle lube through the transmission system.<\/span><\/p>\n

\u201cGenerally, the transmission will run on different fluids, automatic transmission fluid, for example, or some other fluid that\u2019s different than the axle lube,\u201d Bennett explained. \u201cBecause our system is fully integrated and we didn\u2019t want to have to service multiple lubes, it\u2019s just one oil, and it\u2019s typical axle oil that runs through the whole integrated system. We did that for ease of maintenance.\u201d<\/span><\/p>\n

Dana also has simplified e-axle lubrication for fleets.<\/span><\/p>\n

\u201cThe only standard maintenance that\u2019s required on our e-axles is your traditional axle lubrication interval,\u201d said Freznick, who added Dana also utilizes special lubricating fluid. \u201cYou do have to pay attention to some of the powertrain cooling fluid intervals, which are typically 100,000 miles.\u201d<\/span><\/p>\n

Traditional gear oil is used in the differential, though, and has the same gear lube interval change as a traditional axle.<\/span><\/p>\n

\u201cYou\u2019ve got a typical drain plug you pull; catch the gear oil like you would with the traditional axle,\u201d Freznick advised. \u201cYou change your coolant every 100,000 miles and you\u2019re good to go.\u201d<\/span><\/p>\n

Freznick stressed that wiring and cable checks will need to be added to the inspection list.<\/span><\/p>\n

\u201cThere\u2019s a high voltage interlock that is the job one would do before performing any kind of checks or maintenance,\u201d he said. \u201cBasically, it shuts down the high voltage cable and de-energizes the system. You want to de-energize your system before you\u2019re doing any of that maintenance work.<\/span><\/p>\n

\u201cThere is always some hesitation because it\u2019s new,\u201d Freznick attested in regard of the adoption of e-axles. \u201cBut, the majority, if not everybody who\u2019s been through the safety training understands, what you need to do is provide a safe work environment. Everybody feels very comfortable with the systems at that point. Once the newness wears off, and you can appreciate that, really, once you de-energize the system, things are just like you would expect with a traditional drive axle and drive shaft.\u201d<\/span><\/p>\n

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This article originally appeared on Fleet Maintenance<\/a>.<\/i><\/p>\n

By John Hitch<\/a> , <\/span>Tyler Fussner<\/a> <\/span><\/p>\n

Source: https:\/\/www.fleetowner.com\/<\/a><\/span><\/p>\n

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KNOW WHO WE ARE<\/strong><\/a><\/h1>\n

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What the maintenance sector should know about the next evolution in driveline technology. With the increase of hybrid and battery-electric tractors on the road, it\u2019s time for the commercial vehicle maintenance sector to get up to speed on electric axles, or e-axles, and what to expect in terms of maintenance. The first thing to know…<\/p>\n","protected":false},"author":3,"featured_media":13035,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[18],"tags":[53],"_links":{"self":[{"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/posts\/13034"}],"collection":[{"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/comments?post=13034"}],"version-history":[{"count":1,"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/posts\/13034\/revisions"}],"predecessor-version":[{"id":13036,"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/posts\/13034\/revisions\/13036"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/media\/13035"}],"wp:attachment":[{"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/media?parent=13034"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/categories?post=13034"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/advancedfleetmanagementconsulting.com\/eng\/wp-json\/wp\/v2\/tags?post=13034"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}