22 September/October 2025 | E-Mobility Engineering horsepower for this application, so we had to wait for it to mature. “Our engineering playground involves all sorts of applications. The thought of hybridisation was there, but at the end of the day, we thought why complicate it with two systems when you can simplify it with one very efficient system? The application was perfect for fully electric technology; so, when it was ready, we implemented it. “We used a lot of the common architecture and shared technology from the Group, and this is not actually the first-generation battery. We started this vehicle off on the Group’s generation two unit and have already upgraded it to a generation three, which offers 42% more power. That shows how quickly things are moving in this space.” Powertrain development At the heart of the LRe is a pair of AC motors, coupled to a two-speed transmission optimised for this very specific heavy-duty refuse use case. Running on 600 V architecture, the motors drive two sets of rear wheels, providing 334 kW (440 bhp) of continuous power, peak power output of 400 kW (536 bhp) and 4050 lb-ft of torque. The two units are integrated into their respective housings within the existing baseline chassis and mated to the transmission. They are designed to be independently replaceable, and with no other equipment around them to get in the way, it is a far simpler setup than is found in the ICE version. The way the motors are managed is key to the vehicle’s operation and Fotopoulos explains: “We have 100% of torque from zero rpm to 3500 rpm. Then, at that point, you don’t need torque, you need horsepower. So, the torque starts to drop off and from 3500 rpm to the limit of 10,000 rpm, we have 100% horsepower. “The two motors go into the geared system, and that drives the two rear axles. It looks like a combined unit, but it’s actually modular – there are two motors and a transmission mated together in the centre of the chassis, with a prop shaft that goes back to the traditional axis to provide the drive.” The transmission’s two-speed shift is software-driven with the change point determined by the vehicle’s overall speed. This is typically around the region of 20 to 25 mph but will depend on various factors that feed into the software, including the environment, the level of incline up or down and the weight of the payload onboard. The two electric motors are set to always run at different speeds, with different gear ratios that are specifically designed to optimise harmonics and minimise noise and vibration. Fotopoulos continues: “Motor number two always runs at the same speed using a ratio of 3.67, but motor number one changes speed, depending on the gearing. “In gear one, it has a ratio of 9.26, so it runs at approximately three times the speed of motor two. In gear two, it comes much closer to motor two, with a ratio of 3.52 compared to motor two’s 3.67, so the two run at marginally different speeds. It’s a very little difference, less than a thousand rpm but it keeps everything in harmony.” Each motor has its own electric motor drive – or its own brain, as Fotopoulos describes it – and the modular layout supports easy replacement if necessary. In fact, in the case of a motor failure, the split architecture even allows the software to adapt and run the remaining motor independently, albeit at lower power, to enable an emergency ‘limp-home’ mode. In comparison to its ICE equivalent, the electric version has more power, faster acceleration and, from a driver’s perspective, much improved overall performance. It is also significantly more efficient, and Fotopoulos notes: “The LR ICE has an efficiency of about 55,600 BTUs per mile, while the LR Electric is 15,300 BTUs per mile – so it’s almost 400% more efficient. Dossier | Mack Trucks LR Electric The LRe is an electric version of Mack Trucks’ industry-leading refuse truck
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