Tech insider Chevrolet eCOPO Camaro Concept

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Drag Act Chevrolet’s eCOPO Camaro Concept offers a vision of how electric powertrains could slot into the vibrant OE performance parts market. Words: Graham Heeps.


TECH INSIDER CHEVROLET eCOPO CAMARO CONCEPT


During a stroll around the Las Vegas halls of the 2017 SEMA aftermarket show, Russ O’Blenes, GM’s director of performance variants, parts and motorsport, stumbled upon Shock and Awe. This Pontiac Firebird-based, electric drag race car was the brainchild of teacher Patrick McCue and his automotive technology program at Bothell High School near Seattle, Washington. Working with the respected Hancock & Lane (H&L) drag race team, more than a dozen students had participated in its development and assembly.


Tech insider Chevrolet eCOPO Camaro Concept
Chevrolet eCOPO Camaro Concept

“When I talked to Pat, I saw the link to GM’s commitment to engaging young minds in STEM education,” says O’Blenes. “It also represents our goal of a world with zero emissions, with the next generation of engineers and scientists who will help us get there.”

Seeing Shock and Awe fed into thoughts that O’Blenes and his colleagues had been having as to the right place to engage in electric motorsport. “Formula E’s cool, but this [drag racing] is the perfect opportunity to do fast learning on battery technology, for example. The 32kWh in our battery pack is a perfect number: you can do three runs without charging, or do a fast recharge in-between and run all weekend. “What else is interesting is that although you would have to make a big initial investment, there’s almost no maintenance,” continues O’Blenes. “The electric motors are designed to run forever, and the battery life would be very long, given how a race car cycle would be. Racers in the Comp or Stock classes are [already] spending US$60,000-80,000 on a motor that will make 50 passes before it needs rebuilding. People just don’t want to add up how much we spend on racing – we’re all in denial!”


Crate engine concept

GM hatched a plan to draw on the experience of its own engineers, as well as McCue, Hancock & Lane, and other outside partners, to create a concept electric drag racer for the 2018 SEMA Show.

The result – built and owned by the McCue/H&L team – is the eCOPO Camaro Concept, which marries a dual-motor stack and a four-module Li-ion battery pack to a conventional drag-race transmission and driveline in a regular COPO rolling chassis. COPO stands for Central Office Production Order; Chevrolet has offered 69 of the special-order performance Camaros for sale each year since 1969.

The goal from the start was to mimic the plug-and-play setup of Chevrolet’s successful Performance Parts program, which offers crate engines and associated systems under the Connect & Cruise banner to amateur racers and street-car builders.

“I’m not saying it’s happening tomorrow, but I wanted to get ahead of the game,” says O’Blenes. “Crate engines are our bread and butter, so we had that mindset from the beginning. What’s neat is that everything has a modular design. The eCOPO package has two motors in it, but you can build it with one, two or three, for 350, 700 or 1,050bhp [355, 710 or 1,065ps]. It gives flexibility for how we might do stuff in the future.”

The electric crate motor concept shown at SEMA was designed and built at GM. It comprises two BorgWarner (ex-Delco Remy) HVH 250-115 motors, each making around 420Nm of torque for a combined 840Nm, and two Rinehart Motion Systems PM250DX propulsion inverters.

The motor stack bolts to the COPO’s regular Turbo 400, 3-speed automatic gearbox using the same bell housing mounting pattern and crankshaft flange as the gasoline-powered, LS-family crate engines. That was partly to fit the vision of plug-in power, but also for performance reasons in this specialized drag-race application.

“One advantage is that you get the torque multiplication of the converter,” says O’Blenes. “You lose some efficiency from the hydraulic losses, but also in terms of getting down the track, it’s better. You really want to be able to hit the tire hard and this setup has a two-step [rev limiter launch control], just like in a regular engine, so you can set the exact power and RPM you want to leave [the start line] at.”


Power cells

Design and construction of the battery pack was a major challenge for the four-and-a-half-month eCOPO program. The pack is split into four, with two modules in the back seat (one either side of the driveshaft) and two in the trunk. Each module contains 48 Xalt Energy pouch power cells for around 1,400A at full power. Like the motors, the pack’s modular design would enable the pack to be scaled to different vehicles.

“The main simulation we did for eCOPO was on the battery,” says O’Blenes. “Unfortunately, when you get into these types of discharge rates, the cell choices are pretty small. Availability is even more of a challenge. It seems that everybody’s making energy cells, but no one’s making power cells! These were literally the last 225 cells [of their type] in the world and it was a struggle to get them.”

The team turned to GM’s internal resources for cell choices and for sign-off on system safety: “It was critical that we had good oversight of how the contactor worked, the e-stops and electrical isolation,” he adds. Starting with a battery box design from EV hot rod pioneer, Bloodshed Motors, the integration of cells and BMS was a joint effort by GM, McCue/H&L and Hybrid Design Services in Troy, Michigan, which has been a Tier 2 for GM through LG and had experience in the motorsport niche. O’Blenes notes that without the input of the various external partners, the project would not have been completed so quickly.

Each module contains 48 pouch cells and an integrated BMS to monitor cell voltages and temperatures. In turn, each BMS is connected via CAN to a ‘watchdog’ that monitors the BMSs, motors and inverters to ensure safety of the overall electrical system.

The four modules supply 200V each and are connected in series to give 800V, more than twice the voltage of the production Volt and Bolt battery packs. The arrangement is said to support more efficient power transfer to the electric motors and faster recharging, which is important for the limited time between elimination rounds in drag racing. Each pack has its own fuse, plus a main fuse in the custom-designed contactor box.

GM hasn’t measured the range that the 1P pack arrangement would offer, but O’Blenes envisions offering other pack options for use in street car applications such as restomod EV conversions.

“People who take their cars to a cruise night wouldn’t need this much power, so you could throttle back and do a 2P pack, or put some energy cells in it,” he muses. “How cool would it be to show up in a ’70 Chevelle, lift up the trunk… people would be blown away!”

Two of the eCOPO’s battery modules are located in the trunk. Two more modules are located in the back seat. Each module contains 48V Xalt Energy pouch power cells.

Tipping the scales at 1,580kg (3,480 lb), the eCOPO is around 91kg (200 lb) heavier than a supercharged COPO Camaro. At 136kg (300 lb), the motor assembly is lighter than gasoline equivalents but the 318kg (700 lb) battery packs add mass.


VITAL STATISTICS

Motors: 2x BorgWarner

HVH250-115. Total 700bhp (710ps), 840Nm

Inverters: 2x Rinehart

Motion Systems PM250DX

Battery pack: 4x 48-cell modules in series.

Total 800V, 32kWh

Cells: Xalt Energy pouch-type

Transmission: Turbo 400 3-speed auto

Quarter-mile: 9 seconds (estimate)


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