2024 dual-propulsion sports car features electric motor and a small-block V-8
The 2024 model year Chevrolet Corvette E-Ray, an electrified, all-wheel-drive sports car, won the 2023 Vehicle Engineering Team Award given by the Automotive Division of SPE. Sharing the award were a team from General Motors Co. and suppliers that developed the groundbreaking, first-of-its-kind Corvette.
The E-Ray is not a plug-in hybrid—rather, it utilizes two propulsion systems: a naturally aspirated 6.2-liter, small-block V-8 engine, which powers the rear wheels and generates 495 horsepower and 470 foot-pounds of torque, and an electric motor, which contributes an additional 160 horsepower and 125 foot-pounds of torque to the front wheels via a 1.9-kilowatt battery pack positioned in the tunnel area between the seats.
The E-Ray’s torque lets it accelerate from 0 to 60 mph in 2.5 seconds, reportedly making it the fastest-accelerating Corvette in Chevrolet history.
Powerful Car Includes a ‘Stealth Mode’ Startup Feature
Electrification enhances the E-Ray’s performance. Battery packs replenish their charge via regenerative energy during coasting and braking as well as driving. The battery packs provide the vehicle with an electric-only, stealth driving mode at startup that provides top speeds of 45 mph and limited range so the car can exit a neighborhood or other venue quietly before the engine kicks in.
Carbon ceramic brakes and magnetic ride control complement the vehicle’s staggered 20- and 21-inch Michelin all-season tires when not racing, making it all-season road capable.
Testbed for Advanced Plastics and Composites
The E-Ray, predictably, features numerous plastic and composite innovations that support the multi-patented electrified propulsion system. Many of these technologies were nominated in other categories of the 2023 Automotive Innovation Awards Competition, including:
- Aftermarket & Limited Edition/Specialty Vehicles Category: Carbon Fiber Wheel. This fifth-generation carbon fiber-reinforced epoxy wheel features new diamond weave technology and satin-finish paint to achieve a Class A finish and is produced in a patented process that is scalable and reproducible. Versus aluminum wheels, mass is 30 to 50 percent lower yet meets stringent OEM durability and performance requirements. With lower un-sprung mass, the composite wheels improve traction and braking, suspension responsiveness and dynamic steering, plus acceleration. Lighter, with higher stiffness and resonant frequency and better damping, the wheels also reduce noise transmission to the driver. The supplier and material processor for this application is Carbon Revolution. The material used is woven carbon fiber-reinforced epoxy.
- Aftermarket & Limited Edition/Specialty Vehicles Category: Hybrid Battery Interconnect Board (ICB). The patented hybrid battery interconnect board features small and delicate metal current collectors, buss bars and sense lines in a compact design to fit limited packaging space. The 20 percent glass fiber-reinforced polyamide 6 (GR/PA6) grade was specified for its ability to offer high levels of functional integration in limited space plus be compatible with snap fits, heat staking, ultrasonic welding and adhesive bonding. The material is heat stabilized and flame retardant. Laminated core-block inserts were used in rotary injection tooling for venting and to control stampings during overmolding. The supplier, processor and tooling supplier for the application is Sun Microstamping Technologies; the material supplier is BASF Corp.; and the material is Ultramid B3UG4 PA6.
- Aftermarket & Limited Edition/Specialty Vehicles Category: Plastic Oil Cooling Lines. Replacing aluminum with flexible rubber hose, for the first time an injected molded fitting is laser welded to extruded plastic tubing and assembled to an aluminum block with a steel plate for structural rigidity while permitting the system interfaces to be used in limited packaging space. Mass was reduced 30 percent and direct cost 23 percent. The oil-cooling circuit pressure drop improved by 51 percent versus benchmark technology. The neat, semi-flexible PA6/10 polymer contains 62 percent biobased monomer and offers good cold-temperature impact strength, chemical resistance and withstands short-term temperature spikes. The supplier, processor and tooling supplier for this application is Automotive Veritas de México, S.A. de C.V.; the material supplier is EMS-Grivory; and the polymer is Grilamid XE 3975 PA6 and Grilamid 2S25WHLX/10 HIP.
- Materials Category: Battery Module Side Plates. By replacing metals with UL94 V0 glass fiber-reinforced polyarylamide resin to injection mold the side plates for this battery module, extremely flat parts with high dimensional accuracy, stiffness and strength were achieved in a complex geometry. The high-modulus, creep-resistant flame-retardant polymer eliminates the need for compression limiters and electrical isolation films, yet withstands extreme pressures from cell expansion and meets all mechanical requirements. Additionally, part count was reduced from four to one and many functional features were incorporated in the patented side plates that would not have been possible in metals. Mass was reduced 37 percent and cost 55 percent. The system supplier and processor for the application is Novares Group; the toolmaker is Liberty Molds; and the material supplier is RTP Co.; the material is RTP 299 K X 138337 E BLACK.
- Process/Assembly/Enabling Technologies Category: Battery Module Structure. This thermoplastic structure combines two side plates and 45 repeating spacers bolted together to hold pouch-style batteries. The patented, volumetrically efficient design withstands high cell expansion forces during battery use while eliminating the need for 55 compression limiters plus isolation countermeasures necessary with metals. Side plates are injection molded of 50 percent glass fiber-reinforced polyarylamide (PAA) while spacers are injection molded of 45 percent glass-reinforced polyphthalamide (PPA). Both materials required high molding precision, dimensional accuracy, flame retardance and the ability to integrate functional features that facilitate assembly. Versus aluminum, both mass and cost are reduced. GM is the systems supplier; Novares Group is the processor; Liberty Molds is the toolmaker; RTP Co. and Solvay SA are the material suppliers; the polymers are RTP 299 K X 133837 E Black PAA for side plates and Amodel A-1145 HS BK 324 PPA/glass fiber 45) for the repeating frames.
Engineering Team Winners Will Be Feted at November Gala
The OEM and supplier teams that worked on the 2024 Chevrolet Corvette E-Ray will be honored at this year’s SPE Automotive Innovation Awards Gala on Nov. 8, at Burton Manor in Livonia, Mich.
SPE’s Automotive Innovation Awards Program is the oldest and largest competition of its kind in automotive plastics. The annual event typically draws up to 800 OEM engineers, automotive and plastics industry executives, and media. Funds from the event support SPE educational efforts and technical seminars.