A five-door production hatchback served as a base point for engineers to design and develop a range-extended electric vehicle (ReEV) propulsion system.
One of several vehicles on display at booth 1425, the Dodge Caliber ReEV concept showcases an FEV-developed propulsion system with the company's technical specialists handling numerous tasks, including design, analysis and packaging; performance modeling and simulations; component selection and procurement; hybrid controls and powertrain development and testing; vehicle exhaust and evaporative emissions calibration; NVH optimization; and high-voltage system architecture, development, and integration.
"The packaging of the battery pack has, so far, been one of the main challenges," said Joachim Wolschendorf, Chief Technology Officer and the Vice President of the Vehicle and Drivetrain Engineering Division, FEV Inc. "We wanted to locate it in a safe area—without reducing any interior space—and avoid any crash-critical areas."
Replacing the production Dodge Caliber's four-cylinder engine (available in 1.8-, 2.0-, and 2.4-L displacements) is a 1.0-L, three-cylinder, four-valve engine. The engine is mated to a UQM PowerPhase75 generator, providing 41 kW of continuous power in extended-range mode and peak power of 75 kW. A 20 kW-h liquid-cooled lithium-ion battery pack operates at 346 V with a Delphi dc/dc converter. A UQM PowerPhase125EX traction motor powers the wheels.
"We packaged the engine and the generator in the engine compartment in conjunction with the traction motor and transaxle. The energy-storage system's battery is packaged into the tunnel area in a T-shape, so it is outside of any crash-critical area of the vehicle," noted Wolschendorf. "We did not consider a nickel metal-hydride battery for this application. Given the packaging challenges, we would have had to significantly reduce the goal of an all-electric range of 40 miles. Our target was to meet or exceed the performance specifications of the production vehicle. The acceleration performance was even improved by about 20 percent."
The project's overall R&D work remains unfinished. "The goal is to evaluate different operating strategies for the engine/generator unit initially within one of FEV's hybrid powertrain development test cells, while also evaluating different engine concepts—i.e., comparing a three-cylinder engine with a rotary engine. FEV can then place the selected propulsion system into the vehicle and calibrate the driveability with our hybrid chassis dynamometer prior to on-road validation," explained Wolshendorf. "Our objective is the vehicle [will have] a driveable calibration in the summertime."
FEV engineers started work on the compact hatchback a few weeks ago. "From the initial performance simulations and packaging studies to the demonstrator displayed at the SAE Congress, it was approximately a two-month duration," Wolschendorf said. "The most impressive feature of this vehicle is that we could use an existing production vehicle and convert it into a ReEV without a significant re-work of the vehicle and at the same time keep the full interior and trunk space. Essentially, this vehicle could come off the production line as a glider and the ReEV could be integrated as a bolt-on."