When the Dodge electric muscle car hits the streets in 2024 it could show up with a high-performance pushrod suspension designed by Italian engineers. Patent documents discovered within the U.S Patent and Trademark Database by MC&T indicate upcoming battery electric vehicles from Stellantis are likely to use a pushrod suspension setup using horizontal dampers, active control elements, coupled with either a transverse leaf spring or traditional coil springs. While they’ve been around for a while, pushrod suspension setups are considered to be exotic, and are normally reserved for motorsports applications like Formula 1. Below is a 10-year-old Engineering Explained video showing how pushrod suspension systems work:
The document predates the creation of Stellantis and was originally filed in 2019 by Fiat Chrysler Automobiles as a solution for Dodge, Chrysler, Alfa Romeo, and Maserati electric vehicles. The Italian engineers outline a new way of packaging electric drive unit subassemblies using horizontal suspension dampers which could be installed either above or below the electric drive motor.
One of the obvious benefits is a reduction in the vertical dimensions of the suspension, offering benefits in terms of front-end aerodynamics or rear cargo space. The document also claims the horizontal layout would provide a considerable reduction of suspension stresses due to optimized force transfer. Movement of the control arm would be transferred via pushrod to a rocker arm which in turn compresses the inboard damper. Along with Formula 1, similar pushrod suspension applications can be found throughout the motorsport world, including IndyCar, and IMSA or WEC prototypes.
According to the document, the preferred embodiment would employ a transverse leaf spring, likely made of composite material, similar to the C7 Corvette. Transverse leaf springs offer packaging and weight-saving advantages, and the drawings indicate that a leaf spring could be mounted above or below the electric motor depending on damper placement. The other embodiment includes coil springs and damper-mounted actuator devices for active suspension control, these would be mounted above the electric motor due to the larger size of the damper assembly.
It’s made clear the horizontal damper arrangement has been developed with performance in mind. The document states “the ability to arrange each steering axis along a direction passing through the wheel center gives the possibility of exploiting the very high torque provided by electric motors”. As a bonus, FCA’s design of this pushrod setup would have zero kingpin offset and would eliminate any variations in caster angle under hard braking.
At the time, FCA was aiming to create an electric vehicle subassembly that could be integrated into a modular production vision which would simplify production and reduce cost. Fast forward today and those goals sound a lot like the upcoming STLA modular BEV platforms, specifically the three unibody programs STLA Small, Medium, and Large. It’s believe that the arrival of STLA modularity spells the end of the athletic Alfa Romeo Giorgio platform, the stalwart Chrysler LX platform, and the Fiat Compact Wide platform.
By the looks of it, the transverse leaf spring design could be used for regular passenger cars and crossovers developed to utilize the STLA Small and Medium platforms. This is likely to make up the bulk of Fiat, Peugeot, Citroen, Opel, and Vauxhall products, including smaller Jeep BEV crossovers. The more exotic design with active suspension control could be reserved for Stellantis’ higher-end or higher-performance models expected to ride on STLA Large. This would include Dodge’s electric muscle car, Alfa Romeo’s electric Giulia replacement, and the electric Maserati Gran Turismo.