Powertrain 2025 – 75 g CO₂/km One Base Engine for the Entire Fleet?

Authors

Matthias Kratzsch, Dr. Christoph Danzer, Tobias Günther, Gerrit Albrecht, Mark Vallon,
IAV GmbH, Berlin

Summary

Globally optimized hybrid powertrains can be identified for not only for single vehicle applications but also for the complete fleet. The optimal fleet configuration largely depends in detail on boundary conditions, such as performance requirements, hybrid functionalities, the applied operating strategy, cost scaling effects and the share of sales. In this context, IAV developed the methodology of Powertrain Synthesis, which provides a way of systematically investigation of all technically feasible combinations
of engines, electric motors and transmissions by varying parameters, maps and technologies. The methodology permits the transparent evaluation of global development potentials and sensitivities of different hybrid topologies for a flexible level of
detail. Besides simulating the fuel efficiency and performance behavior, cost models for the powertrain components are also integrated. Furthermore, a special platform tool can assess the large amount of powertrain solutions. This enables the identification of platform-optimal powertrain configurations for a complete vehicle fleet.

To identify fleet-optimal powertrain technologies a variation study was conducted for an exemplary fleet scenario. The systematic investigation of all possible powertrain configurations includes the variation of technologies and parameters for the engine, the transmission, the electric motor and the battery for three powertrain topologies and in total six different vehicles. The combination of those systems, parameters and maps leads to a number of about 40 Mio. powertrain configurations. For each individual variant a cycle simulation at WLTP, a detailed performance analysis and a
cost evaluation is carried out.

As an intermediate step the P0-topology with 15 kW and 48 V-components are assessed under fleet-conditions. This leads to a minimal fleet emission of 96.25 g/km CO2. With a P2-Hybrid topology a CO₂-emission level of less than 76 g/km can be
achieved with a fuel efficient technology combination of engine and transmission with in maximum only 50 kW electric peak power. To reduce the total powertrain costs for the vehicle fleet the combination of parameters, technologies, maps and layouts were
optimized under the restriction of only one base engine (equal number of cylinders and displacement) and maximum two different transmissions. This leads to the proposal of a 3-cylinder engine family with and without turbocharging and transmission systems with 4- and 6-speeds. This platform scenario increases the fleet
emission level of more than 81 g/km CO₂ but helps to reduce the additional average powertrain costs down to 764 € per unit compared with a conventional non-hybrid powertrain system.

Members Login