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The development of a Powertrain Matching Analysis Tool (PMAT) addresses the challenge of matching the powertrain hardware and control strategy to specific vehicle attributes and driver applications for improved overall vehicle system efficiency. PMAT consists of a reverse tractive road load demand model and a dynamic optimization algorithm developed in MATLAB® and Simulink®. The reverse tractive road load demand model propagates the required wheel torque and speed derived from vehicle speed and road grade through the powertrain system to determine the required fuel flow for various states. The control strategy is treated as a multi-stage, multi-dimension decision process, where dynamic programming is applied to find an optimal control policy that minimizes the accumulated fuel flow over a drive cycle. PMAT is used to assess and develop transmission shift and lock-up control strategies, evaluate powertrain hardware configurations, and establish design criteria.

A greater understanding of where fuel energy is being demanded from a vehicle system standpoint is necessary for developing more fuel efficient vehicles. This paper presents an overview of the development and application of a vehicle energy analysis methodology and a MATLAB®/Simulink® based tool that uses empirical data and first principles to identify vehicle subsystem energy supply and demand. An accurate analysis requires the tool to be populated with chassis dynamometer drive cycle data as well as vehicle and component information. The tool can be used to investigate vehicle system energy requirements, prevailing fuel economy factors, and incremental hypothetical fuel saving scenarios that could not otherwise be measured due to inherent test-to-test variability.

The simultaneous demand for improvements to performance, drivability, emissions, and fuel economy are driving increasingly complex automotive powertrain solutions. New controls strategies are required to effectively manage and fully utilize the opportunities presented by these new powertrains. This paper outlines the advance powertrain controls development work underway within DaimlerChrysler Corporation, in support of these requirements. A powertrain coordination strategy that translates the driver demand into the most effective combination of all powertrain elements is described. A common interface to the powertrain elements is proposed.