In recent years, the use of Continuously Variable Transmissions (CVT) in automotive applications has seen a strong worldwide growth. With a 10% annual growth rate, the CVT based on the pushbelt principle takes the lead. This growth, that is foreseen to intensify the coming years, is driven by several Key Performance Indicators (KPI). A first KPI is the high level of comfort, which for many consumers defines the benchmark. A second KPI is the excellent fuel economy of CVT equipped drivelines that responds to the present needs in the market. This paper discusses the efforts to support these KPI. While giving an update of the actual status on fuel economy, efficiency, power density and NVH, new developments are highlighted that enable further optimizations of the pushbelt CVT in an ever-demanding market.
Injury prediction based on data from event data recorder in automatic collision notification is expected to reduce trauma deaths. Known to affect on injury, the crash pattern is required to be classified to accurately predict injury. We performed crash simulations with a full-vehicle finite element model, and determined typical vehicle acceleration profiles of each crash pattern. A method to classify a crash pattern by comparing vehicle acceleration with the typical profiles was found to be effective. We also performed multi-body simulations with a vehicle interior and a dummy model, and developed injury prediction algorithms of each crash pattern.
In this paper, the necessary in-cylinder conditions for the transition from spark ignion (SI) to homogeneous charge compression ignition (HCCI) are analyzed. The hereby important factors for ignition time are investigated analytically. A control oriented combustion model, that is validated by experimental data, is used for sensivity analysis and a Monte-Carlo approach is taken to identify the important factors for transient HCCI and combustion mode switch.
As a result, it was shown that the in-cylinder temperature plays a major role, exceeding other factors, such as the air-fuel ratio. The analytical conclusions are illustrated by numerical simulations after which the feasibility for actuation will be discussed. Final goal is to ensure a stable combustion in each cycle without crossing unstable combustion conditions.