In the ongoing competition of powertrain concepts the Internal Combustion Engine (ICE) will also have to demonstrate its potential for increased efficiency [1]. Variable Compression Ratio (VCR) Systems for Internal Combustion Engines (ICE) can make an important contribution to meeting stringent global fuel economy and CO2 standards.
Using such technology a CO2 reduction of between 5% and 9% in the World Harmonized Light-Duty Vehicle Test Cycle (WLTC) are achievable, depending on vehicle class, load profile and power rating [2].
This paper provides a detailed description of the measurement approaches that are used during development of the AVL Dual Mode VCSTM and other VCR systems in fired operation.
Results obtained from these measurements are typically used to calibrate or verify simulation models, which themselves are an integral part of the development of these systems [3].
The described measurement tasks deal primarily with the analysis of physical phenomena in hydraulically actuated variable-length conrod systems. An interactive development between metrology, design and simulation experts is a key success factor and described here by means of selected measurement tasks.
In addition to measurements performed on the moving conrods, multiple methods using stationary sensors were developed for determining the piston position, and therefore the compression ratio. Significant effort is also devoted to the analysis of compression ratio switching events, as the switch times are an especially important aspect of any VCR system.