6. Observation and measurement methods

Historically, for the injection function, various classic forms of flowmetering have been used to estimate the quantity of fuel injected. However, more detailed determination of droplet size, fuel distribution in the chamber or instantaneous injector flow rate has been developed and is now beginning to find industrial application. A schematic description of these techniques gives an overview of the possibilities open to designers and developers. The measurement methods available for internal combustion engines are limited by the high values of certain variables (combustion chamber temperature and pressure), and also by the short time frame in which certain phenomena take place (pulsed flows). It should also be noted that some of these measurements (flow, temperature, pressure, displacement, concentration) have to be taken on board production engines to provide the ECU with the data it needs...