Abstract
Key words:
Diesel engine, fuel consumption optimization, mathematical model, informational system
ABSTRACT
The paper presents the theoretical and experimental researches made in order to design and test an onboard informational system having functions of indicating the appropriate actions to be taken by the driver to optimize the fuel consumption. The system is useful mainly for diesel engines with direct injection, which usually equip off-road vehicles. The research methodology had its starting point in obtaining the mathematical models necessary to draw the optimum functioning map of the engine. For a diesel engine of such type, following the system identification type procedures, the authors obtained the algorithms of the dependences among the specific fuel consumption, effective engine torque and engine speed. Analyzing this map, the economical functioning fields were traced, this way establishing for the engine speed and engine torque the maximum and minimum level depending on the nominal values, useful as input data for the informational system. The design of the system initially imposed the working out of the specific procedures and of the logical diagram, then based upon this, the authors devised (with the use of some overlap comparator connections, signal adapters and solid-state circuits) the followings: velocity step detector, real speed module, comparing maximum speed value per gear module, speed engine comparing and engine torque comparing modules. The implementation of the logical diagram was made with AND, NAND, NOR gates and the conceived modules were integrated using the appropriate electronic components. The test of the informational system was made using programming sequences of some dedicated soft and the simulation of the optimization can be outlined with a vibration frequency meter module, the obtained results validating this technical solution.