Controller Design for a Diesel Engine Eco Start/Stop System based on the Frequency Response Technique

The eco start/stop is a system implemented on micro hybrid vehicles and hybrid electric vehicles (HEVs). The job of this system is to start and stop the fuel engine in order to reduce fuel consumption and eventually, the product of pollutants in urban driving. The coupling of the alternator starter with the internal combustion engine either by a belt or being integrated is one of the most easily noticeable configurations in case of fuel economy savings. As starting the engine is a challenging drivability issue because of the torque demand, a perfect implementation of a belted alternator starter (BAS) technology contains a compensator in order to start and stop the engine quickly and smoothly with no or very little noise, vibrations and harshness (NVH) signature. This problem becomes even more critical in case of a diesel engine since the instantaneous compression torque is significantly larger. In this paper the design of the needed controllers via frequency response techniques for a BAS in a diesel engine is discussed. After that, the controllers are assessed in different fields to find out both the advantages and disadvantages of the controllers. Finally, a comparison between the controllers designed in this paper and the controllers designed in the relevant studies for the BAS in a diesel engine gives a technical point of view of the different characteristics of each controller and makes it easier to choose among them greatly.