ABSTRACT
Figure 1 shows the schematic of the experimental set-up. The pressure regulator of the CNG injector and the fuel rail which maintained the pressure in the line at a constant value was driven by an electronic operating system. The maximum of the instantaneous HC emission was measured by a Cambustion HFR500 fast response hydrocarbon analyzer. Additionally, the operating equivalence ratio was accurately from a CNG engine during the hot starting process for the stratified charge mode. A three-stage split injection strategy is adopted to achieve stratified combustion and low HC emissions. The primary injection performed in
1 INTRODUCTION
Because of limited reserves of petroleum, development of the start-stop system for significantly improving fuel economy with minimal cost or affect on vehicle performance has attracted more and more attention in the automotive industry. With the functionality of engine shut-down when the vehicle is stopped or decelerating, and rapid engine re-start for the vehicle launch, this technology can avoid unnecessary fuel consumption and CO2 emissions during periods where the engine is not being utilized [1]. In addition, This stop-start technology has recently been applied to some types of hybrid electric vehicles with belted starter alternators or integrated starter alternators, appearing to be even more successful in saving fuel on heavily congested roads or in city traffic [2].
