Characteristics of Particulates Emitted by IC Engines Using Advanced Combustion Strategies

Abstract

Particulates emission is a common problem for both conventional compression ignition (CI) and spark ignition (SI) engines, and it creates issues related to environment, human health, and engine efficiency. For particulate reduction, the use of after-treatment systems/devices has been debated since last two decades; however, cost and system complexity issues are the main hurdles for adaptation of these systems in the engines. Therefore, advanced combustion technologies have been developed to achieve cleaner combustion, especially lower oxides of nitrogen (NOx) and particulates. Most of these advanced combustion strategies are categorized as low temperature combustion (LTC). LTC is a novel combustion technology, in which simultaneous reduction of NOx and particulates can be achieved without affecting the engine performance. LTC strategies include mainly homogeneous charge compression ignition (HCCI), partially-premixed charge compression ignition (PCCI), and reactivity controlled compression ignition (RCCI) combustion. In LTC strategies, early fuel injection provides sufficient time for fuel–air mixing before combustion, or a homogeneous fuel–air mixture is supplied to the combustion chamber, which results in complete absence of fuel-rich regions, leading to lower particulate formation. This chapter discusses all these advanced combustion technologies and describes the effect of different control parameters on particulate characteristics emitted from these strategies. A section including particulate formation mechanism and its structure has been included in this chapter for better understanding of the effects of different parameters on particulate emissions. This chapter presents the current technology status and the future research directions for these technologies so that these combustion concepts can be adapted for developing new generation vehicles.