Abstract
Although after-treatment devices have been widely employed to mitigate exhaust emissions from internal-combustion engines, backpressure produced due to the presence of such devices in the exhaust line negatively affects the engine working conditions. Hence, a 1.5L diesel engine equipped with integrated after-treatment device is used to see the interaction between after-treatment components and engine characteristics during loading phase. Besides, regeneration study is carried out to estimate the fuel penalty. The significance of this study is to assist the vehicle and catalyst designers to optimally lay out the integrated after-treatment system with optimum backpressure threshold, otherwise the engine will be at a high-risk working condition. According to the results, the current integrated after-treatment system has caused a 6% decline in both brake power and torque. By backpressure evolution from 3 to 22 kPa, more fuel is injected to overcome the power loss so that it leads to a 7% increase in brake-specific fuel consumption (BSFC). In fact, adverse effects of backpressure importantly emerge as fuel economy. On the other hand, engine thermal efficiency declines by 5% since pumping losses and friction increases. When particulates are fully accumulated and backpressure reaches to its threshold value of 22 kPa, regeneration process begins and the values of BSFC and thermal efficiency improve by 12 and 15%, respectively.