# Effect of PODE on Emission Characteristics of a China VI Heavy-Duty Diesel Engine  
Yanju Wei  
School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China; [EMAIL_ADDRESS] (YW. ); [EMAIL_ADDRESS] (Y.Z. ); [EMAIL_ADDRESS] (Z.Z. ); [EMAIL_ADDRESS] (_X.Z. ); [EMAIL_ADDRESS] (H.G.) Yajie Zhang  
School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China; [EMAIL_ADDRESS] (YW. ); [EMAIL_ADDRESS] (Y.Z. ); [EMAIL_ADDRESS] (Z.Z. ); [EMAIL_ADDRESS] (_X.Z. ); [EMAIL_ADDRESS] (H.G.) Zengqiang Zhu  
School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China; [EMAIL_ADDRESS] (YW. ); [EMAIL_ADDRESS] (Y.Z. ); [EMAIL_ADDRESS] (Z.Z. ); [EMAIL_ADDRESS] (_X.Z. ); [EMAIL_ADDRESS] (H.G.) Zhu  
School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China; [EMAIL_ADDRESS] (Y.W. ); [EMAIL_ADDRESS] (Y.Z. ); [EMAIL_ADDRESS] (Z.Z. ); [EMAIL_ADDRESS] (_X.Z. ); [EMAIL_ADDRESS] (H.G.) Y. Zhu  
School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China; [EMAIL_ADDRESS] (Y.W. ); zyj0509@stu. NOx and soot emissions can be balanced when adding PODE and gasoline to diesel by 10% volume simultaneously. By blending PODE and ethanol with diesel, the combustion and emission characteristics were studied by [PERSON] et al. [10] on a turbocharged heavy-duty diesel engine (Euro IV), and they found that alcohols can be used as cosolvent of PODE/diesel mixture, which prolongs the ignition delay, reduces brake thermal efficiency, accelerates the combustion rate at the later stage of combustion under different loads and significantly reduces HC and soot emissions with a slight increase in NOx emissions. [PERSON] et al. [11] measured and evaluated the emission performance of neat PODE and a blend of 10% PODE and 90% commercial diesel fuel in an old Euro-2 diesel car over the NEDC driving cycle. Their results showed that PM emissions of neat PODE could be reduced by 77%, which is under the value of Euro 4, but NOx and CO emissions increase, compared to diesel. The preceding studies demonstrated that PODE, alone or in combination with diesel, can significantly improve engine combustion while also lowering soot emissions, but the addition of PODE increased NOx emissions that also pointed out by other works [8; 12; 13]. However, some researchers have found positive conclusions about NOx emissions [5; 14; 15]. The EGR strategy is an effective method to control diesel engine NOx emissions [16]. By using diesel/PODE blended fuel, with an even higher EGR rate, diesel engines can change the trade-off relationship between NOx and soot emissions, making it easier to meet emission regulations. [PERSON] et al. [17; 18] carried out experiments with a single-cylinder engine to examine the effects of PODE and EGR rate on the engine combustion and emission characteristics. [PERSON] et al. [14] studied the influence of blending PODE coupled with EGR strategy on emissions of a six-cylinder heavy-duty diesel engine, too. Their above experimental results showed that PODE could improve BTE even at a high load with a higher EGR rate on the one hand, and on the other hand, it can reduce soot and NOx emissions significantly. Additionally, [PERSON] et al. [19] investigated the influence of EGR rates (0-40%) on the combustion and emission characteristics of n-butanol/diesel/PODE3-4 blends at low-temperature combustion mode in a diesel engine. The results show that as the EGR rate grows, the emission of NOx is sharply reduced; when the EGR rate is above 30%, as it grows, the emissions of soot, CO and HC drastically rise. As the EGR rate grows, the total particulate matter (PM) number concentrations first decline and then rise. From the above works, the engines with PODE/diesel blends are all under the China VI level. Therefore, it is important to re-evaluate the effects of diesel/PODE blends on emissions for China VI diesel engines. In particular, whether or not mixing in PODE has a negative impact on NOx emissions still remains inconclusive.