# Effects of Propanol on the Performance and Emissions of a Dual-Fuel Industrial Diesel Engine
## 4 Conclusions  
The paper presents experimental studies of a dual-fuel compression-ignition engine powered by diesel and propyl alcohol. The engine allowed for the co-combustion of conventional hydrocarbon fuel with biofuel, the energy share of which was up to 65%. The combustion process in the cylinder and the engine exhaust emissions were analyzed. Based on the research results, it can be concluded that:  
* with an increase in the proportion of propanol, the value of the maximum pressure (p\({}_{\text{max}}\)) increases to its 50% share in relation to the value obtained for the reference fuel; the highest difference in p\({}_{\text{max}}\) is for 30% propanol and it was 0.3 MPa;
* analyzing the courses of the heat release rate and the peak pressure rate, it can be seen that up to 30% propanol share, there is a clear increase in HRR and PPR, by approximately 30 J/deg and 0.25 MPa/deg, respectively, compared to the diesel fuel supply;
* an increase in the proportion of propanol in the process of co-combustion with diesel fuel causes an increase in the ignition delay time; significantly reduces the combustion duration (CD);
* the highest ITE was recorded for a 50% proportion of propanol, compared to D100 it was higher by 1.95%,
* the proportion of propanol in the combustion process in a compression ignition engine increases the COVIMEP value by nearly 2%, for a share of 15 to 50%, which proves a slightly deteriorated stability of the engine operation;
* the combustion of diesel fuel with propanol, up to 30%, causes an increase in nitrogen oxide emissions, for DP30 compared to D100 there was an increase by 292 ppm,
* the co-combustion of diesel with propanol, up to 50%, contributes to a decrease in HC emissions, for DP15, DP30 and DP50 the decrease was respectively 56 ppm (26.5%), 47 (22.3%) ppm and 39 ppm (18.5%);
* the addition of alcohol in the fuel-air mixture supplied to a compression-ignition engine results in a significant reduction of the soot concentration in the exhaust of this engine; the highest, almost complete reduction was recorded for DP65, which was 1114 mg/m\({}^{3}\).  
It turns out that powering the engine in a dual-fuel system, even with such an old design, gives positive results. Having a modern injection system opens up several interesting possibilities, such as the optimization of the engine thermal cycle according to the CA50 angle, the influence of the pilot dose, or a more advanced distribution of the diesel fuel stream. A modern injection system will most likely minimize the amount that initiates combustion.  
Figure 11: Soot emission for dual-fuel engine fueled by diesel and propanol.  
**Author Contributions:** Conceptualization, A.J., W.T. and K.G.-R.; data curation, A.J., W.T. and K.G.-R.; formal analysis, A.J.; investigation, A.J., W.T. and K.G.-R.; methodology, A.J. and W.T.; writing--original draft, A.J.; writing--review and editing, W.T. and K.G.-R. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Ministry of Science and Higher Education of Poland from the funds dedicated to scientific research No. BS-PB-1-100-3011/2021/P.  
Not applicable.  
The authors declare no conflict of interest.