As a result of increased metropolitan expansion and industrialisation, global energy consumption is constantly growing. Currently, finite fossil fuels such as crude oil, natural gas, and coal are regarded as the primary energy sources. Petroleum prices have been highly volatile because of the heavy reliance on petroleum derivatives in energy generation and transportation (Sadaf et al., 2018; Kurowska et al., 2020). Both environmental and energy degradation are considered severe issues that may be alleviated using alternative green and sustainable energy sources. Bioenergy, wind, and solar energy are the primary renewable resources that might help reduce reliance on fossil fuels (Kurowska et al., 2020; Yaqoob et al., 2021). Because of the crucial need to lessen dependency on fossil fuels, technical improvements in the biofuel industry as an alternative to petroleum diesel has accelerated (Yaqoob et al., 2021). Biodiesel is mainly made from edible oils such as olive, sunflower, rapeseed, and palm oil. So far, the most significant impediment to the commercialisation of biodiesel production has been the high cost of feedstock (Poudel et al., 2017; Xie et al., 2020). WCO (waste cooking oil) has been proposed as a workable fuel for biodiesel generation. WCO application in biodiesel production offers various advantages, including lower biodiesel feedstock costs and less waste disposal (Aboelazayem et al., 2018; Hsiao et al., 2021). Diesel engines are a significant contributor to air pollution. Diesel engines, on the other hand, are appealing power units extensively employed in many industries due to substantial benefits over gasoline engines, such as reduced fuel consumption, fewer carbon monoxide emissions, greater torque characteristics, and improved durability (Ali et al., 2014; Ong et al., 2014; Yasin et al., 2014). Because of these features, diesel engines account for a significant share of the overall petroleum usage. Diesel engines, on the other hand, are the primary contributors to air pollution for many pollutants, particularly particulates and nitrogen oxides, due to their lean-burning nature and elevated temperatures and pressures in the combustion process (NOx). Thus, one of the most essential parts of current air quality management is the control of these emissions. According to research, diesel engines powered by palm oil can reduce emissions of smoke, particulate matter, hydrocarbons, sulphur oxide, and carbon monoxide (Kumar and Chauhan, 2013). As a result, several scientists and policymakers have collaborated to address challenges from different viewpoints. The epidemiological and toxicological effects of airborne contaminants were investigated. Diesel cars contribute significantly to the problem of particle air pollution, particularly in emerging Asian cities (Jin et al., 2014). Corn, starch, sugarcane, and other crops produce ethanol. Because ethanol has a high latent heat of vaporisation, it can reduce the intake in charge temperature inside the cylinder and greatly enhance volumetric efficiency (Sathiyamoorthi and Sankaranarayanan, 2017). Ethanol can be injected directly into the cylinder or blended with other fuels (Lei et al., 2012). At lower loads, one research found that a more significant proportion of ethanol with diesel reduced brake thermal efficiency (BTE) relative to diesel, but a lower ratio of ethanol with diesel boosted BTE (Kurre et al., 2015). This can be attributable to proper combustion diffusion. Over the whole load range, lower quantities of ethanol with Rice Bran Biodiesel (RBD) were evaluated (Venkata Subbaiah and Raja Gopal, 2011; Khan et al., 2019; Khan et al., 2020; Khan et al., 2021; Ullah et al., 2021; Raziq et al., 2022). Lean combustion and a lengthy ignition delay let ethanol blends burn more fuel in the premixed combustion zone, increasing BTE for all blends. Another research looked at the mixture of biodiesel with ethanol and methanol (Venu et al., 2020). Adding methanol to biodiesel resulted in greater brake-specific fuel consumption (BSFC) than adding ethanol to biodiesel. BSFC rose as the concentrations of both alcohols increased. In a similar study, coconut biodiesel with less ethanol was tested (Yilmaz, 2012). B20E5 has a 2.0%–2.7% increase in fuel consumption. Compared to diesel, additives such as n-butanol and diethyl ether have lower BSFC and greater BTE (How et al., 2014; Imtenan et al., 2014). The antioxidant ingredient BHA is more stable than BHT in mixed biodiesel (Roy et al., 2014). It has been found that adding antioxidants to biodiesel lowers CO and HC emissions while increasing NO_x emissions (Xingcai et al., 2004; Tan et al., 2017). Blends of waste cooking oil and bioethanol from liquefied sago starch (LSS) reduced CO₂ emissions by 57% (Aydın and Öğüt, 2017). With ethanol emulsions in various amounts, NOx emissions rose at lower and higher engine speeds (Labeckas et al., 2014). While running faster, CO emissions from ethanol and biodiesel emulsions decreased dramatically (Fattah et al., 2014).

The literature review reflects that significant studies have been conducted to investigate compression ignition engine emissions using different fuels. However, minimal studies have been reported in the literature to investigate compression ignition engine parameters using clove oil. In addition, the analysis is made on a short-term basis. Moreover, carbon deposition was also not reported. Therefore, investigation of carbon deposition during the endurance test of C. I use biodiesel and clove oil as additives to better explore the engine’s life.

The objective of this study was to investigate the particulate matter (PM) emissions and carbon deposition in a four-stroke cylinder speed diesel engine when fueled with different blends of biodiesel and clove oil. The analysis was conducted under varying load conditions to assess the impact of fuel composition on engine performance and emissions the experimental setup shown in Table 1; Figure 1.

Particulate matter is a broad phrase that refers to a diverse array of air pollutants that vary in size and structure. Particulate matter is classified into coarse particles (more than 2.5 mm) and tiny particles (less than 2.5 mm). Soot is a small particulate matter (Kurien et al., 2018) Soot and soluble organic components comprise engine exhaust particulate matter (Bermúdez et al., 2015). Soot particles develop in the cylinder with high fuel and a low oxygen concentration, and soot absorbs soluble organic fractions on its surface (Serrano et al., 2016; Kurien et al., 2018). Several phases Fuel pyrolysis produces precursors or the fundamental building blocks for soot by changing the molecular structure of organic molecules in fuel at high temperatures in the presence of low oxygen concentrations (Mohankumar and Senthilkumar, 2017). The fuel’s carbon and hydrogen content also influences the soot formation rate, i.e., a higher carbon content in fuel leads to a higher soot formation rate and vice versa. (Trubetskaya et al., 2018). Adding biodiesel and clove oil could reduce particulate matter emissions from the engine (Rusli et al., 2022). This research aimed to see how different fuelling alternatives, such as pure diesel, biodiesel mixed, and biodiesel blended with clove oil, affected particle matter emissions significantly in standard diesel engines with little or no modification. Figure 1, PM1.0 displays the findings of average percentages of particulate matter emission as D100 (39.46%), B30 (29.97%), and B30+CL (26.093%), showing that PM1.0 is greater in diesel fuel than in biodiesel mixed with clove oil. Figure 2 depicts PM2.5 outcomes such as (40.62%), (33.38%), and (25.98%) respectively, lower values in biodiesel and antioxidants. Figure 3 PM7 results (39.20%), (33.90%), and (26.88%) and Figure 4 PM10 results of average percentages of particulate matter emission such as (36.66%), (34.78), and (28.67%) D100, B300, and B30 +CL, respectively, from the results show that particulate matter emission level of PM1, PM2.5, PM7, and PM10 higher in diesel fuel to compare with Furthermore, added clove oil to biodiesel as an antioxidant improves the oxidative stability of the biodiesel. Compared to mixed biodiesel diesel, when antioxidants are added to biodiesel blends, the percentage of particulate matter emissions is lowered.

Table 3 shows the particulate emissions from compression ignition engine using biodiesel and clove oil as a blended fuel, when operated for 25 and 50 h.

• Particulate Matter Emissions: Were highest with pure diesel fuel (D100), reduced with biodiesel blended fuel (B30), and lowest with the addition of clove oil to the biodiesel blend.

The addition of clove oil at 3000 PPM to biodiesel blends offers a promising approach to improving combustion efficiency, reducing particulate emissions, and minimizing carbon deposition in compression ignition engines. These findings highlight the potential environmental and operational benefits of using clove oil as an additive in biodiesel fuels shown in (Figures 7, 8).