Engine Test Research Articles

Advanced Numerical Analysis of In-Cylinder Combustion and NOx Formation Using Different Chamber Geometries

In diesel engines, emission formation inside the combustion chamber is a complex phenomenon. The combustion events inside the chamber occur in microseconds, affecting the overall engine performance and emissions characteristics. This study opted for using computational fluid dynamics (CFD) to investigate the combustion patterns and how these events affect nitrogen oxide (NOx) emissions. In this study, a diesel engine model with a flat combustion chamber (FCC) was developed for the simulation. The simulation result of the heat release rate (HRR) and cylinder pressure was validated with the experimental test data (the engine test was conducted at 1500 rpm at full load conditions). The validated model and its respective boundary conditions were used to investigate the effect of modified combustion chamber profiles on NOx emissions. Modified chambers, such as a bathtub combustion chamber (BTCC) and a shallow depth chamber (SCC), were developed, and their combustion events were analysed with respect to the FCC. This study revealed that combustion events such as fuel distribution, unburnt mass fractions, temperature and turbulent zones directly impact NOx emissions. The modified chambers controlled the spread of combustion and provided better fuel distribution, improving engine performance and combustion rates. The SCC (63.2 bar) showed peak pressure rates compared to the FCC (63.02 bar) and BTCC (62.72 bar). This study concluded that the SCC showed better results than other chambers. This study further recommends conducting lean fuel mixture combustion with chamber modifications and optimising fuel spray, such as by adjusting the fuel injection profile, spray angle and injection timing, which has a better tendency to create complete combustion.

Engine performance of a single cylinder direct injection diesel engine fuelled with blends of Jatropha Curcas oil and standard diesel fuel

Blends of Jatropha Curcas oil and standard diesel fuel were evaluated (without pre-heating). The engine tests for the blends were performed in a Petter single cylinder direct injection diesel engine under steady state conditions at high loads. Engine speeds between 1300-1700 rpm were selected for the engine tests. Torque, power output, specific fuel consumption, in cylinder pressure, ignition delay, rate of heat released and exhaust composition were evaluated. The tested blends between 10-20% of oil shown lower effective torque and power output joint to a higher specific fuel consumption related to the lower heating value of Jatropha oil compared to diesel fuel. Lower pressure peaks and rates or pressure rises were observed when Jatropha blends are used. A decrease in the rate of heat released and shorter ignition delay were observed for the blends. Decreases in HCand CO emissions were observed for blends compared to diesel fuel. Both alternatives assessed shown that the differences observed compared to diesel fuel, can be partially restored with engines regulation. The use of Jatropha oil in order to be a partial or full alternative to the use of diesel fuel for energy production was achieved.

Performance of a single cylinder diesel engine fuelled with emulsified residual oleins and standard diesel fuel

Emulsified residual oleins and standard diesel fuel were evaluated. The engine tests for the fuels analyzed were performed in a Petter single cylinder direct injection diesel engine under steady state conditions at fixed torque values (20 Nm and 34 Nm) and the engine speeds (n) between 1300-1700 rpm. Power output, specific fuel consumption, ignition delay and exhaust composition were evaluated. The emulsified residual oleins (ERO) shown lower power output joint to a higher specific fuel consumption related to the lower heating value of residual oleins compared to diesel fuel. A shorter ignition delay was observed for the ERO. Decreases in NOx emission were obtained for ERO compared to diesel fuel. The use of ERO in order to be a partial or full alternative to the use of diesel fuel for energy production was achieved.

Pilot scale production of biodiesel from Azolla oil via heterogeneous catalysis and diesel engine analysis: kinetic and techno-economic analysis considerations

ABSTRACT The use of Azolla pinnata oil for the production of biodiesel, coupled with the use of industrial waste dolomite as a catalyst, represents a novel approach with significant potential. This innovative process offers several key advantages, such as utilizing a non-edible feedstock, reducing waste generation, and providing an alternative to fossil fuels. This research aims to investigate the viability of creating biodiesel using Azolla pinnata oil and evaluate its technical and economic appropriateness for large-scale manufacturing. A pilot plant reactor with a 10 L biodiesel capacity carries out the transesterification reaction, using dolomite from industrial waste as a heterogeneous catalyst. The reaction was conducted for 4 h at a temperature of 70°C, and biodiesel yielded approximately 99.14%. Aspen Plus is employed to simulate and design a biodiesel plant, with the reaction kinetics derived from the pilot plant reaction and inputted into Aspen Plus. Plant optimization and economic analysis are performed using the Aspen Economic Analyzer. The biodiesel blends (Azolla 20, Azolla 40, and Azolla 60) were tested in a CI engine and compared with diesel results. Based on the engine test results, the Azolla 20 blend provides less HC (12.9%), CO (13.07%), and smoke (10%) emissions; therefore, it can serve as a better alternative to neat diesel. The primary units of the proposed plant have been designed, and the process’s economic viability was determined. It was discovered that the total capital investment needed is approximately 5.054 million USD, which will be repaid within 1.97 years of operation. This research encompasses pilot plant experiments, process simulation, engine testing, and economic analysis, demonstrating the novelty, technical feasibility, and potential socio-economic impact of this biodiesel production process.

Recursive signal denoising method for predictive maintenance of equipment by using deep learning based temporal masking

In the data driven predictive maintenance, high quality data is the premise of high accuracy diagnosis and prediction. In the industrial practice, reducing the noise is of great significance to ensure data quality. This paper proposes a recursive denoising method for manufacturing equipment signals in the data driven predictive maintenance. First, in signal decomposition method, equipment mixed signal is decomposed by temporal masking with dilated convolution neural network to generate a noise mask, which realizes signal decomposition of using recursive operation of temporal masking model. Second, in signal components recognition method, signal component features similarities are calculated, which act on the parameter regulation of signal recognition meta-learning model. The experimental results demonstrated that the proposed method effectively solves the noise reduction problem of the equipment signal. Further engineering tests of a chemical winding machine vibration signal decomposition and recognition show that the proposed method has strong adaptive performance for noise reduction.

Experimental study of lube oil pre-ignition in an optical gas engine test rig

Lean-premixed gas combustion is an attractive option for meeting future emission standards toward considerably lower particulate matter and emissions while obtaining an efficiency comparable to diesel combustion. However, ignition processes still pose considerable challenges, with pre-ignition being a major issue. The pre-ignition phenomenon might result from the self-ignition of lube oil in hot zones, making it challenging to observe in real engines. To study single or sparsely separated lube oil droplets under engine-like conditions, the “Flex-OeCoS” experimental test facility was used. To be able to induce such pre-ignitions artificially a novel piezo droplet injector was developed and manufactured, which enabled the metering of minor amounts of lubricating oil or even the injection of single droplets. High-speed cameras and specially developed and partially automatable and adaptive evaluation algorithms were used to record and track the behavior of the injected droplet using overlaid schlieren and OH* chemiluminescence. During the measurement campaigns, relevant operating parameters were varied, and optical investigations were carried out with an ignitable mixture on the Flex-OeCoS test facility under engine-relevant operating conditions. Spontaneous ignition of the vaporized lubricating oil was observed, which subsequently led to ignition of the whole air-fuel mixture in the optical combustion chamber. This was especially evident for lean methane-air mixtures up to an air-fuel ratio of 2.0. With this approach, information could be gathered about the necessary internal engine conditions that lead to pre-ignition in lean mixtures and where their limits lie.

Development of thermo-physical property database and code of fusion materials for CFETR blankets

The conceptual design of China Fusion Engineering Test Reactor (CFETR) has been completed and is currently in the engineering design phase. In this paper, focusing on three categories of candidate blanket designs and divertor designs, the selection schemes for materials of plasma-facing components, solid structure, tritium breeding materials, neutron multiplier, coolant, and divertor were extracted. Thermo-physical property data was compiled to form a material thermo-physical property database, named Thermo-physical Property Database (ThePD), which is the first advanced thermo-physical database for materials of CFETR blankets. Besides, the callable code was generated, which can be directly applied in the system code for the blanket. Based on internationally available database from National Institute of Standards and Technology (NIST) and similar software AP1700, the correctness of the data and the transitional analysis of regions designed by International Association for the Properties of Water and Steam (IAPWS) were verified. Using the thermal-hydraulic system analysis code, integrated validation was performed for the validated thermo-physical property data and code, demonstrating the applicability and accuracy of the data. ThePD is conducive to addressing the issue of incomplete thermo-physical property data faced by blanket design and safety analysis software for CFETR, and it can fill this gap.

A Model of How Students Engineer Test Cases With Feedback

Background and Context. Students’ programming projects are often assessed on the basis of their tests as well as their implementations, most commonly using test adequacy criteria like branch coverage, or, in some cases, mutation analysis. As a result, students are implicitly encouraged to use these tools during their development process (i.e., so they have awareness of the strength of their own test suites). Objectives. Little is known about how students choose test cases for their software while being guided by these feedback mechanisms. We aim to explore the interaction between students and commonly used testing feedback mechanisms (in this case, branch coverage and mutation-based feedback). Method. We use grounded theory to explore this interaction. We conducted 12 think-aloud interviews with students as they were asked to complete a series of software testing tasks, each of which involved a different feedback mechanism. Interviews were recorded and transcripts were analyzed, and we present the overarching themes that emerged from our analysis. Findings. Our findings are organized into a process model describing how students completed software testing tasks while being guided by a test adequacy criterion. Program comprehension strategies were commonly employed to reason about feedback and devise test cases. Mutation-based feedback tended to be cognitively overwhelming for students, and they resorted to weaker heuristics in order to address this feedback. Implications. In the presence of testing feedback, students did not appear to consider problem coverage as a testing goal so much as program coverage . While test adequacy criteria can be useful for assessment of software tests, we must consider whether they represent good goals for testing, and if our current methods of practice and assessment are encouraging poor testing habits.

Particle Number Concentration and SEM-EDX Analyses of an Auxiliary Heating Device in Operation with Different Fossil and Renewable Fuel

Pollution from road vehicles enters the air environment from many sources. One such source could be if the vehicle is equipped with an auxiliary heater. They can be classified according to whether they work with diesel or gasoline and whether they heat water or air. The subject of our research series is an additional heating system that heats the air, the original fuel is gasoline. This device has been built up in a modern engine test bench, where the environmental parameters can be controlled. The length of the test cycle was chosen to be 30 min. The tested fuels were E10, E30, E100 and B7. A 30-min operating period has been chosen in the NORMAL operating mode of the device as a test cycle. The focus of the tests was particle number concentration and soot composition. The results of the particle number concentration showed that renewable fuel content significantly reduces the number concentration of the emitted particles (9.56 × 108 #/cycle for E10 vs. 1.65 × 108 #/cycle for E100), while B7 causes a significantly higher number of emissions than E10 (3.92 × 1010 #/cycle for B7). Based on the elemental analysis, most deposits are elemental carbon, but non-organic compounds are also present. Carbon (92.18 m/m% for E10), oxygen (6.34 m/m% for E10), fluorine (0.64 m/m% for E10), and zinc (0.56 m/m% for E10) have been found in the largest quantity of deposits taken form the combustion chamber.

Effect of pilot fuel quantity and fuel injection pressure on combustion, performance and emission characteristics of an automotive diesel engine

The work presented here experimentally investigates the effect of pilot quantity (PQ) on combustion, performance and emission characteristics of an automotive diesel engine. All the experiments were performed at max torque speed of the test engine (1600 rpm) and 75 % of full engine load. Three PQs under consideration are 10 %, 20 % and 30 % of total fuel mass per cycle while maintaining the fixed pilot as well as main injection timings. The minimum PQ (10 %) considered in the study was found sufficient to enhance the in-cylinder thermodynamic conditions before main injection starts. Also, fuel injection pressure (FIP) was maintained constant at 500 bar initially. Obtained results showed that the pilot injection mode with 30 % PQ reduced nitrogen oxide (NO) emission as well as brake specific fuel consumption (BSFC) by 21.87 % and 1.46 % respectively compared to reference single injection mode while smoke emissions were increased by 77.64 %. In order to curb this negative effect of higher smoke emissions offered by pilot injection, FIP was increased from 500 bar to 700 bar and similar experiments were repeated. The experimental results demonstrated that higher FIP significantly reduced smoke emissions as well as fuel consumption under all the considered pilot injection modes with acceptable rise of NO emission which was still considerably lower than reference single injection mode. For e.g., when FIP was increased from 500 bar to 700 bar in case of pilot injection mode with 30 % PQ, smoke emissions and BSFC were reduced by 26.40 % and 2.14 % respectively, while NO emission was increased by 6.30 %. Therefore, it can be said that combination of pilot injection and high FIP leads to overall improvement in performance and emission characteristics of the test engine.

Equivalent simulation method for total pressure distortion of ship inlet

According to the use of marine gas turbines, inlet distortion is caused by the bending of the compressor inlet port. The total pressure distortion is the external stability reduction factor that has the greatest impact on the engine’s aerodynamic stability. This research designs a pressure distortion simulation device, which achieves the goal of providing the target distortion flow field for marine compressors by inserting plugboards of different heights and shapes into the inlet duct. The variation pattern of the entire flow field after inserting different parameter plugboards is obtained through distortion experiments and numerical simulations. Summarizes a prediction formula for total pressure distortion under different working conditions, with a verified error of less than 1.5%. In addition, the straight plugboard is changed to arc plugboard or concave and convex plugboard, the total pressure distortion distribution pattern can be changed while the range of the circumferential low-pressure zone remains unchanged. The distortion index of the distortion simulator designed by this research institute can be adjusted within the range of 0.5%–5%, while providing various distortion pattern. The distortion simulator meets the requirements of the comprehensive distortion index needed for the relevant distortion test of the marine engine and provides assistance for ship engine design and optimization.

ВОЗДУШНЫЙ РЕЖИМ ВЫСОТНЫХ ЗДАНИЙ

The air regime of multi-stores buildings is formed under the influence of wind pressure, air per-meability of enclosing structures, and the characteristics of the functioning of ventilation systems. The complex task of ensuring standardized air parameters in high-rise buildings is quite complex due to the presence of the stack effect, the action of which in the cold season leads to an increase in infiltration and energy consumption. In design practice, infiltration calculations are carried out using engineering methods that do not provide identical solutions. To assess the impact of in-filtration on the air regime of unique buildings, numerical calculations or modeling in wind tun-nels are used, which have a certain degree of reliability. The paper reviews the work on the influ-ence of the stack effect on the location of the neutral axis of the building and infiltration. One of the main measures to reduce infiltration is the use of façade structures with low air permeability. The selection of façade structures is more reliably carried out taking into account test results. Ex-perimental data are presented for determining the air permeability of a fragment of a modular fa-cade and their comparison with the regulatory requirements of the Russian Federation and differ-ent countries. The discrepancy between the calculation results using engineering methods and test results is shown. It is proposed to use the volume flow coefficient to determine the volume of infil-tration air when the pressure difference changes over a wide range. Tested structures can be rec-ommended for high-rise buildings to ensure the required tightness.

Influence of Stress Disturbance on the Deformation of Nearby Cemented Roadways following the Excavation of Chambers

Based on the engineering background of weakly cemented roadways and adjacent chambers in Western China, a numerical simulation method was used to examine the changes in stress distribution and increment in the surrounding rock of weakly cemented roadways adjacent to chambers. The results show that the surrounding rock stress of the weakly cemented roadway adjacent to the chambers increases by approximately 30%. The vertical stress of the surrounding rock mainly expands along the vertical direction, and the expansion range is 7–12 times that of the chamber height. The horizontal stress of the surrounding rock mainly expands along the horizontal direction, and the expansion range is 3–6 times that of the chamber width. Based on the support idea of “allowable deformation” + “relief pressure” + “maintaining roadway shape”, the support technology of weakly cemented roadways adjacent to chambers is established with “full section U-shaped steel shed + filling flexible materials between the steel shed and surrounding rock + patching the roof bolt + laying concrete on floor”. An engineering test based on the above support technology was carried out, and it was found that the deformation of the weakly cemented roadway adjacent to the chambers was 0 in 20 days.

UEDGE modeling of plasma detachment of CFETR with ITER‐like divertor geometry by external impurity seeding

AbstractEfficient handling of high heat flux on the plasma‐facing components, particularly the divertor targets, poses a significant challenge for the Chinese Fusion Engineering Testing Reactor (CFETR) with fusion power of Gigawatt. This work investigates the divertor plasma detachment of CFETR with a standard ITER‐like divertor geometry by neon (Ne) or argon (Ar) impurity seeding using UEDGE code. The cross‐field drifts terms are switched off, and fluid neutral models and a “fixed‐fraction” impurity model are applied to enable efficient simulations for the study of CFETR detachment. In order to reduce the heat load on the divertor targets below the acceptable level (<10 MW/m2), the impurity fraction (f), pumping speed (S), and upstream density are varied to identify the suitable operations window during Ne seeding. The effects of Ne and Ar impurities on the plasma detachment are compared. It is found that with the power across the core‐edge interface PSOL = 200 MW and separatrix density of 2.8 1019 , Ne impurity fraction ≥1.7%, and Ar impurity fraction ≥0.24% can achieve the partial detachment. Achieving similar total radiation power (˜148 MW), the Ne fraction is 2.3% and the Ar fraction is 0.24%. Moreover, the simulation results indicate that Ar exhibits better power radiation efficiency and core compatibility compared with Ne.

Development and verification of tritium transport code based on RELAP5/MOD3.3 with generic model towards COOL blanket

Tritium evaluation is a critical issue in fusion reactors. For the tritium self-sufficiency and safety concern, it is crucial to develop tritium analysis techniques to study its behavior in various conditions including steady states and dynamic states. The supercritical CO2 cOoled Lithium-Lead (COOL) blanket is an advanced blanket concept for the Chinese Fusion Engineering Testing Reactor (CFETR) and one of its major functions is to realize tritium self-sufficiency. Therefore, it is necessary to conduct comprehensive analyses for design and optimization from the perspective of tritium transport. In this work, the tritium transport module is integrated inside RELAP5/MOD3.3. Then the modified RELAP5 facilitates transient analyses to examine coupled thermal hydraulics and tritium transport responses. The code includes 1-D tritium permeation, tritium transport in fluid and tritium extraction, which are associated with thermodynamic parameters to cover the multi-physics processes of the COOL blanket. The modified RELAP5 is verified by the code-to-code benchmark. The results demonstrate the successful integration of the tritium transport capabilities in RELAP5. Furthermore, the code is applied to the heat exchanger and simplified PbLi loop to obtain tritium concentration to highlight its capability in both generic modeling and dynamic analysis.

Discernment of transformer oil stray gassing anomalies using machine learning classification techniques

This work examines the application of machine learning (ML) algorithms to evaluate dissolved gas analysis (DGA) data to quickly identify incipient faults in oil-immersed transformers (OITs). Transformers are pivotal equipment in the transmission and distribution of electrical power. The failure of a particular unit during service may interrupt a massive number of consumers and disrupt commercial activities in that area. Therefore, several monitoring techniques are proposed to ensure that the unit maintains an adequate level of functionality in addition to an extended useful lifespan. DGA is a technique commonly employed for monitoring the state of OITs. The understanding of DGA samples is conversely unsatisfactory from the perspective of evaluating incipient faults and relies mainly on the proficiency of test engineers. In the current work, a multi-classification model that is centered on ML algorithms is demonstrated to have a logical, precise, and perfect understanding of DGA. The proposed model is used to analyze 138 transformer oil (TO) samples that exhibited different stray gassing characteristics in various South African substations. The proposed model combines the design of four ML classifiers and enhances diagnosis accuracy and trust between the transformer manufacturer and power utility. Furthermore, case reports on transformer failure analysis using the proposed model, IEC 60599:2022, and Eskom (Specification—Ref: 240-75661431) standards are presented. In addition, a comparison analysis is conducted in this work against the conventional DGA approaches to validate the proposed model. The proposed model demonstrates the highest degree of accuracy of 87.7%, which was produced by Bagged Trees, followed by Fine KNN with 86.2%, and the third in rank is Quadratic SVM with 84.1%.

Reducing NOx emission from palm biodiesel/diesel blends in CI engine: A comparative study of cetane improvement techniques through hydrogenation and fuel additives

In this study, the trans-esterification process prepared palm oil biodiesel and 20% biodiesel blended with diesel (PB20) by volume as test fuel. Unsaturated fatty acids are majorly influenced by biodiesel cetane number. This work examines two-fuel reformulation methods of fuel hydrogenation and addition of fuel additive di-tert-butyl peroxide (DTBP) to enhance the engine characteristics of a PB20 blend while maintaining emission control. A reactor (autoclave) was utilized for hydrogenating the palm biodiesel and examining the change in fuel composition using gas chromatography. DTBP is selected as the cetane enhancer and combined with PB20 at a 2000 ppm concentration. Tamson FBT equipment was utilized to evaluate the test fuel's filterability. The filterability, engine characteristics, and emissions were investigated for diesel (D0), PB20, HPB20, and PB20 + DTBP fuel blends in the compression ignition test engine. The FBT results reveal that PB20 and HPB20 have better filtration quality, which aligns with the standard requirements (ASTM D2068-14). An improved NOx (10.2%) and brake thermal efficiency (6.7%) are seen at engine full loads when using modified B20 fuels. The hydrocarbon, carbon monoxide, and smoke emissions decreased by 8.3%, 6%, and 10.14% compared to diesel fuel. Hence, partial hydrogenation has been a better approach to improving biodiesel trade-off features than DTBP addition.

The influence of plastic pyrolysis oil on fuel lubricity and diesel engine performance.

This study investigates the viability of using plastic oils derived from High-density polyethylene (HDPE), Polypropylene (PP), and Polystyrene (PS) as alternative fuels for diesel engines. The research focuses on comparing the physical and chemical properties, fuel lubricity, engine performance, combustion characteristics, and exhaust emissions of these plastic oils. Analysis revealed that PS exhibits different fuel properties compared to diesel, with a carbon range distribution similar to gasoline, while HDPE and PP properties closely resemble diesel fuel. To prevent potential engine damage, PS was excluded from engine tests. PP displayed the best fuel lubricity, attributed to its higher kinematic viscosity and sulphur content, reducing direct friction. Diesel followed, with PS and HDPE in decreasing order of lubricity. Diesel's lubricity was influenced by the 7% palmitic methyl ester content in the fuel. In engine tests, HDPE demonstrated BTE similar to diesel, while PP exhibited lower BTE due to combustion retardation, leading to increased energy losses and higher BSFC. The combustion characteristics, in-cylinder pressure, and heat release rate of HDPE closely resembled diesel, while PP showed significantly delayed combustion due to low oxygen content and higher kinematic viscosity. Notably, NOX emissions from PP were lower than diesel and HDPE at all engine loads due to heat losses, resulting in a low in-cylinder temperature unsuitable for NOX emission. HDPE produced higher NOX emissions than diesel at low and middle loads due to its higher H/C ratio, promoting high thermal NOX formation. HC emissions from both HDPE and PP were higher than diesel due to increased fuel supply, hindering chemical bond breakdown. Similarly, CO emissions increased for HDPE and PP due to insufficient time for complete combustion, with HDPE producing more CO due to its heavy composites and lower cetane index. Smoke emissions from both HDPE and PP surpassed diesel, attributed to lower oxygen and higher sulphur content, leading to increased sulphurate particulate matter formation, and lower fuel density referring to the high amount of fuel supplied to the engine.

Effect of Fuel Injection Strategies on Performance, Regulated and Unregulated Emissions of a Gasoline Compression Ignition Engine

Abstract Gasoline compression ignition (GCI) mode engines are characterized by partially premixed charge combustion, leading to significant and simultaneous reductions of nitrogen oxides and particulate matter emissions. However, gasoline compression ignition engine operation suffers from a limited operating window. Air preheating and low-research octane number fuels are required to improve the engine performance. This experimental study used a blend of 70% (v/v) gasoline and 30% diesel as test fuel in a direct injection medium-duty compression ignition engine. Experiments were carried out at 5- and 10-bar brake mean effective pressure (BMEP) engine loads at 1500–2500 rpm engine speeds using a triple injection strategy (two pilots and one main injection) for all test conditions. The combustion phasing was kept constant with respect to crank angle to produce a high power output. The investigations examined engine performance and regulated and unregulated emissions. The test engine was initially operated in conventional diesel combustion mode with diesel for baseline data generation. Gasoline compression ignition mode operation demonstrated a remarkable 16% increase in the brake thermal efficiency and a substantial reduction of 65% in nitrogen oxide emissions compared to the baseline conventional diesel combustion mode. The GCI engine exhaust showed higher concentrations of regulated emissions, namely hydrocarbons and carbon monoxide, and unregulated trace emissions, such as methane, acetylene, toluene, inorganic gaseous species, and unsaturated hydrocarbons.

Emission Properties of a Diesel Engine Fuelled with Snake Gourd Biodiesel and Blends

In this study, snake gourd biodiesel (SGB) was used as an alternative fuel in a four-stroke, one-cylinder, direct injection, 14.7 kW diesel engine. A test was carried out in which the engine was fuelled with petroleum diesel, SGB and five different blends of diesel/biodiesel (B10, B20, B30, B50 and B80). The test engine was run at 0 kW load and 12.3 kW load, and the results were analyzed. The biodiesel and its blends produced significantly less emissions than the petroleum diesel, which could be attributed to better combustion efficiency. The use of biodiesel resulted in lower emissions of CO, SO2, particulate matter (PM) and increased emissions of NO2. The results also showed that increasing the load from 0 kW to 12.3 kW resulted to an overall increase in the emissions and CO, SO2, and PM emissions were lower with SGB by 86.6%, 93.02%, and 91.80% at 0 kW load and 62.48%, 86.79%, and 72.72% at 12.3 kW load conditions. while NO2 emissions were higher by 90.91% and 93.02% at 0 kW and 12.3 kW load conditions respectively than that of the petrol diesel. This study showed that the exhaust emissions of SGB and its blends are lower than those of the petrol diesels, which indicates that SGB and its blends when used in diesel engines has more favorable effects on air quality.