**4.1 Combustion and emission characteristics of petroleum diesel fuels**

Figures 11 and 12 show the engine performance and emissions using conventional petroleum Diesel fuel at different engine speed or rotation per minutes (RPM). The engine starts running at low RPM (~ 1230 RPM) for six seconds after that the RPM of the engine was increased until it reached the maximum value of 3650 RPM. The engine performances (engine horse power and torque) and emissions (CO2, CO, HC and NOX) were recorded for about 18 seconds during this change of the engine RPM. Figure 11 shows that horse power increases from 2.3 HP at low RPM to about 8 HP at high RPM and the torque increases from 10 ft lb at low RPM to about 12 ft lb at high RPM. Figure 12 shows the variation of the engine emissions (CO2, CO, NOX, HCs) with the engine speed or RPM.

A gas analyzer DYNOmite EMS (See Figure 9) was used in this study to measure the emissions from the engine. The real time gas analyzer is used to measure the concentrations of oxygen (O2), carbon monoxide (CO), carbon dioxide (CO2), hydrocarbons (HC) and nitrogen oxides NOx. The gas emissions from the engine are recorded simultaneously during engine dynamometer testing using the data acquisition system. The torque; RPM; horse power; O2, CO, CO2, HC's and NOx concentrations are

The dynamometer data acquisition system (see Figure 10) is used to record the engine performance (Torque, RPM, and Horse power), fuel consumption and the exhaust gas emissions (CO, CO2, NOx, and HCs). All these data are recorded simultaneously during

Figures 11 and 12 show the engine performance and emissions using conventional petroleum Diesel fuel at different engine speed or rotation per minutes (RPM). The engine starts running at low RPM (~ 1230 RPM) for six seconds after that the RPM of the engine was increased until it reached the maximum value of 3650 RPM. The engine performances (engine horse power and torque) and emissions (CO2, CO, HC and NOX) were recorded for about 18 seconds during this change of the engine RPM. Figure 11 shows that horse power increases from 2.3 HP at low RPM to about 8 HP at high RPM and the torque increases from 10 ft lb at low RPM to about 12 ft lb at high RPM. Figure 12 shows the variation of the engine emissions (CO2, CO, NOX, HCs) with the engine

**4.1 Combustion and emission characteristics of petroleum diesel fuels** 

**3.4 Emissions characterization - Engine exhaust gas measurements** 

measured simultaneously.

Fig. 9. Gas Analyszer and emission probe

**3.5 Data acquisition system** 

**4. Results and discussions** 

engine testing.

speed or RPM.

Fig. 10. Data acquisition system

Fig. 11. Engine horse power, torque, and RPM - Petroleum Diesel fuel

Fig. 12. Engine emissions at different RPM - Petroleum Diesel fuel

Fig. 11. Engine horse power, torque, and RPM - Petroleum Diesel fuel

Fig. 12. Engine emissions at different RPM - Petroleum Diesel fuel

#### **4.2 Combustion and emission characteristics of biodiesel fuel blends**

Four different oil feed stocks were used in this study to produce pure bio-diesel fuel. The Biodiesel fuel produced from each oil feed stocks was converted into fuel blends of B5, B10, B15, and B20. The Biodiesel fuel blends are obtained by mixing biodiesel fuel with petroleum Diesel fuel (ex: B5: 5% Biodiesel and 95% Diesel fuel by volume). Two of the oil feed stocks are waste cooking oil collected from two different restaurants. The first waste cooking oil was collected from Coyote Jacks, a restaurant located inside the premises of Florida Atlantic University. This restaurant is more focused on deep fried fast food, and the oil is used over and over for up to 3 weeks before it is changed. The second waste cooking oil comes from J.C. Alexander restaurant located outside Florida Atlantic University. This restaurant uses its oil for shorter periods of time, and is mainly used to sauté food instead of deep frying. The reason for using two different waste cooking oils from two different places is to see if the quality of the oil feed stocks will affect the quality of the biodiesel produced. The third and fourth oils tested in this study were Peanut and Coconut oils (not used oils). The peanut and coconut oils have not been used for cooking prior to being converted into bio-diesel fuel. The procedure for each test was: (1) the engine was allowed to run for 2 minutes to allow the engine to clear any residue from previous tests with different fuel blends, and warm up the engine and catalyst, (2) after the 2 minutes warm up, the engine was run at high RPM (3550 rpm) for 5 minutes, (3) drop the engine speed to medium RPM (2400 rpm) and run the engine for 5 minutes, and (4) finally set the engine to low RPM (1250 rpm) and run for 5 minutes. The sampling rate was set to 1 Hz. This will produce a total of 300 data points for each RPM. For each Biodiesel fuel blend and for each RPM, the measurement was run at least three times to check the consistency of the data produced. The data produced from these tests includes: Torque (lbs-feet), Horse Power (HP), Carbon Dioxide CO2 (%), Carbon Monoxide CO (%), Oxygen O2 (%), Hydro Carbon HC (ppm) and Nitric Oxide NOx (ppm). The torque and horsepower readings where measured directly from the dynamometer, while the emissions where obtained from the gas analyzer. The mean value (over 5 minutes) of the diesel engine tests for low, medium and high RPM using petroleum diesel (benchmark) are shown in Table 1. It is noted that the horse power, CO2 and CO emissions increase and the HC and NOx emissions decrease when the speed (rpm) of the engine increases. The baseline data with the petroleum Diesel fuel will be compared to those obtained with Biodiesel fuel blends using different type of oil feed stocks. Typical results of the Diesel engine tests at high RPM using biodiesel fuel blends (B5, B10, B15 and B20) produced from waste vegetable oil coyote Jacks are shown in Table 2. The results show a small change of the engine horse power, torque, CO2 and NOx emissions when the amount of biodiesel blended with petroleum Diesel increases from 5% to 20%. The CO emissions dropped from 0.27% to 0.25% and the HC emissions from 14.06 ppm to 12.14 ppm.


Table 1. Mean value of the Diesel engine tests using petroleum Diesel


Table 2. Mean value of the Diesel engine tests at high RPM (3550) using Biodiesel Fuel Blends produced from waste vegetable oil Coyote Jacks

The results obtained in this study with the three other oil feed stocks (waste cooking oil JC Alexander, peanut and coconut oils) show the same trends. Figure 13 shows the percentage difference of the data obtained with the Biodiesel fuel blend B20 from the four oil feed stocks and the petroleum diesel fuel. The results show a net decrease of the Hydrocarbons HC and CO emissions for the B20 biodiesel fuel blend compared to the petroleum diesel fuel for all the four oil feed stocks. Biodiesel fuel contains fewer hydrocarbons than those present in petroleum diesel. It is natural to expect a decrease in HC emissions as the blends increase. The Hydrocarbons emissions for the B20 decreases by about 20% compared to the petroleum Diesel fuel. The carbon monoxide emissions decrease by about 12 % for the B20. Although the hydrocarbon HC and CO emissions decreased drastically, a small change (< 2%) of the engine power HP and CO2 emissions are reported for the B20 compared to the petroleum Diesel fuel. The NOx emissions also increase by about 2% for the B20. This is due probably to an increase of thermal NOx because of the combustion temperature increase for the B20.

Fig. 13. Percentage difference of the B20 (produced from different oil feed stocks) with Respect to Petroleum Diesel

Table 2. Mean value of the Diesel engine tests at high RPM (3550) using Biodiesel Fuel

of thermal NOx because of the combustion temperature increase for the B20.

Fig. 13. Percentage difference of the B20 (produced from different oil feed stocks) with

Respect to Petroleum Diesel

The results obtained in this study with the three other oil feed stocks (waste cooking oil JC Alexander, peanut and coconut oils) show the same trends. Figure 13 shows the percentage difference of the data obtained with the Biodiesel fuel blend B20 from the four oil feed stocks and the petroleum diesel fuel. The results show a net decrease of the Hydrocarbons HC and CO emissions for the B20 biodiesel fuel blend compared to the petroleum diesel fuel for all the four oil feed stocks. Biodiesel fuel contains fewer hydrocarbons than those present in petroleum diesel. It is natural to expect a decrease in HC emissions as the blends increase. The Hydrocarbons emissions for the B20 decreases by about 20% compared to the petroleum Diesel fuel. The carbon monoxide emissions decrease by about 12 % for the B20. Although the hydrocarbon HC and CO emissions decreased drastically, a small change (< 2%) of the engine power HP and CO2 emissions are reported for the B20 compared to the petroleum Diesel fuel. The NOx emissions also increase by about 2% for the B20. This is due probably to an increase

Blends produced from waste vegetable oil Coyote Jacks

Figure 14 shows the overall effect by averaging all the four diverse oils and normalizing them over the petroleum diesel (baseline data). It is shown clearly the benefits of Biodiesel fuel blends compared to the petroleum diesel fuel. The HC and CO emissions decrease drastically by increasing the amount of biodiesel blended with Diesel fuel, while the power of the engine is kept almost the same and the NOx emissions increase by not more than 2%.

Fig. 14. Overall percentage differences of biodiesel fuel blends with respect to petroleum Diesel
