DYNAMOMETER EMISSIONS TEST COMPARISONS ON A 5.9L DIRECT INJECTED DIESEL POWERED PICKUP. Jeffrey S. Taberski and Charles L.

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1 DYNAMOMETER EMISSIONS TEST COMPARISONS ON A 5.9L DIRECT INJECTED DIESEL POWERED PICKUP Jeffrey S. Taberski and Charles L. Peterson ABSTRACT A pickup truck with a 5.9 L turbo-charged and inter-cooled direct injection diesel engine was tested for regulated emissions at the Los Angeles County Metropolitan Transit Authority Emissions Testing Facility. Emissions testing was conducted using the Dynamometer Driving Schedule for Heavy Duty Vehicles (40CFR Part 86, Appendix 1, Cycle D). Emissions data generated included total hydrocarbons (HC), carbon monoxide (CO), carbon dioxide (CO& oxides of nitrogen (NOx) and particulate matter (PM). The vehicle was tested in 1995 at 5,955 km (3,700 miles) and again in 1998 at 139,466 km (86,660 miles). The test data presented in this report represents the emissions of three biodiesel fuel blends. These fuel blends were certification low-sulfur #2 diesel fuel (diesel), 100% rape ethyl ester (looree), 50% REE-50% diesel (SOREE) and 20% REE- 80% diesel (20REE). All fuels were tested with and without the vehicle catalytic converter installed. The 1995 tests resulted in reductions of HC (63%) CO (34%), NOx (10%) and no difference in CO;! and an increase in PM (34%) compared to diesel. The 1998 tests resulted in reductions in HC (62%), CO (46%), NOx (9%), no difference in C02, and increases of PM (23%) for 100% REE compared to D2. The catalytic converter had only an effect on HC and PM. Keywords: biodiesel, emissions, chassis dynamometer INTRODUCTION The Los Angeles Metropolitan Transportation Authority (LAMTA) conducts exhaust emissions tests on heavy-duty vehicles at their Emissions Testing Facility (ETF). The ETF is a state-of-the-art laboratory specifically designed and built for the purpose of collecting exhaust emissions data from heavy-duty vehicles during transient chassis dynamometer operations. Biological and Agricultural Engineering Department, University of Idaho, Moscow, ID

2 Several different biodiesel fuel blends were evaluated during the testing program. This paper reports on this cooperative transient dynamometer test of gaseous emissions using the LAMTA ETF with diesel on-road vehicles fueled with vegetable oil esters produced by the Biological and Agricultural Engineering Department at the University of Idaho. Certification low-sulfur diesel fuel was also tested to provide a baseline reference point. The test vehicle used was a 1995 Dodge 3/4 ton, four wheel drive pickup truck with a 5.9-liter turbo-charged and inter-cooled Cummins diesel engine. The first test took place at 5,955 km (3,700 mi.) and the final test took place at 139,466 km (86,660 mi.). OBJECTIVES The objectives of this experiment were: 1) Obtain emissions data for 100% REE, and 50% and 20% blends of REE with diesel control fuel. 2) Compare regulated emissions data including total hydrocarbons (HC), carbon monoxide (CO), carbon dioxide (CO& nitrogen oxides (NOx), and particulate matter (PM), for REE, REE blends, and diesel control fuel; 3) Compare emission levels for the 1995 and 1998 tests using these fuels. 4) Determine baseline emissions data on the vehicle with and without the OEM catalytic converter and to determine catalytic converter efficiency after operating for a long period of time on 1OOREE. MATERIALS AND METHODS The emissions tests were conducted at the Los Angeles Metropolitan Transit Authority (LAMTA) Emissions Testing Facility (ETF) located in Los Angeles, California. This facility has instrumentation to measure all regulated emissions: total hydrocarbons (HC), carbon monoxide (CO), carbon dioxide (CO;?), nitrogen oxides (NOx), and particulate matter (PM). The ETF provides quality assurance test results and calibrations in accordance with California Air Resources Board (CARB) quality assurance recommendations (Dunlap, 1994). The vehicle tested was a 1995 Dodge 3/4 ton, 4x4 pickup truck rated at 3900 kg (8,600 lb.) gross vehicle weight (GVW). The vehicle was powered by a 5.9 liter, turbo-charged and inter-cooled Cummins* diesel engine. The vehicle had accumulated 5,955 km (3,700 mi.) at the time of the first test and 139,466 km (86,660 mi.) at the time of the second test. The weight used for testing was 3,692 km (8,140 lb.). The vehicle was driven from Moscow, Idaho to Los Angeles, California on 100% REE fuel for testing. The engine was not modified in any way for use with the vegetable oil fuels. The fuel delivery system was modified only for convenience of changing fuels between test runs. Fuel delivery and fuel return lines were broken so that quick couplers could be installed. 2 Brand names and models are given for reference only and do not represent an endorsement by the University of Idaho. 983

3 Individual 19-liter (5-gallon) fuel tanks were modified with fuel filter and flexible lines which could be connected to the quick couplers. For the tests, the fuel filter assembly mounted on the engine was removed and replaced with an aluminum block with internal connecting ports to minimize the volume of fuel in the system when a fuel switch was made. The EPA Urban Dynamometer Driving Schedule for Heavy-Duty Vehicles was used as the test cycle for both the 1995 and 1998 tests. The EPA cycle has a total time of 1060 seconds and is shown graphically in figure Cycle Time (set) Figure 1. EPA Urban Dynamometer Driving Schedule for Heavy-Duty Vehicles. Fuels tested during both years tests included: (1) Phillips D2 low-sulfur diesel control fuel (DIESEL or D2); (2) 100% rapeseed ethyl ester (IOOREE); (3) 50% REE - 50% diesel (SOREE); (4) 20% REE - 80% diesel (20REE). The REE was produced in the Biological and Agricultural Engineering Laboratory at the University of Idaho. Fuel consumption was determined by direct weighing. The fuel containers were placed on an electric scale accurate to the nearest 0.02 pound. The weight of fuel was recorded at the start and end of each test. The test facility was scheduled for one week during which time all testing had to be completed. The fuels were tested in blocks to reduce the amount of time to change fuels and to help reduce waste fuel from line flushing. Ideally, fuels would have been randomized, but due to time and fuel constraints, this was not possible. At least 3 repetitions of each fuel blend were performed with and without the catalytic converter except for SOREE without the catalytic converter in The last repetition was omitted due to time restraints. There was one cold start with and without the catalytic converter for both 100REE and D2 in 1995 and PRESENTATION AND DISCUSSION OF RESULTS Since a large amount of data was collected, only data collected during the 1995 and 1998 emissions tests which provide comparisons will be presented in this paper. A general 984

4 overview of the 1995 test compared to the 1998 test is shown in Figure 2 through Figure 6. With the exception of PM, exhaust emissions were generally lowest with 100% REE when compared to diesel. HC emissions generally decreased as the percentage of REE was increased in the fuel blend. The mean average emissions for HC for both the 1995 and 1998 tests both with and without the catalytic converter are shown graphically in Figure 2. Hydrocarbons (HC), With Catalytic Converter W/O Catalytic Converter Percent Biodiesel in Blend Figure and 1998 data for HC for the EPA cycle and variouiblends. CO emissions decreased as the percentage of REE was increased regardless of the vehicle test configuration. In 1995, the decrease was less when increasing from SOREE to 1OOREE. CO emissions for both 1995 and 1998 tests with and without the catalytic converter are shown graphically in Figure 3. Carbon Monoxide (CO) 4 With Catalytic Converter W/O Catalytic Converter.- E E g 2.5 s 2 I l- Q $ 0.5 o Percent Biodiesel in Blend I Figure and 1998 data for CO for the EPA cycle and various blends. NO, emissions decreased as the percentage of REE was increased with the catalytic converter installed on the vehicle. However, in 1995, NO, emissions increased from the 20REE to SOREE when the vehicle was tested without the catalyst installed. NO, emissions for both 1995 and 1998 with and without the catalytic converter are shown in Figure

5 Oxides of Nitrogen (NOx), o With Catalytic Converter W/O Catalytic Converter I ii 1 I t g 2-0 o Percent Biodiesel in Blend Figure and 1998 data for NO, for the EPA cycle and various blends of diesel and REE. The percentage of REE had no significant effect on CO2 emissions. CO2 emissions for both 1995 and 1998 with and without the catalytic converter are shown graphically in Figure 5. Carbon Dioxide (C02), ooo yith Catalytic Converter W/O Catalytic Converter III 0 1 I Percent Biodiesel in Blend Figure and 1998 data for CO2 for the EPA cycle and various blends. PM emissions generally increased as the REE percent concentration was increased regardless of the vehicle test configuration. However, PM emissions were higher with the exhaust catalyst removed from the test vehicle, indicating the effect of the catalytic converter. PM emissions for both 1995 and 1998 without the catalytic converter are shown graphically in Figure

6 Particulate Matter (PM).E c g 0.2 z e 0.05 I? Percent Biodiesel in Blend I data Figure and 1998 data for PM for the EPA cycle and variouy blends. In both tests, comparisons were made between blends of rapeseed oil ethyl ester and diesel reference fuel with and without the catalytic converter. Rapid relative comparisons are provided in the tables and any desired absolute value can be found through multiplication. For clarity figures 2-6 were provided to give an overview of the data trends Emissions Data The data collected in 1995 for each of the regulated emission compounds are shown in tables 1 and 2. The results shown in the tables are for diesel reference fuel, 20% REE, 50% REE and 100% REE and are expressed in grams/mile. Table Emissions Data, EPA Cycle (with catalytic converter; gm/mile) *Numbers in the same column followed by the same letter of the alphabet are not significantly different according to Fischer s protected LSD comparison. *Numbers in the same column followed by the same letter of the alphabet are not significantly different according to Fischer s protected LSD comparison.

7 1998 Emissions Data The data collected in 1998 for each of the regulated emission compounds are shown in tables 3 and 4. The results shown in the tables are for diesel reference fuel, 20% REE, 50% REE and 100% REE and are expressed in grams/mile. *Numbers in the same column followed by the same letter of the alphabet are not significantly different according to Fischer s protected LSD comparison. Table Emissions Data, EPA Cycle (no catalytic converter; gm/mile) HC co NOx co2 PM Diesel 0.858a 3.133a 7.773a a 0.172b 20REE 0.671b 2.263b 7.553b a 0.173b SOREE 0.551c 2.030b 7.197c a 0.230a 1 OOREE 0.316d 1.733c 7.133c a 0.232a Averages *Numbers in the same column followed by the same letter of the alphabet are not significantly different according to Fischer s protected LSD comparison vs With and Without the Catalvtic Converter Tables 5 and 6 show the comparison of the 1995 and 1998 tests; the numbers shown are the ratio of 1995 divided by 1998 for the EPA cycle for all test fuels with the catalytic converter. In general, there was a significant difference between the 1995 and 1998 emissions levels for most fuels. Table 5. A Comparison of Emission Data for 1995 and 1998 (with catalytic converter) (ratio 1995/1998; a number of 1 indicates equal values each year) HC co NOx co2 PM Diesel REE * SOREE * OOREE *Numbers followed by an asterisk imply a significant difference between 1995 and 1998 for that comparison according to Fischer s protected LSD (p ~0.05). 988

8 Table 6. Comparison of Emission Data for 1995 and 1998 (without catalytic converter) (ratio 1995/1998; a number of 1 indicates equal values each year) HC co NOx co2 PM Diesel REE * SOREE 0.876* OOREE * *Numbers followed by an asterisk imply a significant difference between 1995 and 1998 for that comparison according to Fischer s protected LSD (p ~0.05). Catalvtic Converter Vs. No Catalytic Converter Tables 7 and 8 show the comparison of the 1995 and 1998 test data with and without the OEM catalytic converter for the same fuels as reported in the other tests. In general, the catalytic converter reduced HC and PM emissions, with PM emissions being most heavily affected. Table 7. Comparison of 1995 Data With and Without Catalytic Converter (ratio With Converter/Without Converter: a number of 1 indicates no charme) HC co NOx co2 PM 1 Diesel I REE * SOREE OOREE 0.857* Numbers followed by an asterisk imply a significant difference between with the catalytic converter and without the catalytic converter for that comparison according to Fischer s protected LSD (p <0.05). Table 8. Comparison of 1998 Data With and Without the Catalytic Converter (ratio With Converter/Without Converter; a number of 1 indicates no change) HC co NOx co2 PM Diesel REE * SOREE OOREE *Numbers followed by an asterisk imply a significant difference between with the catalytic converter and without the catalytic converter for that comparison according to Fischer s protected LSD (p <0.05). General Observations These data show a significant reduction in HC, CO, and NOx as percent of vegetable oil is increased and a non-significant increase in PM. These data show that HC levels for 100REE were reduced by more than 60% compared to the D2 levels and CO levels for 1OOREE were reduced by more than 50% compared to the D2 levels. The CO2 showed no significant differences for any fuel tested. NOx was generally decreased with increasing ester. PM generally increased with increasing ester in the fuel blend. 989

9 It has generally been found that the fatty acid esters increase NOx and decrease PM, however in these tests, generally speaking, the reverse was true. One might speculate that this trend is due to the fatty acid constituents of rapeseed esters tested or that it is a characteristic of this particular engine. Also, most other emissions tests involving esters used a PTO engine test cycle instead of a chassis test. Cycle differences and test condition differences between the driving cycle and the PTO cycle could possibly influence NOx formation. In either case, the results were consistent for both years of testing. The catalytic converter had a consistently significant effect on the PM and HC emissions, reducing PM by approximately 50% for 1OOREE. It is interesting to note that the OEM catalytic converter did not seem to be poisoned by the long-term use of ethyl esters in this engine. CONCLUSIONS Specific conclusions of this study are: 1. HC and CO decreased as the percentage of REE was increased. PM generally increased with increased REE and there was no statistically significant change in CO2 for any of the fuels. HC decreased nearly linearly with blend of Biodiesel, while CO had most of its decrease in the 0-50% blend range. 2. NOx decreased as the percentage of REE was increased in the fuel with the exception of the 50% REE data point in 1995 without a catalytic converter. 3. HC emissions for 1OOREE were only 36% of diesel in 1995 and 39% of diesel in 1998 with the catalytic converter installed. HC emissions for 100REE were 38% of diesel in 1995 and 37% of diesel in 1998 without the catalytic converter installed. HC emissions were slightly affected by the presence of the catalytic converter. 4. CO emissions for 100REE were only 67% of diesel in 1995 and 53% of diesel in 1998 with the catalytic converter installed. Without the catalytic converter installed, 1OOREE emissions were 65% of diesel in 1995 and 55% of diesel in CO is not significantly affected by the catalytic converter. 5. NOx emissions for 100REE were reduced to 92% of diesel in 1995 and 91% of diesel in 1998 with the catalytic converter installed. NOx emissions were reduced to 88% of diesel in 1995 and 92% of diesel in 1998 without the catalytic converter installed. 6. CO2 emissions were not significantly different for fuels tested in 1995 or 1998, but CO2 emissions were significantly different between 1995 and 1998 tests for the same fuels. 7. PM emissions for 100REE compared to diesel were increased 26% in 1995 and 11% in 1998 with the catalytic converter installed. Without the catalytic converter installed, PM emissions for 100REE were 42% higher than diesel in 1995 and 35% higher than diesel in Overall, the catalytic converter reduced PM by over 50% for 1OOREE. The catalytic converter seemed to have more effect on REE PM emissions than any other fuel s emissions. 8. Use of biodiesel for nearly 139,466 km (86,660 miles) did not have any effect on the efficiency of the catalytic converter. 990

10 9. Cold start data was limited, but it shows that HC, CO, and PM seemed to increase more for diesel cold starts than REE cold starts compared to hot starts with the same fuel. 10. Fuel use increased by 14% from 1995 to REFERENCES Dunlap, Lauren S., Vince Pellegrin, Randal Ikeda, Ray Wilson, Sylvia Stanley and Harvey Porter Chassis Dynamometer Emissions Testing Results for Diesel and Alternative-Fueled Transit Buses. SAE Technical Paper Series SAE, Warrendale, PA Dunlap, Lauren Final Report to University of Idaho for Emissions Testing Conducted on Biodiesel Fueled Pickup Truck. Los Angeles County Metropolitan Authority Emissions Testing Facility, Los Angeles CA. Transit Environmental Protection Agency Environmental Fact Sheet. EPA420-F-95- OlOa. EPA, Washington, D.C. Environmental Protection Agency Emission Standards Reference Guide for Heavy-Duty and Nonroad Engines. EPA420-F EPA, Washington, D.C. Peterson, Charles L. and Daryl L. Reece Emissions Tests with an On-Road Vehicle Fueled with Methyl and Ethyl Esters of Rapeseed Oil. ASAE Paper No , ASAE, St. Joseph, MI