EPA-AA-TAEB 76-22 Exhaust Emissions from an Opel Diesel Equipped with Reverse Flow Damping Valves June 1976 Technology Assessment and Evaluation Branch Emission Control Technology Division Office of Mobile Source Air Pollution Control Environmental Protection Agency ------- Background The Environmental Protection Agency receives information about many systems which appear to offer potential for emission reduction or fuel economy improvement compared to conventional engines and vehicles. EPA's Emission Control Technology Division is interested in evaluating all such systems, because of the obvious benefits to the Nation from the identification of systems that can reduce emissions, improve economy, or both. EPA invites developers of such systems to provide to the "EPA complete technical data on the system's principle of operation, together with available test data on the system. In those cases in which review by EPA technical staff suggests that the data available show promise, attempts are made to schedule tests at the EPA Emission Laboratory at Ann Arbor, Michigan. The results of all such test projects are set forth in a series of Technology Assessment arid Evaluation Reports, of which this report is one. The conclusions drawn from the EPA evaluation tests are necessarily of limited applicability. A complete evaluation of the effectiveness of an emission control system in achieving performance improvements on the many different types of vehicles that are in actual use requires a much larger sample of test vehicles than is economically feasible in the evaluation test projects conducted by EPA. For promising systems it is necessary that more extensive test programs be-carried out. The conclusions from the EPA evaluation test can be considered to be quantitatively valid only for the specific test vehicle used, however, it is reasonable to extrapolate the results from the EPA test to other types of vehicles in a directional or qualitative manner, i.e., to suggest that similar results are likely to be achieved on other types of vehicles. As part of an ongoing program to evaluate the exhaust emissions and fuel economy of light-duty Diesel-powered vehicles, the EPA agreed to test an Opel Rekord 2100D supplied by Ford Motor Company. The purpose of the test program would be to evaluate a reverse flow damping valve designed by Bosch for installation in the injector lines. The damper valve is designed to eliminate undesirable erratic injection into the combustion chamber due to stray pressure pulses in the injection lines. Test Vehicle Description The test vehicle is an Opel Rekord 2100D, powered by a 2100cc Diesel engine, and equipped with a four-speed manual transmission. The inertia class is 3000 Ibs. A tabulation of pertinent vehicle statistics is given in the Vehicle Description on page 7. ------- Stray pressure pulses normally exist in the injection lines following injection of fuel into the combustion chamber. These pulses can cause the injector to "dribble" small amounts of fuel into the combustion chamber. By installing valves in the injection lines to dampen the stray pressure pulses, the dribbling of the injector is reduced or eliminated and a small decrease in emissions of unburned hydrocarbons may occur. The reverse flow damper valve is placed in the injection system between the injection line and fuel pump. One valve is used in each injection line. Test Program The test program was conducted in accordance with the 1975 Federal Test Procedure ('75 FTP) for light-duty Diesel vehicles (Federal Register, October 22, 1974, Vol. 39 No. 205, Part III). Testing included measure- ment of exhaust emissions and fuel economy according to the '75 FTP and the EPA Highway Fuel Economy Test (HFET). The vehicle was tested in two configurations. The first configura- tion, the baseline, involved no changes to the manufacturer's production injection system. The second configuration was with the damper valves installed in the injection lines. In both configurations the vehicle was tested twice according to the '75 FTP and once according to the HFET. Test Results Exhaust emissions and fuel economy measured during the "75 FTP are presented in the following table: '75 FTP mass emissions in grams per mile (grams per kilometer) Fuel Economy HC CO NOx (Fuel Consumption) 0.41 1.5 1.21 27.6 miles/gal. (0.26) (0.9) (0.75) (8.5 liters/lOOkm) 0.38 1.5 1.18 27.9 miles/gal. (0.24) (0.9) (0.74) (8.4 liters/lOOkm) -7% 0 -2% +1% (-1%) Baseline-avg. of 2 tests Damper valves avg. of 2 tests % Change from baseline A further breakdown of '75 FTP emissions and fuel economy is given in Tables I and II. Highway Cycle emissions and fuel economy are presented in Table III. ------- At the low exhaust emission levels measured from the test vehicle, it is difficult to attach importance to percent changes in emissions. For instance, the 7% reduction in HC emissions during the '75 FTP corresponds to a change in mass emissions of only 0.03 gram per mile. Based on an average of only two tests, a change of this magnitude cannot be accurately quantified. The 7% change in HC emissions can be taken to be representative of a trend toward lower HC emissions with the damper valves installed. Conclusions 1. Installation of the damper valves resulted in a small decrease in unburned hydrocarbon emissions. Further testing is required to more accurately quantify this reduction. 2. No significant effect on fuel economy occurred during the '75 FTP and Highway Fuel Economy test. ------- Table I '75 FTP mass emissions in grams per mile (grams per kilometer) Test # Baseline 77-1634 77-1635 Average Damper Valves 77-1677 77-1678 Average % change from baseline HC 0.43 (0.27) 0.39 (0.24) 0.41 (0.26) Installed 0.37 (0.23) 0.38 (0.24) 0.38 (0.24) -7% CO 1.5 (0.9) 1.5 (0.9) 1.5 (0.9) 1.5 (0.9) 1.4 (0.9) 1.5 (0.9) 0 CO 2 361. (224.) 371. (230.) 366. (228.) 356. (221.) 369. (229.) 363. (225.) -1% NOx 1.19 (0.74) 1.22 (0.76) 1.21 (0.75) 1.17 (0.73) 1.19 (0.74) 1.18 (0.74) -2% miles/gal. 28.0 (8.4) 27.2 (8.6) 27.6 (8.5) 28.3 (8.3) 27.4 (8.6) 27.9 (8.4) +1% (-1%) ------- Table II Individual Bag Emissions in grams per mile Bag 1: Cold Transient Test # Baseline 77-1634 77-1635 Average Damper Valves 77-1677 77-1678 Average % change from base- line HC : 0.44 0.43 0.44 0.40 0.43 0.42 -5% CO 1.6 1.6 1.6 1.5 1.5 1.5 -6% CO 39.1. 402. 397. 394. 399. 397. 0 NOX 1.20 1.25 1.23 1.18 1.20 1.19 -3% MPG 25.8 25.1 25.5 25.6 25.3 25.5 0 Bag 2: Stabilized HC CO CO NOx MPG 0.45 0.41 0.43 0.38 0.40 0.39 1.5 1.6 . .1.6 1.7 1.5 1.6 360. 368. 364. 351. 367. 359. 1.22 1.25 1.24 1.21 1.23 1.22 28.0 27.4 27.7 28.8 27.5 28.2 -10% 0 -1% -2% +2% Bag 3: HC 0.35 0.33 0.34 0.32 0.32 0.32 CO 1.2 1.2 1.2 1.3 1.2 1.3 Hot Transient CO 340. 352. 346. 337. 350. 344. NOx 1.11 1.15 1.13 1.07 1.10 1.09 MPG 29.7 28.7 29.2 29.9 28.9 29.4 +8% -1% -4% +1% ------- Table III Test # Baseline 77-1639 HC 0.22 (0.14) HFET mass emissions in grams per mile (grams per kilometer) CO 0.9 (0.6) C02 276. (172.) NOx 0.97 (0.60) miles/gal. (liters/lOOkm) 36.6 (6.4) Damper Valves installed 77-1679 0.25 (0.16) 0.9 (0.6) 271. (168.) 0.90 (0.56) 37.3 (6.3) ------- TEST VEHICLE DESCRIPTION Chassis model year/make - Opel Rekord 2100D Emission Control system - None Engine type 4 stroke, Diesel, 1-4, ohv, indirect injection bore x stroke . . . 3.47 x 3.34 in./88.2 x 84.8 mm displacement 126 cu in./2070 cc compression ratio 22:1 maximum power @ rpm 68 bhp/50.7 kW @ 4300 rpm fuel metering Bosch fuel injection fuel requirement #2 Diesel Drive Train transmission type 4 speed manual Chassis type front engine, rear wheel drive tire size 165 x 14 inertia weight 3000 Ib. passenger capacity 5 Emission Control System basic type None durability accumulated on system . . 3400 mi/5400 km ------- |