1、American API PUBL*4637 96 I 0732290 05.51695 130 I Petroleum Institute Analysis of Causes of Failure in High Emitting Cars Health and Environmental Sciences Department Publication Number 4637 February 1996 API PUBLx4637 96 W 0732290 055Lbb O77 W ANALYSIS OF CAUSES OF FAILURE IN HIGH EMITTING CARS He
2、alth and Environmental Sciences Department API PUBLICATION NUMBER 4637 PREPARED UNDER CONTRACT BY: PHILIP L. HEIRIGS, THOMAS C. AUSTIN, LAWRENCE S. CARE-ITO, THOMAS R. CARLSON, AND ROBERT L. HUGHES SIERRA RESEARCH, INC. 1801 J STREET SACRAMENTO, CALIFORNIA 9581 4 OCTOBER 1995 American Petroleum Ins
3、titute API PUBL*:463? 96 0732290 0553697 TO3 = FOREWORD API PUBLICATIONS NECESSARILY ADDRESS PROBLEMS OF A GENERAL NATURE. WITH RESPECT TO PARTICULAR CIRCUMSTANCES, LOCAL, STATE, AND FEDERAL LAWS AND REGULATIONS SHOULD BE REVIEWED. API IS NOT UNDERTAKING TO MEET THE DUTIES OF EMPLOYERS, MANUFAC- TUR
4、ERS, OR SUPPLERS TO WARN AND PROPERLY TRAIN AND EQUIP THEIR EMPLOYEES, AND OTHERS EXPOSED, CONCERNING HEALTH AND SAFETY RISKS AND PRECAUTIONS, NOR UNDERTAKING THEIR OBLIGATIONS UNDER LOCAL, STATE, OR FEDERAL LAWS. NOTHING CONTAINED IN ANY API PUBLICATION IS TO BE CONSTRUED AS GRANTING ANY RIGHT, BY
5、IMPLICATION OR OTHERWISE, FOR THE MANU- FACTURE, SALE, OR USE OF ANY METHOD, APPARATUS, OR PRODUCT COV- ERED BY LETTERS PATENT. NEITHER SHOULD ANYTHING CONTAINED IN ITY FOR INFRINGEMENT OF LETERS PAm. THE PUBLICATION BE CONSTRUED AS INSURING ANYONE AGAINST LIABIL- Copyright Q 1996 American Petroleum
6、 institute i API PUBLX4637 9b = 0732290 055Lb9B 94T ACKNOWLEDGMENTS THE FOLLOWING PEOPLE ARE RECOGNIZED FOR THEIR CONTRIBUTIONS OF TIME AND EXPERTISE DURING THIS STUDY AND IN THE PREPARATION OF THIS REPORT API STAFF CONTACT David Lax, Health and Environmental Sciences Department MEMBERS OF THE VEHI
7、CLE EMISSIONS TASK FORCE Steve Welstand, Chairperson, Chevron Research and Technology Bill Bandy, Amoco Research Center Helen Doherty, Sun Refining and Marketing Company Dennis Feist, Shell Development Company Frank S. Gerry, BP America, Inc. Peter Jessup, Unocal Corporation George S. Musser, Exxon
8、Research and Engineering Company Michael Payne, Arco Products Company Robert M. Reuter, Texaco, Inc. Rick Riley, Phillips Petroleum Charles Schleyer, Mobil Research and Development PREFACE by The American Petroleum Institute Although new vehicles are designed to control exhaust emissions to specific
9、 levels for a significant portion of their useful lives, it is well known that these standards are substantially exceeded on average by vehicles in actual use. Inadequate maintenance, component failures, and tampering with emissions control systems are known to contribute to this problem. In 1994 th
10、e American Petroleum Institute (API) sponsored a study to evaluate the primary causes of high emissions in the lightduty vehicle fleet. The effort focused on an analysis of emissions data from tests conducted both before and after the performance of repairs on 1981 and newer model vehicles. The data
11、 were compiled from five independently conducted programs which assessed the maintenance condition of vehicles representative of the in-use fleet. The compiled database was analyzed to: (i) assess the prevalence of different types of emission control system defects in the fleet; (2) classify the cau
12、ses of those defects (e.g., malmaintenance, component failure, tampering, etc.) and (3) determine the contribution of those defects to fleet-average emissions. Summary of fleet characteristics The compiled database contained emissions and repair information on about 800 carbureted and fuel-injected
13、automobiles representing a broad spectrum of geographic areas, maintenance histories and operating conditions. The carbureted cars were generally older models with higher odometer mileage (and thus higher emissions) than the fuel injected vehicles utilized in this study. Results This study produced
14、the following results: There are a substanfial number of tampered or failed components, as well as nomal maintenance items, on in-use light duty motor vehicles which are repairable. Large reductions in in-use emissions wowld accompany the repair of these components. One EPA survey of vehicles that h
15、ad not been exposed to any incpectionimaintenance programs found that, on a fleet-wide basis, carbureted cars contained an average of 2.8 failed components in contrast to an average of 1.2 failed components for fuel injected automobiles. It was estimated that the repair of all failed components on t
16、his fleet of API PUBLX(4637 96 = 0732290 0553700 328 vehicles would reduce composite (HC+NOx+CO/I O) exhaust emissions by 69% for carbureted automobiles and by 39% for fuel injected cars. There are several classifications or categories of faults that cause excess emissions. These faults are related
17、to either I) component failures (both mechanical and electrical); 2) need for replacement or adjustment of maintenance items (spark plugs, ignition timing, etc.); and 3) tampering of emissions control components. The percentage of overall failures seen in each of these categories was as follows: Per
18、cent o f Failures bv Cateaory Fuel Mechanical Electrical Malmaint- Svstem Failures Failures enance Tamperinq Carburetor 37 28 25 10 Fuel Injection 24 57 18 1 Failures of mechanical and electrical components are substantially more prevalent than tampering and maintenance related items - particularly
19、in newer, fuel injected vehicles. There are a few specfic types of faults which have a signficant effect on overall fleet emissions. About 35% of the composite fleet emissions of carbureted vehicles is due to defective fuel metering systems. Defective oxygen sensors contribute an additional 10% of e
20、missions. Ignition tune-up faults cause about 9% of the emissions. Defective oxygen sensors cause from 22% to 15% of the emissions from lightduty fuel- injected vehicles. The variation in effect may be related to whether or not the fleet evaluated was subject to inspection and maintenance. Ignition
21、tune-up was the only other fault that had a pronounced effect on the composite emissions from fuel-injected vehicles, ranging from 8% to 3%, depending on the test fleet. Replacement of defective catalysts provides only small benefits for both carbureted and fuel injected vehicles. Vehicle emissions
22、warranty recalls provide only small reductions in fleet composite emissions. Vehicle emissions warranty recalls are conducted regardless of the magnitude of the impact of the fault on emissions. In addition, the small emissions reductions from recall API PUBLx4b37 b = 0732270 0553703 2b4 = repairs m
23、ay be related to the fact that these benefits have been based on tests of well- maintained vehicles with under 50,000 odometer miles. Therefore, many recall repairs probably have negligible benefits. It also should be noted that the purpose of warranty recalls may not necessarily be to provide signi
24、ficant reductions of in-use emissions. Conclusions The results of this study can be helpful in focusing on productive, cost-effective strategies for reducing excessive in-use vehicle emissions. For instance, the following strategies are worth evaluating: The periodic replacement of oxygen sensors as
25、 a routine engine maintenance requirement, similar to current requirements for spark plug replacement. A greater emphasis on improvements in component durability. Recently instituted I O year/l 00,000 mile emissions warranty requirements by the EPA and the California Air Resources Board should resul
26、t in increased durability. Identification of high-effectiveness repair strategies for inspection and maintenance programs. Comprehensive evaluations to determine which repair items are most effective in reducing emissions will provide benefits to consumers, repair technicians and air quality. API PU
27、BLa4637 96 W 0732290 0553702 LTO W TABLE OF CONTENTS Section EXECUTIVE SUMMARY . ES-I I . INTRODUCTION . 1-1 ORGANIZATION OF THE REPORT 1-2 2 . ANALYSIS OF DIAGNOSTIC DATA . 2-1 DATABASE DESCRIPTION . 2-2 Cooperative Test Program (CTP) Data . 2-2 EPA Indiana Data . 2-4 EPA Arizona Data . 2-5 CARB Fu
28、el-Injected (CARBFI) Vehicle Study . 2-5 CARB I/M Pilot Project Data . 2-6 SUMMARY STATISTICS . 2-7 DATABASE REFORMATTING 2-10 EMISSION REDUCTIONS FROM REPAIR 2-16 Methodology to Estimate the Effects of Individual Component Repair 2-18 Results of the Regression Analysis . 2.19 EXCESS EMISSIONS VERSU
29、S NATURE OF DEFECT . 2-27 PREVALENCE OF EMISSION CONTROL SYSTEM DEFECTS IN THE FLEET . 2-29 Hammond and Phoenix Component Failure Rates . 2.30 CARB I/M Pilot Project Component Failure Rates 2-32 API PUBLr4637 96 0732290 0553703 O37 W TABLE OF CONTENTS (continued) Section Paae 2 . ANALYSIS OF DIAGNOS
30、TIC DATA (continued) OVEFWLL IMPACT OF SPECIFIC DEFECTS ON FLEET-AVERAGE EMISSIONS 2-33 PCV SYSTEM DEFECTS 2-40 3 . REVIEW OF CARBS OBDII ANALYSIS 3-1 DATABASE DESCRIPTION AND SUMMARY STATISTICS . 3-2 COMPONENT FAILURE RATES . 3-3 EFFECT OF COMPONENT REPAIR . 3-4 Methodology 3-4 Average Emission Red
31、uctions from Individual Repairs . 3-5 Fleet-Average Emission Reductions . 3-7 4 . REVIEW OF EPA AND CARB RECALL DATA 4-1 REFERENCES R-I Appendix A REGRESSION RESULTS FOR ANALYSIS OF FTP REDUCTIONS FROM REPAIRS API PUBL+4637 96 0732290 0553704 T73 LIST OF FIGURES Figure Paae ES-1. Contribution of Rep
32、airable Defects Relative to the Fleet- Average Emission Standard (HC + NOx + CO/lO) for the Hammond Database . ES-I2 2-1 a. Comparison of Mean Baseline and After-Repair FTP Emission Rates from 1981 and Later Model Year Carbureted Vehicles Receiving Repair in the CTP, Hammond, and California I/M Pilo
33、t Project Databases 2-11 2-1 b. Comparison of Mean Baseline and After-Repair FTP Emission Rates from 1981 and Later Model Year Fuel-Injected Vehicles Receiving Repair in the CTP, Hammond, Phoenix, CARBFI and California I/M Pilot Project Databases .2-12 2-2. The Effect of Repairing Identified Defects
34、 in the Hammond Fuel-Injected Fleet Relative to the Emission Standards .2-39 4-1. Contribution of Repairable Defects Relative to the Fleet-Average Emission Standard (HC + NOx + CO/lO) for the Hammond Database . 4-6 - API PUBL+4637 96 = 0732290 0553705 90T LIST OF TABLES Table ES-I . ES-2. ES-3. 2-1.
35、 2-2. 2-3. 2-4a. 24b. 2-5a. 2-5b. 2-6. 2-7. 2-8a. Paae Emission Reductions Associated with the Repair of Fuel-Injected Vehicles ES4 Baseline Component Failure Rates for the Hammond Fleet, Including Vehicles Passing and Failing the IM240 Test ES-7 Contribution of Defective Components to the Fleet-Ave
36、rage Emission Rate for the Hammond Database ES-I O Baseline FTP Emission Levels of the CTP, Hammond, Arizona, CARBFI, and California I/M Pilot Project Databases. . 2-8 System and Component Codes Used to Standardize Repair Data from the CTP, Hammond Phoenix, CARBFI, and California I/M Pilot Project D
37、atabases 2-14 Sample Spreadsheet Identifying Repair Actions in a Common Format - CTP Database 2-1 7 Emission Reductions Associated with the Repair of Carbureted Vehicles with “OK“ Diagnoses . 2-21 Emission Reductions Associated with the Repair of Fuel- Injected Vehicles with “OK1 Diagnoses . .2-22 E
38、mission Reductions Associated with the Repair of Carbureted Vehicles with “OK Diagnoses - Segregated into “High“ and “NormaVModerate“ Emitters .2-25 Emission Reductions Associated with the Repair of Fuel- Injected Vehicles with “OK“ Diagnoses - Segregated into “High“ and “Normal/Moderate“ Emitters .
39、 2-26 FTP Emission Reductions by Repair Reason 2-28 Contribution of Mechanical Failures, Electrical Failures, Malmaintenance, and Tampering to Emission Reductions from Repair .2-29 Component Failure Rates for the Hammond Database. . .2-31 Table 2-8b. 2-9. 2-1 o. 2-1 1. 2-1 2. 2-1 3. 3-1. 3-2. 3-3. 3
40、-4. 4-1. 4-2. LIST OF TABLES (continued) Paae Component Failure Rates for the Phoenix Database 2-31 Component Failure Rates for the California I/M Pilot Project Database . .2-33 Contribution of Defective Components to the Fleet-Average Emission Rate for the Hammond Database. 2-36 Contribution of Def
41、ective Components to the Fleet-Average Emission Rate for the Phoenix Database .2-37 Contribution of Defective Components to the Fleet-Average Emission Rate for the CARB I/M Pilot Project Database . 2-37 Effect of Correcting All Repairable Defects on the Fleet- Average Emissions . .2-38 Baseline FTP
42、Emission Levels of the CARB OBDII Database . .3-3 Baseline Component Failure Rates for 1981 and Later Model Year Vehicles in the OBDII Database . 3-4 Reduction in FTP Emissions as a Result of Repair Based on the CARB OBDII Database 3-6 Contribution of Defective Components to the OBDII Fleet- Average
43、 Emission Rates 3-7 Summary of EPAs I994 Recall List . 4-2 Number of Vehicles Subject to EPA Recall Action by Calendar Year (Including Voluntary Recalls). . .4-3 EXECUTIVE SUMMARY Under contract to the American Petroleum Institute (API), Sierra Research, Inc. (Sierra) analyzed emissions and diagnost
44、ic data collected from vehicles recruited from customer service to determine the primary causes of excessive exhaust emissions in the motor vehicle fleet.* The primary data sources used for this study were two programs conducted by the U.S. Environmental Protection Agency (EPA), two programs conduct
45、ed by the California Air Resources Board (CARB), and one joint EPA- Industry program. The focus of the effort was on 1981 and later model year passenger cars and light-duty trucks. In addition to analyzing emissions test data from those five programs, data presented in CARBs Technical Support Docume
46、nt prepared for on- board diagnostic system regulations were reviewed. That report contained emissions data for catalyst, oxygen sensor, and exhaust gas recirculation (EGR) system repairs. Finally, a limited review of EPA and CARB recall data was performed to determine the fraction of fleet-average
47、emissions that is reduced through recall actions. ANALYSIS OF IN-USE DATA Data from five sources were evaluated for this project: 0 EPA-Industry Cooperative Test Program (CTP); EPA Hammond, IN Test Program; 0 EPA Phoenix, AZ Test Program; 0 CAR9 Fuel-Injected Vehicles Study; and 0 CARB Enhanced I/M
48、Pilot Project. The databases contained baseline (.e. , as-received) emission results conducted using the Federal Test Procedure (FTP) for over 1 O00 vehicles. Nearly 800 of those vehicles * Note that this study did not evaluate evaporative control system defects, which could be a significant source
49、of excessive hydrocarbon emissions. ES-I API PUBLx4637 9b 0732290 0551708 619 also received repair to the emission control system (in some cases multiple repairs were performed) and were tested again over the FTP before being released to the owner. The repair information was used to identify the types of defects corrected and to determine the emission reductions from repair. Because of the large number of individual emission control components that can be repaired on a vehicle (Le., well over 200), the repairs were classified according to the following cat
