start Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 OBJECTIVES: After studying Chapter 61, the reader should be able to: • Prepare for ASE A8 certification test content area “D” (Emissions Control Systems Diagnosis and Repair) and ASE L1 certification test content area “F” (I/M Failure Diagnosis) • • Discuss emission standards Identify the reasons why excessive amounts of HC, CO, and NO X exhaust emissions are created Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 OBJECTIVES: After studying Chapter 61, the reader should be able to: • • Describe how to baseline a vehicle after an exhaust emission failure List acceptable levels of HC, CO, CO2, and O2 with and without a catalytic converter • List four possible causes for high readings for HC, CO, and NOX Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 KEY TERMS: acceleration simulation mode (ASM) • ASM 25/25 test • ASM 50/15 test Federal Test Procedure (FTP) I/M 240 test lean indicator • non-methane hydrocarbon (NMHC) ozone Sealed Housing for Evaporative Determination (SHED) test • smog • State Implementation Plan (SIP) Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 EMISSION STANDARDS IN THE UNITED STATES In the US, emissions standards are managed by the Environmental Protection Agency (EPA) as well as some U.S state governments Some of the strictest standards in the world are formulated in California by the California Air Resources Board (CARB) Tier and Tier Federal emission standards are set by the clean air act amendments (CAAA) of 1990 grouped by tier Current Tier standards are different between automobiles and light trucks, but Tier standards will be the same for both types There are several ratings given to vehicles, and a certain percentage of a manufacturer’s vehicles must meet different levels in order for the company to sell its products in affected regions Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Beyond Tier 1, and in order by stringency, are the following levels: TLEV—Transitional Low-Emission Vehicle—More stringent for HC than Tier LEV—(also known as: LEV I) Low-Emission Vehicle, an intermediate California standard about twice as stringent as Tier for HC and NOX ULEV (also known as ULEV I),—Ultra-Low-Emission Vehicle—A stronger California standard emphasizing very low HC emissions ULEV II—Ultra-Low-Emission Vehicle—A cleaner-thanaverage vehicle certified under the Phase II LEV standard Hydrocarbon and carbon monoxide emissions levels are nearly 50% lower than those of a LEV II-certified vehicle See Figure 61–1 Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman Continued ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 NOTE: A battery-powered electric vehicle charged from the power grid will still be up to 10 times cleaner than even the cleanest gasoline vehicles over their respective lifetimes Figure 61–1 The underhood decal showing that this Lexus RX-330 meets both national Tier 2; BIN 5) and California LEV-II (ULEV) regulation standards Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 SULEV—Super-Ultra-Low-Emission Vehicle—A California standard even tighter than ULEV, including much lower HC and NOX emissions; roughly equivalent to Tier Bin vehicles ZEV—Zero-Emission Vehicle—A California standard prohibiting any tailpipe emissions The ZEV category is largely restricted to electric vehicles and hydrogen-fueled vehicles In these cases, any emissions that are created are produced at another site, such as a power plant or hydrogen reforming center, unless such sites run on renewable energy PZEV—Partial Zero-Emission Vehicle—Compliant with the SULEV standard; additionally has near-zero evaporative emissions and a 15-year/150,000-mile warranty on its emission control equipment Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Tier standards are even more stringent Tier variations are appended with “II,” such as LEV II or SULEV II Other categories have also been created: ILEV—Inherently Low-Emission Vehicle AT-PZEV—Advanced Technology Partial ZeroEmissionVehicle—If a vehicle meets the PZEV standards and is using high-technology features, such as an electric motor or high-pressure gaseous fuel tanks for compressed natural gas, it qualifies as an AT-PZEV Hybrid electric vehicles such as the Toyota Prius can qualify, as can internal combustion engine vehicles that run on natural gas (CNG), such as the Honda Civic GX Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 NLEV—National Low-Emission Vehicle—All vehicles nationwide must meet this standard, which started in 2001.See Tables 61.1, 61.2, and 61.3 See the table on Page 734 of your textbook Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Figure 61–7 Exhaust emissions are very complex When the air–fuel mixture becomes richer, some exhaust emissions are reduced, while others increase Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Find a Leak in the Exhaust System - Part A hole in the exhaust system can dilute the exhaust gases with additional oxygen (O2) This additional O2 in the exhaust can lead the service technician to believe that the air–fuel mixture is too lean Figure 61–8 A hole in the exhaust system can cause outside air (containing oxygen) to be drawn into the exhaust system This extra oxygen can be confusing to a service technician because the extra O2 in the exhaust stream could be misinterpreted as a too-lean air–fuel mixture Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Find a Leak in the Exhaust System - Part To help identify an exhaust leak, perform an exhaust analysis at idle and at 2500 rpm (fast idle) and compare with the following: • If the O2 is high at idle and at 2500 rpm, the mixture is lean at both idle and at 2500 rpm • If the O2 is low at idle and high at 2500 rpm, this usually means the vehicle is equipped with a working AIR pump • If the O2 is high at idle, but OK at 2500 rpm, indicates a hole in the exhaust or a small vacuum leak that is “covered up” at higher speed Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Your Nose Knows - Part Using the nose, a technician can often home in on a major problem without having to connect the vehicle to an exhaust analyzer For example: • The strong smell of exhaust is due to excessive unburned hydrocarbon (HC) emissions Look for an ignition system fault that could prevent the proper burning of the fuel A vacuum leak could also cause a lean misfire and cause excessive HC exhaust emissions • Dizzy feeling or headache This is commonly caused by excessive carbon monoxide (CO) exhaust emissions Get into fresh air as soon as possible A probable cause of high levels of CO is an excessively rich air–fuel mixture Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Your Nose Knows - Part Using the nose, a technician can often home in on a major problem… • If your eyes start to burn or water, suspect excessive oxides of nitrogen (NOX) emissions The oxides of nitrogen combine with the moisture in the eyes to form a mild solution of nitric acid The acid formation causes the eyes to burn and water Excessive NOX exhaust emissions can be caused by: • A vacuum leak causing higher-than-normal combustion chamber temperature • Overadvanced ignition timing causing higher-than-normal combustion chamber temperature • Lack of proper amount of exhaust gas recirculation (EGR) (This is usually noticed above idle on most vehicles.) Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 PHOTOCHEMICAL SMOG INFORMATION Oxides of nitrogen are formed by high temperature—over 2500°F (1370°C)—and/or pressures inside the combustion chamber Oxides of nitrogen contribute to the formation of photochemical smog when sunlight reacts chemically with NOX and unburned hydrocarbons (HC) Smog is a term derived by combining the words smoke and fog Ground-level ozone is PART of smog Ozone is an enriched oxygen molecule with three atoms of oxygen (O3) instead of the normal two atoms of oxygen (O2) Ozone in the upper atmosphere is beneficial because it blocks out harmful ultraviolet rays that contribute to skin cancer Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 TESTING FOR OXIDES OF NITROGEN Because the formation of NOX occurs mostly under load, the most efficient method to test for NOX is to use a portable exhaust analyzer that can be carried in the vehicle while the vehicle is being driven under a variety of conditions Specifications for NOX From experience, a maximum reading of 1,000 parts per million (ppm) of NO X under loaded driving conditions will generally mean that the vehicle will pass an enhanced I/M roller test A reading of over 100 ppm at idle should be considered excessive Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 Check For Dog Food? A commonly experienced problem in many parts of the country involves squirrels or other animals placing dog food into the air intake ducts of vehicles Dog food is often found packed tight in the ducts against the air filter An air intake restriction occurs and drives the fuel mixture richer than normal and reduces engine power and vehicle performance as well as creating high CO exhaust emissions Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 The Case of the Retarded Exhaust Camshaft - Part A Toyota equipped with a double overhead camshaft (DOHC) inline six-cylinder engine failed the state-mandated enhanced exhaust emission test for NOX The engine ran perfectly without spark knocking (ping), which is usually a major reason for excessive NOX emissions The technician checked the following: • The ignition timing, which was found to be set to specifications (if too far advanced, can cause excessive NOX) • The cylinders, which were decarbonized using top engine cleaner • The EGR valve, which was inspected and EGR passages cleaned After all the items were completed, the vehicle was returned to the inspection station where the vehicle again failed for excessive NOX emissions (better, but still over the maximum allowable limit) Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 The Case of the Retarded Exhaust Camshaft - Part After additional hours of troubleshooting, the technician decided to go back to basics and start over again A check of the vehicle history with the owner indicated that the only previous work performed on the engine was a replacement timing belt over a year before The technician discovered that the exhaust cam timing was retarded two teeth, resulting in late closing of the exhaust valve The proper exhaust valve timing resulted in a slight amount of exhaust being retained in the cylinder This extra exhaust was added to the amount supplied by the EGR valve and helped reduce NOX emissions After repositioning the timing belt, the vehicle passed the emissions test well within the limits Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 See the chart on Page 740 of your textbook Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 O2 Shows Rich, But Pulse Width is Low A tech was attempting to solve a driveability problem The computer did not indicate any trouble codes (DTCs) A check of oxygen sensor voltage indicated higher-than-normal reading almost all the time The pulse width to the port injectors was lower than normal The lower-than-normal pulse width indicates the computer is attempting to reduce fuel flow to the engine by decreasing the on-time for all injectors What could cause a rich mixture if the injectors were being commanded to deliver a lean mixture? Finally the technician shut off the engine and took a careful look at the entire fuel-injection system Although the vacuum hose was removed from the fuel-pressure regulator, fuel was found dripping from the vacuum hose The problem was a defective fuel-pressure regulator that allowed an uncontrolled amount of fuel to be drawn by the intake manifold vacuum into the cylinders While the computer tried to reduce fuel by reducing the pulse width signal to the injectors, the extra fuel being drawn directly from the fuel rail caused the engine to operate with too rich an air–fuel mixture Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 SUMMARY Excessive hydrocarbon (HC) exhaust emissions are created by a lack of proper combustion such as a fault in the ignition system, too lean an air–fuel mixture, or too cold engine operation Excessive carbon monoxide (CO) exhaust emissions are usually created by a rich air–fuel mixture Excessive oxides of nitrogen (NOX) exhaust emissions are usually created by excessive heat or pressure in the combustion chamber or a lack of the proper amount of exhaust gas recirculation (EGR) Continued Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 SUMMARY (cont.) Carbon dioxide (CO2) levels indicate efficiency The higher the CO2, the more efficient the engine operation Oxygen (O2) indicates leanness The higher the O2, the leaner the air–fuel mixture A vehicle should be driven about 20 miles, especially during cold weather, to allow the engine to be fully warm before an enhanced emissions test Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458 end Automotive Technology: Principles, Diagnosis, and Service, 3rd Edition By James D Halderman ©©2008 2009Pearson PearsonEducation, Education,Inc Inc Pearson PearsonPrentice PrenticeHall Hall- -Upper UpperSaddle SaddleRiver, River,NJ NJ07458 07458