Developing Emission Reduction Strategies

8.2 On-Road Mobile Sources

8.2.6 Compliance Program
New vehicle standards are only beneficial to the degree that they result in actual reductions in emissions from vehicles as they are normally driven in use. To minimize deterioration of emissions controls which result from new vehicle standards and to assure that vehicles achieve the full emissions reductions that they are capable of, it is necessary to have an in use vehicle focus including a well thought out compliance program.

New vehicle standards are not intended to apply only when the vehicle comes off the assembly line but rather are intended to define the vehicle manufacturers responsibilities over a reasonable period of actual in use driving. For example, the current EU requirements provide that the vehicle manufacturer is responsible for assuring that vehicles meet standards in use for 80,000 kilometres. In the US, they apply for 160,000 km. If substantial numbers of vehicles, which are properly cared for and driven, fail to meet their new vehicle standards in use over the defined period, they can be subject to a recall program whereby, at the manufacturers costs, defective vehicles will be repaired. Further, defective parts for individual vehicles are covered by a warranty.

To trigger these recall or Conformity of Production programs, individual member states in the EU and the EPA in the US carry out in use testing programs using the same test procedures as the Type Approval or certification programs.

The United States has required the introduction of onboard diagnostic or OBD systems since 1996 and they are required in Europe with the introduction of vehicles meeting Euro 3 requirements. OBD systems can identify failures to vehicle owners as well as to in use vehicle inspectors. In the meantime, in order to assure that vehicles in use are properly cared for, many countries adopt in use standards based on short tests that are much less expensive to operate than typical Type Approval tests. The U.S. Light Duty Vehicle Compliance Program

Three main programs have been used to ensure that light-duty vehicles and light-duty trucks comply with mandated emission standards: certification, assembly line testing (known as Selective Enforcement Audits or SEAs) and recall. The following discussion briefly summarizes these programs. Certification

Under the US Clean Air Act (Section 203(a) (1)), a motor vehicle manufacturer must obtain a certificate of conformity indicating compliance with emission standards prior to selling new cars. Issuance of a certificate is based on a showing that the new motor vehicles have been designed to meet emission standards for their useful lives. A manufacturer submits information to EPA, including test data demonstrating that its new motor vehicles will comply with the applicable emission standards. After reviewing this information for completeness and compliance with the standards, EPA issues a certificate of conformity. This must occur prior to the sale of the new motor vehicles, necessitating the use of pre-production vehicles to demonstrate compliance. A new certificate must be obtained each model year.

Since it is a pre-production program, manufacturers must use predictive tools to demonstrate that a vehicle will conform to the applicable emission standards. The certification program accomplishes this by assessing the emissions control deterioration characteristics of the vehicle ("durability") and applying this assessment to emissions data from low mileage, production-intent vehicles, that is, vehicles assembled as closely as possible to those which are planned to be produced. This is done specifically for each "engine family" which is a group of vehicles that have engines and emission control systems with similar operational and emission characteristics, as defined in regulations. A separate certificate of conformity must be obtained for each engine family. Within each engine family, the manufacturer must determine the emission deterioration factors (DFs) by using either bench aging techniques or by operating prototype vehicles for the useful life mileage and testing at periodic intervals. The manufacturer must then test a number of production-intent vehicles with stabilized mileages (usually 4,000 miles) for each engine family. These low mileage test vehicles are called emission-data vehicles (EDVs). The test results from the emission-data vehicles are adjusted by the DFs to project useful life emission levels (called "certification levels"). The useful lives of motor vehicles for emission compliance purposes are defined in Section 202(d) of the Clean Air Act and are implemented through the regulations. If the certification levels are below the applicable standard and the manufacturer has demonstrated that the vehicle meets all emission requirements, a Certificate of Conformity can be issued. Selective Enforcement Audit (SEA)

Section 206(b) of the Clean Air Act authorizes EPA to conduct testing of new motor vehicles or engines at the time they are produced to determine whether they comply with the applicable emission standards. This testing may be conducted by the Agency or, under conditions specified by the Agency, by the manufacturer. If the Agency determines based on this testing that the vehicles or engines do not comply with those regulations, the Agency may suspend or revoke the applicable certificate.

The SEA program accomplishes two goals. First, it provides the Agency with an early opportunity to evaluate the emissions performance of actual production vehicles for which certificates have been issued. In the case of classes of vehicles which are found to be high emitters, this allows EPA to obtain repair of vehicles already in owners' hands and to ensure that vehicles subsequently produced comply with applicable requirements. Second, EPA’s ability to test new vehicles and to revoke or suspend the certificate encourages manufacturers to conduct their own testing of new vehicles. This allows manufacturers to identify and correct high emitting classes of vehicles early in their production life, providing an opportunity to prevent excessive emissions during the life of the vehicles. Recall

When and if the EPA Administrator determines that a class or category of vehicles or engines, although properly maintained and used, does not conform with the applicable regulations when in actual use throughout its useful life, the manufacturer is required to submit a plan to remedy the non-conformity at the manufacturer's expense. This remedy is available to the owners of all vehicles of the relevant class regardless of the age or mileage of the vehicles.

EPA tests in-use vehicles under the current recall program and uses the resultant data to evaluate the emission performance of vehicles in actual use. As the evaluation is based on vehicles which have experienced real life operation by actual owners over a number of years, it provides the Agency and the industry with a particularly accurate picture of the emission performance of properly maintained and used vehicles. In appropriate cases EPA requires manufacturers to repair non-complying classes. In many cases a manufacturer will voluntarily recall vehicles if problems are discovered through EPA’s test program.

The recall program accomplishes its emission reduction goals not only through the repair of non-conforming vehicles classes, but also through the deterrent effect created by the substantial expense to manufacturers associated with conducting a recall. The potential expense associated with vehicles which demonstrate inadequate in-use emissions durability encourages manufacturers to design and build vehicles which are durable in actual use, thus addressing the real world emissions of the motor vehicle fleet. Manufacturer In Use Verification Testing

Over many years, EPA concluded that it was important to redirect industry and Agency resources from pre-production certification to focus on improved in-use emissions performance. Accordingly, new regulations were adopted that require manufacturers, under the authority of section 208(a) of the Act, to provide EPA with emission test data on a specified number of in-use vehicles, procured and tested at the manufacturer's expense (either via a contract test facility or by the manufacturer's own laboratory) . The program consists of two basic categories of manufacturer-funded in-use testing: (1) in-use verification testing of vehicles representing virtually all of the test groups produced by each manufacturer in each model year and, (2) in-use confirmatory testing consisting of additional, more rigorous, testing of test groups or subsets of these test groups (limited to transmission types) which, in the in-use verification testing, demonstrated potentially high emissions.

The purpose of the "In-Use Verification Program" (IUVP) is to provide the Agency and the industry with emission data feedback from vehicles driven under real-world conditions. The data generated from the IUVP is used to assess and improve the effectiveness of the manufacturer's certification durability and emission demonstration processes. In addition, the IUVP data is used to determine the need for further manufacturer funded in-use testing (In-Use Confirmatory Testing) which could be used by the Agency in determining non-conformity under Section 207(c) of the Act.

The basic elements of the proposed IUVP are low mileage (10,000 mile minimum vehicle mileage, approximately one year of operation) and high mileage (50,000 mile minimum mileage and approximately four years of operation) emission testing of in-use vehicles. These mileage and age test points were selected to provide feedback to the Agency and the industry on the emission performance of vehicles at both an early point in their operating life (to allow early identification of any problems which occur in production or early in the life of the vehicle to minimize the emission impact of the defect or deficient design), and at a point well into the vehicle’s statutorily-defined useful life (to identify and correct any problems which occur only after extended in-use operation) but not at such a high mileage that high emitting vehicles would not be identified until the end of their useful life. Heavy-duty In Use Compliance in the U.S.

Based on the above, one can see a clear path to achieving good in use compliance with standards for light-duty vehicles. However, the problem of in use compliance for heavy-duty vehicles has been much more problematical. Experience in the US will be reviewed below along with suggested remedies.

The goal of tighter standards is to ensure real-world emissions control over the broad range of in-use speed and load combinations that can occur, rather than just controlling emissions under certain laboratory conditions. Historically, EPA’s approach to setting emission standards has been to establish a numerical emission standard on a specified test procedure and rely on the prohibition of defeat devices to ensure in-use control over the range of operation not included in the test procedure. Defeat devices are devices which reduce or eliminate the performance of emission control devices or systems under actual driving conditions.

No single test procedure can cover all real-world operations or conditions, particularly where certification is comprised of an engine-based test procedure rather than a vehicle-based procedure as is the case with heavy-duty engines. For example, the same engine used in both a 9,000-pound and a 15,000-pound vehicle would likely see much higher loads, on average, in the 15,000-pound vehicle. The defeat device prohibition is designed to ensure that emissions controls are employed during real-world operation and not just under laboratory or test procedure conditions. However, the defeat device prohibition is not a quantified numerical standard and does not have an associated test procedure. As a result, the current focus on a standardized test procedure makes it harder to ensure that engines will operate with the same level of control in the real world as in the test cell.

In an October 1997 final rule, EPA adopted a number of measures designed to improve in-use compliance for heavy-duty diesel engines. In summary, these measures included 1) extending the engines’ useful life; 2) increasing the maintenance intervals for emissions-related components; 3) strengthening the warranty provisions for emissions defects and emission performance; 4) requiring that manufacturers provide owners with guidance on maintenance for emissions-related components and on responding to emissions-related codes from onboard diagnostic systems; and 5) strengthening “anti-tampering” requirements for engine rebuilding. Supplemental Standards and Test Requirements

Subsequently, it became clear that many heavy-duty engines were not meeting emission standards in use. EPA issued enforcement policy guidance to partially address this problem. Beyond this, EPA has added two supplemental sets of standards and test requirements for heavy-duty diesel engines: 1) a supplemental steady-state test and accompanying standards and 2) Not-to-Exceed (NTE) limits. Like current standards, these new standards apply to certification, production line testing and vehicles in actual use. All existing provisions regarding standards (e.g., warranty, certification, recall) would be applicable to these new standards, as well. The steady-state test is proposed because it represents a significant portion of in-use operation of heavy-duty diesel engines that is not adequately represented by the FTP.

Recent advances in engine technology, such as electronic controls, have created the opportunity for a broader gap to exist between typical real-world operating conditions and those conditions represented by the current EPA test cycle. The inconsistencies between lab and real-world emissions reduce the certainty that emission standards will achieve their intended benefits. Enforcing compliance with the current regulations, including the defeat device prohibition, on a case-by-case basis has not been very successful and could actually become more difficult in future years as technology advances. Steady State Test Cycle

US EPA has concluded that one remedy is to require manufacturers to meet the standards under a steady state test cycle, as well using the current test procedure (including the current transient test cycle). These requirements are consistent with those in the Consent Decrees signed in July 1999 with several heavy-duty diesel engine manufacturers. The supplemental steady-state test cycle is needed so that the FTP reflects a greater range of driving conditions experienced on the road, especially those relying on the increased use of electronic engine management systems. These electronic systems have the ability to optimize fuel economy during real-world driving, but often at the expense of emissions. The steady-state test cycle represents an important type of modern engine operation in power and speed ranges that are typically used in practice. The mid-speeds and mid-to-high loads represented by the steady-state test are the speeds and loads at which these engines are designed to operate for maximum efficiency and durability. Specifically, highway cruise speeds and loads fall into the operation represented by the proposed steady-state test.

[SECTION|Not-to-Exceed (NTE) Limits

To help ensure that heavy-duty engine emissions are controlled over the full range of speed and load combinations commonly experienced in use, EPA has adopted NTE limits to heavy-duty diesel engines. The NTE approach establishes an area (the “NTE zone”) under the torque curve of an engine where emissions must not exceed a specified value for any of the regulated pollutants. The NTE standard would apply under any conditions that could reasonably be expected to be seen by that engine in normal vehicle operation and use. In addition, EPA has decided that the whole range of real ambient conditions be included in NTE testing.

One of the important benefits of the NTE approach, in addition to helping to ensure emission benefits over the full range of in-use operating conditions, is that the NTE requirements are also expected to be an effective element of an in-use compliance testing program. At the time of certification, manufacturers would have to submit a statement that their engines will comply with these requirements under all conditions that may reasonably be expected to occur in normal vehicle operation and use. The manufacturer must provide a detailed description of all testing, engineering analysis and other information that forms the basis for the statement. This certification statement must be based on testing and/or research reasonably necessary to support such a statement and on good engineering judgment.

There are significant advantages to taking this sort of approach for heavy-duty engines. The test procedure is very flexible, so it can represent most in-use operation and ambient conditions. Therefore, the NTE approach takes all of the benefits of a numerical standard and test procedure and expands them to cover a broad range of conditions. Also, with the NTE approach, in-use testing and compliance become much easier, since emissions may be sampled during normal vehicle use. A standard that relies on laboratory testing over a very specific driving schedule makes it harder to perform in-use testing, especially for engines, since the engines would have to be removed from the vehicle. Testing during normal vehicle use, using an objective numerical standard, makes enforcement easier and provides more certainty of what is occurring in use versus a fixed laboratory procedure.

Coupled with the introduction of OBD for heavy-duty vehicles, it is expected that these approaches will enhance the in use emission performance of heavy-duty vehicles. Conclusions Regarding Compliance

A great deal of progress has been made in reducing vehicle emissions in many countries with the result that many cities have experienced actual air quality improvements. However certain problems remain and with continued growth in vehicle populations are likely to continue to be significant problems in the future without focused actions. These problems include toxic emissions, especially diesel particulate, climate change and in use compliance with standards, especially for heavy-duty vehicles.

As countries proceed toward adoption of state of the art vehicle emissions standards it is critically important that it also include a strong in use directed compliance program to assure that the full benefits are achieved.