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HEAVY-DUTY DIESEL I/M: ISSUES AND OPTIONS

HEAVY-DUTY DIESEL I/M: ISSUES AND OPTIONS. K.G.DULEEP MANAGING DIRECTOR ENERGY & ENVIRONMENTAL ANALYSIS. Diesel Emissions Technology. Diesel emission control has evolved rapidly in the last 20 years.

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HEAVY-DUTY DIESEL I/M: ISSUES AND OPTIONS

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  1. HEAVY-DUTY DIESEL I/M: ISSUES AND OPTIONS K.G.DULEEP MANAGING DIRECTOR ENERGY & ENVIRONMENTAL ANALYSIS

  2. Diesel Emissions Technology • Diesel emission control has evolved rapidly in the last 20 years. • New engines sold in Europe and the USA do not now resemble most engines used in developing countries. • Modern Euro 3/4 or US Tier 2 diesels are highly turbocharged, use very high pressure electronic FI systems and oxd. catalysts.

  3. In-Use Emissions • Limited data from tests in Europe and USA show a significant fraction of engines with high PM emissions (over std.) • Much smaller proportion of trucks have high NOx emissions. • Overall performance improving due to less potential to tamper or mal-adjust new electronically controlled systems.

  4. Causes of High Emissions • All high emissions due to fuel introduced to the combustion chamber at the wrong time or in excess quantity. • Typical causes of high emissions: • Incorrect max. fuel stop (tampering) • maladjusted injection pump • leaky injectors • AF ratio control (turbo) • worn rings/ high oil consumption

  5. Control of In-use Emissions • Although Arizona has had a smoke inspection program from the 1970’s, only California embarked on detailed analysis of benefits, in 1990. • California study examined available test methods, viable pass/fail standards, program structure and emission benefits.

  6. EXISTING TEST METHODS • Little research had been done on short tests for diesels. Major drawback of existing test methods are that they focus on smoke. • Available methods are only suitable for detecting potentially gross PM and HC emitters, with little research on NOx. • However, more sophisticated tests may be necessary for very high levels of control.

  7. Conclusions of California Study • A J1667 test standard of 55% opacity could be easily met by pre-1991 US diesels. • Estimated benefits of a 29% reduction in HC and a 40% reduction in PM in CY1995. • Roadside enforcement was far more cost effective than any annual program. • Significant emissions benefit from self repair due to fear of being caught.

  8. Diesel IM in North America • Many states have followed California’s lead and set up heavy-duty diesel IM programs. • 17 states in the US and Ontario in Canada now have active programs. All except two use the J1667 test and California standards. • Many Western states require annual inspection, while most Eastern states and California have a roadside program.

  9. States with IM Programs

  10. Results from Existing Programs • Most states with programs in operation for several years have seen big decrease in number of smoky (mostly older) trucks. • Typical failure rate is in the 5 to 6 percent range after some years, down from starting rates of 12 to 15 percent. • The lug down test fails fewer trucks than the J1667 test.

  11. Opacity before IM Program Start

  12. Opacity after IM Program Start

  13. The J1667 Test for Asia • Snap, or free acceleration test, useful for most mechanically controlled FI systems, and is a good diagnostic tool as an indicator of engine mal-performance. • Correlation with PM emissions is an irrelevant issue as it is a pass/fail test. • Key to proper test execution is correct smoke averaging, and acceleration at WOT.

  14. New Test Methods for Asia • Truck engine emission testing is expensive due to need for large dyno and sampler. • New simpler test cycles (without inertia weights) with an acceleration and lug down cycle are promising. • New portable emissions equipment allows measurement during on-road driving. • Unfortunately, methods are not yet fully developed for implementation.

  15. OPERATIONAL ISSUES • In developed countries, very few of the Euro 2 and later or US 1997+ trucks appear to be high emitters. • In this context, centralized inspection is very cumbersome since trucks can move outside enforcement area. • Targeted roadside inspections for high PM emitters and mandatory maintenance may be more cost effective in Asia.

  16. SUMMARY • Existing I/M tests - snap and lug down - better suited to older technology, and can spot potentially high PM and HC emitters. • No well developed test exists for detecting high NOx emitters, but it is not clear if this is a real problem. • New approaches for better control with newer technology are being developed but are not yet well proven in the field.

  17. SUMMARY • The properly executed J1667 test can be useful pass-fail test for diesels to identify high PM and HC emitters in Asia. • Roadside inspections with mobile teams is a better solution for heavy-duty trucks. • Non-turbo trucks can use a much tighter opacity standard, lower than 40% opacity • Capability of service industry to correctly repair trucks need further study

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