HEAVYDUTY DIESEL IM: ISSUES AND OPTIONS

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 1970s, 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 Californias 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