Particles Matter to be published in December 2021

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Quick particle test verifies effectiveness of particulate filter

While the diesel engine may not pave the way in the energy transition, it will be with us for decades to come.

Within Europe, approximately 80 million diesel vehicles are fitted with a diesel particulate filter. Provided these filters work properly, emissions of harmful particulates are reduced by more than 95%. An impressive achievement that is reversed when the filter develops a fault. So how can we check - quickly, reliably and cost-effectively - that a particulate filter functions properly? And how do we embed this check in the periodic technical inspection (PTI)?

Several Dutch parties have, since 2012, worked on the development of a new particle test to verify the correct functioning of diesel particulate filters. The test is conducted using an affordable, uncomplicated particle counter, capable of measuring high particle concentrations. It takes a mere 90 second, and is carried out with the engine idling.

In 2022, the Dutch and Belgian authorities will introduce a compulsory PTI particulate filter check based on the particle test. Germany will introduce a similar check in 2023. It is expected that other countries will follow suit over the coming years. Within Europe, as many as 53 million diesel vehicles could be checked every year.

By answering 91 questions, Particles Matter explains the PTI particulate filter check, the particle test, the particle counter, and the complex technical ins and out of the diesel particulate filter. The book is intended for PTI inspectors, mechanics and policy-makers.

Table of contents.

Foreword

  1. Introduction to the PTI particulate filter check
  2. Basic explanation of particulate filters and particulate emissions
  3. The particle test in practice
  4. PTI threshold limit values (TLVs) for particle concentration
  5. Different types of particle counter and counter requirements
  6. The particle counter in everyday use
  7. Conducting a particle test - tips and suggestions
  8. Maintenance and technical inspection of the particle counter
  9. Defective DPFs - causes and consequences
  10. Particle tests for petrol vehicles
  11. International developments

 

Bibliography

Afterword

List of abbreviations

Overview of existing particle counters

 

The following 91 questions are used to explain the particle test and particulate filter technology in general.

 

Chapter 1

Introduction to the PTI particulate filter check

  1. Introduction to the diesel particulate filter (DPF)
  2. From exhaust gas opacity test to particle test
  3. The particle test
  4. What is a diesel particulate filter (DPF)?
  5. Why is the particle test necessary? What purpose does it serve?
  6. How many vehicles are fitted with a diesel particulate filter (DPF)?
  7. Who developed the PTI particulate filter check?
  8. What does the particle test entail?
  9. How is the particle test conducted?
  10. What are the technical attributes of a particulate counter? Which measuring principles are applied?
  11. How is a vehicle prepared for the PTI particulate filter check?
  12. Which particulate emissions will the particle test identify?

 

Chapter 2

Basic information on particulate filters and particulate emissions.

  1. How effective is a diesel particulate filter (DPF)?
  2. Which particulate types are found in diesel exhaust gas?
  3. How are particulate emissions measured?
  4. How are particulate number emissions measured for the purposes of vehicle type approval?
  5. Which types of particulate filter are currently in use?
  6. Which filter materials are used in a DFP?
  7. Which components does a DPF consist of?
  8. How does a DPF work?
  9. How big are the openings in the porous wall of a DPF?
  10. How is a DPF regenerated?
  11. Why are DPFs occasionally removed and cleaned?
  12. Under what circumstances do DPFs develop faults?
  13. Which factors influence the particulate emissions of a diesel engine?
  14. Are there significant differences between the particulate emissions of diesel cars, vans and trucks?
  15. How have particulate emissions from diesel vehicles historically been measured during a PTI?

 

Chapter 3

The particle test in practice.

  1. How is the PTI particulate filter check carried out?
  2. How do you start and initiate a particle counter?
  3. How is the sampling probe placed in the exhaust?
  4. How long does a particle test take?
  5. Why is the particle test performed at idle speed?
  6. How is a vehicle prepared for the particle test?
  7. Under which (standard) conditions is a particle test conducted?
  8. Can a particle test be conducted under non-standard conditions?
  9. Which particle concentration levels can be expected in practice?
  10. How is average particle concentration determined?
  11. What is a fast-fail option, and why is it included in the procedure?
  12. How can variations in the test results arise?
  13. How does exhaust gas recirculation (EGR) affect engine emissions?
  14. How does the particle test compare to the exhaust gas opacity test?
  15. Which steps does the PTI particulate filter check flowchart include?

 

Chapter 4

PTI threshold limit values (TLVs) for particle concentration levels.

  1. How are diesel vehicles fitted with a DPF expected for perform in the new PTI particulate filter check?
  2. Which PTI threshold limit values for particulate concentration levels will apply ?
  3. How strictly are the threshold limit values applied?
  4. How will the introduction of the PTI particulate filter check affect air quality?
  5. What is the correlation between the threshold limit values (TLVs) and the filtration efficiency of a DPF?
  6. Which threshold limit values will be applied when the PTI particulate filter check is introduced?

 

Chapter 5

Particle counters - types and technical requirements.

  1. Where are the technical requirements for particle counters recorded?
  2. What are the technical attributes of a particulate counter?
  3. Which measuring principles are used in particle counters?
  4. Which components does a particle counter consist of?
  5. What types of sampling systems are used?
  6. How is exhaust gas conditioned?
  7. Which particulate sizes does a particle counter measure?
  8. Which requirements have been defined for measuring accuracy?
  9. Within which temperature range can a particle counter be used?
  10. Can a particle counter be used at higher altitudes?
  11. How often should a particle counter be calibrated?

 

Chapter 6

Particle counters in everyday use.

  1. Can the particle counter be deployed at different test stations?
  2. Which particle counter initiation sequence could be used?
  3. Which everyday tests can a particle counter conduct?
  4. What is the purpose of a HEPA filter?
  5. What happens if too much or too little exhaust gas is drawn into the particle counter?
  6. How should the sampling probe be placed in the exhaust?
  7. How can unnecessary contamination of the particle counter be avoided?

 

Chapter 7

Conducting a particle test - tips and suggestions.

  1. What conclusions can be drawn from carbon deposits in the exhaust system?
  2. Which parameters affect the outcome of the particle test?
  3. Which parameters affect the accuracy of the measurement data?
  4. Can an additional test be conducted if particle concentration levels measured during the first test are too high?

 

Chapter 8

Maintenance and technical inspection of the particle counter.

  1. Why is a technical inspection of the particle counter necessary?
  2. To what extent can the measurement results obtained from different (certified) particle counters differ?
  3. Why does a particle counter require maintenance?
  4. How is a the technical inspection of a particle counter performed?

 

Chapter 9

Defective DFPs - causes and consequences.

  1. What is the expected life of a DPF?
  2. Why do DPFs fail?
  3. Under what operating conditions can DPFs fail?
  4. What happens to a DPF fitted to a vehicle that makes many short journeys?
  5. How do particulate emissions develop over the lifetime of a diesel engine?
  6. What are the main causes of increased engine particulate emissions?
  7. How do increased particulate emissions affect a DPF?
  8. What does an OBD (on-board diagnostics) system detect?
  9. Which course of action is appropriate if a defective DPF is defective?

 

Chapter 10

Particle test for petrol vehicles.

  1. Can the particle test be used for petrol vehicles?
  2. Can the particle counter be used to measure emissions from petrol engines?
  3. How does the composition of diesel exhaust gas differ from that of petrol exhaust gas?
  4. How do the particulate emissions of a petrol engine compare to those of a diesel engine?
  5. How do the particulate emissions of different types of petrol engine compare?
  6. How does the size of particulates emitted by a petrol engine compare to those of a diesel engine?
  7. Why are petrol vehicles fitted with a gasoline particulate filter (GPF)?
  8. Which modifications are required to make the particle test suitable for petrol vehicles?