Vehicle Exhaust Pollution Measurement
VEHICLE EXHAUST POLLUTION MEASUREMENT
FOR DIFFERENT TYPES OF ROAD VEHICLES
If it’s time to renew your car insurance or vehicle
registration, your vehicle could also be up for an emissions test or smog
check. This means your car may have to undergo periodic testing to ensure it’s
within BS standards and is limiting its negative impact on the environment.
Testing
procedure
Testing procedures gauge your car’s emissions and ability to
track the pollutants it releases. In particular, a test can potentially review
the levels of carbon dioxide (CO2), hydrocarbons (HC), carbon monoxide (CO),
oxides of nitrogen (NOx) and other emissions coming from your car.2
Depending on your state’s process, testing can take 15 to 30
minutes. Although there are a variety of inspections that can check your
vehicle’s emissions, the following are the most common types.
On-Board Diagnostic (OBD) inspection
For model year 1996 and later vehicles, the OBD inspection is
the most conventional test.This test verifies the data from your car’s internal
emissions diagnostics system and ensures that your Malfunction Indicator Light
(MIL), the “check engine” light, is working properly.
Acceleration Simulation Mode (ASM) test
Many cars made in 1995 or earlier don’t have an OBD system
installed, so they require a different method to test their emissions, such as
an ASM test.Using a dynamometer — similar to a treadmill — and a tailpipe
sensor, these tests simulate driving conditions to measure your car’s
emissions.
Two-Speed Idle (TSI) test
A TSI test is generally reserved for older cars. It tracks
exhaust emissions when the engine is idling at a high and a low speed.
BS VI (Euro 6 equivalent) gasoline vehicles are certified with E10
and diesel vehicles with B7. In-use compliance test procedures, including real
world driving cycle emission measurement using PEMS, for BS VI vehicles are
defined in an Automotive Industry Standard (AIS-137) to be published by the
Automotive Research Association of India.
Testing Methods Formulated by
India:
o The Indian
Drive Cycle (IDC) was the first driving cycle formulated for vehicle
testing and certification in India based on extensive road tests.
·
The IDC was a short cycle
comprising six driving cycle modes of 108 seconds (reflecting a pattern of
acceleration, deceleration and idling).
o But
the IDC did not cover all the complex driving conditions that are
normally observed on Indian roads.
o Subsequently,
as an improvement over IDC, the Modified Indian Drive Cycle
(MIDC) was adopted, which is equivalent to the New European Driving
Cycle (NEDC).
·
MIDC accounts for wider speed
profiles and is a better-suited cycle than the IDC.
·
MIDC is also significantly
close to the idling conditions observed in real-world driving.
o Despite the improvements, MIDC may still represent vehicular emissions during on-road conditions adequately because of variations in traffic density, land-use patterns, road infrastructure and poor traffic management.
WHAT IS WLTP?
The Worldwide Harmonized Light Vehicles Test Procedure (WLTP),
which is applicable across the EU as well as China, Japan, India, Korea and
other countries, mandates the use of harmonised test procedures that can
evaluate emissions and fuel efficiency in a consistently repeatable and
reproducible manner. Specific assessments under the WLTP include exhaust gases
concentrations, particulate mass and particulate number, CO2 emissions, fuel
and electrical energy consumption and electrical operating range. Testing
cycles are generally determined by vehicle class (Class 1, 2 or 3), which are
defined by the vehicle’s power/weight ratio. The WLTP includes several changes
from existing requirements under the EU’s New European Driving Cycle (NEDC)
procedure.
WHAT
IS RDE?
The European Union’s Real Driving Emissions (RDE) regulations
require the use of a portable emissions measuring system (PEMS) attached to the
vehicle to measure vehicle pollutant emissions under actual driving conditions.
RDE test results are then correlated with emissions results obtained in the
testing laboratory. Testing under the EU’s RDE is now required and, since 1
September 2017, type approval requirements also consider emissions levels
identified during RDE testing. As of that date, vehicles that fail RDE testing
cannot be placed on the market.
EQUIPMENT SPECIFICATIONS FOR
EMISSION SAMPLING SYSTEMS.
This section specifies equipment related to emission testing,
other than measurement instruments. This equipment includes dynamometers
(described further in subpart C of this part) and various emission-sampling
hardware.
The following equipment specifications apply for testing under
this part:
(1) Connect a vehicle's exhaust system to any dilution stage as
follows:
(i) Minimize lengths of laboratory exhaust tubing. You may use a
total length of laboratory exhaust tubing up to 4 m without needing to heat or
insulate the tubing. However, you may use a total length of laboratory exhaust
tubing up to 10 m, or up to 15 m for samples not involving PM measurement, if
you insulate and/or heat the tubing to minimize the temperature difference
between the exhaust gas and the whole tubing wall over the course of the
emission test. The laboratory exhaust tubing starts at the end of the vehicle's
tailpipe and ends at the first sample point or the first dilution point. The
laboratory exhaust tubing may include flexible sections, but we recommend that
you limit the amount of flexible tubing to the extent practicable. For
multiple-tailpipe configurations where the tailpipes combine into a single flow
path for emission sampling, the start of the laboratory exhaust tubing may be
taken at the last joint where the exhaust flow first becomes a single, combined
flow.
(ii) For vehicles above 14,000 pounds GVWR, you may shorten the
tailpipe up to the outlet of the last aftertreatment device or silencer,
whichever is furthest downstream.
(iii) You may insulate or heat any laboratory exhaust tubing.
TWO-WHEELER
EMISSION TEST IN INDIA
According to the Central
Motor Vehicles Act 1989, a vehicle can be driven on the public roads only if it
has a legitimate PUC (Pollution under Control) Certificate. To get a PUC
certificate, the vehicle needs to pass the emission test. Here you can know in
detail about a PUC certificate and two-wheeler emission test to get that.
What
is a two-wheeler emission test?
A two-wheeler emission test
measures whether the vehicle’s emissions are in line with the legally
permissible amount or not. In the emission test, the professionals check the amount
of CO (Carbon Monoxide) in percent and other hydrocarbons in ppm against the
prescribed criteria. To ensure that the pollutants emitted from the vehicles on
road do not surpass the maximum limit. After passing the emission test, the
vehicle owners are granted a Pollution Under Control certificate. As per the
Indian Motor Vehicle rules, it is mandatory to carry this legal document while
driving your vehicle on the public road.
What
is the procedure for conducting an emission test?
Before starting with the
process of emission test, the testing centre prepares the vehicle for the same,
if required. After that, the testing process finally starts. For testing the
exhaust emissions of diesel vehicles, the accelerator of the two-wheeler is
completely pressed, and the readings of pollution levels are carefully
observed. The process is repeated for five times, known as test cycles, and the
average of all the readings is computed to get the final reading. In the case
of petrol vehicles, while measuring the emissions, the two-wheeler vehicles are
kept in an idle mode without pressing the accelerator and the emission values
are recorded. Only one reading is taken and this is taken as the final reading.
During the test, if the two-wheeler is found to release higher levels of
emission (carbon and hydrocarbons) than the permissible limits, the testing
centre reports the registration number of the vehicle to the RTO, Deputy RTO,
or Assistant RTO within 24 hours.
TWO/FOUR
-WHEELER EMISSION TEST CRITERIA
Two/Four -wheelers undergoing
an emission test should meet the following standard carbon and hydrocarbon
emissions criteria to successfully clear the test:
|
Category of the vehicle |
HC (in PPM) |
% of CO |
|
2 and 3
wheelers (2/4 - stroke) manufactured on or before 31st March 2000 |
4.5 |
9,000 |
|
2 and 3
wheelers (2 - stroke) manufactured after 31st March 2000 |
3.5 |
6,000 |
|
2 and 3
wheelers (4 - stroke) manufactured after 31st March 2000 |
3.5 |
4,500 |
|
4
wheelers manufactured according to Pre Bharat-Stage II Norms |
3 |
1,500 |
|
4
wheelers manufactured according to Pre Bharat-Stage II, Stage III, or
subsequent Norms |
0.5 |
750 |
