Exhaust

Applicable legislation

• Land Transport Rule: Vehicle Exhaust Emissions 2007, section 3.

Application

Group M or N vehicles less than 20 years old (Note 4) and certified for entry on or after 1 May 2008 must pass a prescribed metered exhaust emissions test, according to the following procedures and requirements.

Procedure for measuring exhaust emissions of petrol, LPG or CNG vehicles

1. The test equipment must be warmed up and calibrated before use, in accordance with the equipment manufacturer’s instructions.

2. Ensure the vehicle has reached normal operating temperature, as recommended by the vehicle manufacturer.

3. Insert the sampling probe (ie the exhaust gas sampling part of the measuring equipment) far enough into the exhaust pipe to prevent the admission of open air. This is to ensure that only exhaust gas is sampled.

4. For the duration of the test:

a) the vehicle’s engine must be idling, and

b) the acceleratior pedal must be released, and

c) the handbrake must be applied, and

d) the vehicle’s transmission must be

i. in neutral, or

ii. if the vehicle is an automatic, in park.

Pass requirements

A petrol, LPG or CNG vehicle must not exceed the applicable maximum carbon monoxide and hydrocarbon emissions limits set out in below.

Re-testing

If a vehicle fails the test, it may be necessary to ensure the vehicle has reached normal operating temperature, as recommended by the manufacturer.

Procedure for measuring exhaust emissions of diesel vehicles (using an opacimeter)

Pre-testing

1. The vehicle must be brought to the normal operating temperature as recommended by the manufacturer.

2. The equipment must be readied before use, in accordance with the equipment manufacturer’s instructions.

During testing

For the duration of the test:

a) the vehicle must be stationary, and

b) the handbrake must be applied, and

c) the vehicle’s transmission must be:

i. in neutral, or

ii. if the vehicle is an automatic, in park.

Operation of the vehicle while testing

During the test procedure, the vehicle operation cycle must follow these phases (refer to Figure 11-3-1):

1. Purge

a) Residual smoke must be purged from the vehicle’s exhaust system before the vehicle’s diesel smoke is sampled.

2. Inserting probe

a) The probe (the exhaust gas sampling part of the measuring equipment) must be inserted sufficiently into the exhaust pipe to prevent outside air from entering the probe and ensure that only exhaust gas is sampled.

3. Idling before testing

a) The engine must be run at idle for five or six seconds before the first test cycle.

4. Test cycle

a) The accelerator pedal must be fully and rapidly depressed, held in this state for two seconds, then released for three seconds (refer to Figure 11-3-2).

b) Despite the above, if the opacimeter has a function allowing the measurement of the engine revloutions per minute (RPM), the accelerator pedal should only be depressed until the maximum available RPM is indicated by the opacimeter (rather than for the fixed period of two seconds).

c) The exhaust emissions must be sampled throughout this (five-second) period.

5. Idling between test cycles

a) The engine must be run at idle for 4–10 seconds between each test cycle that is performed.

Measured values

1. One, two or three test cycles must be performed as necessary.

a) If the result of measurement 1 is:

i. less than or equal to an optical absorption coefficient (OAC) of 0.64m-1, the vehicle passes the test,

ii. more than an OAC of 0.64m-1, the test cycle must be repeated.

b) If the result of measurement 2 is:

i. less than or equal to an OAC of 0.64m-1, the vehicle passes the test,

ii. more than 0.64m-1, the test cycle must be repeated.

c) If the average of the three measurements is:

i. less than or equal to an OAC of 0.80m-1, the vehicle passes the test,

ii more than an OAC of 0.80m-1, the vehicle fails the test.

2. To avoid doubt, if the vehicle does not meet the prescribed standard after three test cycles, the vehicle fails the test.