Schedule 1DT80 transient test procedure for testing of diesel‑fuelled vehicle exhaust emissions

Schedule 1—DT80 transient test procedure for testing of diesel‑fuelled vehicle exhaust emissions

(rule 147A)

1 Secure the vehicle on the dynamometer. 2 Set the dynamometer to simulate the correct load and inertia for the vehicle. 3 Start sampling. 4 Idle for 60 seconds. 5 Accelerate rapidly to 80 km/hr under simulated inertia using wide open throttle, making gear changes as required for smooth acceleration. 6 Decelerate by removing all pressure from the accelerator pedal, disengaging the gears and gently applying brakes to bring the vehicle to a standstill. 7 Idle for 10 seconds. 8 Accelerate rapidly to 80 km/hr under simulated inertia, using wide open throttle, making gear changes as required for smooth acceleration. 9 Decelerate by removing all pressure from the accelerator pedal, disengaging the gears and gently applying brakes to bring the vehicle to a standstill. 10 Idle for 10 seconds. 11 Accelerate rapidly to 80 km/hr under simulated inertia using wide open throttle, making gear changes as required for smooth acceleration. 12 Maintain speed at 80 km/hr for 60 seconds, then stop sampling. Bring the vehicle to rest.

Note: Explanation of the test procedure

Note: This test has been designed to evaluate vehicle emissions during typical ‘real‑world’ operating modes and conditions. There are 3 simple modes:

• 3 idle periods
• acceleration to 80 km/h 3 times
• maintain speed at 80 km/h.

Note: The graph below indicates the modes of operation. The actual test will result in a graph that has more variation than the indicative graph below, because of the need to change gears when accelerating. Modes B – D and E –G and H – I have no specific time interval. All the specified time periods have an error margin of ± 1 second.

Note: The vehicle is accelerated rapidly to 80 km/h 3 times by applying wide‑open throttle.

Note: The driver selects the most appropriate gear change points for the vehicle being tested to achieve the correct speed.

Note: The vehicle test mass for road load and inertia settings must be equal to the mass of the vehicle when operating with ½ its nominal payload (that is, GVM + tare mass)  2).

Note: The vehicle’s rolling resistance (based on tyre and bearing losses, frontal area and drag coefficient) must also be calculated and continuously factored into the dynamometer tractive effort calculations to ensure correct loading.

Note: Empirical algorithms, based on vehicle test mass, GVM or other known parameters, may be used to automatically calculate realistic coefficients for these variables.