Document ID: chunk:federal_register_of_legislation:F2023C00229:reg:3
Version: federal_register_of_legislation:F2023C00229
Segment Type: reg
Provision Reference: reg 3
Character Range: 774082–775977

3                          Construction Requirements

3.1                     The SCR system on the vehicle shall be designed to:

3.1.1              keep the temperature of the urea solution liquid at low atmospheric temperature in order to prevent phase separation;

3.1.2              prevent urea from staying at the injection nozzle when the engine stops in order to prevent phase separation;

3.1.3              prevent high urea solution temperatures by adopting shields or other measures in order to maintain the quality of the urea solution in the tank;

3.1.4              provide a pressure regulator in urea solution tank in order to prevent excessively high pressures in the tank;

3.1.5              prevent urea solution from freezing while the engine is running in order to secure proper injection rates for the urea solution; and

3.1.6              use parts which are durable and resist corrosion by the urea solution and other material.

3.2                     In order to keep the emission of ammonia as low as possible, a vehicle equipped with an SCR system shall:

3.2.1              be fitted with oxidation catalyst downstream of the SCR system, which has enough oxidation capability to keep emissions of ammonia as low as possible; and

3.2.2              utilise a pressure regulator in the urea tank which incorporates a mechanism to keep emissions of ammonia as low as possible.

3.3                     A vehicle equipped with an SCR system should be provided with a meter, which indicates the balance of urea solution in the tank so that the driver is able to refill properly.

3.4                     Any catalyst used as part of, or in conjunction with, an SCR system must not emit any of the following metals into the atmosphere:
           * Vanadium
           * Chromium
           * Manganese
           * Cobalt
           * Nickel
           * Copper