Service Information: Fluid for new AdBlue(R) injection system

New ARLA32 liquid supply system

The object of this Service Information is to introduce the new ARLA32 liquid volumetric metering system for the Blue Tec5 emission after-treatment system. The main feature of this new system, called Liquid Only, is the absence of compressed air in the ARLA32 injection process, thus eliminating any possibility of crystallization in the injection system (injection tubing and nozzles).

B14.40-0160-06

Old system for ARLA32 injection/dosing

1 Vehicle system

2 Auxiliary 5 liter cylinder

A Urea tank

B Urea return

C Urea suction

D Dosing pump

E Air supply

F Dosing unit

G Urea pressure

H SCR control unit

J MR2

K Water valve, cooling

L Air control

M Motor

N Air valve

P Silencer with catalyser

B14.40-0161-06

New system for ARLA32 injection/dosing

A Urea tank

C Urea suction

J MR2

R Urea return

S EDU

T Dosing pump

U Dosing unit

V Silencer with catalyser

MAIN MODIFICATIONS

B14.40-0162-01

New dosing unit

More compact design, with all sensors (temperature and pressure) integrated internally, with only one electric connector (5), one input line (1, and one return line (2). The injector nozzle (4) was located in the base of the dosing unit which in turn was installed at the entrance of the catalyser tubing.See illustration above (New system for ARLA32 injection/dosing).

B14.40-0164-01

B14.40-0163-01

New dosing pump

Different from the previous pump with a weight of 5,8 kg, the new pump had its weight reduced to approximately 2 kg, and its dimensions were also reduced.

1 Electronic control unit for volumetric ARLA32 metering. The SCR control unit is now incorporated in the pump area, whereas in the previous system it had to be fastened to the vehicle chassis.

2 The actual dosing pump, now piston-driven, is capable of delivering pressures up to 10 bar. Maximum pressure produced by the previous diaphragm pump was 5 bar.

3 Aluminum block. With one ARLA32 liquid input (6) and one output (5) and one coolant input (8) and one coolant output (7) (vehicle engine coolant) which is used only in regions with very low temperatures.

4 Filter, with the same function, however, with a new geometry.

Maintenance made easier

Apart from the technical improvements and dimensional reductions, space was gained in the engine compartment next to the exhaust collector pipe thanks to the removal of the old dosing unit with its components, such as: tubings, electric wiring harnesses, and fastening support brackets.