Love this, proper control
What sort of pressure are you running behind those injectors?
Have you seen the OE setup that BMW did on the fancy M4?
https://www.bmw-m.com/en/topics/magazin ... orses.html
Functional description;
Water injectionS55
The water injection is installed in the M4 GTS for the purpose of an increase in performance. The only change on the known engine S55 is the equipment of the intake plenum with the three water injection valves. The functions of the engine control unit were expanded accordingly.
Description
The water injection sprays distilled water into the intake air and thereby causes cooling of the condensed intake air. As a result, the temperature drops during compression and combustion, so that better ignition points can be driven. The better combustion efficiency increases the maximum power.
The water is injected with a pressure of 10 bar. After stopping the engine, the system is automatically drained into the water tank.
Figure 1: Schematic representation of water injection.
Item Explanation Item Explanation
A Water intake pipe B Water pressure lines (10 bar)
C Sensor signals D Actuating wires from the engine control unit
E 12 V actuating wires, switched by relay
1 Engine control unit 2 Water injection valves
3 Water injection relay 4 Water pressure sensor
5 Reversible flow valve 2 6 Valve block, water injection
7 Reversible flow valve 8 Shut-off valve
9 Water tank 10 Water pressure sensor and filling level sensor
11 Water pump 12 Water injection relay 2
Preconditions for the activation of the water injection
The water injection is activated by the engine control unit under the following preconditions:
Coolant temperature above 60°C.
Ambient temperature above 5 °C.
Water temperature above 5 °C.
Engine is operated in maximum power range.
Components of water injection
Water pump
The water pump is activated via the relay 2 water injection of the engine control unit and has two functions:
Generating the fuel injection pressure of 10 bar.
Draining the system back into the water tank.
Water injection valves
The three water injection valves are activated by the engine control unit and spray the water for cooling the intake air into the intake plenum.
Water tank
The water tank holds the 5 l water for the water injection and is equipped with a filling level sensor and water temperature sensor.
Reversible flow valve (integrated in valve block)
The two reversible flow valves (reversible flow valve and reversible flow valve 2) are activated via the water injection relay of the engine control unit. With the help of the reversible flow valves, the water pump can, depending on the valve position, either build the fuel injection pressure or drain the system.
Water pressure sensor (integrated in valve block)
The water pressure sensor measures the prevailing pressure in the system.
Shutoff valve (integrated in valve block)
The shutoff valve prevents the water from running back into the water tank on its own when the water pump is shut down.
The shutoff valve is activated by the relay 2 water injection, which also activates the water pump.