DME FEED SYSTEM
WMI has developed a DME feed unit to prepare the fuel for the injection system. In the case of DME fuel that has a propensity to default to vapor state, specially under fast fluid motion taking place during injection events, the present system closely monitors pressure and flow to ensure fuel is delivered under a liquid phase and yet limiting the work required from the pump unit. Very important too is the need to evacuate the pressure lines upon shut down as this ensures operation safety. The DME feed system features an evacuation procedure specially design to avoid seal damage from near vacuum operation.
DME pumps for vehicle applications resemble LPG automotive systems, where pumps are located inside the tanks. The advantage is they are submerged in liquid, easing the pumping of the fuel.
PUMPS OUTSIDE THE FUEL TANKS
Pumps located outside the tanks need to handle DME in gas and liquid phases. Pumps pull fuel from tank creating a momentary expansion likely to transition fuel from liquid to vapor. Pumps need therefore to be very effective pumping gases and recompress them into liquid phase before pressure can be built up in the system.
WMI FEED PUMPS ADVANTAGES:
1.EASE OF USE:
WMI pumps are designed for facilitate more flexibility. Customers can use standard tanks and connect to them directly.
2.LARGE FLOWS AND PUMPING EFFICIENCY:
Pumps are high-efficiency piston pumps proven to operate under significant distances from the fuel tank.
3.ROBUST TO TEMPERATURES:
Pumps for liquefied gases are highly sensitive to ambient temperatures and WMI pumps are designed to meet flow requirements across a wide range of temperatures.
Readily integrated to the engine electrical system.
WMI FEED PUMPS performance curves
with various feed configurations representing distances to the tank at a range of ambient temperatures.
Sample of power consumption curves at pressure settings
The electronic control over pressure and pump speed shows optimum pump speeds and pressure settings required to reduce engine throttle setting
FEED MODULE SPECIFICATIONS:
Pressure Sensor: 0-20mA
Pump Voltage: 12V
Drive Control: PWM Signal
Max Current: 30A
Safety Valve: Sevo Motor 5-12V
Position: CLOSED (no current) / OPEN
Evacuation Valve: 12Vc
Position: FEED (no current) / EVA