WMI

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.

SUBMERGED PUMPS

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.

4.12V OPERATION:

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:

 

Flowrate:         0.25LPM

Pressure:         30Bar

 

Pressure Sensor:  0-20mA

 

Pump Voltage:     12V

Drive Control:    PWM Signal

Speed:            Variable

Max Current:      30A

 

Safety Valve:     Sevo Motor 5-12V

Position:         CLOSED (no current) / OPEN

Optional:

Evacuation Valve: 12Vc

Position:         FEED (no current) / EVA