jetnewbie
17th May 2014, 01:26
Hi guys,
I'm a newbie is this field. I loosely understand that Hydromechanical unit (HMU) is a unit in the engine that takes gas control law from the Engine Control Unit (ECU) to control the Fuel Metering Valve (FMV) inside the HMU. I need to know some terms that are used within the HMU and FMV itself.
So my questions are:
1. Is there a difference between Main Metering Valve (MMV) and Fuel Metering Valve (FMV)? Or it's just 2 different terms for the same thing?
2. What is meant by Supply Pressure (psi) and Return Pressure (psi)?
3. What is meant by Fuel Flow Demand (pph)? From what I understand, this is a constant value, fed into the ECU acting as a reference point so that the control law can be determined. Can anyone verify this? If this is incorrect, kindly elaborate.
4. What is meant by MMV Feedback (inches), MMV Demand (inches), MMV Position (inches), Actual Fuel Flow (pph) and MMV Current (mA)? In order for a control law to be determined, which of these terms play a role?
5. What is meant by FMVTMC (mA)?
6. In what way does a Servo Pressure Compensation play a role in determining the control law for a MMV?
Note that I'm assuming FMV and MMV meant the same thing. Correct me if I'm wrong.
Thanks to everyone to took the time to read this and answer them. Really appreciate it :ok:
I'm a newbie is this field. I loosely understand that Hydromechanical unit (HMU) is a unit in the engine that takes gas control law from the Engine Control Unit (ECU) to control the Fuel Metering Valve (FMV) inside the HMU. I need to know some terms that are used within the HMU and FMV itself.
So my questions are:
1. Is there a difference between Main Metering Valve (MMV) and Fuel Metering Valve (FMV)? Or it's just 2 different terms for the same thing?
2. What is meant by Supply Pressure (psi) and Return Pressure (psi)?
3. What is meant by Fuel Flow Demand (pph)? From what I understand, this is a constant value, fed into the ECU acting as a reference point so that the control law can be determined. Can anyone verify this? If this is incorrect, kindly elaborate.
4. What is meant by MMV Feedback (inches), MMV Demand (inches), MMV Position (inches), Actual Fuel Flow (pph) and MMV Current (mA)? In order for a control law to be determined, which of these terms play a role?
5. What is meant by FMVTMC (mA)?
6. In what way does a Servo Pressure Compensation play a role in determining the control law for a MMV?
Note that I'm assuming FMV and MMV meant the same thing. Correct me if I'm wrong.
Thanks to everyone to took the time to read this and answer them. Really appreciate it :ok: