Answer
LGIP- Liquid Gas Injection Propane.
The main components are:
1) The gas control blocks. – on cylinder head
2) FBIV-P (Fuel Booster Injection Valve- Propane) main component.
3) Piping.
4) Accumulators.
1). Gas control block- contains
a) ELWI- electronic window and gas shut down valve which will activate the window valve to pressurize or boost the LPG to the desired pressure ie 50 bar gas to the FBIV-P. It provides the window function. so within that window the injection will take place.
b) ELGI- Electronic gas injection valve will be used for admitting gas at correct timing and duration of LPG injection. This valve will allow hydraulic control oil of pressure 600-700bar to go and activate the FBIV-P valve. Both ELWI and ELGI will provide double safety.
Operation- first ELWI than ELGI and close in reverse direction
2) FBIV-P: The function is to further boost up the pressure of liquid gas to around 600-700bar from 50 bar supply pressure. To control the FBIV-P operation hydraulic oil supply will come at press sure 600-700bar. Sealing oil will provide sealing so that the gas should not pass through to hydraulic oil side. So sealing oil will be supplied either separately through separate servo oil system or from the same control oil system tap piping will be taken. Sealing oil must be greater than 50 bar pressure. Small amount can burn in engine is allowed. Once the gas pressure is reached 80 bar there is a non-return valve which opens, it will close for additional safety at 50 bar supply pressure.
3) Piping system is provided with double wall safety and ventilation system provided in the double wall space with HC sensors.
4) Accumulators: have capacity to store additional capacity of 20 injection cycles. Two functions
a). To limit the pressure fluctuations. Max allowed pr drop (20-30bar)
b). To form an important part of the safety system.
Relative pressure drops in the accumulator is measured continuously. Any larger pr reassure drop would indicate a severe leakage in the gas injection v/v or fractured pipe. The safety system will detect this and shut down the gas mode and change over to fuel mode.
Safety requirements:
1.Double wall piping for gas suppply in engine room.
2.Ventilation of the double wall piping space exhaust to gas safe zone.
3.HC sensors in ventilation space to detect any abnormal leakages from the seals.
4.Accumulator relative pressure drop measurement to detect leakage and change over to gas safe mode with alarm.
5.Any leakage detected by HC sensors will change over from gas mode to fuel mode with alarm.
6.Double valve safety with ELWI a and ELGI provided.
7.In case of any gas alarm the changeover will take place from gas mode to fuel mode with purging of the gas line upto FBIV-P including accumulator with nitrogen.
Gas safe machinery space: Arrangements in the machinery space are such that spaces are considered gas safe under all conditions that means if there is a single failure take place there will be no release of gas in the machinery space. So that type of protection or shielding is required.
