Bonjour,
Pour relancer un peu le sujet ;-)
Un peu de lecture sur les nouvelles pompes apparues en octobre 2007, les PTS au fonctionnement identique des pompes à essence
Citation: MultiValve S
Compared to the PTC system, the PTS system has a number of component changes. For starters, the pressure regulator is removed and there is a new type of multivalve fitted: the Multivalve 3.
The operating principle of PTS is different than that of the PTC system. The PTC pump works with varying speeds, always with 5 bar above the tank pressure. This is done in combination with a pressure regulator. The PTS system is different. The pressure is determined by the amount of gas exitting the pump and a caliber in the return connection of the Multivalve S. The pump is running at one speed and delivers its maximum pressure at engine idle speed.
The PTS system was introduced to the market in October 2007. At that time only the Seat Leon 1.6 was equipped with PTS, but by now it has grown to include multiple models.
LPG filter
The construction of the Multivalve S is almost equal to that of the Multivalve 2. However, a number of components have changed or have been added. The filter that previously was installed inside the pump motor is now mounted on top of the Multivalve S. This filter is placed in a housing under the filling connection and filters the incoming LPG of any particles. This filter is very fine (10 μ) and can easily be replaced. A non-return valve beneath the filter ensures that during replacement no LPG can escape from the tank. Under normal circumstances this filter does not need to be replaced unless the filling time increases noticeably. This is possible without draining the tan
Return Line Restrictor
Under the return connection at the multivalve a restrictor (calibrated orifice) is fitted and in combination with the pump, determines the system pressure. For the various pumps, various calibres are used.
Pressure Sensor
The pressure sensor which was previously placed in the coupling block is now housed in the multivalve. This is placed behind the return connection and measures the system pressure in the return line before the caliber. The pressure sensor can not be exchanged with that of the coupling block. The operation however is similar.
Pump PTS
Models
The Multivalve S can be equipped with 2 different pumps. These differ in their capacity. Because of the higher fuel demand for higher performance engines, a pump with a high capacity is chosen. The other pump is suitable for all other engine types.
When the multivalve is installed, on the basis of an engraved code on the multivalve is to be determined which type of pump is mounted.
• 10 = PTC
• 20 = PTC-EL (new version 2008)
• 30 = PTS
• 50 = PTS (High capacity)
The turbine pump
The PTS pump is a turbine pump. The turbine pump is equipped with a DC motor which driven by battery voltage. It always runs at maximum speed all the time. The advantage of a turbine pump is that it is very compact. The pump section consists of a turbine wheel that rotates in a turbine housing. The rotating movement of the turbine wheel inside the turbine housing, will cause the liquid LPG to be transported. The capacity of this pump depends on the pump speed, and the composition and temperature of the LPG. The intake side of the pump housing has a filter. This filter protects the system against any contaminates that can occur during the production of the tank and because the filling connection has a very fine filter installed, in principle, the pump filter will not become contaminated and will not need replacing.
Pressure relief valve
The pressure of both PTS pumps is limited by a pressure relief valve. In the 30 pump a pressure relief valve is integrated in the pump itself and limits the pressure at 4.5 Bar above tank pressure. Practically however, the pressure can get higher because the LPG consumption at idle speed is very low and the pressure relief valve only has a certain capacity.
The 50 pump has no internal pressure relief valve. To prevent overloading of the pump due to the very high capacity, it is equipped with an external pressure relief valve which limits the pressure at 3.8 Bar above tank pressure.
If while driving the pressure in the system decreases as more LPG is injected, the pump will, due to the pressure loss, adopt to a higher speed and more LPG can be delivered.
We can conclude that the system pressure is dependent on:
• Pump capacity
• Pressure relief valve
• LPG consumption of injectors
• Restrictor diameter
Lubrication
The turbine pump makes oil lubrication unnecessary. The pump is cooled by liquid LPG while suppling the system. It is therefore essential that the pump is in liquid LPG at all times. If this is not the case, within a few minutes, the pump will be irreparably damaged. To prevent this, the LPE software is programmed to see a pressure rise in a pre-determined time and if this is not registered, the pump is turned off. One example of this is after a system installation, LPG is chosen before the tank is filled. The system will activate AFS (Automatic Fuel Switch) which ensures the pump can not be activated. After AFS is activated you can not activate the pump using the LDT software (with a PTC pump this is possible).
Buffer container
The buffer container is similar in operation to the
swirl pot in the petrol injection system which is
to maintain a usable level of fuel during surge
situations. The buffer container and the pump
of the multivalve is mounted on springs, which
has these 2 advantages:
• The tank can be run almost empty because the buffer container is always pressed to the bottom of the tank. Therefore the pump is always at the lowest possible point.
• The cross on the bottom of the buffer container is forced to the bottom of the tank to ensure the buffer container stays in contact with the tank bottom and ensures optimum filling of the container.
The formed cross on the bottom of the container is situated right in the middle of the one way valve at the bottom of the buffer container. When the liquid in the tank moves backwards and forwards it is pushed in to the corners of the cross and forced through the one-way valve, upwards, inside the buffer container. Because of this, the LPG level inside the buffer container is always higher than the LPG level in the tank.
The guide pins for the buffer container, have a small length of rubber hose pushed over each of them to ensure that the container remains parallel to the guide pins and keeps the buffer container flat on the bottom of the tank. If the buffer container does not maintain contact with the bottom of the tank then the one way valve in the bottom of the buffer container will not operate correctly.
Tank content measurement
De tank content measurement of the Multivalve S is the same as the Multivalve 2.
Pump controll
Because a DC motor is used, the pump controller, as it is known in the PTC pump, is not used. Because the turbine pump is fed with board voltage, it always runs on one speed, maximum speed.
Shutt-off valve
The shutt-off valve of the Multivalve S equals the one of the Multivalve.
Connection Unit PTS
The PTS system has no pressure regulator. To connect the fuellines a new connector is developed which is called Connection Unit PTS. It contains a valve and a line connector. The Connection Unit creates the connection between the tank and injectors and is mounted inside the engine compartment. It contains an electromagnetic shut off valve contained in a synthetic block with four brass connectors, for flexible high pressure lines. The actual connection is made with a banjo and banjo bolt. It is important not to change the direction due to the leak back design of the lock-off valve. The direction of flow is indicated on the housing by arrows.
Because a DC motor is used, the pump controller, as it is known in the PTC pump, is not used. Because the turbine pump is fed with board voltage, it always runs on one speed, maximum speed.
Flo.
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