Fuel tank
The illustration shows an example of a marine fuel tank installation.
Position
If the fuel tank is placed higher than the engine feed pump, a shut-off cock should be installed in the fuel line to the feed pump. During downtime, this cock should be closed. Maximum permitted fuel level in the fuel tank is 3.5 m in relation to the feed pump.
scania di13 087m The fuel tank must not be positioned so low that the vacuum in feed pump suction pipe is greater than 0.3 bar. The risk of air leaks in the suction pipe increases with increased vacuum. See also the section Flow and pressure.
If the fuel tank is mounted so low that the maximum permissible vacuum is exceeded,or if a large fuel tank is required which cannot be mounted close to the engine, a buffer tank must be installed at a suitable distance and height. A feed pump must be fitted directly downstream of the tank. The flow for the auxiliary feed pump must be minimum 15% higher than the flows specified in the Feed pump flow rates section, scania trucks,trucks scania,scania trucking,scania cars,scania car,scania truck usa.
scania di13 marine engine manual If a reliable and quick starting response is required, the buffer tank should be positioned adjacent to the engine with the lowest fuel level at the same level as the feed pump. If the fuel tank(s) are built in, the space should be well ventilated. The fuel tank should normally be drained once a year, but this may vary depending on the quality of the fuel.
Example of a fuel tank installation.
- Bleed pipe.
- Fuel filler pipe with filler cap.
- Lead-through sleeve of fuel-resistant rubber.
- Inspection hatch.
- Baffle plate.
- Fuel cocks.
- Prefilter.
- Drain tap for sludge and water.
- Suction pipe with strainer.
- Return pipe. Note: For XPI engines, it should enter below the lowest fuel level.
- Ground connection.
The fuel tanks must be fully welded, and should have internal baffle plates to prevent the fuel being thrown about in heavy seas. Both fuel filling components and the fuel tank must be grounded to prevent sparking from static electricity. The fuel tank must have the following devices:
- A drain tap for emptying sludge and water that has sunk to the bottom.
- A ventilation or bleed line from the upper part of the fuel tank to the outside of the hull. It should be designed so that water cannot enter and so that fuel cannot run out when the ship is leaning heavily.
- Protection or filter to prevent contaminants entering during filling.
- There must always be a fuel cock in the suction line and in the return line if its outlet in the tank is higher than the outlet from the engine. The return line should be routed to the upper part of the fuel tank.
- Main tanks must be fitted with inspection hatches so that they can be inspected and cleaned inside.
scania d13 New fuel tanks must be thoroughly cleaned and rinsed internally using clean fuel. They must also be pressure tested to 0.3 bar. Fuel tanks manufactured from materials which are not resistant to corrosion must be treated externally with corrosion protection. The fuel tanks must not be painted internally nor be zinc-coated or galvanised.
PDE and XPI engines
The engines are equipped with an engine-mounted fuel filter. PDE engines also have the option of commutative engine-mounted fuel filters which can be renewed during operation.
scania di13 077m All engines must also be fitted with a water separating prefilter. PDE engines require one prefilter XPI engines require two prefilters, see next section. All connections on the suction side of the feed pump must be thoroughly sealed so that no air is drawn in during operation. The water separating prefilter should be changed at the same intervals as the mainfilter.
scania marine engine specifications The prefilter should not be installed directly on the engine. If the fuel tank is positioned higher than the engine, a shut-off cock must be installed on the fuel pipe to the
feed pump, to prevent fuel running out into the hull during maintenance. Information about how the single prefilter connector is connected is available in 03:01 Electrical system.
Scania Fuel grade and power for PDE engines
Different fuel properties such as viscosity, density and temperature influence the power available from the engine. See the charts on the next page.
The listed engine power assumes fuel with a density of 0.84 kg/dm3 and specific calorific value of 42,700 kJ/kg at a fuel temperature of 15°C.
Since it is difficult to measure the exact calorific value for the fuel in question, viscosity, density and temperature can be used instead to obtain a corrected engine power as a percentage for each of the properties.
The read corrected engine powers as a percentage from the figures must first be added together to obtain the final corrected engine power. Multiply this with Scania's
specified engine power to obtain the corrected engine power in kW. Then add or subtract from Scania's specified engine power to obtain the corrected engine power within the given tolerances.
If you have measured the current engine power for a particular engine instead and wish to convert it to normal power, change the sign in front of the corrected engine power in the charts.