7 семестр (Бормотов А) / 1man_bw_l23_30_chn_23_30_instruktsiya_po_ekspluatatsii / MAN-BW L23-30 (ЧН 225_300)+ / MAN-BW L23-30 H Vol-1 (Instruction)+

General

The lubricating oil system is based on wet sump lubrication. All moving parts of the engine are lubricated with oil circulating under pressure in a closed built-on system.

The lubricating oil is furthermore used for the purpose of cooling the pistons.

System Flow

The lubricating oil pump draws oil from the oil sump and presses the oil through the cooler and filter to the main lubricating oil pipe, from where the oil is distributed to the individual lubricating points. From the lubricating points the oil returns by gravity to the oil sump.

The main groups of components to be lubricated are:

1 - Turbocharger

2- Main bearings, big-end bearing ect.

3- Camshaft drive

4- Governor drive

5- Rocker arms

6- Camshaft

ad 1) For priming and during operation, the turbocharger is connected to the lub. oil circuit of the engine, the oil serves for bearing lubrication.

The inlet line to the turbocharger is equipped with a fixed throttle in order to adjust the oil flow and a nonreturn valve to prevent draining during stand-still.

The non-return valve has back-pressure function requiring a pressure slightly above the priming pressure to open in normal flow direction. In this way overflooding of the turbocharger is prevented during stand-still periods, where the prelubricating pump is running.

L23/30H

ad 2) Lubricating oil for the main bearings is supplied through holes drilled in the engine frame. From the main bearings it passes through bores in the crankshaft to the connecting rod big-end bearings.

The connecting rods have bored channels for supply of oil from the big-end bearings to the small-end bearings, which has an inner circumferential groove, and a pocket for distribution of oil in the bush itself and for supply of oil to the pin bosses and the piston cooling through holes and channels in the piston pin.

From the front main bearings channels are bored in the crankshaft for lubricating of the pump drive.

ad 3) The lubricating oil pipes, for the camshaft drive gear wheels, are equipped with nozzles which are adjusted to apply the oil at the points where the gear wheels are in mesh.

ad 4) The lubricating oil pipe, and the gear wheels for the governor drive are adjusted to apply the oil at the points where the gear wheels are in mesh.

ad 5) The lubricating oil to the rocker arms is led through pipes to each cylinder head. It continues through bores in the cylinder head and rocker arm to the movable parts to be lubricated at rocker arms and valve bridge. Further, lub. oil is led to the movable parts in need of lubrication.

ad 6) Through a bore in the frame lub. oil is led to the first camshaft bearing and through bores in the camshaft from where it is distributed to the other camshaft bearings.

Lubricating Oil Pump

The lubricating oil pump, which is of the gear wheel type, is mounted on the front end of the engine and is driven by means of the crankshaft through a coupling or a gear wheel.

The pressure regulator forms part of the lubricating oil pump. Adjustment of the oil pressure is done by removing the cap nut and turning the adjusting screw until reading the pressure stated in description 500.30.

Operating of Pre-lubricating Pump

As standard the engine is equipped with an electricdriven prelub. pump mounted parallel to the main pump. The pump must be arranged for automatic operation, ensuring stand-still of the prelubricating pump when the engine is running, and running during engine stand-still in stand-by position.

Running period of the prelubricating pump is preferably to be continuous. If intermittent running is required for energy saving purpose, the timing equipment should be set for shortest possible intervals, say 2 minutes of running, 10 minutes of stand-still, etc. Further, it is recommended that the prelub. pump is led from the emergency switch board thus securing that the engine is not started without prelubrication.

Lubricating Oil Filter

The lubricating oil filter is a double filter which is generally used with only one filter chamber being in operation, the other filter chamber being stand-by.

If the filter chamber in operation needs to be serviced, the operation can be switched to the other filter chamber without any interruption in lubricating oil supply to the engine.

Servicing is generally restricted to replacing of the paper cartridges, cleaning of the radial mesh insert and inspection of sealings, the latter to be replaced if damages observed.

Each filter chamber is equipped with 1 or 2 replaceable paper cartridges of fineness 10-15 microns.

In the centre of each filter chamber a filter basket (central element) is situated. This filter basket is acting as a safety filter, having a fineness of about 60 microns.

During operation an increased pressure drop across the filter will be observed as dirt particles will deposit on the filtration surfaces of the paper cartridges and thus increase the flow resistance through the filter.

If the pressure drop across the filter exceeds 2.0 bar, a release valve will open and by-pass the 10-15 microns filter element, and the engine will run with only the 60 microns safety filter.

To ensure safe filtering of the lubricating oil, none of the by-pass valves must open during normal service and the elements should be replaced at a pressure drop across the filter of 1.5 bar.

Servicing is essential the exchange of the paper cartridges.

When exchanging cartridges, it is advisable to release any old oil remaining in the filter housing by means of the drain plug provided for this purpose, and to wipe out the housing with a cloth.

The filter chambers can be serviced successively during operation or when the engine is at standstill.

It is essential to follow the instructions in work card 515-01.10 closely when replacing filter cartridges.

Filter cartridges must under no circumstances be cleaned and used again.

Thermostatic Valve

The thermostatic valve is designed as a T-piece with the inlet in the cover (A) under which the thermostatic elements are located.

The outlet to the engine (by-passing cooler) is marked (B) and outlet to the cooler is marked (C). In the warming up period, the oil is by-passing the cooler. When the oil from the engine reaches the normal temperature (see section 500, data 500.30) a controlled amount af oil passes through the cooler.

The thermostatic elements must be replaced if the temperature during normal operation deviates essential from the one stated in the test report.

The valve cannot be set or adjusted, and it requires no maintenance.

A

C B

Fig. 1. Thermostatic Valve

The built-on lubricating oil cooler is a plate heat exchanger.

The plate heat exchanger consist of a number of cold pressed plates which are compressed between a frame plate (head) and the pressure plate (follow) by means of tie bolts.

The plates are made with special corrugations, which ensures turbolent flow and high heat transfer cofficients.

After clamping of the plate pack, the plates - which are fitted gaskets - ensure an effective seal between fluids and atmosphere. In addition, intermixing of the fluids is eliminated by a double gasket seal around the inlet ports.

Every second plate is turned through 180°. This means that the double gasket seal occurs around every second inlet to the channels between the plates.

The plate pack now forms a series of parallel flow channels in which the fluids flow in a counter current regime.

The centrifugal filter is a by-pass filter mounted directly at the engine base frame. The centrifugal filter is a supplement to the main filter.

During service, a part of the lubricating oil supplied from the engine driven lubricating oil pump enters the centrifugal filter and returns to the oil sump in the base frame.

The centrifugal filter relies on the centrifugal force and can therefore remove high density, sub-micron particles.

Principle of Operation

Oil enters the base of the filter and depresses the cutoff valve (A) which has a pre-set pressure valve. The cut-off valve is fitted to ensure that at low pressure and flow conditions the entire oil pump output is suppliedtotheengineworkingparts.Havingdepressed the cut-off valve the oil travels up the centre of the spindle. Through holes at the top (B) and enters the rotor (C) at the maximum height above the stand tube. The oil completely fills the cleaning chamber (D) and travels through the strainer (E) into the drive chamber (F), leaving under pressure via diametrically opposed tangential nozzles in the bottom of the rotor.

The reaction of the oil leaving the nozzles provides the driving force causing the rotor to spin about the spindle at high speed. The oil leaving the nozzles is then allowed to drain back to the sump, by gravity at atmospheric pressure.

The centrifugal force field within the spinning rotor forces the contaminants to travel to the inner wall of the rotor, where they form a dense rubber-like sludge which is easily removed.

For proper filtration, it is important that the rotor is always correctly balanced.

An out-of-balance condition can occur as a result of an uneven built-up of sludge or as a result of excessive bearing or spindle wear.

D

B

E

C

F

A

Fig 1. Diagram showing Principle of Operation.

08028-0D/H5250/94.08.12

L23/30H

Disassembly:

1)Remove the coupling part or gear wheel (1), see fig. 2, by means of a puller or a soft hammer.

2)Remove screws (2) and dismount the cover

(3).

3)Dismount the locking ring (4), screws (5) and remove the cover (6) with the overspeed device.

4)Remove the gear wheel (7 and 8).

5)Dismounting of the spring loaded adjustable by-pass valve.

Remove the cap nut (9), nut (10), spring housing (11), spring (12) and the cylinder (13). If the piston (14) cannot be pulled out from the same side, the plug screw (15) can be removed and the piston can be pressed out from this side with a screw driver or the like.

Before the gear wheels (7 and 8) can be mounted the bearing bush must be adjusted with a reamer or a bearing scraper, so that the gear wheel can run easily when the pump is assembled.

8) Inspect all other parts for wear and damage, and renew, if necessary.

Fig. 1.

Overhaul.

6)Clean all the parts with gas oil and a hard brush, (never use a steel brush). The parts are blown clean with working air.

7)If the bearing bush is to be removed the existing bearing bush is plugged out by means of a mandrel, the bores are cleaned and new bearing bush is mounted, see fig. 1.

Fig. 2.

Assembly:

9)Mount the gear wheel (7 and 8).

Coat the sealing lip with silastene or similar and mount the cover (6) with gear wheel and locking ring

(4).

10)Mount the cover (3) with gasket.

11)Mount the gear wheel or coupling part (1).

For tightening the nut for gear wheel, see page 500.40.

12) Mount the spring loaded by-pass valve, nut (10) with gasket, cap nut (9) and plug screw (15).

08028-0D/H5250/94.08.12

Adjusting of Lub. Oil Pressure.

13) The outlet pressure of the lub. oil pump, can be adjusted by means of a adjusting screw in the bypass valve.

Remove the cap nut (9) and loosen the nut (10).

L23/30H

By turning the spring housing clockwise the pressure is raised and reverse the pressure is lowered by turning the spring housing (11) anti-clockwise. When the correct pressure is reached , see page 500.30, the spring housing (11) is locked with nut (10) and finally the gasket and cap nut (9) are mounted.

08028-0D/H5250/94.08.12

L23/30H

Related procedure:

L23/30H

Overhauls.

Overhauls for the purpose of avoiding functional trouble are not normally necessary for the prelubricating pumps, when properly used, there is very little wear on the pump gear shaft.

Spare Parts.

Before any overhaul is done, please note the following:

If a pump gets unusable by wear, it must be replaced. Installation of spare parts cannot bring it back to normal condition.

It pays to keep extra pumps in stock or to have repairs (overhauls) carried out at our repair shop.

The shaft seal needs only to be replaced in case of leakage or after dismounting of drive shaft. The marks from the seal do not necessarily mean that the sealing is defective, but there is a risk of leakage after replacement of sealing.

We advise not to change the bearing bushes. In connection with damages on the bearings it is normal that also the shafts and the parts in the gear box will be damaged.

When ordering spare parts, do not forget to state the factory no. of the pump.

Replacement of mechanical seal.

1)Disconnect the cable and pipe connection to the pump.

2)Remove the pump from the engine base frame.

3)Separate the pump and the el-motor.

4)Remove the coupling part and key (12), see fig 1, from the driving gear shaft (4).

5)Tighten the pump to the flange. Pressure control valve (3) upwards.

6)Loosen screws (9) and take off the pressure control valve (3).