Intake And Exhaust System of Diesel Generator Set

The installation method of diesel generator intake and exhaust system is as follow:

Intake system installation

In order to provide enough fresh air for diesel generator set operation, diesel engine intake should be arranged in the air circulation place outside the engine room. Diesel intake pipes for diesel generator set should be avoided as far as possible and the number of bends should be reduced, or use a large arc transition. The inner diameter of the intake pipe should not be less than 200mm, and the inner wall of the pipe should be smooth without soldering slag particles. Dust and debris should be avoided during installation. At the same time, the connecting pipe between air filter and diesel supercharger must be well sealed and no cracks and leakage should be found. The air filter inlet should be properly protected (such as a protective net) to prevent water or foreign matter from entering the diesel engine. The air inlet should be located away from all kinds of heat sources, and the exhaust gas from the exhaust pipe should not be inhaled into the intake pipe. If the air filter is installed in the engine room, the engine room must be well ventilated to ensure the normal operation of the diesel engine.

Exhaust system installation

The external exhaust pipe is made of steel pipe, and the turbocharger of the diesel engine must be flexible connected. The inner diameter of the external inlet pipe should be larger than the expansion joint, and too much bending should be avoided. The external exhaust pipe should be firmly fixed to the hull without vibration and its weight should not be applied to the expansion tube of the diesel engine. Expansion joints are not allowed to eliminate misalignment between tubes.

Note: after installation of exhaust system, diesel engine back pressure must not be greater than 6KPA, otherwise diesel engine performance will be affected.

Exhaust system must be able to prevent seawater, rain water, sundries and so on from entering the diesel engine. Due to the high surface temperature of the exhaust pipe when the diesel generator set works, the installation of the exhaust pipe should avoid approaching the flammable object.

Note: In order to prevent fire, scalded staff and other accidents. Please install heat insulation measures on the surface of the external exhaust pipe.

When several diesel generators are installed together, some problems may arise if a general external exhaust pipe is used. When several diesel generating units are working at different times, condensate water produced by diesel engine exhaust will enter the non-working diesel engine and will easily damage the diesel engine parts. Therefore, each diesel engine should use a separate exhaust system. If the exhaust system of diesel generator set needs to add exhaust muffler, the muffler should be reasonably selected and installed to minimize the back pressure of exhaust system caused by muffler installation.

How to check the intake system of diesel generator set?

The methods for checking the intake system of a diesel generator are as follows.

Check for cracks or perforations in the hose, soft movement of the clamp, tighten or replace if found, to ensure that the intake system does not leak.

Check and maintain intercooler

Use the naked eye to check the inlet air cooler for cracks, perforations, or other damage to the air chamber, pipes, radiators, etc.

Check the air filter

When the air filter resistance exceeds the following values, the air filter element shall be replaced.

Supercharged and supercharged intercooled type: 6.2KPA;

Natural suction: 5.0Kpa.

Note: air filter resistance should be checked when the diesel engine is calibrated.

If the air filter is equipped with a maintenance indicator, check periodically, and replace the air filter element if the red flag 2 has risen to the inspection port position.

After replacing the air filter element, press the button switch on the end of the maintenance indicator to reset it.

Warning: do not allow the operation of diesel generator sets without air filters. Otherwise, it is easy to cause early wear and tear of diesel generator set.

Fault diagnosis analysis of intake and exhaust system of diesel generator set.

The intake system of the diesel generator set is equipped with dry air filter and air filter and air resistance indicator, with exhaust gas turbocharger, full intake and guaranteed performance. Pules dry exhaust pipe is used in the exhaust system of diesel generator set, which can make full use of exhaust energy and give full play to engine performance. In addition, the genset is equipped with a diameter of 127mm exhaust elbow and exhaust bellows, easy to connect. Therefore, the intake and exhaust system of diesel generator sets is very important to ensure the performance of the generator. So how to diagnose and analyze the intake and exhaust system of diesel generator.

Air entering the unit cylinder should be kept clean (if the air enters the cylinder with dust and dirt, it will cause early wear and tear of the cylinder sleeve, piston ring, and also damage the valve rod and duct. Larger waste can also damage the blades of the turbocharger. Therefore, diesel generator units should be equipped with intake air filters.

1. Intake air leakage of diesel generator set

（1） Too much air intake resistance causes black smoke and power reduction (air filter can be blown three times with compressed air and will have to be replaced later).

（2） Too much smoke or lower power of turbocharged diesel engine may be due to loosening of pressure section of intake pipe or serious leakage of rubber pipe.

（3） Air leakage in the intake system, in addition to inspection with the naked eye, but also with soap foam in the possible leak to check.

2. Diesel generator exhaust part fault

Check exhaust leakage, gasket leakage, exhaust pipe, silencer resistance of exhaust pipe and supercharger. The increase of exhaust leakage and resistance will lead to the decrease of turbocharger speed, the reduction of air volume, the decrease of intake pressure, the increase of exhaust smoke and the decrease of power. Leakage of exhaust gas usually detects leakage sound or can be seen that high temperature gas discolors the material near the leak. If the exhaust is blocked, the turbocharger can not work effectively, so the factor of power reduction caused by exhaust resistance cannot be ignored.

（1） The breakdown of supercharger reduces its supercharging efficiency and causes the decrease of diesel engine power and the increase of smoke.

（2） Diesel generator oil supplies the supercharger with bearings and provides some cooling with its working oil pressure through the tubing. The return pipe is connected to the bottom of the middle shell of the supercharger, and the oil goes back to the diesel fuel pan along the return pipe. Seal rings are arranged at both ends of the rotor part of the supercharger. The main role of the seal ring is to prevent exhaust and pressurized air intake supercharger in the middle shell. Oil leakage from the seal ring is rare, but it can still occur.

If the pressure of the crankcase is too high, it will hinder the return of the turbocharger and fill the oil with the middle shell. The oil will pass through the compressor seal ring and blow into the cylinder of the diesel engine with the pressurized air.

If the return tube of the supercharger is blocked or damaged, the oil pressure in the middle shell will rise and the oil will flow along the seal to the compressor or turbine inlet vortex shell.

High intake and exhaust resistance creates a vacuum between the compressor and the supercharger housing, causing the sealing ring to leak oil.

Check: the above problem can be removed turbine exhaust pipe and compressor outlet pipe, check for oil leaking from the seal ring.

（3） A leak in the intake and exhaust system of a diesel generator makes additional noise (usually a very sharp whistle).