Is high exhaust temp bad?

What Causes High Exhaust Temperatures In Diesel Engines

Too much fuel and not enough air in the cylinders of a diesel engine results in high exhaust gas temperatures.

Allow more clean air to flow into the motor and reset the optimum air-to-fuel ratios, resulting in more efficient fuel use and lower exhaust temperatures.

10 Main Reasons For High Exhaust Temperature

1. Poor fuel treatment or quality

Before utilizing bad gasoline, you should have it serviced. That is why sending a sample of HFO or MDO to a laboratory for testing is critical.

Based on the test findings and how much temperature to maintain throughout purification, you can figure out how many temperatures and viscosities to keep.

2. Fuel valve/ Injectors

When the apertures in the fuel valve nozzles are widened, there’s a chance that too much fuel will enter the combination chamber.

These fuels may go unburned or burn at the exhaust manifold, resulting in greater temperatures than necessary.

3. Fuel Pump and Delivery valve

If the high-pressure fuel supply pump or its delivery valve fails, surplus fuel may be forced into the fuel valve, resulting in high exhaust temperatures or excessive smoke from the funnel.

4. Engine Timing setting

If the engine timing settings are incorrect, the engine’s operating condition will be inaccurate. As a result, it is critical to establish an appropriate or suggested time.

5. Increase in load

The higher the load, the more fuel supply, combustion, and exhaust outlet for the primary ship propulsion engine or main auxiliary engine.

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While loads grow, if all systems are in excellent working order, the temperature will remain at the appropriate level.

6. Valve seat damage

Blow-by occurs when a leak in your valve seats or head during compression and combustion.

Place a pressure sensor on the indicator cook and slowly crank the engine to discover the unit in question. If the pressure rises and falls quicker than expected, look for leaks in the valves.

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7. Air Supply to T/C insufficient

T/C are meant to suck air from the outside. However, if a second blower is fitted to deliver air to the turbocharger, it will be easier to maintain airflow.

8. Clogged turbocharger

The combusted gas may find it harder to flow through your nozzle rings if there is greater carbon buildup. Blowing out gas may not be enough if the blades are worn out or clogged.

9. Scavenge and exhaust manifold clogged

You should constantly follow cleaning regimens for the T/C air cooler and manifold inspection, which will enable more booster air entry and, if the exhaust is clean, flow out.

10. Scavenge Air leakage

When there is leakage after T/C, air delivery to the main manifold may be reduced, resulting in less outflow and a higher temperature.

Exhaust Gas Temp Management

Are you experiencing high temperatures in your exhaust? You can watch this video on YouTube to learn more about Exhaust Temperature Management:

YouTube video

The video starts with why the exhaust gas temperature (EGT) has to be monitored.

The host answers this question by mentioning that the exhaust temperature is not the main concern in this situation but the condition within your vehicle’s combustion chamber.

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Other topics in this video include the difference in tuning Diesel & Gasoline engines, measuring your EGT, EGT data setup, thermocouple fitment, what high EGTs do, and much more.

Nejčastější dotazy

What does high exhaust temp mean?

The HEST Lamp lights signal that high exhaust temperatures may be present after treatment regeneration. When this lamp is turned on, make sure the exhaust pipe outlet isn’t pointed at anything that can melt, burn, or explode.

How hot is too hot for diesel exhaust?

Any engine that runs at 1,800° to 2,000° EGT for more than a few seconds should be serviced every season since it may cause damage to the turbocharger, cylinder head, or pistons.

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How Do I Control EGT?

In a diesel engine, the most frequent technique to increase power is to add fuel, and this extra fuel produces heat.

Larger turbochargers, aftermarket intercoolers, and water injection can be used to regulate it, although these items can cost thousands of dollars.

Exhaust gas temperature naturally is high, since it’s a product of combusted fuel. Depends on the engine design and metal strength, the manufacturer always specify limits or rang of the exhaust gas temperature outlet.

The limitations could be ranging from 300 – 500 maximum while on load. Without load could be between 100 – 250 maximum. This limit as earlier said are set as per the manufacturer recommendations ( see workshop test records and other engine documents).

Having known that, in this article, I will like to share with you causes or possibly reasons which may lead to exhaust gas temperature exceeding limits set for it normal operation. Also will tell you precautions or solutions to guide you solve such problems.

Why could an exhaust gas temperature exceed limits or very high than recommended

There are several reasons or cause of exhaust gas temperature higher than normal operation recommended range, these includes:

– Poor fuel treatment or quality: Bad fuel should be treated before using it. That is why it’s very important to send HFO or MDO sample to laboratory for test. With test results, you can understand how many temperature and viscosity to maintain, how much temperature to maintain during purification, etc.

– Fuel valve/ Injectors : When fuel valve nozzles holes enlarged, there’s possible of supplying excess amount of fuel into the combination chamber. Those fuel might remain unburnt or burn at the exhaust manifold, which creates higher temperatures than required.

– Fuel Pump and Delivery valve: If high pressure fuel supply pump or it delivery valve have problems, there maybe a chance of force excess fuel into the fuel valve, which will result to high exhaust temperature or excess smoke from the funnel.

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– Engine Timing setting: if engine timing settings are incorrect, the it working condition will also be wrong. Therefore, setting a proper or recommended timing is very important.

– Increase in load: For main ship propulsion engine or main auxiliary engine, the higher the load, the more fuel supply, combustion and higher the exhaust outlet. If all mechanisms are in good condition, while loads increases, the temperature will still remain as recommended.

– Poškození sedla ventilu: when you have a leakage on your valve seats or head, then you will have blow-by during compression and combustion. To find the unit in question, simple insert a pressure gauge on the indicator cook and turn the engine gradually. If pressure increases and drop faster than required, then check the valves for leakage.

– Air Supply to T/C insufficient: T/C are designed to take air suction from outside. But when installed additional blower to supply air to turbocharger, then it will be more easy for it to maintain air flow.

– Clogged turbocharger: when there’s more carbon build up on your nozzles rings, the combusted gas might find it difficult to flow through. Also if the blades are worn out or clogs, then blowing off gas might be not enough.

Scavenge and exhaust manifold clogged: always maintain cleaning routines on either T/C air cooler and manifold inspection. This will allow you have more booster air inlet and if exhaust is clear too, then flow out.

– Scavenge Air leakage: when you have leakage after T/C, then air delivery to the main manifold might be less, creating less out flow and high temperature comes in.

Consequence Of Diesel Engines High exhaust temperature

There are lots of consequences which high exhaust gas temperature can cause to the engine parts, these are:

– exhaust valve life time reduces up to 50% if continue with same high temperature.

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– Cylinder liners wear more faster as required. Since liner is more expensive, I think the earlier you solve the temperature problem the better.

– Piston rings and piston itself might wear down or get damaged.

Poznámka: Once observe any of the above mentioned symptoms or problem, try to solve them as soon as possible. For fuel pump and fuel valve can be replace (if found bad), or make lapping renew some parts and test them before installing into the engine in question.

Do you have more experience on what causes high exhaust gas temperature? We will appreciate hearing from your opinion, drop it on the comment box below.

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