Main Engine Exhaust Valve

The Main Engine Exhaust valve works under stress and in a high-temperature environment. The exhaust valves are fitted in a separate casing which allows the exhaust valve to be opened and overhauled without removing the cylinder head.
The Construction of the exhaust valve is done using high-temperature resistant alloys of steel having anti-corrosive and high-stress absorption properties. Marine engine exhaust valve is an integral part of the main engine and failure of any one of the exhaust valve may result in halting the operation of the whole engine and will bring the ship in no propulsion power condition. It is important for marine engineers to understand the construction and working or marine engine exhaust valves for efficient engine operation.
The operating system has been evolved from mechanical (rocker arm) to the hydraulic system, making it more reliable and long-lasting. This video shows the main engine exhaust valve working animation including its construction.
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Video Credit - @hake_lee (instagram)
C/E Maksym Veshnevetskyi

[@ulascancakmak4977]

your videos are very useful please continue to upload.we learn a lot about our profession from your videos

[@marineinsight]

Thank you for commenting. We will definitely continue our effort of sharing maritime knowledge. Please do share the video and support us. 👍🏻

[@durkostren]

Great work. Understood very well! Thank you!

[@marineinsight]

Glad you found it useful. Please do share and support

[@fernandohurtadop.7599]

Gracias mil,muy buena explicacion y didactico sobretodo.THANKS A LOT.

[@marineinsight]

Thank you Fernando. Please do share and support. 👍🏻 Muchas gracias

[@bubbahkiriza]

Very well explained. Thank you

[@bykrb]

This videos help me so much! thanks!!!

[@marineinsight]

Happy to help!

[@vaibhavtandon3572]

really nice video.....one doubt am having that what is mean by possitive closing of valve in this?

[@marineworld8389]

I have been seeing yours video, this video is fabulous. I request you to make video on cam less operated exhaust valve.. hope you will do⚓

[@marineinsight]

Thank you Akshay for the support. It is a team effort. We will forward your suggestion to the team. 👍🏻

[@verminer7]

What does it mean by damping and what what does the damping pin do, what did it mean by stops knocking?? Please answer

[@ritikrajsoni6676]

How do we know that the exh valve is rotating??

[@lorantonbanda7214]

where the oil going after valve closing and how it go

[@giridharannedumaran6389]

Why exhaust valve don't fall in liner when spring air is not present?

[@MenteFriaTV]

Brilliant!

[@marineinsight]

Thank you. Please do share and support 👍🏻

[@Marinernagesh001]

Plz advise if under pistons coming dirty sludge in one unit running condition what the reason and how it solve .

[@subithmariner5244]

What about the ME ( electronic) engine exhaust valve closing method?

[@TheEmdadhossain]

Help post: What is the possible causes for burning exhaust valve of all unit frequently (both 2 and 4 stroke engine)..

[@ramsrirammarsea]

What is virtual tappet in exhaust valve of main engine? Where exactly throttle is located?

[@nerdsroblox01]

Why we need to close spring air valve when stopping LO pump?

[@radhikakhant8424]

Worth watching

[@marineinsight]

Thank you for your comment

[@thiruvengatamvenkattaraman1405]

Super... We are like that this type of video and very useful

[@marineinsight]

Glad you are finding our videos useful. Please share and support 👍🏻

[@kenikabilanfernando6074]

If sir pressure goes 2bar what we can do in engine running situation

[@ksudhan4381]

Why do need hydraulic system to activate cam ? Likes a normal ic engine we can activate cam by crank right?

[@anilkumar7424]

Loved it

[@marineinsight]

Glad you liked it. Please do share and support

[@TheAnimesh008]

What is Rotocap? Please describe me

[@selva-the-sailor77]

Plss do some videos about VIT ( variable injection timing method )

[@marineinsight]

Thank you for the suggestion, we will forward this to our video team 👍🏻

[@phonemoesataung166]

Thanks madam

[@marineinsight]

You are welcome

[@skyflaker._]

How air supply to air chamber

[@kushmeetsingh7500]

Can some body tell function of sealing air control unit .

[@shipsailorsureshbishnoi620]

Please make a video on VIT AND SUPER VIT.

[@marineinsight]

Hi Suresh. Thank you for the suggestion. We will definitely work in this topic

[@aparnamanjrekar1786]

Dear All , can somebody please advise on below incident .Upon leaving anchorage, vessel have reported ME slowdown and upon investigation (air spring tightness test). It was discovered that the fault was due to a leak in the air piston, this is the second failure in 2 days. So, vessel have pulled 2 exhaust valves in the past 2 days, investigations on this matter are ongoing. The lab reports for fuel and lube analysis are normal. The Main Engine Make & Model is MAN B&W 6S50 MC , 10996 HP.

[@sanjaychauhan3211]

Agr valve cylinder head me fas gya h kaise nikale

[@AnishW]

Some of the inclusions in the modern marine engine exhaust valves are- Variable closing timing Puncture valve W valve seat

[@marineinsight]

Thank you for these inputs. 👍🏻

[@vishwarajpoty]

@@marineinsight I'm sorry guys but this is not the answer I was looking for. My question was entirely different. What would you do if spring air fails? Means exhaust valve won't close now, once it's open by hydraulic pressure. Now there's no pneumatic pressure available to close it. What's our line of action?

[@AnishW]

@@vishwarajpoty Already replied 👍🏻

[@marineinsight]

@@AnishW 👍🏻

[@ahmedalraji319]

During opeing of the exh. V/V is the air inside the air spring chamber goes out or compressed itself fully?

[@marineinsight]

As the air is compressible, it will get compressed in the chamber.

[@karthikeyanradhakrishnan9138]

Where will be the throttle valve located for bleeding. I'm referring to the word virtual tappet. If so., the bleed will be continuous and very small quantity. And is the drain of the oil is open always allowing some oil to go out at the same time of building up the hydraulic pressure.

[@karthikeyanradhakrishnan9138]

I'm confused in these areas. Can you please help me out of this?

[@satishmaurya8799]

What is the use of winged wall rotater in spindle ??

[@marineinsight]

The hydraulically operated Exhaust valve spindle is fitted with wings (vanes), due to which as the exhaust gas strikes it, the kinetic energy of the exhaust gas rotates the valve at small amount as it passes. It prevents localised burning and avoids the accumulation of carbon deposits.

[@kvsalahuddin5]

What is meant by overhauling exhaust valve?..When and how it is done?

[@marineinsight]

Overhauling is a detailed process of opening, cleaning and checking the machinery. Any damaged or wornout parts are replaced during this process. There are running hours prescribed by the makers post which the overhauling should be done. We will pass on your suggestion to make a video on this topic to the team. Thank you for your support. 👍🏻

[@sundarnarasimhan4648]

is this the arrangement of exhaust valve for both sulzer and man b&w?

[@praveenpatidar4056]

This one is of Mitsubishi UEC engine series, which uses hydraulic oil for opening the EV and Air at around 7 bar at under piston to close it.

[@zh9528]

Hello, some of the exhaust valve spindles have the guided vanes to rotate the valve and grind away the carbon deposit on the valve seats (K.E of the exhaust), however there are some exhaust valve with Rotocap, I know rotocaps contain ball bearing and spring inside but how does it helps with the rotation of the exhaust valve?

[@zh9528]

So how does the Rotocap/spring retainer works?

[@marineinsight]

Please do check this post- forums.marineinsight.com/forum/marine-engineering/5305-rotocap-in-exhaust-valve

[@baratamgoutam1964]

Why the safety valve on exhaust valve is set to 2.3MPa ..hydraulic oil operating pressure goes up to 220 bar and spring air for closing is 7 bar . Why 2.3 MPa

[@ripudamansingh8418]

Why exhaust valve opening hydraulic pressure is 200bar and for closing the exhaust valve it is 7 bar control air(spring air) , why the opening and closing pressure are different?

[@antonmothes3160]

Because pressure difference in combustion chamber. Once the valve is opened, the boost will scavenge the combustion chamber and the pressure difference is zero and closing the valve doesn't need much pressure.

[@vishwarajpoty]

URGENT!! What to do if spring air fails during maneuvering? Is there any other option besides stopping the engine and repairing it?

[@AnishW]

If the spring air fails, the valve will not close....the quickest solution during the manoeuvring is to cutoff the unit and continue running the engine without stopping the ship as it will be in traffic, channel or near port. Once the ship is stopped, repair the valve.

[@marineinsight]

@@AnishW Thank you Anish 👍🏻

[@yasirbasha5688]

Tell me about main lubrication system

[@marineinsight]

Thank you for your suggestion. We do have a video on cylinder lubrication - kzbin.info/www/bejne/kGndamOcl9WYeJo

[@pradipnandy1960]

If the engine is stop that time all exust valve in closed position?

[@marineinsight]

Not necessary

[@adarshsingh4359]

Please make a complete video on boilers

[@marineinsight]

Please do check our boiler videos - kzbin.info/www/bejne/h3m2Y6R-jp2ri9k

[@adarshsingh4359]

@@marineinsight thank u

[@MERCHANTENGG]

mam please make a video on camless hydraulic exhaust valve

[@marineinsight]

Thank you for the feed back Chandan. Will try

[@ajithakk3178]

Sir, during normal operation ,how we will get to know tht exhaust valve is working fine , during our watch ,one more query ,is it possible to confirm the valve rotation during our rounds ,if yes how ?

[@anantanandi1957]

In Yanamar model E220 or similar A drop of yellow paint, on rotating disc, check in round,you will find easily that valve is rotating.

[@ashusingh-jc2ns]

Purpose of oil sealing unit

[@mayankjoshi2250]

Sir , what is variable exhaust closing ?

[@marineinsight]

In VEC, the timing of valve closing is altered to achieve better or early combustion - During the VEC operation, the exhaust valve is closed EARLIER which increases the compression stroke of the piston leading to higher compression pressures and temperatures.

[@NAVEENKUMAR-fr8be]

Hello sir, how the hydraulic oil will come out from the valve after push the spindle (after open the valve)...

[@Complete501]

With the help of Air pressure the spindle will move up and remaining oil will from hydraulic chamber will be drain out

[@purnaprasanthpalli5814]

What arrangement is made to prevent exhaust valve spindle falling inside combustion chamber

[@praveenpatidar4056]

Please answer this question if you have got it already.

[@purnaprasanthpalli5814]

@@praveenpatidar4056 Air piston inside the chamber with spring air....

[@shubhamjain550]

what we will do if spring air is not working ..?

[@marineinsight]

If the engine can be stopped, repair should be done to resume the air supply. In case the ship cannot be stopped due to manoeuvring or traffic, the unit fule supply to be cut off.

[@saravanakumar-pq8jv]

why air should be opened before hydraulic oil after overhaul?

[@marineinsight]

So that it has the cushioning affect to tackle hydraulic oil pressure.

[@denizci75]

@@marineinsight what does the sealing control unit do

[@MyMrrose]

after closing thhe valve what happend with air where it is going

[@marineinsight]

Once the exhaust valve is closed, air inside the cylinder is compressed and used for combustion.

[@MyMrrose]

Thank u ......

[@marineinsight]

@@MyMrrose You are welcome 👍🏻

[@karthikeyanradhakrishnan9138]

He's asked the spring air.

[@mariner6669]

How valve rotor works????

[@marineinsight]

The hydraulically operated Exhaust valve spindle is fitted with wings (vanes), due to which as the exhaust gas strikes it, the kinetic energy of the exhaust gas rotates the valve at small amount as it passes. It prevents localised burning and avoids the accumulation of carbon deposits.

[@sujinsundar9639]

@@marineinsight very useful....thanks a lot

[@maleksohil6932]

Only one valve not two ????

[@marineinsight]

@Malek: Usually, all 2 stoke large bore engines are provided with one exhaust valve per cylinder. For smaller, 4 stroke engines, there can be 4 valves - 2 inlet and 2 exhaust.

[@dreambigwav]

ja volv

[@VijaySingh-ip8tf]

You said fuel is compressed. Sorry but scavenge air compressed not fuel.

[@marineinsight]

Yes. The air is compressed to burn air fuel mixture.

[@VijaySingh-ip8tf]

@@marineinsight Air-Fuel mixture in case of medium speed engines. Air in case of slow speed engines. But in video you are telling slow speed engines, so it is scavenge air which is compressed not air-fuel mixture.

[@AnishW]

@@VijaySingh-ip8tf In Actual scenarios, the atomised fuel is injected when the piston is about to reach TDC. Once the droplets in the atomized fuel spray evaporate quickly and mix with the compressed air. This air fuel is mixture is further compressed and the fuel is ignited shortly after the piston has passed TDC due to the high gas temperature in the cylinder.

[@VijaySingh-ip8tf]

@@AnishW Yes.

[@aparnamanjrekar1786]

Dear All , can somebody please advise on below incident .Upon leaving anchorage, vessel have reported ME slowdown and upon investigation (air spring tightness test). It was discovered that the fault was due to a leak in the air piston, this is the second failure in 2 days. So, vessel have pulled 2 exhaust valves in the past 2 days, investigations on this matter are ongoing. The lab reports for fuel and lube analysis are normal. The Main Engine Make & Model is MAN B&W 6S50 MC , 10996 HP.