Help Finding Exhaust Valve for Newbie Engineer

In summary, a newbie studying general engineering was having difficulty finding materials on exhaust valves and asked for help. Some recommended books were suggested, but it was mentioned that they may be too advanced for a general engineering course. Others discussed the types of materials used for exhaust valves, such as high temperature steel, cast iron, and alloys like nickel and nitrogen. It was also mentioned that some race engines use titanium, but it's not practical for street use. The idea of using plastic or composite materials for engine parts was brought up, but it was noted that there are challenges with thin stems and bulkiness. The conversation then shifted to the concept of solenoid operated valves, which can eliminate the need for a camshaft and provide better engine
  • #1
kehn
1
0
Hi,
I'm a newbie :frown:
Now,I'm studying about general engineering!
And I had difficulty finding materials of EXHAUST VALVE.
Everyone,can you help me?
Where and how I can get them?
 
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  • #2
I've always found the Bosch mechanical engineering handbooks to be awesome, but I'm not sure how much they have on the materials used.
 
  • #3
kehn said:
Hi,
I'm a newbie :frown:
Now,I'm studying about general engineering!
And I had difficulty finding materials of EXHAUST VALVE.
Everyone,can you help me?
Where and how I can get them?

A good book that I picked up a couple of years ago is Internal Combustion Engines & Air Pollution by Edward F. Obert. It's VERY indepth when it comes to the math and may be a little too much if your taking just a general engineering course. The book is written towards teaching an engineering major the fundamentals (and advanced processes) of an ICE.

Although written in the late 50's (maybe 60's) the majority of the concepts still apply today.
 
  • #4
In that vein, Heywood is also quite a comprehensive text and has been updated sometime in the last 50 years. ;)
 
  • #5
While Heywood's is an excellent reference, it doesn't discuss engine design, and you won't find anything about exhaust valve material in there.

Anyway, you'd be looking at some high temperature steel for a normal exhaust valve.
 
  • #6
most valves both intake and exhaust are cast iron
there are many types of cast iron
the cast iron used for the valves is also heat treaded so they can take the heat
hope this helps
 
  • #7
I think exhaust valves are never cast iron. Because of the need for strength in the high temperature and corrosive exhaust gas environment, they are alloyed (cobalt steel, stainless, etc.) and sometimes the stems are chrome plated (or even a different steel altogether) for wear resistance. Only cylinder blocks and heads are cast.

Look up 21/4N stainless and stellite
 
  • #8
Porsche and other auto manufacturers have experimented with sodium filled exhaust valves. The new Chevrolet Z06 has them i believe.
 
  • #9
Porsche and other auto manufacturers have experimented with sodium filled exhaust valves. The new Chevrolet Z06 has them i believe.
This is not a new idea, some older Ford and GMC truck engines had sodium filled valves. Always easy to spot because the stems are much thicker than normal. :wink:

moo
__________________
moo (moo') adj. Of no practical importance; irrelevant, such as a moo point (i.e. a cow's opinion).
 
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  • #10
moo said:
This is not a new idea, some older Ford and GMC truck engines had sodium filled valves. Always easy to spot because the stems are much thicker than normal. :wink:

moo
__________________
moo (moo') adj. Of no practical importance; irrelevant, such as a moo point (i.e. a cow's opinion).

Oh it's deffinately nothing new. Porsche was experimenting with it back in the 60's and the original idea came up long before that. It's just neat that it's made its way into mass production vehicles.
 
  • #11
Nickel and Nitrogen are also popular to alloy with.
 
  • #12
And some race motors use titanium, but it's not practical for street use (cost-effectively, I mean).
I wonder how long it will be before they start using plastic. The good stuff, such as Torlon, is already being used for rods and pistons.
 
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  • #13
Actually seems a bit odd that sodium valves would be considered in hi-perf engines, as the idea is generally to keep the valve train light as possible. But stranger things have happened.

Hey Danger - I don't know about plastic valves, the outer edge of exhaust valves stay pretty much red hot at high RPMs. I had heard about plastic rods, but wasn't aware of any used for pistons yet.

But there's a lot of stuff I'm not aware of... :biggrin:

moo
__________________
moo (moo') adj. Of no practical importance; irrelevant, such as a moo point (i.e. a cow's opinion).
 
  • #14
I'm not sure if the pistons are out of the experimental stage yet. As far as I can recall, they were plated with aluminum or such for flame resistance... at least on top. I would expect that if they ever do go to plastic valves, the same would apply. I should point out that I get sloppy with terms in cases like this. When I said 'plastic', that includes composites like Kevlar or carbon fibre materials. I suspect that carbon, with perhaps a vapour-deposition coat of something like nickel, would be suitable.
 
  • #15
Another problem with plastic valves is prolly the thin stem. I know the rods are beefed up a lot compared to steel/aluminum, although still lighter of course. Not much room to add bulk to a valve stem without hindering air flow though.

A little off topic here, but one experimental design I find particularly intriguing is solenoid operated valves, which eliminates the need for a camshaft and the hp needed to drive it. Not to mention the practically instant open/close action compared to the travel time lost on a cam.

moo
__________________
moo (moo') adj. Of no practical importance; irrelevant, such as a moo point (i.e. a cow's opinion).
 
  • #16
moo said:
Another problem with plastic valves is prolly the thin stem. I know the rods are beefed up a lot compared to steel/aluminum, although still lighter of course. Not much room to add bulk to a valve stem without hindering air flow though.

A little off topic here, but one experimental design I find particularly intriguing is solenoid operated valves, which eliminates the need for a camshaft and the hp needed to drive it. Not to mention the practically instant open/close action compared to the travel time lost on a cam.

moo
__________________
moo (moo') adj. Of no practical importance; irrelevant, such as a moo point (i.e. a cow's opinion).


That technology is really cool. I know pneumatic valvesprings have been used in F1 Indycar engines for a time too. The parts that i really find interesting is the fact that you could throttle the engine itself simply by "throttling" the intake and exhaust valves. The engine would also have excellent cylinder filling ability throughout the entire rev range. A constant "perfect cam" in a way. They could also shut down extra cylinders when the additional power isn't needed, helping fuel economy. A much better way than the old Displacement On Demand technology. The valves are actually held closed and the air that's trapped in the "dead" cylinder acts somewhat like a spring during the cycle and doesn't make the cylinder as much a dead load.

After thinking about it for a second, I don't see why you couldn't just rid of an engine starter all together... open a couple of the valves just enough to let a little air in, squirt a little fuel, spark the chamber... boom.
 
  • #17
B. Elliott said:
I don't see why you couldn't just rid of an engine starter all together... open a couple of the valves just enough to let a little air in, squirt a little fuel, spark the chamber... boom.
That has got to be the first time in my life that I've ever heard that suggestion, and it makes perfect sense (well, with injectors; it wouldn't work with a carb).
Well, there's also the possibility that it wouldn't be too effective in my territory in winter. It takes more than that to get something turning over in -40 temperatures.
 
  • #18
After thinking about it for a second, I don't see why you couldn't just rid of an engine starter all together... open a couple of the valves just enough to let a little air in, squirt a little fuel, spark the chamber... boom.
Well... first there's the nightmare of monitoring various positions the engine might have stopped at, and picking a piston in the proper range (we can't crank it backwards). And it's possible that occasionally none would be in that proper position.

But without compression, it's more likely to just start a fire (or make a "poof" rather than a "boom" with enough force to turn the engine).

moo
__________________
moo (moo') adj. Of no practical importance; irrelevant, such as a moo point (i.e. a cow's opinion).
 
  • #19
Actually, moo, there's no problem to determining the engine position; just take a reading from the distributor. And if it's any kind of a decent engine (ie: 8 or more cylinders; all else is crap), at least one of those pistons will be near the start of a power stroke.
 
  • #20
just take a reading from the distributor
Uh... read what exactly? Something would have to register tiny increments because it won't know where the engine stopped, and without movement there's no induced current.

And then there's all those cars without distributors (especially a camless one!)... :biggrin:

[EDIT] Btw - even with 8 cylinders, only every other stroke is compression, so odds aren't that low for none to be near the top of one. Although I guess with electronic valves you could turn an exhaust stroke into compression if necessary, then just change all the others to stay in sync.

But there's still the absence of compression, unless you add something to move the piston. Like... oh, I dunno... maybe a starter? :smile:

moo

__________________
moo (moo') adj. Of no practical importance; irrelevant, such as a moo point (i.e. a cow's opinion).
 
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  • #21
moo said:
Uh... read what exactly? Something would have to register tiny increments because it won't know where the engine stopped, and without movement there's no induced current.

And then there's all those cars without distributors (especially a camless one!)... :biggrin:

[EDIT] Btw - even with 8 cylinders, only every other stroke is compression, so odds aren't that low for none to be near the top of one. Although I guess with electronic valves you could turn an exhaust stroke into compression if necessary, then just change all the others to stay in sync.

But there's still the absence of compression, unless you add something to move the piston. Like... oh, I dunno... maybe a starter? :smile:

moo

__________________
moo (moo') adj. Of no practical importance; irrelevant, such as a moo point (i.e. a cow's opinion).

Good points deffinately but, i still believe it's possible to start the engine without full compression. Direct cylinder injection would probably be very helpful with this. Look at how effective a potato gun is at making combustion without ANY compression at all. I also don't see any problem the the ECU not knowing where the pistons are located after shutdown. The ECUs do have a memory and provide power to almost all sensors just by turning the key to the ON position. You have to remember that if we're to the point where we can control the engine by precisely manipulating the valves, that alone let's us most likely choose WHERE we want the engine to come to a halt, just to start again later.

http://en.etasgroup.com/downloads/rt/rt_2006_01_34_en.pdf"

Good thread btw :smile:
 
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  • #22
You have to remember that if we're to the point where we can control the engine by precisely manipulating the valves, that alone let's us most likely choose WHERE we want the engine to come to a halt
Unless some guy with a standard tranny let's it roll an inch or two. Wonder how many times that happens in a day worldwide... :wink:

From your PDF article:
"For a host of compelling reasons, the
assistance of a starter motor – albeit
smaller and adapted to direct starting
– continues to be indispensable."


Good point about the spud gun though, and that is a cool PDF article that I intend to keep. Thanks for the link. :smile:

moo
__________________
moo (moo') adj. Of no practical importance; irrelevant, such as a moo point (i.e. a cow's opinion).
 
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  • #23
You could just rewire the starter to "park" the motor in exactly the right position after the ignition is turned off (like windshield wipers) for the "single spark start", and than just hook up a pump to the chosen cylinder to compress it to the right ratio. :biggrin:
...I wrote this as a joke but now that I think of it I imagine it would reduce wear and increase the life of the motor. (would whip the oil up faster than a conventional crank & start motor)

you would need some sort of pump though because the cylinder would loose pressure if the car was parked for any length of time.
 
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  • #24
Where we were talking of the materials used in the exhaust valve, i think currently it is the cast iron and chromium alloy being used in majority of street cars and titanium is used where very high octane fuel such as nitro methane and stuff are used. However, carbon fibre may be a good option though any research going on in the field is beyond me. Its got plenty of supportive properties.
 
  • #25
Denni, I don't think that a pump is required. All you need to do is inject fuel into a cylinder that's starting a down-stroke. As B. Elliott pointed out, compression shouldn't be necessary. You can turn an engine over by hand using the crank pulley, so a lot of force isn't required. The process might have to be repeated a couple of times, particularly in cold weather, but it should work. If anybody out there has an engine-shop available, maybe some cheap-and-dirty experimentation can resolve the issue.
 
  • #26
moo said:
Actually seems a bit odd that sodium valves would be considered in hi-perf engines, as the idea is generally to keep the valve train light as possible. But stranger things have happened.

FYI, the sodium filled valves on the LS6 engine are lighter than the non-sodium filled valves.

Stainless steel, titanium, nickel based alloys (Inconel), are all common in the performance aftermarket.
http://www.ferrea.com/products.php
http://www.delwestusa.com/manufactured/ [Broken]
 
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  • #27
Danger said:
Denni, I don't think that a pump is required. All you need to do is inject fuel into a cylinder that's starting a down-stroke. As B. Elliott pointed out, compression shouldn't be necessary. You can turn an engine over by hand using the crank pulley, so a lot of force isn't required. The process might have to be repeated a couple of times, particularly in cold weather, but it should work. If anybody out there has an engine-shop available, maybe some cheap-and-dirty experimentation can resolve the issue.

Are you sure about that? Are the first two strokes on a four stroke identical to the last two? As far as the valvetrain positions that is. does a cam run 1/2x faster than the crankshaft or 2x? Not trying to be a wiseguy, I really don't know. I'm just thinking it can't be just any downstroke, but the compression downstroke. It could drastically reduce the odds that any cylinder is positioned right.

(after some thinking...) - Yeah it can't just be any down stroke. the piston would be in a down stroke on the intake stroke and the combustion stroke. but if you spark some gas on an intake stroke you might blow engine parts through the hood!:cry:
 
  • #28
The camshaft rotates at half running speed on a four-stroke engine. That's how you achieve compression and expansion strokes. So no, it can't be any down stroke, it would have to be an expansion down stroke.
 
  • #29
Correct about the stroke on a cammed engine. With programmable valves, however, any downstroke can be designated either an intake or power stroke. Likewise for compression/exhaust upstrokes. What I have in mind here is to inject the fuel at the start of the power stroke instead of the intake one, and ignite it immediately. Do that with a couple of cylinders sequentially, and leave the rest to start in the normal manner. As soon as it catches, switch all controls back to the normal cycle.
 
  • #30
krislou80 sounds like an advertisement.
 
  • #31
I believe this will help the OP out.
http://www.enginebuildermag.com/Article/1171/valve_selection_hot_valve_materials_for_hot_engines.aspx [Broken]
 
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  • #32
Since his post the OP could have gone to university, got a degree, gone back for a Masters, and worked all this out for himself.
 

1. What is an exhaust valve and why is it important?

An exhaust valve is a mechanical component that controls the flow of exhaust gases from an engine. It is important because it helps to regulate the engine's performance, improve fuel efficiency, and reduce emissions.

2. How do I know which type of exhaust valve is compatible with my engine?

The best way to determine compatibility is to consult the manufacturer's specifications for your engine. You can also bring your engine model and specifications to a specialist or a reputable auto parts store for assistance.

3. Where can I purchase an exhaust valve for my engine?

You can purchase an exhaust valve from a variety of sources, such as auto parts stores, online retailers, or directly from the manufacturer. It is important to make sure you are purchasing the correct type and size for your engine.

4. How often should I replace my exhaust valve?

The frequency of exhaust valve replacement depends on the type of engine and its usage. Generally, it is recommended to replace exhaust valves every 50,000-100,000 miles or as recommended by the manufacturer.

5. Can I replace the exhaust valve myself or do I need a professional?

Replacing an exhaust valve can be a complex process and requires some mechanical knowledge and experience. It is recommended to have a professional mechanic or engineer handle the replacement to ensure it is done correctly and safely.

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