7 votes
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IC engine where the piston is the spark plug

Well, you'd still need something to generate the high voltage for the spark, so there isn't much overall simplification. A magneto driven by points is about as simple as it gets. But more importantly,...
Dave Tweed's user avatar
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5 votes
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How to increase the speed of exhaust gas?

The speed of exhaust gases from a stack is governed (approximately) by: $V=C\sqrt{2gH\frac{T_i-T_o}{T_i}}$, where: $C$ is the discharge coefficient (typically between 0.65-0.7, but can vary based on ...
costrom's user avatar
  • 229
5 votes

Why is soot produced in diesel exhaust, since diesel runs lean?

From the Wikipedia article: All diesel engines can be considered to be lean-burning with respect to the total volume, however the fuel and air is not well mixed before the combustion. Most of the ...
Chuck's user avatar
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5 votes
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Why does hydrogen fuel produce less horsepower than gasoline in internal combustion engines?

One consideration is the relative densities of hydrocarbon fuels compared to hydrogen. If we assume that the fuels are completely vapourised in the combustion chamber then the mass of fuel depends on ...
Chris Johns's user avatar
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5 votes
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How do I choose a blower design for an induced draft brick kiln?

Normally fans are not custom built by a company that does not build fans. The concept of a centrifugal fan is not particularly complicated, but it is difficult to achieve target flow rate, pressure, ...
ericnutsch's user avatar
  • 8,146
5 votes

Is high pressure combustion hotter than atmospheric pressure combustion

The maximum temperature is the adiabatic flame (combustion) temperature. All else being equal, the combustion temperature will approach this to the extent that using higher pressure air puts the ...
Jeffrey J Weimer's user avatar
5 votes

What is the maximum possible compression with fuel injection in a gasoline combustion engine?

If you want to turn the engine into a compression-ignition one, I suppose there isn't really a limit other than physical based on strength of materials. Your proposed solution is rather how diesel ...
Tiger Guy's user avatar
  • 6,891
4 votes

How can I estimate the rate of consumption of oxygen in a car engine?

Do the math. Pick a reference car and get its fuel milage at some speed. From that you can compute the amount of gasoline used in one minute. Now look at the chemistry of gasoline and figure out ...
Olin Lathrop's user avatar
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4 votes
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How do you prevent ignition of the gas-air mixture before it reaches the burner nozzle?

Depending on fuel, a flame has a certain propagation speed - the speed with which the flame wanders through the medium. If the fuel - oxygen mixture moves faster through the pipe than the propagation ...
mart's user avatar
  • 4,771
3 votes

Why afterburners are needed instead of burning more fuel inside the turbine?

After burner primary task is to add extra thrust to a jet engine by heating the jet stream after the turbine via injecting and burning fuel in it. The reason they just don't add more fuel in the jet ...
kamran's user avatar
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3 votes

Why is "regular" gasoline standard instead of something more knock-resistant?

Well first and foremost, refiners are a business so they must make the decisions that make them the most money. Considering this, lets think about cracking and isomerization via catalysis. The refiner ...
ChemE mang's user avatar
3 votes

How to increase the speed of exhaust gas?

If the tube is acting as a chimney, then i would first try a longer tube, and add lots of insulation to the outside of it too. The hotter gases inside it would be less dense and want to rise faster, ...
Netduke's user avatar
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3 votes
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Can I increase the range of a howitzer by using more propellant?

Here are the limitations to this approach. First of all a howitzer is specifically designed for relatively short-range use, by using a very steep (in some cases, almost vertical) launch angle which ...
niels nielsen's user avatar
3 votes

What is the maximum possible compression with fuel injection in a gasoline combustion engine?

Calculate the temperature of the air in the cylinder after compression - if that exceeds the self-ignition temperature of the fuel injected then that is a problem.
Solar Mike's user avatar
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3 votes
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Throttle position as a function of engine torque and speed

why does the torque value at a specific rpm vary for different throttle positions This is the difference in acceleration when you fully open the throttle versus open it part-way. For a spark-...
Tiger Guy's user avatar
  • 6,891
3 votes

NOx emissions in diesel engines

NOx is formed at high combustion temperatures, in the presence of abundant nitrogen. Diesels get high combustion temperatures by virtue of their high compression ratios, which are necessary for ...
niels nielsen's user avatar
2 votes
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Why is soot produced in diesel exhaust, since diesel runs lean?

One important reason is that diesel fuel had a high molecular weight compared to gasoline this means that is is more difficult to disperse as it forms liquid droplets as opposed to vapour and even ...
Chris Johns's user avatar
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2 votes

How do you prevent ignition of the gas-air mixture before it reaches the burner nozzle?

No fuel (in the conventional sense) will burn without being mixed with oxygen. However it is entirely possible for air to get mixed with fuel in unexpected ways, especially if you have leaks in the ...
Chris Johns's user avatar
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2 votes

How can I estimate the rate of consumption of oxygen in a car engine?

You need to do a "mass balance". Here's roughly how: How many litres of fuel per hour does the car use? Work out the mass of this volume of fuel (I assume we can look up the density somewhere.) ...
Andy's user avatar
  • 275
2 votes

What happens when you put the wrong type of fuel in an internal combustion engine?

IC engines work in cycles, in a four-stroke IC engine there are four cycles Intake stroke Compression stroke Combustion stroke Exhaust stroke During intake stroke the air-fuel mixture is sent into ...
ajay reddy's user avatar
2 votes

Can a water pressure switch be used as a low-water cutoff means for a steam boiler?

Hydrostatic pressure of water changes per depth according to Pascal's law which equates to $1 \text{Pa} = 1000 \text{kg}/\text{m}^3 * 9.81 \text{m}/\text{s}^2 * h$ or $101 \text{Pa} /\text{m}$ or $1....
ratchet freak's user avatar
2 votes

How to calculate the pressure loading of a vented silo explosion?

The pressure in the silo is determined by the temperature rise, caused by the combustion. The end temperature after combustion can be calculated like this: $$T_{end}= \dfrac{E}{(m_{air}+m_{fuel})C_V}+...
Bart's user avatar
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2 votes

Preheating Diesel before injection?

Consider how much energy is needed to heat the fuel that is injected each time compared to the energy that can be recovered from the turbo-charger for example. One thing to note is that many of the ...
Solar Mike's user avatar
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2 votes
Accepted

What is the real CO2 emission for cars? 1g/km or >100g/km?

Q1. The CO is Carbon Monoxide Level, and CO2 is the Carbon Dioxide Level. The difference is huge because the potent levels for both of them are very different. Generally for clean fresh air there ...
Jan's user avatar
  • 38
2 votes

Engine Combustion Cylinder Wall Thickness

You text says cylinder head, not cylinder. A cylinder would be easier as it has a cast iron liner (usually) in the aluminum casting. I can promise you the head is not 6061 or any other wrought alloy. ...
blacksmith37's user avatar
  • 6,144
2 votes
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Calculating Mass Fractions of a Hydrogen and Oxygen Gas Mixture Pre Ignition

The derivation has a mistake in setting $FA = \phi n_{fs}/n_{O2s}$. Here is the correction. For simplicity, I use $F$ rather than $FA$, $m_O$ and $n_O$ as the mass and moles, respectively, for O$_2$, ...
Jeffrey J Weimer's user avatar
2 votes
Accepted

Recovering mechanical energy from natural gas water boiler

Check out combined heat and power systems... generates electricity and makes use of the waste heat to heat water - but is only really efficient when there is sufficient hot water demand ie heating ...
Solar Mike's user avatar
  • 15.8k
2 votes

What is the purpose of combustor in a gas turbine

The turbine blades are what turns the compressor blades in the first place. They do this by extracting work from the hot gas shooting out of the combustors at high speed, and feeding it forward on a ...
niels nielsen's user avatar
2 votes
Accepted

Why this engine can work without a timing belt?

It has no conventional valves that need to be moved; and no cam. 2-cycle engines have a variety of strange ( to me ) valves ; some like flappers.
blacksmith37's user avatar
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