Physics Report. Car engines...

[Adam95GT]

I have to write an extra credit report on car engines and how they work. can someone read this over... this is mostly just strait from my head... except for the history. Does it do a good job explaining the actual engine. I still havent gotten in to how the 4 stroke system works... dont realy know where to start taking about it and spark


Car Engines

The first self powered road vehicles date back to late 1700’s in France. These vehicles were powered not by the engines used today but instead by an external combustion steam engine. Over the years our understanding of physics has helped motivate our need for mobility and speed. With knowledge we have obtained over the years we have been able to make more advanced engines. Today the most widely used engine is the internal combustion gasoline engine.
An internal combustion engine is any engine that uses the explosion of a combustible fuel to push a piston in a cylinder. The first internal combustion engine was designed by Christian Huygens in 1680 and was fueled by gun powder. This engine however was never built. It wasn’t until 1807 that the first car powered by an internal combustion engine was built. It was built by Francious Issac De Rivaz of Switzerland and was fueled by a mixture of hydrogen and oxygen. These early automotive engines were not reliable and it wasn’t until 1885 that the engine that was considered to be the prototype for our modern gasoline engines was built. It was invented by Gottlieb Daimler and consisted of a vertical cylinder with gasoline injected through a carburetor. The engine was first installed in a two wheeled carriage it was not until a year later that this engine entered what would be considered the first four wheeled car. And on January 29th in 1886 Karl Benz received the first patent for a gas fueled car.
Today modern engines use newer technology but still have their roots in the late 1800’s. The whole purpose of the engine is to turn your fuel in to motion. Almost all cars use what is known as the 4 stroke compression cycle. The four stroke cycle is made up of the intake stroke, the compression stroke, the combustion stroke, and the exhaust stroke. In order to understand the 4 stroke cycle you need to have an idea of what the inside of the engine is like. Current gasoline engines are comprised of an engine block which consists the cylinder walls and coolant and oil passages. Inside the block is where you find the pistons, connecting rods, and crankshaft. The pistons are connected to the rods by wrist pins which allow the piston to be able to pivot on the rod. The crankshaft is connected to the rods and as the fuel in the engine is being combusted the crankshaft is what connects to your transmission and drive train which, transfers the motion to the wheels of your car. The top end of the engine is comprised of your air intake system as well as you fuel injection system rather it be a carburetor or fuel injectors. Along with your intake and injection system are the cylinder heads. The cylinder heads are what allows the air in to your engine and your exhaust gasses to be able to exit. It does this using a system of valves that lead in to the combustion chamber. The valves are controlled by a cam shaft which is connected in time with your crankshaft. The lobes on the cam either directly or indirectly open the valves to allow air in and exhaust out. The spark plugs which ignite your fuel are also located inside the cylinder head with the electrode itself being inside the combustion chamber.
During the intake stroke the piston is at the top of the cylinder. As the piston moves down the intake valve opens and air is pulled in to the cylinder while fuel is injected. The next step is the compression stroke during the compression stroke the piston moves back up in the cylinder and compresses the air and fuel this makes the small explosion more powerful. During the combustion stroke the spark plug ignites the air fuel mixture and the explosion pushes the piston downward and creates the force needed to turn the crankshaft. Once the piston is at the bottom of the stroke the exhaust

 

[5spd GT]

I seen a few spots where some commas need to be inserted and some "run-on" sentences. Other than that, it is a good start.

This is from my camshaft link in my signature, which may help with the cycles. It is pretty general...

There are 4 simple strokes to an engine: Power, Exhaust, Intake, and Compression.

First, there is the power stroke, which is created after the spark ignites the compressed air/fuel mixture the piston is pushed downwards and relates the power to the crankshaft.

Second, there is the exhaust stroke where the piston is now coming up and the exhaust valve opens to push the excess air out the exhaust port into the exhaust manifold.

Third, there is the intake stroke in which air is pushed down into cylinder as it travels downward.

Fourth, there is the compression stroke in which the piston moves upwards to compress the air/fuel mixture that entered the cylinder on the previous stroke.

One should notice that the intake opening typically happens before top dead center (BTDC) and the intake closing typically occurs after top dead center (ATDC). The exhaust opening typically happens before bottom dead center and the exhaust closing typically occurs after top dead center (ATDC).

I will discuss this a little better and try to combine the strokes with the valve timing.

For simplicity I will start with the power stroke. The piston has just been "exploded" downwards to transmit all the power to the crankshaft to rotate it. Before the piston reaches the bottom, the exhaust valve begins to open in order to begin scavenging the exhaust, and after the power stroke passes bottom dead center, the exhaust stroke begins. The reason the exhaust valve will open before the piston reaches the bottom of its travel is because cylinder pressure is much higher, even at this point, than atmospheric pressure. This helps scavenge some of the exhaust out the exhaust port.

As the piston is coming back up to push out the extra gasses out the exhaust, the exhaust valve opens up fully and then begins to close as the piston approaches top dead center. Just before the piston gets to the top and the exhaust valve closes, the intake valve begins to open. At this point, called overlap, both the intake and exhaust valve are open. The exhaust valve closes a little after top dead center (ATDC), which is when the intake stroke begins.

The intake stroke is where the intake valve continues to open and air is pushed in from the atmospheric pressure. The intake valve continues to stay open until just after the piston reached the bottom of its travel, (ABDC). After top dead center and after the intake valve closes, the compression stroke begins to compress all the air/fuel that was just entered into the cylinder. The ignition occurs a little before the piston gets back up to the top dead center position, to continue right into the power stroke. The cycle repeats over and over. Next, the individual valve timing will be explained.

 

[ronstang94]

There are some grammer mistakes, but this is probably not the final product anyways. I just thought I would let you know. Not sure how strict your teachers are, but they might prefer you to use "was not" instead of "wasn't."

You should explain the movement and action of each stroke. IE: On the compression stroke the piston moves from its lowest position in the cylinder to its highest position. This compresses The air and fuel mixture within the cylinder between the top of the piston and the top of the combustion chamber. During this mobvement both the intake and exhaust valves are closed.

The information is good. It is explained clearly. How much longer does it need to be?

 

[Adam95GT]

Yea im typing this now just got the assignment like an hour ago.. I just did the 4 stroke explanation going to go in to engine shapes and sizes and call it done i think... i know grammar is horrible... but i really havent read it over... once im done ill post the final copy up if someone wants to edit it for me... my roommates have no idea haha...

During the intake stroke the piston is at the top of the cylinder. As the piston moves down the intake valve opens and air is pulled in to the cylinder while fuel is injected. The next step is the compression stroke during the compression stroke the piston moves back up in the cylinder and compresses the air and fuel this makes the small explosion more powerful. During the combustion stroke the spark plug ignites the air fuel mixture and the explosion pushes the piston downward and creates the force needed to turn the crankshaft. Once the piston is at the bottom of the stroke the exhaust valve then opens and allows the exhaust gasses to exit the combustion chamber. As all the cylinders go threw the stroke cycle the crankshaft rotates this motion is transferred through the drive train and to the wheels of your car, creating motion.
Engines can be found in all shapes and sizes. The most common being the inline 4 and the v6. There are other variations however there is a flat 4 cylinder as well a W 12 engine that is being produced by Volkswagen which is basically two v6 engines fused together.

 

[Adam95GT]

There are some grammer mistakes, but this is probably not the final product anyways. I just thought I would let you know. Not sure how strict your teachers are, but they might prefer you to use "was not" instead of "wasn't."

You should explain the movement and action of each stroke. IE: On the compression stroke the piston moves from its lowest position in the cylinder to its highest position. This compresses The air and fuel mixture within the cylinder between the top of the piston and the top of the combustion chamber. During this mobvement both the intake and exhaust valves are closed.

The information is good. It is explained clearly. How much longer does it need to be?

Thanks!

 

[Zero Signal]

I would just change "explosion of a combustable fuel" to "deflagration of a fuel"

Seriously though, just turn it in, you'll get the credit for just doing it.

 

[Adam95GT]

I seen a few spots where some commas need to be inserted and some "run-on" sentences. Other than that, it is a good start.

This is from my camshaft link in my signature, which may help with the cycles. It is pretty general...

There are 4 simple strokes to an engine: Power, Exhaust, Intake, and Compression.

First, there is the power stroke, which is created after the spark ignites the compressed air/fuel mixture the piston is pushed downwards and relates the power to the crankshaft.

Second, there is the exhaust stroke where the piston is now coming up and the exhaust valve opens to push the excess air out the exhaust port into the exhaust manifold.

Third, there is the intake stroke in which air is pushed down into cylinder as it travels downward.

Fourth, there is the compression stroke in which the piston moves upwards to compress the air/fuel mixture that entered the cylinder on the previous stroke.

One should notice that the intake opening typically happens before top dead center (BTDC) and the intake closing typically occurs after top dead center (ATDC). The exhaust opening typically happens before bottom dead center and the exhaust closing typically occurs after top dead center (ATDC).

I will discuss this a little better and try to combine the strokes with the valve timing.

For simplicity I will start with the power stroke. The piston has just been "exploded" downwards to transmit all the power to the crankshaft to rotate it. Before the piston reaches the bottom, the exhaust valve begins to open in order to begin scavenging the exhaust, and after the power stroke passes bottom dead center, the exhaust stroke begins. The reason the exhaust valve will open before the piston reaches the bottom of its travel is because cylinder pressure is much higher, even at this point, than atmospheric pressure. This helps scavenge some of the exhaust out the exhaust port.

As the piston is coming back up to push out the extra gasses out the exhaust, the exhaust valve opens up fully and then begins to close as the piston approaches top dead center. Just before the piston gets to the top and the exhaust valve closes, the intake valve begins to open. At this point, called overlap, both the intake and exhaust valve are open. The exhaust valve closes a little after top dead center (ATDC), which is when the intake stroke begins.

The intake stroke is where the intake valve continues to open and air is pushed in from the atmospheric pressure. The intake valve continues to stay open until just after the piston reached the bottom of its travel, (ABDC). After top dead center and after the intake valve closes, the compression stroke begins to compress all the air/fuel that was just entered into the cylinder. The ignition occurs a little before the piston gets back up to the top dead center position, to continue right into the power stroke. The cycle repeats over and over. Next, the individual valve timing will be explained.

Thanks im looking at something very similar...

 

[Adam95GT]

I would just change "explosion of a combustable fuel" to "deflagration of a fuel"

Seriously though, just turn it in, you'll get the credit for just doing it.

Yea i sat down for the final and did 2 questions... so i think i got like a 20... she is one that usually will give you a C for just trying... and i need a C for the class to count toward my chemistry degree...


I asked her if i could do something so to make sure i passed the class and this was her response:

Write an in depth paper on car engine including physics in it. Send it
in by Friday early morning.
I will turn grades in on Friday.


I asked her if she wanted only internal combustion... which im assuming and i asked her how long she wanted it to be. i don't know what her definition of in depth means... So i went in to some history before i started talking about how it works... I dont know what else to include about the physics. should i talk about how then engine makes liner motion rotational or something??? Considering its due Friday i cant imagine it being that in depth.

 

[Adam95GT]

Anyone know where i can add some physics in to the mix. I guess i already did kinda... but i still need more. Does modifications or forced induction fit in here somehow... Im already tired of writing after doing this... IS there anyway to throw in Heat and efficiency.

 

[Adam95GT]

Up Date....

The first self powered road vehicles date back to late 1700’s in France. These vehicles were powered not by the engines used today but instead by an external combustion steam engine. Over the years our understanding of physics has helped motivate our need for mobility and speed. With knowledge we have obtained over the years we have been able to make more advanced engines. Today the most widely used engine is the internal combustion gasoline engine.
An internal combustion engine is any engine that uses the explosion of a combustible fuel to push a piston in a cylinder. The first internal combustion engine was designed by Christian Huygens in 1680 and was fueled by gun powder. This engine however was never built. It wasn’t until 1807 that the first car powered by an internal combustion engine was built. It was built by Francious Issac De Rivaz of Switzerland and was fueled by a mixture of hydrogen and oxygen. These early automotive engines were not reliable and it wasn’t until 1885 that the engine that was considered to be the prototype for our modern gasoline engines was built. It was invented by Gottlieb Daimler and consisted of a vertical cylinder with gasoline injected through a carburetor. The engine was first installed in a two wheeled carriage it was not until a year later that this engine entered what would be considered the first four wheeled car. And on January 29th in 1886 Karl Benz received the first patent for a gas fueled car.
Today modern engines use newer technology but still have their roots in the late 1800’s. The whole purpose of the engine is to turn your fuel in to motion. Almost all cars use what is known as the 4 stroke compression cycle. The four stroke cycle is made up of the intake stroke, the compression stroke, the combustion stroke, and the exhaust stroke. In order to understand the 4 stroke cycle you need to have an idea of what the inside of the engine is like. Current gasoline engines are comprised of an engine block which consists the cylinder walls and coolant and oil passages. Inside the block is where you find the pistons, connecting rods, and crankshaft. The pistons are connected to the rods by wrist pins which allow the piston to be able to rotate on the rod allowing the angle to change as the crankshaft moves. The crankshaft is connected to the rods and as the fuel in the engine is being combusted the crankshaft is what connects to your transmission and drive train which, transfers the motion to the wheels of your car. The top end of the engine is comprised of your air intake system as well as you fuel injection system rather it be a carburetor or fuel injectors. Along with your intake and injection system are the cylinder heads. The cylinder heads are what allows the air in to your engine and your exhaust gasses to be able to exit. It does this using a system of valves that lead in to the combustion chamber. The valves are controlled by a cam shaft which is connected in time with your crankshaft. The lobes on the cam either directly or indirectly open the valves to allow air in and exhaust out. The spark plugs which ignite your fuel are also located inside the cylinder head with the electrode itself being inside the combustion chamber.
During the intake stroke the piston is at the top of the cylinder. As the piston moves down the intake valve opens and air is pulled in to the cylinder while fuel is injected. The next step is the compression stroke during the compression stroke the piston moves back up in the cylinder and compresses the air and fuel this makes the small explosion more powerful. During the combustion stroke the spark plug ignites the air fuel mixture and the explosion pushes the piston downward and creates the force needed to turn the crankshaft. Once the piston is at the bottom of the stroke the exhaust valve then opens and allows the exhaust gasses to exit the combustion chamber. As all the cylinders go threw the stroke cycle the crankshaft rotates this motion is transferred through the drive train and to the wheels of your car, creating motion.
Engines can be found in all shapes and sizes. The most common being the inline 4 and the v6. There are other variations however there is a flat 4 cylinder as well a W 12 engine that is being produced by Volkswagen which is basically two v6 engines fused together. In an inline engine the cylinders are aligned in a strait row in a single bank. In a v style engine, the cylinders are arranged in two angled banks in a v shape as the name implies. In a flat style engine the cylinders are arranged in two banks completely opposite of each other. It is like a 180 degree angled V type engine.
Even though today’s engines are much more efficient and reliable then those of the past there is still a problem with efficiency. Currently your average car engine is only about 20% efficient. Because internal combustion engines are primarily heat engines their efficiency is limited by the heat that the engine looses to its surroundings. The Carnot cycle states that the overall efficiency is dictated by the difference between the lower and upper operating temperatures of the engine. Due to heat from the exhaust as well as that lost to its surroundings today’s engines are not nearly as efficient as we need. Since ceramic is such an incredible material and can be made with higher thermal stability. This stability allows for greater temperature difference between the lower and upper operating temperatures which creates greater thermodynamic efficiency.

 

[Adam95GT]

http://mb-soft.com/public2/engine.html

 

[Adam95GT]

Any other ideas of what to talk about... im stuck

 

[5spd GT]

http://www.shef.ac.uk/physics/people/rjones/PDFs/PHY101/PHY101_RALJ_lecture9.pdf

http://www.unc.edu/~prinarp/jamie.html

Those should help you. Throw some simple math in there.

Talk about volume, temperatures, pressure. Great place to introduce Boyle's and Charles' Law.

Good Luck with it!

 

[Adam95GT]

http://www.shef.ac.uk/physics/people/rjones/PDFs/PHY101/PHY101_RALJ_lecture9.pdf

http://www.unc.edu/~prinarp/jamie.html

Those should help you. Throw some simple math in there.

Talk about volume, temperatures, pressure. Great place to introduce Boyle's and Charles' Law.

Good Luck with it!

Where do you think i should throw this in??? i jut dont know where to put it at

Edited:

The first self powered road vehicles date back to late 1700’s in France. These vehicles were powered, not by the engines used today, but instead by an external combustion steam engine. Over the years, our understanding of physics has helped motivate our need for mobility and speed. With the knowledge we have obtained over the years, we have been able to make more advanced engines.
Today, the most widely used engine is the internal combustion gasoline engine. An internal combustion engine is any engine that uses the explosion of a combustible fuel to push a piston in a cylinder. The first internal combustion engine was designed by Christian Huygens in 1680 and was fueled by gun powder. This engine, however, was never built. It wasn’t until 1807 that the first car powered by an internal combustion engine was built. It was built by Francious Issac De Rivaz of Switzerland and was fueled by a mixture of hydrogen and oxygen. These early automotive engines were not reliable, and it wasn’t until 1885 that the engine that was considered to be the prototype for our modern gasoline engines was built. The prototype was created by Gottlieb Daimler and consisted of a vertical cylinder with gasoline injected through a carburetor. The engine was first installed in a two wheeled carriage and it wasn’t until a year later that this engine entered what would be considered the first four wheeled car. And on January 29th, 1886, Karl Benz received the first patent for a gas fueled car.
Today, modern engines use newer technology but still have their roots in the late 1800’s. The whole purpose of the engine is to turn your fuel in to motion. Almost all cars use what is known as the 4 stroke compression cycle. The four stroke cycle is made up of the intake stroke, the compression stroke, the combustion stroke, and the exhaust stroke. In order to understand the 4 stroke cycle you need to have an idea of what the inside of the engine is like. Current gasoline engines are comprised of an engine block which consists of the cylinder walls with coolant and oil passages. Inside the block is where you find the pistons, connecting rods, and crankshaft. The pistons are connected to the rods by wrist pins which allow the piston to be able to rotate on the rod allowing the angle to change as the crankshaft moves. The crankshaft is connected to the rods and as the fuel in the engine is being combusted, the crankshaft spins and transfers the motion to your drive train. The top end of the engine is comprised of your air intake system as well as your fuel injection system rather it be a carburetor or fuel injectors. Along with your intake and injection system are the cylinder heads. The cylinder heads are what allow the air in to your engine and your exhaust gasses to exit. It does this using a system of valves that lead into the combustion chamber. The valves are controlled by a cam shaft which is connected in time with your crankshaft. The lobes on the cam either directly or indirectly open the valves to allow air in and exhaust out. The spark plugs which ignite your fuel are also located inside the cylinder head with the electrode itself being inside the combustion chamber.
During the intake stroke, the piston is at the top of the cylinder. As the piston moves down, the intake valve opens and air is pulled in to the cylinder while fuel is injected. The next step is the compression stroke. During the compression stroke, the piston moves back up in the cylinder and compresses the air and fuel. This makes the small explosion more powerful. During the combustion stroke, the spark plug ignites the air fuel mixture, and the explosion pushes the piston downward and creates the force needed to turn the crankshaft. Once the piston is at the bottom of the stroke, the exhaust valve then opens and allows the exhaust gasses to exit the combustion chamber. As all the cylinders go through the stroke cycle, the crankshaft rotates. This motion is transferred through the drive train and to the wheels of your car which creates motion.
Engines can be found in all shapes and sizes. The most common engines are the inline 4 and the v6, however there are other variations. These variations include a flat 4 cylinder as well a W 12 engine that is being produced by Volkswagen. The W 12 engine is basically two v6 engines fused together. In an inline engine, the cylinders are aligned in a strait row in a single bank. In a v style engine, the cylinders are arranged in two angled banks which are in the shape of a “V”. In a flat style engine, the cylinders are arranged in two banks completely opposite of each other. It is like a 180 degree angled V type engine.
Even though today’s engines are much more efficient and reliable then those of the past, there is still a problem with efficiency. Currently, the average car engine is only about 20% efficient. Because internal combustion engines are primarily heat engines, their efficiency is limited by the heat that the engine loses to its surroundings. The Carnot cycle states that the overall efficiency is dictated by the difference between the lower and upper operating temperatures of the engine. Due to heat from the exhaust as well as that lost to its surroundings, today’s engines are not nearly as efficient as we need. Since ceramic is such an incredible material, it can be made with higher thermal stability. This stability allows for greater temperature difference between the lower and upper operating temperatures which creates greater thermodynamic efficiency.

 

[Black95GTS]

If you want to talk physics you have to talk about friction, rotational inertia, torque multiplication via the gear set, work done in horse power, joules, watts, etc. How horsepower is calculated via HP = Trq*RPM / 5252. How torque is calculated, why the IC engine is less then 50 percent efficient, the dynamics of air as it passes through the intake tract via manifold vacuum, etc etc.

You have to be careful and not write a science or history report, you need to write a physics report. Just my .02.

Adam

 

[Adam95GT]

If you want to talk physics you have to talk about friction, rotational inertia, torque multiplication via the gear set, work done in horse power, joules, watts, etc. How horsepower is calculated via HP = Trq*RPM / 5252. How torque is calculated, why the IC engine is less then 50 percent efficient, the dynamics of air as it passes through the intake tract via manifold vacuum, etc etc.

You have to be careful and not write a science or history report, you need to write a physics report. Just my .02.

Adam

Talked about efficiency already... might elabobrate a little more... added some stuff about HP and torque... any other ideas???

So far this is what i have:

The first self powered road vehicles date back to late 1700’s in France. These vehicles were powered, not by the engines used today, but instead by an external combustion steam engine. Over the years, our understanding of physics has helped motivate our need for mobility and speed. With the knowledge we have obtained over the years, we have been able to make more advanced engines.
Today, the most widely used engine is the internal combustion gasoline engine. An internal combustion engine is any engine that uses the explosion of a combustible fuel to push a piston in a cylinder. The first internal combustion engine was designed by Christian Huygens in 1680 and was fueled by gun powder. This engine, however, was never built. It wasn’t until 1807 that the first car powered by an internal combustion engine was built. It was built by Francious Issac De Rivaz of Switzerland and was fueled by a mixture of hydrogen and oxygen. These early automotive engines were not reliable, and it wasn’t until 1885 that the engine that was considered to be the prototype for our modern gasoline engines was built. The prototype was created by Gottlieb Daimler and consisted of a vertical cylinder with gasoline injected through a carburetor. The engine was first installed in a two wheeled carriage and it wasn’t until a year later that this engine entered what would be considered the first four wheeled car. And on January 29th, 1886, Karl Benz received the first patent for a gas fueled car.
Today, modern engines use newer technology but still have their roots in the late 1800’s. The whole purpose of the engine is to turn your fuel in to motion. Almost all cars use what is known as the 4 stroke compression cycle. The four stroke cycle is made up of the intake stroke, the compression stroke, the combustion stroke, and the exhaust stroke. In order to understand the 4 stroke cycle you need to have an idea of what the inside of the engine is like. Current gasoline engines are comprised of an engine block which consists of the cylinder walls with coolant and oil passages. Inside the block is where you find the pistons, connecting rods, and crankshaft. The pistons are connected to the rods by wrist pins which allow the piston to be able to rotate on the rod allowing the angle to change as the crankshaft moves. The crankshaft is connected to the rods and as the fuel in the engine is being combusted, the crankshaft spins and transfers the motion to your drive train. The top end of the engine is comprised of your air intake system as well as your fuel injection system rather it be a carburetor or fuel injectors. Along with your intake and injection system are the cylinder heads. The cylinder heads are what allow the air in to your engine and your exhaust gasses to exit. It does this using a system of valves that lead into the combustion chamber. The valves are controlled by a cam shaft which is connected in time with your crankshaft. The lobes on the cam either directly or indirectly open the valves to allow air in and exhaust out. The spark plugs which ignite your fuel are also located inside the cylinder head with the electrode itself being inside the combustion chamber.
During the intake stroke, the piston is at the top of the cylinder. As the piston moves down, the intake valve opens and air is pulled in to the cylinder while fuel is injected. The next step is the compression stroke. During the compression stroke, the piston moves back up in the cylinder and compresses the air and fuel. This makes the small explosion more powerful. During the combustion stroke, the spark plug ignites the air fuel mixture, and the explosion pushes the piston downward and creates the force needed to turn the crankshaft. Once the piston is at the bottom of the stroke, the exhaust valve then opens and allows the exhaust gasses to exit the combustion chamber. As all the cylinders go through the stroke cycle, the crankshaft rotates. This motion is transferred through the drive train and to the wheels of your car which creates motion.
Engines can be found in all shapes and sizes. The most common engines are the inline 4 and the v6, however there are other variations. These variations include a flat 4 cylinder as well a W 12 engine that is being produced by Volkswagen. The W 12 engine is basically two v6 engines fused together. In an inline engine, the cylinders are aligned in a strait row in a single bank. In a v style engine, the cylinders are arranged in two angled banks which are in the shape of a “V”. In a flat style engine, the cylinders are arranged in two banks completely opposite of each other. It is like a 180 degree angled V type engine.
Along with size comes power and engines are commonly rated in two different ways horsepower and torque. The term horse power was invented by James Watt; in Watt’s judgment a horse could do 33,000 pounds of work per minute. He considered this to be 1 horse power. 1 horse power is then equal to 746 watts. The torque can be then calculated from this horsepower by using this relationship (Torque = (Horsepower x 5252)/ Engine Speed in RPMs). Torque and horse power are commonly measured on a Dynamometer where they are plotted on a graph. This makes it easy to see the max torque and horsepower and at what engine speed they occur. Horsepower can be measured at the wheels which accounts for the 10%-20% loss due to the transmission and other drive train components or it can be measured directly at the engine.
Even though today’s engines are much more efficient and reliable then those of the past, there is still a problem with efficiency. Currently, the average car engine is only about 20% efficient. Because internal combustion engines are primarily heat engines, their efficiency is limited by the heat that the engine loses to its surroundings. Most internal combustion engines waste about 36% of the energy as heat lost to the cooling system and another 38% through the exhaust. Finally another 6% is lost to friction. The Carnot cycle states that the overall efficiency is dictated by the difference between the lower and upper operating temperatures of the engine. In order to improve this efficiency scientists have been looking to ceramics as well as alternative engine designs. Since ceramic is such an incredible material, it can be made with higher thermal stability. This stability allows for greater temperature difference between the lower and upper operating temperatures which creates greater thermodynamic efficiency.

 

[Adam95GT]

Can someone read this over for me??? This sound good?

The first self powered road vehicles date back to late 1700’s in France. These vehicles were powered, not by the engines used today, but instead by an external combustion steam engine. Over the years, our understanding of physics has helped motivate our need for mobility and speed. With the knowledge we have obtained over the years, we have been able to make more advanced engines.
Today, the most widely used engine is the internal combustion gasoline engine. An internal combustion engine is any engine that uses the explosion of a combustible fuel to push a piston in a cylinder. The first internal combustion engine was designed by Christian Huygens in 1680 and was fueled by gun powder. This engine, however, was never built. It wasn’t until 1807 that the first car powered by an internal combustion engine was built. It was built by Francious Issac De Rivaz of Switzerland and was fueled by a mixture of hydrogen and oxygen. These early automotive engines were not reliable, and it wasn’t until 1885 that the engine that was considered to be the prototype for our modern gasoline engines was built. The prototype was created by Gottlieb Daimler and consisted of a vertical cylinder with gasoline injected through a carburetor. The engine was first installed in a two wheeled carriage and it wasn’t until a year later that this engine entered what would be considered the first four wheeled car. And on January 29th, 1886, Karl Benz received the first patent for a gas fueled car.
Today, modern engines use newer technology but still have their roots in the late 1800’s. The whole purpose of the engine is to turn your fuel in to motion. Almost all cars use what is known as the 4 stroke compression cycle. The four stroke cycle is made up of
the intake stroke, the compression stroke, the combustion stroke, and the exhaust stroke. In order to understand the 4 stroke cycle you need to have an idea of what the inside of the engine is like. Current gasoline engines are comprised of an engine block which consists of the cylinder walls with coolant and oil passages. Inside the block is where you find the pistons, connecting rods, and crankshaft. The pistons are connected to the rods by wrist pins which allow the piston to be able to rotate on the rod allowing the angle to change as the crankshaft moves. The crankshaft is connected to the rods and as the fuel in the engine is being combusted, the crankshaft spins and transfers the motion to your drive train. The top end of the engine is comprised of your air intake system as well as your fuel injection system rather it be a carburetor or fuel injectors. Along with your intake and injection system are the cylinder heads. The cylinder heads are what allow the air in to your engine and your exhaust gasses to exit. It does this using a system of valves that lead into the combustion chamber. The valves are controlled by a cam shaft which is connected in time with your crankshaft. The lobes on the cam either directly or indirectly open the valves to allow air in and exhaust out. The spark plugs which ignite your fuel are also located inside the cylinder head with the electrode itself being inside the combustion chamber.
During the intake stroke, the piston is at the top of the cylinder. As the piston moves down, the intake valve opens and air is pulled in to the cylinder while fuel is injected. The next step is the compression stroke. During the compression stroke, the piston moves back up in the cylinder and compresses the air and fuel. This makes the small explosion more powerful. During the combustion stroke, the spark plug ignites the air fuel mixture, and the explosion pushes the piston downward and creates the force
needed to turn the crankshaft. Once the piston is at the bottom of the stroke, the exhaust valve then opens and allows the exhaust gasses to exit the combustion chamber. As all the cylinders go through the stroke cycle, the crankshaft rotates. This motion is transferred through the drive train and to the wheels of your car which creates motion.
Engines can be found in all shapes and sizes. The most common engines are the inline 4 and the v6, however there are other variations. These variations include a flat 4 cylinder as well a W 12 engine that is being produced by Volkswagen. The W 12 engine is basically two v6 engines fused together. In an inline engine, the cylinders are aligned in a strait row in a single bank. In a v style engine, the cylinders are arranged in two angled banks which are in the shape of a “V”. In a flat style engine, the cylinders are arranged in two banks completely opposite of each other. It is like a 180 degree angled V type engine.
Along with size comes power and engines are commonly rated in two different ways horsepower and torque. The term horse power was invented by James Watt; in Watt’s judgment a horse could do 33,000 pounds of work per minute. He considered this to be 1 horse power. 1 horse power is then equal to 746 watts. The torque can be then calculated from this horsepower by using this relationship (Torque = (Horsepower x 5252)/ Engine Speed in RPMs). This being stated horsepower will always be equal torque at 5,252 rpm. This also shows that torque will always be greater than horsepower under 5,252 rpm and horsepower will always be greater than torque over 5,252 rpm. Torque and horse power are commonly measured on a Dynamometer where they are plotted on a graph. This makes it easy to see the max torque and horsepower and at what engine speed they occur. Horsepower can be measured at the wheels which accounts for the 10%-20% loss due to the transmission and other drive train components, or it can be measured directly at the engine.
Even though today’s engines are much more efficient and reliable then those of the past, there is still a problem with efficiency. Currently, the average car engine is only about 20% efficient. Because internal combustion engines are primarily heat engines, their efficiency is limited by the heat that the engine loses to its surroundings. Most internal combustion engines waste about 36% of the energy as heat lost to the cooling system and another 38% through the exhaust. Finally another 6% is lost to friction. The Carnot cycle states that the overall efficiency is dictated by the difference between the lower and upper operating temperatures of the engine. In order to improve this efficiency scientists have been looking to ceramics as well as alternative engine designs. Since ceramic is such an incredible material, it can be made with higher thermal stability. This stability allows for greater temperature difference between the lower and upper operating temperatures which creates greater thermodynamic efficiency.
Some think that our grandchildren will see the internal combustion as our generation’s failure. Because of the low efficiency and high rate of pollution it is overall bad for our environment. I do not think this is the case however. The internal combustion engine has played a significant role in our history. However its time is running out and we need to come up with a more efficient means of creating power and motion. Recently it’s trendy to be “Green” I think that this is what we need as a world to take a turn for the best. As scientists explore alternate fuels and materials things can only take a turn for the better.

 

[Adam95GT]

fixed some grammar mistakes

 

[94-302-vert]

I read 90% of this and I will make a few suggestions.

Mention the different types of engines: 2 stroke, 4 stroke, diesel, rotary vane, Other?

Applications for each? Think trains, generators, large gensets, off highway trucks, big rigs, lawnmowers, etc.

Annual volume for each?

Real physics on how the engine works, explosion to create pressure over the area of the piston, etc... this is a physics report... Maybe reference the famed ford 5.0l 302ci measurements...

Graphics are essential to making this work.

What makes one engine more efficient than another?

go into the fuel consumption discussion via load, maybe even efficiency based on engine size and how a turbo or supercharger can make that greater than 100% as it forces more air and therefore more fuel into the cylinder.

Where are you getting your efficiency %tages...

What about Hybrids, what makes them so special (they use gas too)...

Why are diesels so popular overseas, and why is diesel so efficient per gallon over a gas engine?


I think you have a lot of great info here but you need to tie it all together... rember this is a college paper not a freshman in HS paper... organization is key...

What does stroke get you over piston diameter? what is the theoretical perfect engine size (this is out there and I think it is 4.6/4.7l for a V8...

Why have 8 cyl over 4 or 2 REALLY big cylinders?

since you are talking efficency talk about the mileage and efficiency differences in the drivetrain (man trans vs auto)

Center on the physics of the engine and jsut go around everythign else, mention that it is there but the purpose of this paper is to talk about the physics and efficiency of a modern day 4 stroke gasoline engine...

 

[Black95GTS]

1 - Write the paper in the third person. Eliminate all "you, yours, I, mine" etc. Its not an opinion piece and its supposed to be boring.

2 - The formula for horsepower is : HP = (RPM * TRQ) / 5252. For YOUR purposes though, you want to write it as: Horsepower = (Force * Radius * (Rotations/Minute)) / 5252. Then you have to define your constants (5252) and your variables (Force, Radius, and RPM)

3 - I would knock out that stuff about the car and driveline losses. The topic of the paper is the physics of the engine. The driveline losses are fluff, unless the purpose of the paper is the physics of the power and drive train in a vehicle.

4- If you are going to mention percent losses, you have to cite all of your sources and show a sample calculation. A program like MathCad makes this easy.

Maybe I'm going overboard, but I just got an engineering degree so I've been writing papers like this for a while.

Adam