The Eduladder is a community of students, teachers, and programmers just interested to make you pass any exams. So we help you to solve your academic and programming questions fast.
Watch related videos of your favorite subject.
Connect with students from different parts of the world.
See Our team
Wondering how we keep quality?
Got unsolved questions?

CE2352-DESIGN-OF-STEEL-STRUCTURES-->View question

Taged users:

Likes:
Be first to like this question

Dislikes:
Be first to dislike this question
The comparison ratio of the maximum to minimum volume in the cylinder of an internal combustion engine.
In a piston engine, it is the ratio between the volume of the cylinder and combustion chamber when the piston is at the bottom of its stroke, and the volume of the combustion chamber when the piston is at the top of its stroke.
For example, a cylinder and its combustion chamber with the piston at the bottom of its stroke may contain 1000 cc of air (900 cc in the cylinder plus 100 cc in the combustion chamber). When the piston has moved up to the top of its stroke inside the cylinder, and the remaining volume inside the head or combustion chamber has been reduced to 100 cc, then the compression ratio would be proportionally described as 1000:100, or with fractional reduction, a 10:1 compression ratio.
A high compression ratio is desirable because it allows an engine to extract more mechanical energy from a given mass of air–fuel mixture due to its higher thermal efficiency. This occurs because internal combustion engines are heat engines, and higher efficiency is created because higher compression ratios permit the same combustion temperature to be reached with less fuel, while giving a longer expansion cycle, creating more mechanical power output and lowering the exhaust temperature. It may be more helpful to think of it as an "expansion ratio", since more expansion reduces the temperature of the exhaust gases, and therefore the energy wasted to the atmosphere. Diesel engines actually have a higher peak combustion temperature than petrol engines, but the greater expansion means they reject less heat in their cooler exhaust.
On the other hand, diesel engines operate on the principle of compression ignition, so that a fuel which resists autoignition will cause late ignition, which will also lead to engine knock.
Static compression ratio (CR) is calculated by the formula
{\displaystyle {CR}={\frac {V_{d}+V_{c}}{V_{c}}}}
Where:
Vd = displacement volume. This is the volume inside the cylinder displaced by the piston from the beginning of the compression stroke to the end of the stroke.
Vc= clearance volume. This is the volume of the space in the cylinder left at the end of the compression stroke.
Vd can be estimated by the cylinder volume formula
{\displaystyle V_{d}={\tfrac {\pi }{4}}b^{2}s}
Where:
b= cylinder bore (diameter)
s= piston stroke length
Because of the complex shape of V_{c} it is usually measured directly. This is often done by filling the cylinder with liquid and then measuring the volume of the used liquid.

Likes:

Dislikes:
Be first to dislike this answer

### Watch more videos from this user Here

Learn how to upload a video and start earning here

The ratio of the maximum to minimum volume in the cylinder of an internal-combustion engine

Likes:
Be first to like this answer

Dislikes:
Be first to dislike this answer

### Watch more videos from this user Here

Learn how to upload a video and start earning here

The comparison ratio of the maximum to minimum volume in the cylinder of an internal combustion engine.
In a piston engine, it is the ratio between the volume of the cylinder and combustion chamber when the piston is at the bottom of its stroke, and the volume of the combustion chamber when the piston is at the top of its stroke.
For example, a cylinder and its combustion chamber with the piston at the bottom of its stroke may contain 1000 cc of air (900 cc in the cylinder plus 100 cc in the combustion chamber). When the piston has moved up to the top of its stroke inside the cylinder, and the remaining volume inside the head or combustion chamber has been reduced to 100 cc, then the compression ratio would be proportionally described as 1000:100, or with fractional reduction, a 10:1 compression ratio.
A high compression ratio is desirable because it allows an engine to extract more mechanical energy from a given mass of air–fuel mixture due to its higher thermal efficiency. This occurs because internal combustion engines are heat engines, and higher efficiency is created because higher compression ratios permit the same combustion temperature to be reached with less fuel, while giving a longer expansion cycle, creating more mechanical power output and lowering the exhaust temperature. It may be more helpful to think of it as an "expansion ratio", since more expansion reduces the temperature of the exhaust gases, and therefore the energy wasted to the atmosphere. Diesel engines actually have a higher peak combustion temperature than petrol engines, but the greater expansion means they reject less heat in their cooler exhaust.
On the other hand, diesel engines operate on the principle of compression ignition, so that a fuel which resists autoignition will cause late ignition, which will also lead to engine knock.

Static compression ratio (${\displaystyle CR}$) is calculated by the formula

${\displaystyle {CR}={\frac {V_{d}+V_{c}}{V_{c}}}}$

Where:

Vd = displacement volume. This is the volume inside the cylinder displaced by the piston from the beginning of the compression stroke to the end of the stroke.
Vc= clearance volume. This is the volume of the space in the cylinder left at the end of the compression stroke.

Vd can be estimated by the cylinder volume formula

${\displaystyle V_{d}={\tfrac {\pi }{4}}b^{2}s}$

Where:

b= cylinder bore (diameter)
s= piston stroke length

Because of the complex shape of ${\displaystyle V_{c}}$ it is usually measured directly. This is often done by filling the cylinder with liquid and then measuring the volume of the used liquid.

Likes:
Be first to like this answer

Dislikes:
Be first to dislike this answer

### Watch more videos from this user Here

Learn how to upload a video and start earning here

Lets together make the web is a better place

We made eduladder by keeping the ideology of building a supermarket of all the educational material available under one roof. We are doing it with the help of individual contributors like you, interns and employees. So the resources you are looking for can be easily available and accessible also with the freedom of remix reuse and reshare our content under the terms of creative commons license with attribution required close.

You can also contribute to our vision of "Helping student to pass any exams" with these.