Compression of a Jaguar XK8 Cylinder

In summary, a Jaguar XK8 convertible has an eight-cylinder engine and a compression stroke that starts with 499 cm^3 of air at atmospheric pressure and a temperature of 27.0 degrees celsius. At the end of the stroke, the air is compressed to 46.2 cm^3 and the gauge pressure has increased to 2.72 x 10^6 Pa. Using the equation (p1)(V1)/T1 = (p2)(V2)/T2, the temperature is calculated to be 503 degrees celsius.
  • #1
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Homework Statement


A Jaguar XK8 convertible has an eight-cylinder engine. At the beginning of its compression stroke, one of the cylinders contains 499 cm^3 of air at atmospheric pressure (1.01 x 10^5 Pa) and a temperature of 27.0 degrees celsius. At the end of the stroke, the air has been compressed to a volume of 46.2 cm^3 and the gauge pressure has increased to 2.72 x 10^6 Pa.


Homework Equations


(p1)(V1)/T1 = (p2)(V2)/T2
where p = pressure, V = volume, T = temperature


The Attempt at a Solution


What I tried was:
((1.01 x 10^5)(0.0499))/300 = ((2.72 x 10^6)(4.62 x 10^-4))/T2

I converted the 499cm cubed and the 46.2cm cubed to meters cubed, and also for T1 I did 273(kelvins) + 27

There was a hint given that the 'gauge pressure is the difference between the absolute pressure and the atmospheric pressure. Thus, if you measure a gauge pressure pg, then the absolute pressure p is given by p= pa + pg, where pa is the atmospheric pressure.' So I was thinking for p2 to use ((1.01 x 10^5)+(2.72 x 10^6)) but still did not get the right answer.

The answer to this question is 503 degrees Celsius but I just can't figure out what number to use for p2.
 
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  • #2
You don't have to convert the cm^3 to m^3. If they are both in the same units, just use them as they are. The units will cancel out. The pressure goes up by a factor of about 20 and the volume drops by a factor of about 10. The temperature should about double. You are making a mistake in converting the volumes. 499cm^3=4.99*10^(-4)m^3. 46.2cm^3=4.62*10^(-5)m^3. And, yes, use the gauge pressure thing to make fine adjustments.
 
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  • #3
Oh okay thank you for the clarification! I was able to get the answer :)
 

FAQ: Compression of a Jaguar XK8 Cylinder

What is compression of a Jaguar XK8 Cylinder?

Compression of a Jaguar XK8 Cylinder is the process in which the air-fuel mixture inside the cylinder is compressed by the piston before it is ignited by the spark plug. This compression results in a more powerful explosion, which in turn generates more power and torque to the engine.

Why is compression important for a Jaguar XK8 Cylinder?

Compression is important for a Jaguar XK8 Cylinder because it directly affects the performance and efficiency of the engine. A higher compression ratio leads to a more powerful and efficient engine, while a lower compression ratio can result in decreased performance and fuel efficiency.

What is the ideal compression ratio for a Jaguar XK8 Cylinder?

The ideal compression ratio for a Jaguar XK8 Cylinder can vary depending on the specific model and year of the vehicle. However, on average, an ideal compression ratio for a Jaguar XK8 Cylinder ranges from 9:1 to 11:1.

What are some signs of low compression in a Jaguar XK8 Cylinder?

Some common signs of low compression in a Jaguar XK8 Cylinder include a decrease in engine power and acceleration, difficulty starting the engine, and poor fuel efficiency. Additionally, a compression test can be performed to accurately determine the compression levels in each cylinder.

How can I improve the compression of my Jaguar XK8 Cylinder?

To improve the compression of your Jaguar XK8 Cylinder, you can do some routine maintenance such as changing the spark plugs, replacing worn out piston rings, and ensuring the valves are properly adjusted. Additionally, using a higher octane fuel and regularly changing the engine oil can also help improve compression.

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