What limits the compression ratio in the Otto cycle?
Autoignition – Limit for Compression Ratio The unburned mixture may autoignite by detonating from pressure and heat alone, rather than ignite from the spark plug at exactly the right time. The engine knocking can be reduced by using high-octane fuel, which increases the gasoline’s resistance to autoignition.
What is the range of compression ratio for a petrol engine?
10.0:1 to 13.5:1
What is mean effective pressure in Otto cycle?
1 Mean Effective Pressure (MEP; Otto Cycle) Generally, MEP is defined as the ratio of the net work done to the displacement volume of the piston.
What is the 4 1 process in Otto cycle?
Process 4–1 completes the cycle by a constant-volume process in which heat is rejected from the air while the piston is at bottom dead center. Process 1–0 the mass of air is released to the atmosphere in a constant pressure process.
Which fuels can an Otto engine run on?
The Otto Cycle engine was eventually adopted to run on Ligroin and eventually gasoline, and many gases. During WWII Otto engines were run on more than 62 different fuels, such as wood gas, coal gas, propane, hydrogen, benzene, and many more. The engine is limited to light fuels.
What is the difference between Otto cycle and Atkinson cycle?
An Atkinson cycle has a greater work output and a higher thermal efficiency than the Otto cycle at the same operating condition. The compression ratios that maximize the work of the Otto cycle are always found to be higher than those for the Atkinson cycle at the same operating conditions.
What are the four strokes movements in order of a four stroke engine?
An internal-combustion engine goes through four strokes: intake, compression, combustion (power), and exhaust. As the piston moves during each stroke, it turns the crankshaft.
What is the cut off ratio?
The cutoff ratio is the ratio of the volume after combustion to the volume before combustion. However, practical Diesel engines uses higher compression ratios compared to petrol engines and are often quite efficient.
What is the difference between Rankine cycle and Brayton cycle?
The key difference between Rankine cycle and Brayton cycle is that the Rankine cycle is a vapour cycle, whereas the Brayton cycle is a cycle between liquid and vapour phases. Both the Rankine cycle and Brayton cycle are thermodynamic cycles.
How does air cycle occur in 5 sentences?
Plants create oxygen through the help of the sunlight by the process called Photosynthesis. Animals and humans breathe through the use of oxygen. Humans emit a gas called Carbon Dioxide which was helpful with the plant. The plants absorb the Carbon Dioxide present in the atmosphere and process it to become oxygen.
How do air cycle occurs?
How does air cycle work? Air cycle refrigeration works on the reverse Brayton or Joule cycle. Air is compressed and then heat removed, this air is then expanded to a lower temperature than before it was compressed. Work must be taken out of the air during the expansion, otherwise the entropy would increase.
How does oxygen cycle occur?
The entire cycle can be summarized as, the oxygen cycle begins with the process of photosynthesis in the presence of sunlight, releases oxygen back into the atmosphere, which humans and animals breathe in oxygen and breathe out carbon dioxide, and again linking back to the plants.
What is the oxygen cycle and what does it confirm?
Oxygen cycle, circulation of oxygen in various forms through nature. Free in the air and dissolved in water, oxygen is second only to nitrogen in abundance among uncombined elements in the atmosphere. Plants and animals use oxygen to respire and return it to the air and water as carbon dioxide (CO2).
Why is the oxygen cycle important?
This free oxygen then recombines with existing O2 molecules to make O3 or ozone. This cycle is important because it helps to shield the Earth from the majority of harmful ultra violet radiation turning it to harmless heat before it reaches the Earth’s surface.
How are humans affecting the oxygen cycle?
S. The two main human activities that affect the carbon-oxygen cycle are the burning of fossil fuels and the use and change of land. The burning of fossil fuels removes carbon from coal, natural gas or other fuels and emits that carbon as CO2 into the atmosphere.
Which biogeochemical cycle is closely related to the oxygen cycle?
The oxygen cycle is closely linked to the carbon cycle and the water cycle (see hydrological cycle). In the process of respiration oxygen is taken in by living organisms and released into the atmosphere, combined with carbon, in the form of carbon dioxide.
Which two biogeochemical cycles are most closely tied together?
Which two biogeochemical cycles are most closely tied together? Why are they linked? The oxygen & carbon cycles.
How are the oxygen and carbon cycles connected?
When they’re exposed to light, green plants use carbon dioxide from the atmosphere to manufacture living matter and release oxygen into the air. This process is called photosynthesis. Carbon dioxide is produced through the respiration of animals and plants, which consume oxygen and release carbon dioxide.
Why is the oxygen and carbon dioxide cycle considered to be a cycle?
Plants use carbon dioxide in a process known as photosynthesis. During photosynthesis, plants give off oxygen as a waste product. Carbon dioxide moves from the air into the leaves of plants through tiny openings in the plant’s leaves. Animals and plants are connected to each other by the oxygen-carbon dioxide cycle.
Why is the natural process called a cycle?
Why is the natural process called a cycle? its the samething over and over again.
What are the three processes necessary for the carbon dioxide oxygen cycle and how do they work together?
1) What are the three processes necessary for the carbon dioxide–oxygen cycle and how do they work together? Photosynthesis, respiration, and decomposition are processes that are responsible for maintaining the carbon dioxide–oxygen cycle. The process of photosynthesis in plants releases oxygen into the atmosphere.
What is the cycle of carbon dioxide?
When new life is formed, carbon forms key molecules like protein and DNA. It’s also found in our atmosphere in the form of carbon dioxide or CO2. The carbon cycle is nature’s way of reusing carbon atoms, which travel from the atmosphere into organisms in the Earth and then back into the atmosphere over and over again.
What are the 4 steps in the carbon cycle?
The Carbon Cycle
- Carbon moves from the atmosphere to plants.
- Carbon moves from plants to animals.
- Carbon moves from plants and animals to soils.
- Carbon moves from living things to the atmosphere.
- Carbon moves from fossil fuels to the atmosphere when fuels are burned.
- Carbon moves from the atmosphere to the oceans.