How is Otto cycle efficiency calculated?
When we rewrite the expression for thermal efficiency using the compression ratio, we conclude the air-standard Otto cycle thermal efficiency is a function of compression ratio and κ = cp/cv.
What four processes make up the ideal Otto cycle?
The four-stroke Otto cycle is made up of the following four internally reversible processes: 1–2, isentropic compression; 2–3, constant-volume heat addition; 3–4, isentropic expansion; and 4–1, constant-volume heat rejection.
What is difference between Otto and Diesel cycle?
Otto cycle is used by petrol ignition whereas diesel engine uses the diesel cycle. Another noteworthy difference is that the Otto cycle heat occurs at constant volume, whereas the diesel cycle works on constant pressure. This could be the main difference between Otto cycle and diesel cycle.
Which is more efficient Otto or Diesel?
Explanation: Otto cycle is more efficient than Diesel cycle for a given compression ratio. For constant maximum pressure and heat input, the air standard efficiency of the gas power cycle is in the order.
What is the basic diesel cycle?
The idealized Diesel cycle assumes an ideal gas and ignores combustion chemistry, exhaust- and recharge procedures and simply follows four distinct processes: 1→2 : isentropic compression of the fluid (blue) 2→3 : reversible constant pressure heating (red) 3→4 : isentropic expansion (yellow)
What is thermal efficiency formula?
quantities are heat-equivalent values. So, for a boiler that produces 210 kW (or 700,000 BTU/h) output for each 300 kW (or 1,000,000 BTU/h) heat-equivalent input, its thermal efficiency is 210/300 = 0.70, or 70%. This means that 30% of the energy is lost to the environment.
What is standard cycle?
The Otto cycle is an air-standard cycle which approximates the processes in petrol or diesel engines. It is based on constant volume heat addition (combustion) and heat rejection processes, and isentropic compression and expansion.
How does an Otto engine work?
The Otto engine operates with a mixture compressed in a cylinder by a piston. Shortly before the piston reaches the top the mixture is ignited with a spark, and the flame propagates at a normal velocity into the unburned mixture, increasing the pressure and moving the…
Which fuel is used in Otto cycle?
gasoline2
Which fuel 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.
How does a four-stroke engine work?
A four-stroke cycle engine is an internal combustion engine that utilizes four distinct piston strokes (intake, compression, power, and exhaust) to complete one operating cycle. The piston make two complete passes in the cylinder to complete one operating cycle.
What is the difference between a 2 stroke and a 4-stroke engine?
Typically, a 2-stroke engine creates more torque at a higher RPM, while a 4-stroke engine creates a higher torque at a lower RPM. The 4-stroke engine is also much quieter, a 2-stoke engine is significantly louder and has a distinctive, high-pitched “buzzing” sound.
Is there a six stroke engine?
The six-stroke engine is a advance version of internal combustion engine based on the four-stroke engine, but with additional two electric stroke intended to make it more efficient and reduce emissions. It uses fresh air for the second suction (clean air from atmosphere ) the fifth stroke.
What is a four-stroke engine used for?
The four-stroke engine is the most common types of internal combustion engines and is used in various automobiles (that specifically use gasoline as fuel) like cars, trucks, and some motorbikes (many motorbikes use a two stroke engine).
What are the 4 most common types of engine design?
How any why different types of engines work.
- Thermal engines. Internal combustion engines (IC engines) External combustion engines (EC engines) Reaction engines.
- Electrical engines.
- Physical engines.
What causes a 2 stroke to 4-stroke?
Four-stroking in diesels When large two-stroke diesel engines are used, these have scavenging by forced induction and so are generally immune to four-stroking when idling at low speed or low power. These scavenge blowers may be mechanically-driven Roots blowers or turbochargers.
How much compression should a 4-stroke have?
What Outboard Compression Test Results Mean. Results vary depending on whether the outboard is a Four-Stroke or a Two-Stroke. Good results for Four-Strokes should be 180-210 PSI, and Two-Strokes should be around 110-130 PSI.
How much compression should a 250 4 stroke have?
The ideal pressures for an average 2 stroke dirt bike at sea level that is not heavily modified should be in the vicinity of the numbers below. A 50cc, 60cc, 80cc, 100cc, 125cc 200cc or 500cc should be able to squeeze out a reading of 120-190 PSI. A 250cc should be in the neighborhood of 170-240 PSI.
Is 90 psi a good compression?
They shouldn’t vary more than 10% from highest to lowest. That all said, 90 psi is too low, even for a low compression engine.
How many hours should you rebuild a 4 stroke?
A four-stroke top end is generally rebuilt at the 25-30 hour mark if you’re a regular racer, and more importantly on a 250F, which is typically ridden more aggressively. On a 450, or if you’re riding the bike under an ‘easy’ load, then rebuilding the top end between 30-40 hours will be adequate.
What is a top end rebuild 4 stroke?
ProX takes you through the major parts of rebuilding a 4-stroke top end complete with step-by-step guides for each task along the way! Referring to the “top end” of a four-stroke is generally referring to the piston, cylinder, and head, including all the components the head houses.
How much is a top end rebuild on a 4 stroke?
To do a typical top end is about $200-$250 and not a whole lot more work than a 2 stroke on a 250f. A few extra steps and all the wiring is a pain but not as bad as you think it is. Now if you need a head rebuild, etc that would be more but piston/gaskets & timing chain isn’t bad.
How long does a YZ 125 engine last?
35-40 hours
How much HP does a YZ 125 have?
Yamaha YZ125
| Manufacturer | Yamaha |
|---|---|
| Engine | 124 cc (7.6 cu in) reed valve two-stroke single |
| Power | 34 hp (25 kW) |
| Transmission | 5- or 6-speed sequential manual |
| Suspension | Mono-shock, 13 inches travel |
How fast does a YZ125 2 stroke go?
around 70 miles per hour
How much HP does a 250 4 stroke have?
Powering this Japanese motorcycle is a liquid-cooled, DOHC, four-valve, 250cc four-stroke engine. We ran the YZ250F on our rear-wheel dyno to determine peak output from Yamaha’s 250 four-stroke motocross bike. We documented 38.2 hp at 12,500 rpm and 18.5 pound-feet of torque at 8,500 rpm.