What is the relation between compression ratio and the efficiency of the Otto cycle?
Explanation: This is the expression for efficiency of Otto cycle and rk=compression ratio=Vmax/Vmin.
Why is Otto cycle more efficient?
3. 6 Diesel Cycle. Although for a given compression ratio the Otto cycle has higher efficiency, because the Diesel engine can be operated to higher compression ratio, the engine can actually have higher efficiency than an Otto cycle when both are operated at compression ratios that might be achieved in practice.
How does compression increase engine power?
Even with engines having fixed valve timing (non-VVT), the effective compression ratio changes as the engine speed and load change. In short, if it changes the amount of charge in the combustion chamber from cycle to cycle, it changes the expansion ratio, and therefore its power.
How does compression ratio affect engine efficiency?
As the compression ratio increases, the fuel mixture is sufficiently compressed thereby increasing the thermal efficiency, so that less fuel is required to produce the same amount of energy. Fuel consumption is reduced at higher compression ratios between 8 and 9.
What is the best engine compression ratio?
Compression ratios usually range from 8:1 to 10:1. A higher compression ratio — say, from 12:1 to 14:1 — means higher combustion efficiency.
What is the highest compression ratio for 93 octane?
12.8:1
Does higher compression increase horsepower?
The generally accepted gauge for adding compression is that one full point of compression can add between 3 to 4 percent power. So, if an engine is making 50 horsepower and we add a full point of compression (from 11 to 12:1 for example), this could potentially push the power to 51.5 horsepower.
What is the highest compression ratio for 91 octane?
9.3 : 1
Does higher compression make more horsepower?
Since the bigger cam closes the intake later, the piston is higher, and the effective or dynamic compression will drop compared to a shorter cam. So use a higher compression ratio to compensate. (3) With High CR affects the horsepower. An engine that sounds and runs lazy./span>
Do high compression engines run hotter?
The surface of the combustion chamber can be hotter with high compression. Most of the heat absorbed by the head is absorbed in the exhaust port,and that temperature is lower with high compression./span>
What octane is needed for 11 1 compression?
with the right fuel and ignition curves, and the right cam timing, as well as the best exhaust efficiency, 11:1 on the street is doable. by the way i would tune to run 89 octane, that way if 91 goes away, you can still find gas to run./span>
What compression ratio is good for Turbo?
9.5:1
Is high compression good for boost?
Of course, lower compression motors will be able to run more boost, and higher compression motors should run less boost, everything else being equal.
Can you run high compression with Turbo?
Higher compression just makes it slightly harder to make power on low octane, but its probably a fraction of a percent. The biggest issue with high compression is keeping compressor efficiency up. Most turbos are designed to be most efficient at 12-20psi./span>
Why is high compression bad for Turbo?
Higher compression engines are more prone to knock. Since the compression is high the result is that at TDC the air/fuel mixture is heating due to an adiabatic compression process (as the gas is being compress very little energy is transfering to the surroundings requireing that the energy show itself as heat).
Is 15 psi a lot of boost?
Is 15 psi a lot of boost? Well-Known Member. Racey said: 15 psi would double the potential hp of the motor, as atmospheric air pressure is ~15psi, so adding an additional 15psi of boost is actually 30psi of Absolute pressure, twice the air./span>
What happens if engine compression is too high?
If the compression is too high for the fuel used pre ignition will occur, the mixture will ignite from the heat of being compressed before the piston reaches (at least close to) top dead center. Gasoline engines can knock or ping when compression is too high or if octane rating is too low.
Is high compression better for Turbo?
high compression with a turbo will be better and faster. on the other end of the search low compression is better./span>
How can I improve my compression?
The tighter you can get this quench area–or the piston-to-head clearance–the better the engine will run. Moving the piston closer to the deck surface also increases the static compression ratio. There is also a limit to piston-to-head clearance./span>
How do you reduce engine compression?
The second option for lowering the compression is machining the pistons or head(s) and pistons. Just by machining the heads on the VK45DE engine the compression ratio will drop to approx 10 to 1. By machining the heads and the pistons you can achieve a compression ratio of 8.6 to 1./span>
What is the maximum boost pressure for a turbocharger?
The maximum boost pressure (relative) is around 1.5 bar for passenger vehicles, going up to 2.5 – 3.0 bar for high performance engines.
What happens with too much boost?
Increasing boost (within reason) will force more air into the engine, so more fuel can be added to increase the power. So in general, if you add more boost and have an engine tuned to suit will give you more power. Too much boost can cause turbo or engine failure./span>
How much boost can a 2jz handle?
dude with the correct fuel and engine management these motors can withstand up to 36lbs of boost. These motors are basically bullet proof with the correct tune. Some dude from AZ just dynoed his 2jzgte at 36lbs of boost with a ITS 76gts turbo and made at least 750rwhp on supraforums.com./span>
At what RPM does a supercharger kick in?
50,000 RPM
Does a supercharger use more fuel?
Because a supercharger uses the engine’s own power to spin itself, it siphons power—more and more of it as engine revs climb. Supercharged engines tend to be less fuel efficient for this reason./span>
Does a supercharger shorten engine life?
Assuming a properly tuned system, proper oil change and engine maintenance, and similar driving, supercharging generally will not shorten the life of an engine, just as is the case with OEM turbocharging (with proper cooldown for turbochargers. A cooldown period after driving is not necessary with supercharging).
Does a supercharger increase top speed?
Superchargers generally function off the power of the engine, which makes them less efficient, but more powerful at lower RPMs. This means superchargers will increase your boost more noticeably than your top-speed./span>
Is Twin Turbo better than supercharger?
A turbo is more efficient than a supercharger since your engine does not need to work harder to power the turbo. Because a turbo is not connected directly to the engine, it can spin much faster than a supercharger./span>
Should I supercharge or turbocharge?
Which Is Better: Turbo- or Supercharger? Each can be used to increase power, fuel economy, or both, and each has pros and cons. But superchargers can provide their boost almost instantly, whereas turbochargers typically suffer some response lag while the exhaust pressure required to spin the turbine builds./span>
Can you turn a supercharger on and off?
1. The famous scene in the Mad Max film where he switches on the supercharger is commonly said to be unrealistic, but some cars have an electromagnetic supercharger clutch, which means it’s possible fit a switch that would enable you to turn them on and off./span>