1. an ideal thermodynamic combustion cycle, as follows: a compression at constant entropy; a constant-volume heat transfer to the system; an expansion at constant entropy; and a constant-volume heat transfer from the system. The thermal efficiency of the ideal Otto cycle increases with an increasing compression ratio .
How can we increase the efficiency of an engine?
- Run the engine fuel-lean, that is, use excess air. It is well known that fuel-lean running improves the efficiency. ...
- Higher compression ratio. ...
- We need new cycles put into practical use. ...
- Run the engine at optimum conditions, meaning low friction (modest engine speed) and low pumping work (air throttle more open).
Why is Otto cycle more efficient?
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 can we increase the efficiency of a diesel engine?
- Use Diesel Fuel Additives. ...
- Consider Diesel Tuners. ...
- Install Performance Air Filters & Cold Air Intakes. ...
- Upgrade the Exhaust System. ...
- Use DPF, DEF, and EGR Delete Kits. ...
- Upgrade your Diesel Fuel Injectors. ...
- Install a Turbocharger. ...
- Schedule Regular Diesel Engine Tune Ups.
What is the efficiency of the Otto cycle *?
Efficiency of otto cycle = 1 – frac{1}{6^{1.4-1}} =0.511= 51.1% .
What we can make to increase the efficiency and the power for the engine Why *?
Changing an exhaust system can improve the efficiency of air leaving the system. The better the air leaves the better it can enter. This can increase engine performance in a way similar to how adding a cold air intake does. The principle is simple: Increasing oxygen levels allows a better burn.
What affects engine efficiency?
These include the chemical energy loss in emissions, heat losses from the engine and through the exhaust gas , and gas pumping and friction losses in the engine. Accordingly, the overall brake thermal efficiency of the engine is a product of the combustion, thermodynamic, gas exchange, and mechanical efficiency.
Why efficiency of Otto cycle is more than Diesel cycle?
The simple answer is ,In the otto the energy available is fully used to raise the pressure in the cylinder. Higher the pressure implies larger work done. But in diesel cycle, Part of the energy is added only during the expansion, So it does not contribute to the work . Hence Otto cycle is more efficient.
What are the methods to increase the efficiency of Rankine cycle and explain any one?
5: The effect of increasing the boiler pressure on the ideal Rankine cycle. Increasing the operating pressure of the boiler leads to an increase in the temperature at which heat is transferred to the steam and thus raises the efficiency of the cycle.
Why the higher efficiency of the Otto cycle compared to the Diesel cycle?
A diesel cycle can operate with a higher compression ratio than an Otto cycle as there is no risk of auto-ignition of the fuel and only air is compressed. But, for a given compression ratio, the Otto cycle has higher efficiency than the diesel engine.
How do you increase low end diesel torque?
- Upgrade the Air Intake. One sure way to increase the performance of a diesel vehicle is to improve the airflow to the engine. ...
- Change or Reprogram the ECM. ...
- Using New Fuel Injectors. ...
- Turbochargers. ...
- Performance Exhaust.
How do you increase tractor torque?
- Clean House to Increase Horsepower. ...
- Perform a Tune-Up on the Engine. ...
- Install a Turbo Kit or Supercharger. ...
- Install a Cold-Air Intake. ...
- Install an Aftermarket Exhaust System. ...
- Buy an Engine Tuner. ...
- Conclusion.
What is the efficiency of diesel cycle?
A typical diesel automotive engine operates at around 30% to 35% of thermal efficiency . About 65-70% is rejected as waste heat without being converted into useful work, i.e., work delivered to wheels. In general, engines using the Diesel cycle are usually more efficient than engines using the Otto cycle.
How is thermal efficiency of Otto cycle calculated?
In this equation, the ratio V 1 /V 2 is known as the compression ratio, CR. 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 = c p /c v .
Which cycle has highest efficiency?
Any engine that uses the Carnot cycle enjoys the maximum theoretical efficiency. While Carnot engines are ideal engines, in reality, no engine achieves Carnot’s theoretical maximum efficiency, since dissipative processes, such as friction, play a role.
What is efficiency of Carnot cycle?
The efficiency of carnot’s engine is 50% .
How do you increase thermal efficiency?
Lower compression ratios need higher degrees of constant volume to improve the thermal efficiency by cooling loss reductions . Therefore, a method that reduces cooling loss without lowering the degree of constant volume will be effective to improve the thermal efficiency of internal combustion engines.
What is the primary reason why an Otto cycle is less efficient than a Carnot cycle?
The cylinders are not perfectly insulated from the engine block, so heat energy is lost from each cylinder by conduction . This makes the engine less efficient that a Carnot engine, because heat is being discharged at a temperature that is not as cool as the environment.
What is added to petrol to increase the efficiency of engine?
Petrol additives increase petrol’s octane rating or act as corrosion inhibitors or lubricants, thus allowing the use of higher compression ratios for greater efficiency and power. Types of additives include metal deactivators, corrosion inhibitors, oxygenates and antioxidants .
How do you increase low end torque?
- Change the flowing exhausts and intake systems. Replace these components with a new one if you find any damage. ...
- Install some high-quality spark plugs. ...
- Replace the ignition lead with a better one. ...
- Retune the air/fuel ratio (AFR) and the ignition timing maps.
What is ideal cycle efficiency?
Modern engines have compression ratios in the range 8 to 11, resulting in ideal cycle efficiencies of 56% to 61% .
What is engine efficiency?
The efficiency of an engine is defined as ratio of the useful work done to the heat provided . ... This means the friction and other losses are subtracted from the work done by thermodynamic expansion. Thus an engine not delivering any work to the outside environment has zero efficiency.
Which has higher efficiency Otto or Diesel or dual?
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.
Why is Otto cycle more efficient than Diesel cycle for the same compression ratio and heat input in Otto cycle?
Otto cycle efficiency is higher than Diesel cycle efficiency for the same compression ratio and heat input because, in Otto cycle. Combustion is at constant volume . Expansion and compression are isentropic.
Why does Diesel have higher efficiency?
Because diesel fuel contains more energy per gallon , diesel engines travel farther per gallon. That is to say, because diesel contains more energy than gasoline, diesel engines are more fuel efficient than gasoline engines.
Which of the following is the way to improve the efficiency of the Rankine cycle?
The thermal efficiency of the Rankine cycle can also be increased by: Increasing the average temperature of the working fluid at which heat is added to the cycle . Decreasing the average temperature of the working fluid at which heat is rejected by the cycle.
Which gas will produce the highest efficiency in an ideal Otto cycle for same compression ratio?
So out of given options Helium is monoatomic, so efficiency will be highest for Helium for a given compression ratio.
Which cycle has the highest efficiency for the same compression ratio and heat addition?
The cycle which has the least heat rejected will have the highest efficiency. Thus, the Otto cycle is the most efficient and the Diesel cycle is the least efficient of the three cycles.
When cut off ratio is the efficiency of Diesel cycle approaches the efficiency of Otto cycle?
Consequently, for any given compression ratio, except in the limit when the cutoff ratio is zero (i.e., no heat addition to the Diesel cycle), the Otto cycle is theoretically more efficient than the Diesel cycle. The cutoff ratio severely reduces the thermal efficiency of the Diesel cycle as its value increases (Fig.
What are the methods which can lead to increase in thermal efficiency of Rankine cycle?
Increasing the operating pressure of the boiler, automatically raises the temperature at which boiling takes place . This raises the average temperature at which heat is added to the steam and thus raises the thermal efficiency of the cycle..
How can the efficiency of Rankine cycle be improved Mcq?
The thermal efficiency of the Rankine cycle can be increased by the use of a regenerative heat exchanger . ... In this way, the amount of heat added at the low temperatures is reduced and the mean effective temperature of heat addition is increased, thus cycle efficiency is increased.
What is difference between Otto and Diesel cycle?
The Otto cycle has less compression ratio (7:1 to 10:1) but in diesel cycle the compression ratio is high (11:1 to 22:1). In Otto cycle as well as in diesel cycle heat rejection takes place at constant volume. The efficiency of Otto cycle is less as compared with the Diesel cycle.
How efficient is a petrol engine?
Sadly, even with regular car maintenance such as a tune-up or an oil change, today’s gasoline engines are only around 30 to 35 percent efficient , which means roughly 65 cents out of every dollar you spend on gas goes to waste.
What is constant in Otto cycle?
| Otto Cycle Constant volume heat rejection. Constant volume heat addition. | Diesel Cycle Constant pressure heat addition. Constant volume heat rejection. | Dual Cycle Constant volume and constant pressure heat addition Constant volume heat rejection |
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What are two ways to increase torque?
Torque can be increased in two ways: 1) by increasing the moment arm or 2) increasing the perpendicular force applied to the moment arm. The opposite is true for decreasing torque. If an object is at rest the torques on the object are balanced (they cancel out) and sum of those torques is zero.
How do you get more horsepower than torque?
There are several different ways to increase torque and horsepower: Install a cold-air intake : A cold-air intake improves turbulence to the combustion chamber, allowing fuel and air to mix more uniformly and detonate much more evenly; this improves compression and leaves less fuel waste.
Can you increase torque without increasing horsepower?
You cannot have horsepower without torque , but you can have torque without horsepower! ... The most simple means of increasing torque is to run an open exhaust and intake and tune properly. Torque value will increase right along with HP, so long as the tuning is performed properly.
How can I increase my bike torque?
Really the only way is to increase the displacement of the engine , ie increase its cc size by an oversize piston and rebore, or a longer stroke by a different crankshaft, connecting rod and piston. This allows more fuel to be ignited per power stroke, regardless of engine rpm, so increases torque.
How can I increase the torque of my truck?
- LARGER-DIAMETER THROTTLE BODY. ...
- EXHAUST HEADERS & MANIFOLDS. ...
- HIGH-FLOW CATALYTIC CONVERTER. ...
- HIGH-FLOW CAT-BACK EXHAUST SYSTEM. ...
- PERFORMANCE CHIPS & PROGRAMMERS. ...
- FORCED INDUCTION (SUPERCHARGERS & TURBOCHARGERS)
How can I improve the performance of my engine?
- Use Synthetic Lubricants and Additives. ...
- Check Your Ignition. ...
- Install Larger Throttle Body and Injectors. ...
- Ensure Good Compression. ...
- Implement a Cold Air Intake (CAI) ...
- Replace Your Exhaust Manifold With Real Headers. ...
- Use Forced Induction (aka Power Adder) ...
- Maintain Your Vehicle.
Why is Otto cycle more efficient?
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.
What is the efficiency of the Otto cycle *?
Efficiency of otto cycle = 1 – frac{1}{6^{1.4-1}} =0.511= 51.1% .
How do you calculate cycle efficiency?
The cycle efficiency formula is calculated by dividing the value added time by the total cycle time . The value added time is the actual amount of time spent working on the unit. The cycle time is the total time it takes to produce the unit.
