ENGINE PERFORMANCE UNDER HIGH LOAD OPERATION. By Figure 5: The impact of water injection on the "Effective" ON of a fuel. Figure taken. The change in in-cylinder pressure after water injection. When water is injected into the intake airflow towards the end of the compression stroke, it becomes heated due to the high temperature of the compressed air in the cylinder. In internal combustion engines, water injection, also known as anti-detonant injection (ADI), can spray water into the incoming air or fuel-air mixture, or directly into the cylinder to cool certain parts of the induction system where "hot points" could produce premature ignition.‎Theory · ‎Effects · ‎Use in aircraft · ‎Use in automobiles.


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P Vijayabalan professor, department of mechanical engineering for his support to be the project work in right track and also for his valuable suggestions, motivation and guidance to carry out the experiment. References Farrugia M, Busuttil G.

Water injection (engine) - Wikipedia

End-Zone Water injection as a means of suppressing knock in a spark-ignition engine. Further improvements to the water injection in a S. I engine setup, Bachelor of engineering Hons. However, the water vapor displaces some air, water injection in engines some of the denser intake charge benefit.

Knocking is generally more of a problem in forced induction engines rather than naturally aspirated, so this can help prevent it. On electronic ignition systems the ignition timing is generally retarded to prevent knock from occurring but with water injection it can be advanced closer to maximum brake torque MBT timing for additional power.

The water provides the primary cooling effect due to its great density and high heat absorption properties. The alcohol is combustible, and also serves as an antifreeze for the water. The main purpose of the oil is to prevent corrosion of water injection and fuel system components; [2] it may also assist in engine water injection in engines when running in a high power state.

In high performance automotive applications some tuners[ who? Safety concerns and part longevity concerns keep this as a controversial option. Effects[ edit ] In a piston engine, the initial injection of water cools the fuel-air water injection in engines significantly, which increases its density and hence the amount of mixture that enters the cylinder.

How does jet engine water injection work? - Aviation Stack Exchange

The water if in small liquid droplets may absorb heat and lower the water injection in engines as the charge is compressed, thus reducing compression work. This also converts part of combustion energy from the form of heat to the form of pressure.

As the water droplets vaporize by absorbing heat, they turn to high pressure steam. The alcohol in the mixture burns, but is also much more resistant to detonation than gasoline.

The net result is a higher octane charge that supports very high compression ratios or significant forced induction pressures before onset of detonation. Certain other engines can benefit far more from the use of water injection.

Improvement of Fuel Efficiency in a Petrol Engine by using Water Injection

Typical pulse jet engines have extremely poor fuel efficiency, specific fuel consumption, and thrust. The water injection in engines explanation is that the injected water evaporates during the compression stages, and this cools the air think sweat evaporating cooling your skin on a hot day.

Short answer Water injection gives the jet engine the ability to do more work for a short time without exceeding the design limitations of the engine in extreme conditions.

The "design thrust" is usually the static water injection in engines the engine is capable of given standard conditions i.

Improvement of Fuel Efficiency in a Petrol Engine by using Water Injection

Water injection is a method to mitigate this scenario. Used wrongly and it can result in power losses due to a lack of efficiency where the water is filling potential fuel space within the cylinder. The rise of water injection in engines intercooler in the latter decades of the 20th Century nearly consigned water injection to the history books due to its sheer complexity and unless cars are specifically manufactured from stock with water injection, it is water injection in engines difficult to try and tune a car to suddenly using it.


In water injection in engines of the crack down on emissions however, expect to see water injection making a comeback due to its effect on exhaust gas reduction. A mist size of around 50 microns is acceptable with the droplets reducing in size as atomisation occurs.


The engine heat and intake compression heat will finish off the atomisation process. How does one control the quantity of the water injected into the engine? The amount of water should vary according water injection in engines engine load and rpm.

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  • Water injection (engine)

As an example lets look at manifold pressures. Manifold pressures can reach 11psi at rpm and also hit the same 11psi at rpm.


It really does pay to get a good quality water injection controller which takes the RPM and fueling figures into the equation.