48251834 Direct Injection

8/6/2019 48251834 Direct Injection

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What is Gasoline Direct Injection (GDI)?

Major Objectives of the GDI Engine

Transition of fuel supply

When Did Gasoline Direct Injection Engines First Appear?

Why Not Carburetor? Why The GDI ??

Gasoline Direct Injection

How Does Gasoline Direct Injection Work?

Basic Technical Features of GDI Engine

Combustion modes of GDI Engine

Comparison of Fuel consumption of MPI & GDI Engines What are the Benefits of Gasoline Direct Injection?

What are the Disadvantages in Gasoline Direct Injection Engines?

Conclusion

References


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In internal combustionengines, gasoline directgasoline directinjectioninjection is a variant offuel injection employed in

modern two- and four-stroke petrol engines. Thepetrol/gasoline is highlypressurised, and injectedvia a common rail fuel linedirectly into thecombustion chamber ofeach cylinder, as opposedto conventional multi-point fuel injection thathappens in the intake tract,or cylinder port.


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Superior power to conventional MPI engines

Ultra-low fuel consumption that betters that of

even diesel engines


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Carburetor Port Injection

(MPFI)

Direct Injection

(GDI)


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1955 Mercedes Benz 300SLwas the first car to useGasoline direct injection(GDI)technology.

GDI engine tech wasreintroduced by Mitsubishiin 1996 in there Galant.

Now the majority of car

companies such as Nissan,Ford, Mazda, Toyota, Audi,BMW, Volkswagen, GM andFerrari all have at least onevehicle with Direct FuelInjected engines


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Perfect air/fuel mixture cannot be obtained

Low volumetric efficiency

Icing problem in aircraft engines

Vapour Lock

Mechanical device

Compromises on emission


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Lower Fuel Consumption and More Output

Better than the current MPI Style of Fuel Injection

Ultra-precise computer management

The location of the injector

Less pollution from each drop of gasoline.

The World needs a better Environment


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The engine allows air toenter the cylinder whenthe piston moves down(intake stroke).

As the piston moves up(compression stroke) thefuel is injected into thecylinder and then sparkedby the spark plug.

After this the piston movesdown (expansion stroke)and returns back up toforce the exhaust out.


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The Upright Straight Intake Port.

The Curved-top Piston.

The High Pressure Fuel Pump.

The High Pressure Swirl Injector.


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The GDI engine has upright straight intake ports rather thanhorizontal intake ports used in conventional engines. The uprightstraight intake ports efficiently direct the airflow down at thecurved-top piston, which redirects the airflow into a strong

reverse tumble for optimal fuel injection


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Newly developed high-pressure swirl injectors provide the idealspray pattern to match each engine operational modes. And at thesame time by applying highly swirling motion to the entire fuelspray, they enable sufficient fuel atomization that is mandatory

for the GDI even with a relatively low fuel pressure of50kg/cm2


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The curved-top piston controls the shape of the air-fuel mixture aswell as the airflow inside the combustion chamber, and has animportant role in maintaining a compact air fuel mixture. Themixture, which is injected late in the compression stroke, is carried

toward the spark plug before it can disperse.


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Ultra lean combustion Mode

Superior Output mode


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1. Fuel Consumption during Idling

The GDI engine maintains stable combustion even at low idlespeeds. Moreover, it offers greater flexibility in setting the idlespeed. Compared to conventional engines, its fuel consumption

during idling is 40% less.


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2. Fuel Consumption during Cruising Drive

At 40km/h, for example, the GDI engine uses 35% less fuel than acomparably sized conventional engine.


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With direct injection the amount of fuel being put intoan engine is controlled precisely by the ecu. This canenable the engine to have better fuel efficiency.

Also with the fuel being sprayed into the cylinders it is

also able to be broken up into smaller particles whichallows for a more complete combustion. All the fuelgets burned this way.


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1. Engine performanceCompared to conventional MPI engines of a comparable size, the

GDI engine provides approximately 10% greater output andtorque at all speeds.


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2. Vehicle Acceleration

In high-output mode, the GDI engine provides outstanding

acceleration.The following chart compares the performance of the GDI engine

with a conventional MPI engine.


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3. Emission ControlIn the case of GDI engine, 97% NOx reduction is achieved by

utilizing high-rate EGR (Exhaust Gas Ratio) such as 30% that isallowed by the stable combustion unique to the GDI as well as ause of a newly developed lean-NOx catalyst.


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The main disadvantage is that the direct injection

engines are more complex and costly to build. The fuel pump needs to be made to handle the high

pressure that is needed to spray the fuel into thecylinders.

The fuel injectors need to be durable enough to endurehigh amounts of heat constantly.


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In the era of high petrol consumption andheavy air pollution the adaptation of gasolinedirect injection can play a vital role which gives

a total answer to the scenario. The initial cost ofthe engine can be affordable to the commonman when the engine is used or produced ingreater number .Another is the compressionratio and also the fuel efficiency which is more

than that of ordinary diesel engines. Also is theless amount of pollution which is due to thefewer amounts of unburned fuels due to theinjection inside the manifold.


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ENERGY & ENVIRONMENTAL ANALYSIS, INC.Cost & Benefits of the Gasoline Direct InjectionEngine, Arlington, VA 22209.

DANIEL

AS

IANO, Fuel Injection DOMKUNDWAR, A course in IC engines.

www.mitsubishi-motors.co.jp

www.auto.howstuffswork.com

www.delphi.com


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48251834 Direct Injection

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