Fuel injector Nozzle

Fuel injector sprayer— is a high-precision final element of the diesel engine fuel system, which is responsible for direct injection of fuel into the combustion chamber. Its main task is to convert the fuel, supplied under enormous pressure, into a finely dispersed mist (aerosol) and evenly distribute it throughout the entire volume of the combustion chamber.

Why is this so important?

Unlike gasoline engines, in diesel engines the fuel ignites spontaneously upon contact with hot, highly compressed air. The quality of this process directly depends on how finely the fuel is atomized and how well it is mixed with the air.

Key engine performance indicators depend on the serviceability of the sprayer:

• Power and torque: Complete combustion of fuel yields maximum energy.
• Fuel consumption: Efficient combustion means less fuel is wasted.
• Environmental friendliness: Proper spraying reduces soot and other harmful emissions.
• Easy start-up and smooth operation: Stable injection ensures smooth engine operation without vibrations.

Technical specifications

The characteristics of injectors vary significantly depending on the generation and type of fuel system.

Types of sprayers:

• Pin (single-hole):

• Construction: Have a needle with a pin that creates a single cone-shaped spray torch.
• Application: This is an old technology used in indirect injection engines (with pre-chambers or swirl chambers). Today it is almost not found in new technology.
• Multi-hole:
• Construction: The sprayer body has several (from 5 to 10 or more) microscopic holes (0.1-0.2 mm in diameter) located at precisely calculated angles.
• Application: This is standard for all modern direct injection diesel engines, including Common Rail systems. They allow for complex injection geometry for perfect fuel-air mixing.

Modern sprayers have the following key parameters:

• Working pressure: While in old systems the pressure was 150-300 bar, in modern Common Rail systems it reaches 1800-2700 bar. This pressure allows the fuel to be broken into extremely small droplets.
• Speed and multiple injection: Modern injectors are capable of delivering up to 10 very short injections per operating cycle. This allows for:
• Pilot injection: to soften the engine operation.
• Main injection: to create power.
• Post-injection: for regeneration of particulate filters.
• Precision: The precision of manufacturing holes and internal elements is measured in microns (thousandths of a millimeter).

Sprayers: main manufacturers

The world leaders in the production of injectors and fuel systems are:

• Bosch (Germany): The largest manufacturer, supplier for most European cars.
• Delphi (USA/UK): Key supplier for Ford, Renault, Korean brands and many trucks.
• Denso (Japan): Leader in the Asian market, main supplier for Toyota, Nissan, as well as for special equipment manufacturers (John Deere, Komatsu).
• Siemens/VDO/Continental (Germany): Supplier for Ford, PSA (Peugeot/Citroën), Volvo.

Where and in what technique is it used?

Sprayers are an essential component of any diesel engine, so their scope of application is huge:

• Cars, SUVs and pickup trucks: Almost all diesel models from manufacturers VW Group, BMW, Mercedes-Benz, Ford, Toyota, Hyundai/Kia, ISUZU and others.
• Light Commercial Vehicle (LCV): Minibuses and vans such as Mercedes-Benz Sprinter, Ford Transit, Renault Master, VW Crafter.
• Trucks: Long-haul tractors (DAF, Volvo, Scania, MAN, Iveco, Renault Trucks), dump trucks, construction equipment on a car chassis.
• Agricultural machinery: Tractors (John Deere, Case IH, New Holland, Fendt), combines, self-propelled sprayers.
• Construction and special equipment: Excavators, bulldozers, front-end loaders, backhoe loaders (Caterpillar, Komatsu, JCB, Volvo CE, Liebherr).
• Industrial engines: Stationary diesel generators that provide backup or constant power supply.

Need help selecting injectors or other fuel injector components? Contact Aspect Plus for professional advice and technical information.

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