Role of injector in modern diesel engine and impact of its efficiency on correct motor operation and exhaust after-treatment system

A vast majority of the currently manufactured diesel engines used to power various types of vehicles is fitted with Common Rail injection systems. This drive system type, being developed over the last twenty years, enables advanced control of the process of mixture combustion in diesel engine combustion chamber.

 

A very significant design modification of such type of injection system compared to older generation designs is that it is possible to maintain a constant, high pressure throughout the whole fuel injection period, considerably above 1,000 bar and often even 2,500 bar. Increasing of fuel injection pressure has allowed to considerably shorten the time needed to deliver the required amount of fuel to the combustion chamber which has had an effect on limiting the injection time in its individual phases.

The applied technical modifications have allowed to considerably reduce the noise and vibration of a diesel engine with direct fuel injection. This has greatly improved efficiency of the mixture combustion process which had an impact on torque and power increase while reducing the fuel consumption. These changes have allowed for common use of this type of engines in small passenger and commercial vehicles. With such advanced combustion process control obtained in a cylinder it has become possible also to install exhaust after-treatment systems – catalyst converters and diesel particulate filters – in compression ignition engines. This made it possible to significantly reduce the emission of toxic substances.

A key issue to maintain a reliable engine operation throughout the whole useful life is to keep stable fuel supply system operation parameters for as long as possible. Diesel engine injection system is one of elements of a vehicle that are the most sensitive and vulnerable to damage. Most commonly subject to damage are injector precision pairs, i.e. dosage valves and nozzles responsible for supply of properly sprayed fuel dose into corresponding point in the combustion chamber. These parts are exposed to destructive impact of unfavourable factors occurring in the combustion chamber which may cause deterioration of operational and environmental parameters of combustion engine.

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During diesel engine operation, electronic controller checks crankshaft speed by measuring its angular acceleration during power stroke of each cylinder and tends to make these values equalled. This parameter is adjusted by changing injector opening time. In result the amount of fuel delivered to the combustion chamber is either increased or decreased. Correct dosing of fuel by the injector is directly related to its technical condition and the nozzle wear in particular. Any damages of injectors may greatly affect efficiency of the engine and its peripheral systems. Each nozzle, being the most important element of any injector, has an appropriate number of spraying apertures of a dedicated shape and application required for a correct shaping of the fuel stream in the combustion chamber.

Disturbance of the flow changes the amount of the injected fuel which directly results in an increase in exhaust emissions. Due to unfavourable physical and chemical conditions in the combustion chamber and forces occurring as a result of an intensive cooperation between precision pair components, the nozzle is subject to wear and change of its basic parameters responsible for tightness, correct fuel supply direction and dosage. The sprayed fuel should be supplied directly to the combustion chamber located in the piston. If the fuel is supplied into inadequate points in the combustion chamber or is improperly sprayed, thermal damage to the piston or valves may occur. Frequently the nozzle itself is damaged due to a high combustion temperature. Such defects may cause serious failure of the engine as a result of which the major repair or a costly repair of exhaust after-treatment system must be done.

Condition of the injection system in a modern combustion engine, and in particular condition of nozzles, must be verified on a regular basis for operation correctness. Thus it is possible to protect the engine and its fixtures against serious failures requiring considerable financial expenses to recover its full functional efficiency. Bearing in mind how important the nozzle is for correct operation of the injector, the quality of the components used in the recovery process is essential for the efficiency of recovering its factory parameters during any repair. Therefore, proper selection of spare parts supplier is a key thing.

WUZETEM is one of the leading manufacturers of injectors on the global market. This is a Polish company with a nearly 70-year tradition which supplies about 500,000 pieces of spare parts annually to customers in the automotive industry whose business is professional recovery of injection systems to diesel engines. The WUZETEM injectors are a high class alternative to products supplied by the first equipment manufacturers. Fuel equipment tests are carried out in a modern-equipped laboratory where all nozzle functions responsible for correct formation of the mixture in diesel engine, are assessed.

In the production of the offered spare parts the factory uses steel supplied by recognised, approved European manufacturers. In the production processes the most advanced mechanical, thermal, thermal and chemical treatment technologies are used, comparable to the processes applied by manufacturers of the first equipment parts. The company uses advanced measuring techniques which allow for assessment of a product with an accuracy below one micrometer to ensure the highest quality of the offered precision pairs. Between 2002-2010 the company collaborated with Delphi Diesel System, supplying parts to injection systems as the first equipment to Fiat & Peugeot cars. Apart from that the company manufactures injectors for older design engine injectors.

All nozzles manufactured by WUZETEM ensure a reliable, long-lasting and stable operation of injection system, while protecting the engine and its accessories against serious failure.