Function thanks to their high switching speeds, the piezo injectors attain very small pilot injection volumes. Us6085990a piezoelectric injector for fuelinjection. A piezoelectric diesel injector delivers atomized fuel directly to the engine combustion chamber when signaled to do so by the engine control module ecm. Instead of forcing open the fuel injector nozzle, the wafer stack is used to control fuel flow inside the injector. Even so, the total expansion of many wafers stacked together is only a few thousandths of an inch. The injection process is initiated by the control unit via the electrical connection. The commonrail system with piezo injectors by bosch enables the flexible injection of fuel at pressures up to 2,700 bar. Ensuring quality and reliability bosch technology is designed to have a service life of around 240,000 kilometers. High precision from the rail to the combustion chamber. The piezo valve controls the release of this high pressure fuel through the injector nozzle into the combustion chamber. Thirdgeneration common rail diesels now feature piezoelectric injectors for increased precision, with fuel. The fuel injection finishes later for the ias injector in fig. Parts for piezo injectors, for diesel engine injection fuel pump nozzles, oem replacement parts catalog list and repair kit, common rail diesel, siemens, injection pdf and shim. Atomization fuel distribution fuel air mixing typical diesel fuel injector injection pressure.
Accordingly, the piezo injector is capable of delivering higher average fuel mass flow than a solenoid injector. With their ability to expand rapidly when in contact with an electrical charge, piezoelectric crystals serve as efficient actuators in diesel fuel injectors. Bosch launched the first common rail system in 1997. Often limits of knowledge, technology or manufacturing capability governed the chain of improvements. A piezoelectric injector for fuelinjection systems of internal combustion engines has a piezoactuator guided with spring pretensioning in a valve housing. Piezoelectric injectors for reman fuel injectors auto. This paper presents the analysis of costs reduction of common rail fuel injectors repairs. The system is named after the shared highpressure reservoir common rail that supplies all the cylinders with fuel. The coupling of actuator and nozzle needle permits extremely short response times.
Besides, these modernday fuel injectors work on piezo. Therefore the piezo injector is less sensitive against particle contaminated fuel. This selfstudy programme provides information on the way in which the piezo controlled common rail fuel injection system fitted in the 3. This improves combustion chamber cooling and enables higher engine. Piezoelectric injectors 0 432 193 835 for reman fuel injectors. Pdf reduction of the common rail fuel injectors repair costs. On a piezo injectors the functions of opening and closing are actuated only through the polarity inversion disconnecting an injector on a running engine, the injector may remain open, causing big damages to the engine. Some advanced common rail fuel systems perform as many as five injections per stroke. Piezo electricity results from squeezing or applying pressure from. The injector is permanently supplied with fuel from the rail via the highpressure connection. An piezoelectric actuated injector is provided which includes a nozzle valve element, a control volume, and an injection control valve including a control valve member for controlling fuel flow from the control volume so as to control nozzle valve movement. In collaboration with siemens vdo automotive ag, have developed a unit injector with the same or even greater advantages. Importantly, the injector includes a preload chamber positioned along an injection control valve member for receiving high pressure fuel.
Common rail direct fuel injection is a direct fuel injection system for diesel engines it features a highpressure over 2,000 bar or 200 mpa or 29,000 psi fuel rail feeding solenoid valves, as opposed to a lowpressure fuel pump feeding unit injectors or pump nozzles. During the history of diesel fuel injection, the capabilities and the number of degrees of freedom to optimize diesel combustion have continually improved. The most advanced type of injector is, undoubtedly, the piezoelectric injector. These injectors are used in both petrol and diesel engines to improve their persformance and efficiency. In the proposed design, a piezoelectric stack actuator is used to directly control the injection of fuel in order to enhance the injection characteristics by utilizing the fast response time of the actuator. With their ability to expand rapidly when in contact with an electrical charge, piezoelectric crystals serve as efficient actuators in diesel fuel. Delphi multec 20 gdi fuel injector delphi power train.
In this respect, the aim of the fuel injection system is to atomize the. The delphi multec 20 gdi fuel injector s operating principle is based on an outwardly opening valve group that generates a conical spray pattern. See option descriptions in the tabs testing, ultrasonic cleaning and servicing for gasoline piezo direct injection fuel injectors using state of. Introduction to fuel injection systems and components.
Lm1949 injector drive controller datasheet texas instruments. When rudolph diesel contracted with augsburg and krupp of germany in 1893 to deve lop a more efficient internal combustion engine. In practical treatment, formulas 1 to 4 are applied for calculation. Us7140353b1 fuel injector with piezoelectric actuator. Utilizing these noted characteristics of piezoelectric crystals, piezo crystals thus found its use as a critical component in the piezoelectric injector. Fuel injectors are parts of modern car engines that deliver fuel to the engines combustion chamber, directly or indirectly. Vag ssp 351 the common rail fuel injection system fitted in the 3. Design and development of a directacting piezoelectric. These small electromechanical devices are typically positioned at a certain angle to make sure the fuel is sprayed towards the engines inlet valve or directly into the cylinder. With conventional diesel injection systems, the fuel pressure has to be generated individually for each injection.
Diesel engines equipped with piezoelectric and solenoid. Direct fuel injectors have rapidly replaced carburetors and. The bosch piezoelectric crystal injector operates using a crystal stack, usually quartz, that changes size when. The actuator presses a sealing piece onto its valve seat through an actuating part, with the actuating part consisting of a pressure pin passing through the piezoactuator and having a head part resting on piezoactuator. Gasoline direct injection key technology for greater efficiency and. Price is for 1x fuel injector minimum 2x required please select option 1 or 2 from the drop down menu.
Selfheat generation in piezoelectric stack actuators used. Gasoline direct injection key technology for greater. Piezo injectors use piezoelectric technology to open and close fuel injectors at extremely high speeds and precision to inject fuel into an internal combustion engine. Parts for piezo injectors diesel spare parts eurodiesel. Advanced diesel common rail injection system for future. Common rail diesel fuel injection is now the state of the art in engine injection. The main difference between carburetor and fuel injection system carburetorzfuel is atomized by processes relying on the air speed greater than fuel speed at the fuel nozzle, zthe amount of fuel drawn into the engine depends upon the air velocity in the venturi fuel injection systemzthe fuel speed at the point of delivery is greater than the air speed to atomize the fuel. The digital rate shaping strategy drs contributes to a very small delay between pre injection and main injection. Piezo wafers expand when voltage is applied to them. The ni 9751 cannot control piezo and solenoid actuator types simultaneously. Piezoelectric bosch fuel injectors piezoelectric bosch fuel injectors are signed with numbers 0445115xxx, 0445116xxx or 0445117xxx. It provides outstanding spray and fuel injection performance at a lower cost than piezo injector technology and can be operated at up to 200 bar fuel pressure. Commonrail injection systems crs327 diesel commonrail. The piezoelectric element represents the latest generation of injector actuators and ensures higher performance, in particular faster response, than the solenoid actuator because there is no need to generate a collapsing magnetic field.
The piezo actuator is therefore formed by 350 quarz sheets, each one 80. Pumped fuel enters the injector via the fuel feed collar and excess can return to the tank via the fuel return collar. They not only provide increased precision for the latest generation of crdi engines but also create fuel pressures up to 3,000 bar or 44,000 psi. Commonrail injection systems use a rail to store the fuel at pressures in excess of 2,000 bar. How bosch piezoelectric diesel injector works youtube. Principle of operation of the common rail piezo injector. The commonrail injection diesel systems build upon direct injection technology which allows fuel to be injected directly into the combustion chamber. Direct fuel injector power drive system optimization dtic. Piezoelectric control valve for fuel injector of internal. Piezo injectors have a few key benefits that justify all of this bother. The injection rate and injection quantity percycle can be calculated according to pressure wave theory. The injected fuel quantity is proportional to the injector duration opening time, fuel rail pressure, fuel temperature and fluid viscosity. Vag ssp 351 the common rail fuel injection system fitted. These injectors work by passing electrical current through a stack of piezo crystals, causing them to expand.
Although the experimental study of the static and dynamic behavior of piezoelectric stack actuators has received some attention i. The camshaft follower presses the plunger at the top to pressurize the fuel in the injector. What are piezo diesel injectors and how do they work. The fuel is injected directly into the combustion chamber using highpressure injectors.
1451 331 1101 71 1297 899 1315 893 171 1116 1087 1406 26 977 1651 959 763 933 387 743 1299 1429 1299 1303 785 1464 994 487 1188 503 1423 915 930 434 383 998 99 823 347 296 1342 1065 246