Benefits of hydraulic layout over driving system in piezo-injectors and proposal of a new-concept CR injector with an integrated Minirail

The new-generation of solenoid injectors equipped with pressure-balanced pilot valves for energy saving and dynamic response improvement

“…6. In fact, the hydraulic pressure force tends to close the pilot-valve layout in the tested indirect-acting piezoelectric injectors [18]. Such an effect results in a decreasing trend of the K factor with p nom , and this trend counteracts the increase in _ m leak with Dp that would result from Eq.…”

“…13 allows the sensitivity of the injector performance to be analyzed when s is changed to a short ET value, which can be typical of pilot and after injections. As can be inferred, there is a considerable impact on the injected flow-rate peak-value for a change in s. In fact, the injected flow-rate for short ET values is controlled by the needle lift [18], because the restricted flow-area in the nozzle is located at the needle-seat passage. Since the needle lift is influenced by the pilot-valve dynamics (Fig.…”

Comparison of the Emissions, Noise, and Fuel Consumption Comparison of Direct and Indirect Piezoelectric and Solenoid Injectors in a Low-Compression-Ratio Diesel Engine

“…The fuel spray pattern and atomization characteristics of indirect-acting piezo injection systems may be different from those of the solenoid-driven technology, and may be a potential source of improvement for fuel consumption and reduction of exhaust pollutant emissions from the engine [18]. In this regard, not only can the particular driving technology (piezo or solenoid) play an important role, but also the hydraulic layout and the mechanical setup of each injector [19]. If a solenoid-driven injector features an innovative pressure-balanced pilot-valve layout, its static leakage can be reduced significantly, by up to 25% less than similar injectors featuring standard pilot valves [20,21].…”

“…Moreover, a further reduction, of up to 50%, may be obtained if the innovative pressure-balanced pilot-valve is coupled with an integrated Minirail [22]. The hydraulic setups commonly applied to modern indirect-acting piezo injectors may be endowed with 3-way pilot valves [23] and bypass-circuits [19], with both devices affecting the dynamics of the injector control chamber, which is placed at the rear of the needle. The 3-way pilot-valve has the potential to reduce the dynamic leakage of the injector, while the bypass-circuit can improve the dynamic response of the needle during the nozzle closure phase [23].…”

Research on The Drive System of Piezoelectric Injector

“…Compared with the most reliable high-speed electromagnetic injector, Piezoelectric injectors can reduce diesel emissions by 20% of harmful substances in the 16OMPa system pressure and its flexible adjustment can accurately control the quantity of fuel injection, on heavy-duty vehicles can achieve Euro-IV emission standards without the use of post-processing equipment, while improving 5% power, reducing 3Db (A) noise and saving 3% fuel consumption. [1][2][3] …”