Development of a novel miniature high-pressure fuel pump with a low specific speed

Abstract

Whenever a small amount of fluid has to be pumped against a high differential pressure, various types of piston pumps are typically used. However, the need for excellent suction behaviour, for the possibility of a dry run and for minimal manufacturing costs requires the development of alternative pump concepts. This paper presents the development of a novel miniature high-pressure fuel gear pump to replace the feed pump as well as the high-pressure pump in gasoline direct-injection fuel systems. It was found that the clearance between the housing and the rotating gears has to be reduced to a minimum in order to keep the internal leakage at a reasonable level. Based on theoretical predictions a radially and axially pressure-compensated pump concept was developed by incorporation of a floating sealing element able to minimize the tip and face leakages. The design of this sealing element was optimized in the course of experimental investigations. The experiments were carried out using a specifically developed test rig, and the obtained results prove that the optimized pump is able to generate the required differential pressure Dp = 40-50 bar at a specific speed n q = 0.005-0.400 r/min. The measured Dp-Q curves were almost vertical beyond a certain pressure level, yielding a nearly pressure-independent volumetric efficiency of approximately 75%. The developed pump concept finally offers outstanding performance characteristics in an operation range where conventional gear pump concepts usually lose importance owing to unacceptably high volumetric losses.

Experimental and theoretical studies on the pressure fluctuation of an internal gear pump with a high pressure

“…The frequency Z * f n means a period equal to the time required for the revolution of one tooth of the gear shaft, which may result from the inevitable unsteady discharge process of gear pumps. 10 However, regarding a higher rotational speed (e.g. 1450 r/min and 2025 r/min), the main frequency is changed to the rotational frequency ( f n ), implying a period equal to the time required for an entire gear revolution of the gear shaft.…”

“…For instance, Schiffer et al. 10 developed a novel external gear pump and experimentally investigated outlet pressure signals of the pump running at a differential pressure of approximately 4 MPa. Casoli et al.…”

“…Main studies on pressure pulsation behaviors are as follows. For instance, Schiffer et al 10 developed a novel external gear pump and experimentally investigated outlet pressure signals of the pump running at a differential pressure of approximately 4 MPa. Casoli et al 11 predicted the delivery flow ripple and pressure pulsation inside a tooth space volume of an external gear pump with a maximum working pressure of 20 MPa through the software AMESim and experiments.…”

An experimental study for effect factors of the roller tappet induced impact noise in high-pressure fuel system of GDi engine

“…In the past decade, taking advantages of emission reduction, fuel economy and engine performance improvement, gasoline direct injection (GDi) technology has developed quickly. 1,2 This promotes the wide application of direct injection (DI) engine in various types of automotive. [3][4][5] Compared with port fuel injection system, the DI engine improves atomization and mixture process by injecting fuel directly into combustion chamber with higher fuel pressure.…”

The study of leakage of circular arc–involute–circular arc gear pump

“…2 Leakage increases as the outlet pressure increases. Within the literature, 1,[3][4][5][6] the leakage of gear pumps with involute tooth profiles has been investigated. As a result of the very small clearance between the tip of each tooth and the chamber, the model of radial leakage of involute gear pump is assumed to occur in planes that are parallel to the tip surface.…”