A New Method for Measuring Fuel Flow in an Individual Injection in Real Time

Abstract

Knowledge of fuel mass injected in an individual cycle is important for engine performance and modeling. At the moment, such measurements are not possible on-engine or in real-time. In this paper, a new method using Coriolis flow meters (CFMs) and a new, patented, signal processing technique, known as the Prism, is introduced. CFMs are extensively used for flow measurement both in the automotive industry and further afield, and when coupled with the Prism have the potential to make these challenging high-speed measurements. A rig-based feasibility study was conducted injecting very small quantities of diesel (3 mg) at pressures of up to 1000 bar at simulated engine speeds of up to 4000 rpm. The results show that these small quantities can in principle be measured. The results also reveal a previously unknown behaviour of CFMs when measuring very low flow rates at high speed. The study concludes that by combining high-resonant frequency flow tubes with the Prism technology in a new instrument-the Fast Next Generation Coriolis (Fast-NGC) flow meter-it will be possible to measure individual injector flow rates on-engine in real-time.

Fast NGC: A New On-Line Technique for Fuel Flow Measurement

“…A static GDI injector test rig has been used for all of the results reported in this work; the rig has been previously described in [9,15]. It uses a Bosch HDEV-5-1LE type multi-hole injector, of the same type fitted in production engines [16].…”

“…The transmitter initiates and maintains the oscillation of the flow tube, continuously monitoring via two (typically velocity) sensors, which are further used to determine phase difference. A more detailed discussion on the mechanics is included in [9]. While a variety of signal processing techniques have been used to track the essentially sinusoidal sensor signals in conventional Coriolis meters, a new technique, well suited to high noise rejection and fast measurement updates, is used here, based on Prism signal processing [10].…”

“…So far the Prism signal processing coupled with Coriolis meters (together known as Fast Next Generation Coriolis -Fast NGC) has been successfully deployed on a diesel injection test rig tracking individual injections at pressures of up to 1000 bar and simulated engine speeds up to 4000 rpm [9,10,12]. These results showed a previously unseen phenomenon in which the measured phase difference (and hence mass flow rate) exhibited a dependence on the instantaneous flow tube phase, where the injection duration was shorter than the flow tube oscillation period.…”

Electric Current Waveform of the Injector as a Source of Diagnostic Information

“…The model built in this way based on a real object was verified in the ANSYS Maxwell and Simplorer environment. In [ 2 ], apart from determining the influence of control parameters on the resulting magnetic force, the flow of magnetic flux through the injector core was modeled. In [ 3 , 4 ], the simulation results were described, thanks to which the influence of the size and position of individual ferromagnetic elements on the shape of the magnetic flux, including the air gap and input voltage, was determined.…”

Low cost, low pass Prism filtering

“…Prism Signal Processing (PSP) [1] is a new FIR technique particularly suited to metrological tasks in the context of the Internet of Things (IoT) [2]. Measurement applications include pressure sensor validation [3], fast flow measurement [4,5] and condition monitoring of rotating machinery [6,7].…”