Investigation of fuel injection rate identification algorithm based on rail pressure fluctuation characteristics induced by injection

2021 ◽  
pp. 095440702110393
Author(s):  
Xuejian Ma ◽  
Yan Lei ◽  
Tao Qiu ◽  
Jingen Wang ◽  
Guangzhao Yue
Keyword(s):  
Pressure Sensor ◽  
Pressure Fluctuation ◽  
Control Algorithm ◽  
Fuel Injection ◽  
Injection Rate ◽  
Operating Conditions ◽  
Fuel System ◽  
Rail Pressure ◽  
Fuel Injection Rate ◽  
Injection Pulse

As an important part of the common-rail (CR) fuel system for diesel engines, the injector circulation capacity and the fuel injection mass flow rate vary with carbon deposition and wear, affecting the engine output performance. This study proposes a method to identify the fuel injection rate online, based on the rail pressure fluctuation characteristics induced by fuel injection. The control algorithm uses the signal from the existing rail pressure sensor; the diesel engine does not require modification or additional sensors. A quasi-dimensional model of the CR fuel system was built to analyse the rail pressure wave fluctuation characteristics, and a parameter K was defined as the pressure drop rate. Based on K, a control algorithm was proposed. A high-pressure fuel pump test rig was built to test the fuel injection performance under different operating conditions, and the experimental data were processed by wavelet transform. From the test data, the K of the CR system was analysed using the feedback of the rail pressure sensor. The experimental results show that the value of K increases with an increase in the initial pressure and injection pulse, and is independent of the injection mode. The algorithm is feasible, and works more accurately with a longer injection pulse and a lower pump speed. This method uses the existing rail pressure sensor, does not incur extra cost and has great potential for improving the injection accuracy.

scholarly journals Factors affecting diesel fuel degradation using a bespoke high-pressure fuel system rig

2017 ◽  
Vol 232 (1) ◽  
pp. 106-117 ◽  
Author(s):  
Kesavan Gopalan ◽  
Christopher R Smith ◽  
Simon G Pickering ◽  
Christopher J Chuck ◽  
Christopher D Bannister
Keyword(s):  
High Pressure ◽  
Diesel Fuel ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Operating Conditions ◽  
Accelerated Testing ◽  
Fuel System ◽  
Rail Pressure ◽  
Deposit Formation ◽  
Fuel Filter

Recently, there has been automotive-industry-wide impetus to reduce the overall diesel vehicle emissions and the fuel consumption by increasing the fuel injection pressure within common-rail systems. Many production fuel injection systems are now capable of delivering rail pressures of 1800–2000 bar, with those able to achieve 3000 bar under development. In addition, there has been a gradual increase in the permitted fatty acid methyl ester content in EN 590 diesel from 5% to 7% with further increases to 10% proposed. With these changes, there has been mounting speculation that increasing the injection pressure, particularly with an elevated biodiesel content, can contribute to fuel degradation, deposit formation, fuel filter blocking and corresponding vehicle reliability issues. In this investigation, a bespoke high-pressure fuel injection rig was designed and commissioned to mimic conditions representative of those experienced within a modern vehicle engine. The impacts of the rail pressure, the biodiesel content and the accelerated testing conditions on the stability of the diesel fuel and deposit formation leading to filter blocking were assessed. Despite the abundance of literature on laboratory-based biodiesel degradation, in these more realistic operating conditions it was found that biodiesel did not increase the likelihood of deposit formation within the high-pressure fuel system, with the same level of filter blocking observed for both the baseline diesel B0 (i.e. no biodiesel) and the B10 blend (which contains 10% biodiesel). This implies that the filter-blocking problem caused by onboard fuel degradation has the potential to occur broadly in a wide range of different fuel compositions. B10 fuel tested with a rail pressure of 2000 bar resulted in a pressure drop across the fuel filter of 0.5 bar within 12,000 min (approximately 8.3 days), whereas the corresponding experiment at a rail pressure of 1000 bar showed no increase in the filter pressure. When using model (B10) fuel, filter blocking was observed at rail pressures of both 2000 bar and 1000 bar, but with a lower pressure at a much reduced rate, leading to the belief that the increases in the rail pressure towards 2000 bar has a significant effect on the propensity of vehicle diesel filters to block. Measures taken to increase the severity of the test, such as recirculating injected fuel to simulate shear effects, were found to increase the rate of degradation but did not change the chemical composition of the solids formed, thus implying that they were valid methods of reducing the test duration without introducing new degradation mechanisms. The rig presented here is therefore a suitable accelerated testing system for assessing the behaviour of fuels at higher pressures that will be common throughout the global diesel fleet in the near future.

scholarly journals A Study of Combustion Characteristics of Two Gasoline–Biodiesel Mixtures on RCEM Using Various Fuel Injection Pressures

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3265
Author(s):  
Ardhika Setiawan ◽  
Bambang Wahono ◽  
Ocktaeck Lim
Keyword(s):  
Heat Release ◽  
Ignition Delay ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Fuel Mixture ◽  
Injection Rate ◽  
Injection Duration ◽  
Late Start ◽  
Fuel Injection Rate ◽  
Injection Pressures

Experimental research was conducted on a rapid compression and expansion machine (RCEM) that has characteristics similar to a gasoline compression ignition (GCI) engine, using two gasoline–biodiesel (GB) blends—10% and 20% volume—with fuel injection pressures varying from 800 to 1400 bar. Biodiesel content lower than GB10 will result in misfires at fuel injection pressures of 800 bar and 1000 bar due to long ignition delays; this is why GB10 was the lowest biodiesel blend used in this experiment. The engine compression ratio was set at 16, with 1000 µs of injection duration and 12.5 degree before top dead center (BTDC). The results show that the GB20 had a shorter ignition delay than the GB10, and that increasing the injection pressure expedited the autoignition. The rate of heat release for both fuel mixes increased with increasing fuel injection pressure, although there was a degradation of heat release rate for the GB20 at the 1400-bar fuel injection rate due to retarded in-cylinder peak pressure at 0.24 degree BTDC. As the ignition delay decreased, the brake thermal efficiency (BTE) decreased and the fuel consumption increased due to the lack of air–fuel mixture homogeneity caused by the short ignition delay. At the fuel injection rate of 800 bar, the GB10 showed the worst efficiency due to the late start of combustion at 3.5 degree after top dead center (ATDC).

Simulation and Experimental Analysis of Diesel Fuel-Injection Systems With a Double-Stage Injector

1999 ◽  
Vol 121 (2) ◽  
pp. 186-196 ◽  
Author(s):  
A. E. Catania ◽  
C. Dongiovanni ◽  
A. Mittica ◽  
C. Negri ◽  
E. Spessa
Keyword(s):  
Fuel Injection ◽  
Injection Rate ◽  
Operating Conditions ◽  
Flow Coefficient ◽  
Injection System ◽  
System Component ◽  
Local Pressure ◽  
Pump Speed ◽  
Minor Losses ◽  
Set Up

A double-spring, sacless-nozzle injector was fitted to the distributor-pump fuel-injection system of an automotive diesel engine in order to study its effect on the system performance for two different configurations of the pump delivery valve assembly with a constant-pressure valve and with a reflux-hole valve, respectively. Injection-rate shapes and local pressure time histories were both numerically and experimentally investigated. The NAIS simulation program was used for theoretical analysis based on a novel implicit numerical algorithm with a second-order accuracy and a high degree of efficiency. The injector model was set up and stored in a library containing a variety of system component models, which gave a modular structure to the computational code. The program was also capable of simulating possible cavitation propagation phenomena and of taking the fluid property dependence on pressure and temperature, as well as flow shear and minor losses into account. The experimental investigation was performed on a test bench under real operating conditions. Pressures were measured in the pumping chamber at two different pipe locations and in the injector nozzle upstream of the needle-seat opening passage. This last measurement was carried out in order to determine the nozzle-hole discharge flow coefficient under nonstationary flow conditions, which was achieved for the first time in a sacless-nozzle two-stage injector over a wide pump-speed range. The numerical and experimental results were compared and discussed.

Suppression of Instabilities in Gaseous Fuel High-Pressure Combustor Using Non-Coherent Oscillatory Fuel Injection

2003 ◽  
Author(s):  
D. Shcherbik ◽  
E. Lubarsky ◽  
Y. Neumeier ◽  
B. T. Zinn ◽  
K. McManus ◽  
...  
Keyword(s):  
High Pressure ◽  
Active Control ◽  
Fuel Injection ◽  
Injection Rate ◽  
Open Loop ◽  
Combustion Instabilities ◽  
Open Loop Control ◽  
Pressure Oscillations ◽  
Loop Control ◽  
Fuel Injection Rate

This paper describes the application of active, open loop, control in effective damping of severe combustion instabilities in a high pressure (i.e., around 520 psi) gas turbine combustor simulator. Active control was applied by harmonic modulation of the fuel injection rate into the combustor. The open-loop active control system consisted of a pressure sensor and a fast response actuating valve. To determine the dependence of the performance of the active control system upon the frequency, the fuel injection modulation frequency was varied between 300 and 420 Hz while the frequency of instability was around 375 Hz. These tests showed that the amplitude of the combustor pressure oscillations strongly depended upon the frequency of the open loop control. In fact, the amplitude of the combustor pressure oscillations varied ten fold over the range of investigated frequencies, indicating that applying the investigated open loop control approach at the appropriate frequency could effectively damp detrimental combustion instabilities. This was confirmed in subsequent tests in which initiation of open loop modulation of the fuel injection rate at a non resonant frequency of 300Hz during unstable operation with peak to peak instability amplitude of 114 psi and a frequency of 375Hz suppressed the instability to a level of 12 psi within approximately 0.2 sec (i.e., 75 periods). Analysis of the time dependence of the spectra of the pressure oscillations during suppression of the instability strongly suggested that the open loop fuel injection rate modulation effectively damped the instability by “breaking up” (or preventing the establishment of) the feedback loop between the reaction rate and combustor oscillations that drove the instability.

scholarly journals Fuel Injector Testing Through Development of a New Test Rig

2019 ◽  
Vol 8 (9) ◽  
pp. 2904-2909
Keyword(s):  
Fuel Injection ◽  
Cylinder Liner ◽  
Heating System ◽  
Injection Rate ◽  
Engine Fuel ◽  
Exhaust Manifold ◽  
Fuel Injector ◽  
Test Rig ◽  
Recirculation System ◽  
Fuel Injection Rate

A modified version of fuel injector with higher injection capacity has been developed. To achieve this, the injector plunger diameter is increased to 11mm from current 9.5mm. A new test rig is developed to understand the functioning of the injector due to the changes incorporated. The new test rig is designed to test injector operation without burning the fuel. Since internal combustion is not present an external arrangement is required to run the engine. This is achieved through a 3-phase induction motor, which is coupled with the crankshaft of the engine. The injected fuel is collected form the cylinders and it is then recirculated. A fuel cooling circuit is also incorporated along with the fuel recirculation system to maintain the temperature of fuel at inlet of fuel pump. An oil heating system is installed in the test rig to maintain the viscosity of the oil by heating it. The required systems for driving the engine, fuel cooling and oil heating are implemented as per the design. The test is conducted on a 19 L diesel engine. Parts which are not required for this test like piston, piston rings, intake and exhaust manifold etc are removed from the engine. And the cylinder liner is blocked from below using a plate to facilitate the collection of injected fuel. Engine is made to run using the motoring rig at the rated speed of 1500 rpm for a duration of 250 hours. Instrumented push tubes are used to measure the push tube load. Push tube load is observed to be in the range of 2700 to 3100 lbf, which is high as compared to the earlier model of the injector. Fuel injection rate is obtained from the fuel collected from the cylinders. And the average fuel injection rate is observed as 0.116 to 2.35 kg/min. Thus, the increase in plunger diameter has led to an increase in fuel injection rate

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