On-Engine Demonstration of Micro-Pilot Ignition System for a Cooper-Bessemer GMV-4TF

Author(s):  
Jacob A. Brown ◽  
John Mizia ◽  
Daniel B. Olsen ◽  
Bryan D. Wilson

This investigation assesses the benefits of retrofitting a diesel micro-pilot ignition system on a Cooper-Bessemer GMV-4TF two-stroke cycle natural gas engine with a 14” (36 cm) bore and a 14” (36 cm) stroke. The pilot fuel injectors are mounted through an adaptor in one of the spark plug holes in a set of dual-spark plug heads. A high pressure, common-rail, diesel fuel delivery system is employed and customizable power electronics control the current signal to the pilot injectors. Pilot fuel is supplied by a variable displacement, high-pressure pump that is driven with an electric motor. Software is developed that interfaces with the pump and controls and monitors the fuel rail pressure. Micro-pilot quantities from 11.5 to 20 mm3 (.0007 to .0012 in3) are explored at rail pressures from 200 to 1400 bar (2,900 to 20,300 psig). Three independent variables, pilot ignition timing, pilot fuel quantity, and pilot fuel rail pressure, are manipulated. An optimization sequence is performed to minimize total fuel consumption.

Author(s):  
A. K. Chan ◽  
S. H. Waters

An ignition system that is based on the alternating (AC) rather than the traditional direct (DC) current in the spark plug discharge has been developed at the Caterpillar Technical Center. This system can generate a long duration discharge with controllable power. It is believed that such an ignition system can provide both a leaner operating limit and a longer spark plug life than a traditional DC system due to the long discharge duration and the low discharge power. The AC ignition system has successfully been tested on a Caterpillar single cylinder G3500 natural gas engine to determine the effects on the engine performance, combustion characteristics and emissions. The test results indicate that while the AC ignition system has only a small impact on engine performance (with respect to a traditional DC system), it does extend the lean limit with lower NOx emissions. Evidences also show the potential of reduce spark plug electrode erosions from the low breakdown and sustaining discharge powers from the AC ignition system. This paper summarizes the prototype design and engine demonstration results of the AC ignition system.


2016 ◽  
Vol 18 (3) ◽  
pp. 273-290 ◽  
Author(s):  
Alessandro Ferrari ◽  
Pietro Pizzo

A fully predictive model of a Common Rail fuel injection apparatus, which includes a detailed simulation of rail, pump, piping system, injectors and rail pressure control system, is presented and discussed. The high-pressure pump and injector sub-models have been validated separately and then coupled to the rail and pressure control system sub-models. The complete predictive model has been validated and applied to investigate the effects of the dynamics of each component of the injection apparatus on the rail pressure time history. Variable timing of the high-pressure pump delivery phases has also been considered, and the influence of this parameter on the injection performance has been analysed for both single- and multiple-injection events. Furthermore, the injection system dynamics during the transients between steady-state working conditions has been investigated in order to highlight the role played by the dynamic response of the pressure control system on the rail pressure time history.


Author(s):  
David L. Ahrens ◽  
Azer P. Yalin ◽  
Daniel B. Olsen ◽  
Gi-Heon Kim

Using a laser, as opposed to a conventional (electrical) spark plug, to create a combustion initiating spark is potentially advantageous for several reasons: flexibility in choosing and optimizing the spark location, in particular to move the spark away from solid heat sinks; production of a more robust spark containing more energy; and obviation of electrode erosion problems. These advantages may lead to an extension of the lean limit, an increase in engine thermal efficiency, and the concomitant benefits of reduced pollutant emissions. This paper presents the design of a laser ignition system appropriate for a large bore natural gas engine. Design considerations include: optimization of spark location, design of beam delivery system and optical plug, and mitigation of vibration and thermal effects. Engine test results will be presented in the second paper of this two-paper series.


Transport ◽  
2015 ◽  
Vol 31 (3) ◽  
pp. 305-311 ◽  
Author(s):  
Tomas Mickevičius ◽  
Stasys Slavinskas ◽  
Raimondas Kreivaitis

This paper presents a comparative experimental study for determining the effect of ethanol on functionality of a high pressure pump of the common rail fuel injection system. For experimental durability tests were prepared two identical fuel injection systems, which were mounted on a test bed for a fuel injection pump. One of the fuel injection systems was feed with diesel fuel; other fuel injection system was fuelled with ethanol–diesel fuel blend. A blend with 12% v/v ethanol and 88% v/v diesel fuel and low sulphur diesel fuel as a reference fuel were used in this study. To determine the effect of ethanol on the durability of the high pressure pump total fuel delivery performance and surface roughness of pump element were measured prior and after the test. Results show that the use of the ethanol–diesel blend tested produced a negative effect on the durability of the high pressure fuel pump. The wear of plungers and barrels when using ethanol–diesel fuel blend caused a decrease in fuel delivery up to 30% after 100 h of operation.


Author(s):  
David L. Ahrens ◽  
Daniel B. Olsen ◽  
Azer P. Yalin

Using a laser, as opposed to a conventional (electrical) spark plug, to create a combustion initiating spark is potentially advantageous for several reasons: flexibility in choosing and optimizing the spark location, in particular to move the spark away from solid heat sinks; production of a more robust spark containing more energy; and obviation of electrode erosion problems. In this paper we present the on-engine test results of the laser ignition system on a large bore natural gas engine. Test results include: mass fraction burn duration, hydrocarbon emissions data, and combustion stability comparisons to the conventional spark plug ignition system. Design and spark location considerations for the laser ignition system were presented in the first paper of this two-paper series.


Author(s):  
Hongxun Gao ◽  
Ron Matthews ◽  
Sreepati Hari ◽  
Matt Hall

Ignition of extremely lean mixtures is a very challenging problem, especially for the low speed, high load conditions of large-bore natural gas engines. This paper presents initial results from testing a high energy ignition system, the railplug, which can assure ignition of very lean mixtures by means of its high energy deposition and high velocity jet of the plasma. Comparisons of natural gas engine tests using both a spark plug and a railplug are presented and discussed in this paper. The preliminary engine test show that the lean stability limit (LSL) can be extended from an equivalence ratio, φ, of ∼0.63 using a spark plug down to 0.56 using a railplug. The tests show that the railplug is very promising ignition system for lean burn natural gas engines and potentially for other engines that operate with very dilute mixtures. The ignition characteristics of different railplug geometric and circuit designs are also discussed.


Author(s):  
Corey A. Honl

A non-fueled prechamber ignition system was developed to provide for controlled and stable combustion to best support the goals of both Waukesha Engine and the ARES program. This paper will provide details and results of efforts undertaken in optimization of the following design aspects: tangential angle of prechamber orifice channels in relation to head-induced cylinder swirl, prechamber orifice diameter, prechamber volume (spark plug recess in precombustion chamber), and recession of the entire precombustion chamber into the cylinder head. A number of important conclusions will be verified and presented based on the development work done on a laboratory engine.


2017 ◽  
Vol 19 (10) ◽  
pp. 1036-1047 ◽  
Author(s):  
Alessandro Ferrari ◽  
Ruggero Vitali

A mechanical model of a high-pressure pump of a common rail fuel injection system is presented and validated by comparison with experimental instantaneous pump shaft torque and pump piston lift data. The instantaneous torque has been measured with a high-performance torque meter installed on a hydraulic rig for testing pieces of injection apparatus. In the model, the mechanics of the piston plunger and the forces exchanged between pistons and cam are simulated, and friction losses between mobile parts are taken into account. The numerical tool is used to investigate the dynamical performance of the high-pressure pump and to analyse the impact of the rail pressure control strategy on instantaneous torque, energy saving and flow rate ripple. The rail pressure control strategy, based on the application of a fuel metering valve at the pump inlet, gives rise to an improved hydraulic efficiency of the injection system at part loads and to a moderate rate of pressure increase in the pumping chamber at part loads. However, the rail pressure control strategy based on the installation of a pressure control valve at one rail extremity leads to a reduction in the pump flow rate ripple and to a diminution in the fatigue stress. Furthermore, cavitation problems can occur during intake and early compression phases of the pump cycle when the fuel metering unit is working.


Desalination ◽  
2021 ◽  
Vol 507 ◽  
pp. 115033
Author(s):  
Daiwang Song ◽  
Yin Zhang ◽  
Haitao Wang ◽  
Lidong Jiang ◽  
Chengpeng Wang ◽  
...  

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