Research of Working Mode Conversion Based on GDI Engine

2015 ◽  
Vol 741 ◽  
pp. 546-549
Author(s):  
Ying Jie Sun ◽  
Yang Li ◽  
Chun Yu Wang ◽  
Yao Chun Li ◽  
Yun Feng Liang

This paper designs the control strategy of working mode conversion from stoichiometric homogeneous mixture to lean homogeneous mixture. First of all, after the types and parameters of electric hardware were selected in this system, a complete circuit layout of engine control system was designed, which used microcontroller named MC9S12XDP512 as control chip and the test bench was built. Then, we adjust the fuel injection pulse width and throttle opening to realize lean burn (lambda = 1.4) of torque being 40N.m at speed of 2500 r / min, and adjust injection timing to find the best injection timing which is 350 crank angle degree, and adjust the ignition advance angle to find the best ignition advance angle which is 13 crank angle degree. Finally, the work mode conversion was completed by the optimal parameters linear interpolation, reducing the fuel injection pulse width and increasing the throttle opening at the same time.

2014 ◽  
Vol 496-500 ◽  
pp. 1248-1251 ◽  
Author(s):  
Jia Jun Wang ◽  
Jun Wei Tao ◽  
Hong Da Zhang ◽  
Jin Bo Guo

Quasi-homogeneous lean mixture combustion technology can take full advantages of lean-combustion, and help reduce the engine fuel consumption and emissions. Quasi-Homogeneous Lean-burn engine Control System, combined virtual instruments with engine electronic control technology, can precisely control air-fuel ratio injection, timing, fuel injection pulse and ignite on timing, which provides a reliable and convenient platform for the engine lean-burning performance tests..


2013 ◽  
Vol 465-466 ◽  
pp. 448-452
Author(s):  
Mas Fawzi ◽  
Bukhari Manshoor ◽  
Yoshiyuki Kidoguchi ◽  
Yuzuru Nada

Previous work shows that gas-jet ignition with two-stage injection technique is effective to extend lean combustible ranges of CNG engines. In this report, the robustness of the gas-jet ignition with two-stage injection method was investigated purposely to improve the performance of a lean burn direct injection CNG engine. The experiment was conducted using an engine at speed of 900 rpm, fuel-injection-pressure of 3MPa, equivalence ratio at 0.8, and ignition timing at top dead center. The effect of first injection timing on the test engine performance and exhaust emission was analyzed. First injection timings near the gas-jet ignition produced unstable combustion with occurrence of misfires except at a timing which produced distinctively good combustion with low HC and CO emissions. Computational fluid dynamics was used to provide hindsight of the fuel-air mixture distribution that might be the cause of misfires occurrence at certain injection timings.


Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1396
Author(s):  
Hao Guo ◽  
Song Zhou ◽  
Jiaxuan Zou ◽  
Majed Shreka

The global demand for clean fuels is increasing in order to meet the requirements of the International Maritime Organization (IMO) of 0.5% global Sulphur cap and Tier III emission limits. Natural gas has begun to be popularized on liquefied natural gas (LNG) ships because of its low cost and environment friendly. In large-bore marine engines, ignition with pilot fuel in the prechamber is a good way to reduce combustion variability and extend the lean-burn limit. However, the occurrence of knock limits the increase in power. Therefore, this paper investigates the effect of pilot fuel injection conditions on performance and knocking of a marine 2-stroke low-pressure dual-fuel (LP-DF) engine. The engine simulations were performed under different pilot fuel parameters. The results showed that the average in-cylinder temperature, the average in-cylinder pressure, and the NOx emissions gradually decreased with the delay of the pilot injection timing. Furthermore, the combustion situation gradually deteriorated as the pilot injection duration increased. A shorter pilot injection duration was beneficial to reduce NOx pollutant emissions. Moreover, the number of pilot injector orifices affected the ignition of pilot fuel and the flame propagation speed inside the combustion chamber.


2012 ◽  
Vol 614-615 ◽  
pp. 414-421
Author(s):  
Chang Sheng Wang ◽  
Tie Zao Yang ◽  
Haijun Zhang ◽  
Hong Jie Zhao

Cam signals, crankshaft signals and angle signals were simulated by analogue crankshaft position sensors developed by C8051F series micro processors to emulate the operational environment of motorcycle engine. In the software development platform of gasoline engine, software running status of control system was tested. MP424 high-speed sampling card was applied to actually observe properties of ignition advance angle and fuel injection advance angle. The experiment suggested that practically observed fuel injection pulse width, ignition pulse width, properties of ignition advance angle and fuel injection advance angle were the same as those of models of control system software. This proved that the analogue crankshaft position sensor that has been developed is practical and feasible.


2013 ◽  
Vol 448-453 ◽  
pp. 3421-3425
Author(s):  
Tie Zao Yang ◽  
Hai Bo Xue ◽  
Chang Sheng Wang ◽  
Xin Yang Wang ◽  
Lei Yuan

Due to the fact that it is generally difficult to accurately calculate the nonlinear section of flow characteristics curve of small injection pulse width of electronic control injector, it is impossible for electronic control unit (ECU) to accurately control fuel injection quantity when the small engine such as motorcycle is under a working condition of idle speed or small load. This paper introduces the principle and method to make a fitting for flow characteristics of nonlinear section in the developed software system in details. Take the electronic control injector of motorcycle as an example, the programming method combined with LabVIEW and MATLAB is utilized to make a fitting treatment for accurate fuel injection quantity obtained via measuring single-chip microcomputer through Smoothing Spline method, so as to obtain the flow characteristics of small injection pulse width and normal injection pulse width of electronic control injector of motorcycle.


Author(s):  
Jingeun Song ◽  
Mingi Choi ◽  
Daesik Kim ◽  
Sungwook Park

The performance of a methane direct injection engine was investigated under various fuel injection timings and injection pressures. A single-cylinder optical engine was used to acquire in-cylinder pressure data and flame images. An outward-opening injector was installed at the center of the cylinder head. Experimental results showed that the combustion characteristics were strongly influenced by the end of injection timing rather than the start of injection timing. Late injection enhanced the combustion speed because the short duration between the end of injection and the spark induced strong turbulence. The flame propagation speeds under various injection timings were directly compared using crank-angle-resolved sequential flame images. The injection pressure was not an important factor in the combustion; the three injection pressure cases of 0.5, 0.8, and 1.1 MPa yielded similar combustion trends. In the cases of late injection, the injection timings of which were near the Intake Valve Closing (IVC) timing, the volumetric efficiency was higher (by 4%) than in the earlier injection cases. This result implies that the methane direct injection engine can achieve higher torque by means of the late injection strategy.


2014 ◽  
Vol 663 ◽  
pp. 342-346
Author(s):  
Mas Fawzi Mohd Ali ◽  
Amir Khalid ◽  
Yoshiyuki Kidoguchi

Compressed natural gas (CNG) engines normally operate in lean condition to take the advantage of higher efficiency and better fuel economy. Several studies have shown that gas-jet ignition with two-stage injection technique is effective to extend the lean combustible range of CNG engines. This paper investigates the effectiveness of such technique using a prototype lean burn direct injection CNG engine. The experiment was conducted at speed of 900 rpm, fuel injection pressure of 3 MPa, equivalence ratio φ=0.8, and ignition timing at top dead center. The effect of first injection timing on the test engine performance and exhaust emission was analyzed. The result shows that the first injection timing is crucial in determining the performance of the engine. First injection timings when the piston is near to bottom dead center produced relatively stable combustion. First injection timings when the piston is at midpoint produced misfire. First injection timings near the gas-jet ignition produced unstable combustion except at a certain timings which produced acceptable combustion with low hydrocarbon and carbon monoxide emissions.


Author(s):  
Z Huang ◽  
S Shiga ◽  
T Ueda ◽  
H Nakamura ◽  
T Ishima ◽  
...  

A study on the correlation of ignitability with fuel injection timing for direct injection combustion fuelled with natural gas and gasoline was carried out by using a rapid compression machine. The injection pressure of natural gas is 9 MPa and the injection pressure of gasoline is 7 MPa. The study results show that natural gas direct injection possesses higher momentum than that of gasoline, and this is beneficial to the combustion enhancement since a higher intensity of turbulence could be induced. Correlation of ignitability with injection timing shows better behaviour in natural gas direct injection, and this correlation is insensitive to injection modes in the case of natural gas. Thus, natural gas direct injection would have better engine applicability under cold-start conditions. The lean burn limits of natural gas and gasoline direct injection can extend to extremely low equivalence ratio when the ignitable stratified mixture exists around the spark electrode gap by optimizing the injection timing.


Author(s):  
Steven G. Fritz ◽  
John C. Hedrick ◽  
Tom Weidemann

This paper describes the development of a low emissions upgrade kit for EMD GP20D and GP15D locomotives. These locomotives were originally manufactured in 2001, and met EPA Tier 1 locomotive emission regulations. The 1,491 kW (2,000 HP) EMD GP20D locomotives are powered by Caterpillar 3516B engines, and the 1,119 kW (1,500 HP) EMD GP15D locomotives are powered by Caterpillar 3512B engines. CIT Rail owns a fleet of 50 of these locomotives that are approaching their mid-life before first overhaul. Baseline exhaust emissions testing was followed by a low emissions retrofit development focusing on fuel injection timing, crankcase ventilation filtration, and application of a diesel oxidation catalyst (DOC), and then later a diesel particulate filter (DPF). The result was a EPA Tier 0+ certification of the low emissions upgrade kit, with emission levels below EPA Line-Haul Tier 3 NOx, and Tier 4 HC, CO, and PM levels.


Author(s):  
Shuonan Xu ◽  
David Anderson ◽  
Mark Hoffman ◽  
Robert Prucka ◽  
Zoran Filipi

Energy security concerns and an abundant supply of natural gas in the USA provide the impetus for engine designers to consider alternative gaseous fuels in the existing engines. The dual-fuel natural-gas diesel engine concept is attractive because of the minimal design changes, the ability to preserve a high compression ratio of the baseline diesel, and the lack of range anxiety. However, the increased complexity of a dual-fuel engine poses challenges, including the knock limit at a high load, the combustion instability at a low load, and the transient response of an engine with directly injected diesel fuel and port fuel injection of compressed natural gas upstream of the intake manifold. Predictive simulations of the complete engine system are an invaluable tool for investigations of these conditions and development of dual-fuel control strategies. This paper presents the development of a phenomenological combustion model of a heavy-duty dual-fuel engine, aided by insights from experimental data. Heat release analysis is carried out first, using the cylinder pressure data acquired with both diesel-only and dual-fuel (diesel and natural gas) combustion over a wide operating range. A diesel injection timing correlation based on the injector solenoid valve pulse widths is developed, enabling the diesel fuel start of injection to be detected without extra sensors on the fuel injection cam. The experimental heat release trends are obtained with a hybrid triple-Wiebe function for both diesel-only operation and dual-fuel operation. The ignition delay period of dual-fuel operation is examined and estimated with a predictive correlation using the concept of a pseudo-diesel equivalence ratio. A four-stage combustion mechanism is discussed, and it is shown that a triple-Wiebe function has the ability to represent all stages of dual-fuel combustion. This creates a critical building block for modeling a heavy-duty dual-fuel turbocharged engine system.


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