scholarly journals The influence of the ignition control on the performance of an aircraft radial piston engine

2019 ◽  
Vol 177 (2) ◽  
pp. 60-65
Author(s):  
Jacek CZARNIGOWSKI ◽  
Piotr JAKLIŃSKI

Aircraft piston engines are built with compromise on performance and safety. The desire to achieve the highest power-to-weight ratio leads to the search for solutions that optimize the combustion process. On the other hand, the need for maximum reliability leads to the simplification of the design at the costs of performance. An example of such a compromise is the ignition system of the ASz-62IR engine. In this engine there is a double magneto ignition system with a fixed ignition advance angle. As part of the modernisation of this engine, an electronically controlled dual ignition system was developed, which allows for optimum control of the ignition advance angle in terms of power. This article discusses the results of bench tests of the ASZ-62IR-16X engine with fixed ignition timing and variable timing control. Functional parameters and toxicity of exhaust gases were analyzed.

2006 ◽  
Vol 128 (2) ◽  
pp. 377-387 ◽  
Author(s):  
Koudai Yoshizawa ◽  
Atsushi Teraji ◽  
Hiroshi Miyakubo ◽  
Koichi Yamaguchi ◽  
Tomonori Urushihara

In this research, combustion characteristics of gasoline compression ignition engines have been analyzed numerically and experimentally with the aim of expanding the high load operation limit. The mechanism limiting high load operation under homogeneous charge compression ignition (HCCI) combustion was clarified. It was confirmed that retarding the combustion timing from top dead center (TDC) is an effective way to prevent knocking. However, with retarded combustion, combustion timing is substantially influenced by cycle-to-cycle variation of in-cylinder conditions. Therefore, an ignition timing control method is required to achieve stable retarded combustion. Using numerical analysis, it was found that ignition timing control could be achieved by creating a fuel-rich zone at the center of the cylinder. The fuel-rich zone works as an ignition source to ignite the surrounding fuel-lean zone. In this way, combustion consists of two separate auto-ignitions and is thus called two-step combustion. In the simulation, the high load operation limit was expanded using two-step combustion. An engine system identical to a direct-injection gasoline (DIG) engine was then used to validate two-step combustion experimentally. An air-fuel distribution was created by splitting fuel injection into first and second injections. The spark plug was used to ignite the first combustion. This combustion process might better be called spark-ignited compression ignition combustion (SI-CI combustion). Using the spark plug, stable two-step combustion was achieved, thereby validating a means of expanding the operation limit of gasoline compression ignition engines toward a higher load range.


2021 ◽  
Author(s):  
Marek Vorlíček ◽  
◽  
Jozef Čerňan

This paper explains the basic definition of ignition, combustion and description of the ignition system functionality. The ignition systems are divided according to established criteriums into the most used types and descriptions of each ignition system components. It focuses on ignition timing and circumstances that affect it and how they influence the observed parameters. I am using ignition timing as an instrument for the observation and optimization of ignition. These practices are tested on piston engine in the practical part of this paper. It describes the modification of the timing curve, measuring of engine power and comparison between each curve. It is an analysis of engine performance under different conditions. The most efficient timing curve is chosen and further evaluated. The used engine for this paper was a rebuild from a car engine used in Trabant 601, VEB Automobilwerke automobile.


Author(s):  
Toshinori Ogawa ◽  
Yasuo Kawaguchi

Although portable electric devices have become increasingly sophisticated and compact, the amount of energy required for their operation has increased and device performance may be restrained by the energy source in the near future. A small power source is also needed for mobile robots for home usage. Small, portable distributed power sources with higher energy density than the conventional battery are required. Since the energy density of hydrocarbon or hydrogen fuel is quite high compared to the battery, combustion micro engines that use these fuels are promising for this purpose. In this research, we focused on the small glow-ignition engine developed for model airplanes. Since the glow engine does not require an auxiliary electric circuit for ignition, it is suitable for lightweight miniature engines. However, unlike the spark-ignition engine, there is no equipment that controls the ignition timing. In the glow-ignition system, heat is supplied by the following three methods for ignition of the air-fuel mixture: (1) Heat produced from the compression of the air-fuel mixture; (2) Heat remaining in the element from the last explosion; and (3) Heat produced by the catalytic action of an ignition element. In such an ignition system, the combustion state may differ between cycles. In order to clarify the combustion process, a miniature pressure sensor was built into the cylinder head, and pressure fluctuation was measured. Analysis was conducted to detect cycle-to-cycle variation. The base engine used was a commercial glow-ignition four-stroke engine with a swept volume of 4.89 cc. This is a high-speed engine with a maximum engine speed exceeding 14,000 rpm. Although the nominal output was 368 W, the value measured by this research was much lower. Fuel consumption was measured by placing a fuel tank on an electronic balance. The fuel used for the experiment consisted of mainly methanol, nitromethane, and lubricant. Weight ratio of these components and air/fuel ratio were changed independently, and the effect on the combustion pressure was evaluated.


Author(s):  
Koudai Yoshizawa ◽  
Atsushi Teraji ◽  
Hiroshi Miyakubo ◽  
Koichi Yamaguchi ◽  
Tomonori Urushihara

In this research, combustion characteristics of gasoline compression ignition engines have been analyzed numerically and experimentally with the aim of expanding the high load operation limit. The mechanism limiting high load operation under homogeneous charge compression ignition (HCCI) combustion was clarified. It was confirmed that retarding the combustion timing from top dead center (TDC) is an effective way to prevent knocking. However, with retarded combustion, combustion timing is substantially influenced by cycle-to-cycle variation of in-cylinder conditions. Therefore, an ignition timing control method is required to achieve stable retarded combustion. Using numerical analysis, it was found that ignition timing control could be achieved by creating a fuel-rich zone at the center of the cylinder. The fuel-rich zone works as an ignition source to ignite the surrounding fuel-lean zone. In this way, combustion consists of two separate auto-ignitions and is thus called two-step combustion. In the simulation, the high load operation limit was expanded using two-step combustion. An engine system identical to a direct-injection gasoline (DIG) engine was then used to demonstrate two-step combustion experimentally. An air-fuel distribution was created by splitting fuel injection into first and second injections. The spark plug was used to ignite the first combustion. This combustion process might better be called spark-ignited compression ignition combustion (SI-CI combustion). Using the spark plug, stable two-step combustion was achieved, thereby demonstrating a means of expanding the operation limit of gasoline compression ignition engines toward a higher load range.


Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3530
Author(s):  
Fukang Ma ◽  
Shuanlu Zhang ◽  
Zhenfeng Zhao ◽  
Yifang Wang

The hydraulic free-piston engine (HFPE) is a kind of hybrid-powered machine which combines the reciprocating piston-type internal combustion engine and the plunger pump as a whole. In recent years, the HFPE has been investigated by a number of research groups worldwide due to its potential advantages of high efficiency, energy savings, reduced emissions and multi-fuel operation. Therefore, our study aimed to assess the operating characteristics, core questions and research progress of HFPEs via a systematic review and meta-analysis. We included operational control, starting characteristics, misfire characteristics, in-cylinder working processes and operating stability. We conducted the literature search using electronic databases. The research on HFPEs has mainly concentrated on four kinds of free-piston engine, according to piston arrangement form: single piston, dual pistons, opposed pistons and four-cylinder complex configuration. HFPE research in China is mainly conducted in Zhejiang University, Tianjin University, Jilin University and the Beijing Institute of Technology. In addition, in China, research has mainly focused on the in-cylinder combustion process while a piston is free by considering in-cylinder combustion machinery and piston dynamics. Regarding future research, it is very important that we solve the instabilities brought about by chance fluctuations in the combustion process, which will involve the hydraulic system’s efficiency, the cyclical variation, the method of predicting instability and the recovery after instability.


Author(s):  
W Wang ◽  
E. C. Chirwa ◽  
E Zhou ◽  
K Holmes ◽  
C Nwagboso

It is well known that the optimum ignition timing, which gives the maximum brake torque (MBT) for a given engine design, varies with the rate of flame development and propagation in the cylinder. This depends, among other factors, on engine design and operating conditions, and on the properties of the air-fuel mixture. In modern engines the ignition timing is generally controlled by fixed open-loop schedules as functions of engine speed, load and coolant temperature. It is desairable that this ignition timing can be adjusted to the optimum level producing the best torque to obtain minimum fuel consumption and maximum available power. This paper presents an ignition timing control system based on fuzzy logic theory. A pressure sensor system ws developed for the determination of combustion parameters and ignition control on a Ford 1600cm3 four-cylinder engine fuelled with natural gas. Several tests were carried out in optimizing the pressure detection system. The results obtained provide important information compatible with intelligent control of the engine using fuzzy logic technology. Moreover, tests carried out to date using this technology show good results that fit quite well with the original engine output torque characteristics.


2019 ◽  
Vol 252 ◽  
pp. 05007 ◽  
Author(s):  
Łukasz Grabowski ◽  
Ksenia Siadkowska ◽  
Krzysztof Skiba

This paper reports the results of simulation works of Rotax 912 aircraft piston engine, which is a basic unit in most ultra-light aircrafts. The method for preparing the model aircraft engine operation process was presented. Simulation tests were carried out in the AVL Boost programme. The programme allows a full use of zero-dimensional and one-dimensional modelling. It also allows a comparison of other engine models. The developed model has enabled us to simulate the flow of air through the inlet pipes, carburettors, valves and combustion process. The preparation of the model required us to enter parameters that are not available in the manufacturer's catalogue, therefore, necessary measurements and analysis of the engine parts were carried out on a laboratory bench. The calculations in the AVL Boost programme were carried out in the conditions determined for the selected BMEP values with the objective of characterising the engine performance by determining its power, torque and fuel consumption.


2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Wang Xiaogang ◽  
Liu Bolan ◽  
Yu Xiyang ◽  
Yan Chao ◽  
Yu Fei ◽  
...  

Abstract Spark ignition aeropiston engines have good prospects due to light weight and high power to weight ratio. Both gasoline and kerosene can be utilized on these engines by using either traditional port fuel injection (PFI) or the novel air-assisted fuel injection (A2FI). In this article, the effects of different fuels and injection methods on the performance of a four-cylinder opposed aeropiston engine were studied. The spray performance test rig and the engine performance test rig were established. First, the influence of different injection methods on engine performance were compared, which indicated that A2FI is superior to PFI in engine power and starting performance. Furthermore, the fuel performance comparison by using A2FI was conducted, which demonstrates that kerosene is inferior to gasoline in terms of spray characteristics and power performance. Finally, detailed working characteristics of A2FI system using kerosene were studied, which indicated that the stable and reliable operation of the spark-ignition operation can be realized and the kerosene's spark-ignition combustion process can be optimized similar to that of gasoline. Results shows that the use of kerosene combined with A2FI is the best technical way to achieve ideal working process of the spark ignition aeropiston engine.


2020 ◽  
pp. 146808742096087
Author(s):  
Xue Yang ◽  
Yong Cheng ◽  
Pengcheng Wang

The pre-chamber ignition system scavenged with natural gas can effectively improve the in-cylinder combustion process and extend the lean-burn limit of natural gas engines. The scavenging process affects the flow field and fuel-air mixture concentration distribution in the pre-chamber and affects the combustion process in the pre-chamber as well as the ignition process in the main chamber. This has a significant influence on the performance of natural gas engines. It is supposed that the ratio of natural gas remaining in the mixture inside the pre-chamber at the ignition timing affects the combustion process in the pre-chamber. To verify this suppose, an independent injection system for injecting natural gas into the pre-chamber is designed and experiments are carried out on a single-cylinder natural gas engine. The ratio of natural gas remaining in the mixture inside the pre-chamber at the ignition timing is adjusted by changing the injection start angle of the scavenging process. The combustion process in the pre-chamber and the main chamber are analyzed using the in-cylinder pressures. The results indicate that, with the delay of the injection start angle, the ratio of natural gas remaining in the mixture inside the pre-chamber at the ignition timing increases, the combustion process in the pre-chamber is enhanced, the maximum pressure difference between two chambers increases and appears earlier. The energy of the hot jets and the penetration of the jets increase, which enhances the combustion process in the main chamber.


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