Statistical Correlation Between the Crankshaft’s Speed Variation and Engine Performance—Part II: Detection of Deficient Cylinders and Mean Indicated Pressure Calculation

2003 ◽  
Vol 125 (3) ◽  
pp. 797-803 ◽  
Author(s):  
D. Taraza

The goal of this two-part paper is to develop a methodology using the variation of the measured crankshaft speed to calculate the mean indicated pressure (MIP) of a multicylinder engine and to detect cylinders that are lower contributors to the total engine output. The statistical model of a harmonic component of the engine torque developed in the first part of the paper is used to achieve this goal. The analysis of the half-order components of the gas pressure torque permits to identify distinct phase angle domains of the resultant torque vector that are specific for the deficiencies of given cylinders. Based on the rigid-body model of the crankshaft, these phase angle domains are correlated to the phase angle domains of the half-order component of the crankshaft speed. Then, the phase angle of the half-order component of the measured crankshaft speed will identify the deficient cylinder. The amplitude of the first major harmonic component of the measured crankshaft speed is correlated to the corresponding harmonic order of the gas pressure torque and is used to calculate the MIP of the engine. The accuracy limits of this “software dynamometer” are also presented.

2003 ◽  
Vol 125 (3) ◽  
pp. 791-796 ◽  
Author(s):  
D. Taraza

The goal of this two-part paper is to develop a methodology using the variation of the measured crankshaft speed to calculate the mean indicated pressure (MIP) of a multicylinder engine and to detect cylinders that are lower contributors to the total engine output. Both the gas pressure torque and the crankshaft’s speed are, under steady-state operating conditions, periodic functions of the crank angle and may be expressed by Fourier series. For the lower harmonic orders, the dynamic response of the crankshaft approaches the response of a rigid body and that makes it is possible to establish correlations between the amplitudes and phases of the corresponding harmonic orders of the crankshaft’s speed and of the gas pressure torque. The inherent cycle-to-cycle variation in the operation of the cylinders requires a statistical approach to the problem. The first part of the paper introduces the statistical model for a harmonic component of the gas pressure torque and determines the correlation between the amplitudes and phases of the harmonic components of the gas pressure torque and the MIP of the engine. In the second part of the paper the statistical model is used to calculate the MIP and to detect deficient cylinders in the operation of a six-cylinder four-stroke diesel engine.


Author(s):  
Min-Chun Pan ◽  
Yu-Fong Lin

This paper presents advanced order tracking techniques using the Kalman tracking filter with angular information to extract both close and cross order components from measured dynamic signals. Separated order components can be ranked for the purpose of trouble shooting and design modification. In the study, close-order components resulting from shaft unbalancing and gear meshing of a transmission element test bench can be extracted precisely. In addition, for the pass-by noise measurement of CVT-driving electrical scooters, spectral components can be ranked appropriately for a further noise reduction task.


2016 ◽  
Vol 78 (6) ◽  
Author(s):  
Zulkifli Abdul Majid ◽  
Rahmat Mohsin ◽  
Abdul Hakim Shihnan

The performance and exhaust emission of 6 cylinder four stroke direct injection diesel dual fuel (DDF) engine were investigated, the duel fuel used is corn oil methyl esters consist of 5%, 10%, 15% and 20% blends with diesel and compressed natural gas (CNG). Experiment was conducted at a fixed compression ratio of 17.5:1 with variance of engine speed 1400, 1800, 2400 and 2600 rpm. Combination of Biodiesel and CNG showed a better result on engine performance in terms of horse power and engine torque compared to other types of tested fuel. The substantial decrease of 25.6 % in exhaust emission flue was observed, giving lower value of UHC and nitrogen oxide (NOx). However, when the fuel is blended with CNG, a poor performance on exhaust emission was recorded, which include carbon dioxide (CO2), carbon monoxide (CO), unburned hydrocarbon (UHC) and nitrogen oxide (NOx) due to presence of CNG in fuel. 


Author(s):  
Leonard J. Hamilton ◽  
Jim S. Cowart

Intake tuning is a significant method of boosting performance by enhancing volumetric efficiency in a naturally aspirated engine. Elements of intake tuning can involve varying intake runner length, geometry and plenum shape and volume. Previous research has demonstrated the beneficial effects of increasing plenum volume on engine torque. This objective of this study was to evaluate the ability of analytical and two computer based models (simple and complex) to accurately predict the effects of varying plenum volume on steady state and transient engine performance for a small restricted spark ignition engine. The computer models were only moderately successful in characterizing steady state performance. The simple model matched torque peak locations but failed to adequately predict the advantageous effect of plenum volume on torque. The complex model more effectively simulated torque effects of plenum volume increase but did not adequately capture torque peak locations. Both models underestimated mid-range torque by up to 20%. Transient manifold filling was estimated well with both the complex computer model and analytical methods. Transient torque response differed by only 1–2 engine cycles and was also well predicted by the computer simulation.


2013 ◽  
Vol 315 ◽  
pp. 20-24 ◽  
Author(s):  
Taib Iskandar Mohamad ◽  
Mark Jermy ◽  
Matthew Harrison

Power reduction when converting a gasoline engine to propane can be mitigated by designing an injection system so the heat required for evaporation of the propane is drawn from the intake air. Air is cooled and densified, resulting in volumetric efficiency increase. LPG sprays were imaged using Mie and LIF imaging techniques from a port fuel injector, and from long and short connecting pipes. Images were taken in an optically-accessed pressure chamber at atmospheric pressure and fuel pressures of 1.5 MPa. Images of the pipe-coupled injection spray show significant evaporation in the pipe, whose amount depend on the length and diameter of the pipe. The duration of the LPG pulse at the manifold end is, for 300mm pipes, five times the original duration at the injector, and even greater for 600mm pipes. The narrow sprays and the amount of evaporation that occurs before the fuel enters the manifold explains the differences in engine torque and in-cylinder mixture temperature with the different systems.


2020 ◽  
Vol 9 (2) ◽  
pp. 91
Author(s):  
Abdi Hanra Sebayang ◽  
Husin Ibrahim ◽  
Surya Dharma ◽  
Arridina Susan Silitonga ◽  
Berta Br Ginting ◽  
...  

The depletion of fossil fuels, rising of earth temperatures and declining of air quality are an unavoidable phenomenon today. Bioethanol fuel is one solution to reduce this problem that comes from renewable raw materials. The purpose of this study is to investigate engine performance and exhaust emissions at gasoline engine by using the sorghum seeds bioethanol-pertalite blends with different mixed ratios (10%, 15%, and 20%). The test is performed on a four-stroke gasoline engine without modification. Engine speeds vary from 1000 to 4000 rpm, and properties of the sorghum seeds bioethanol-pertalite blends are measured and analyzed. In addition, engine torque, brake power, brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE) as well as carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NOx) emissions are measured. The results show that BSFC decreased while BTE increased for a fuel blends containing 20% bioethanol at 3500 rpm engine speed, with each maximum value of 246.93 g/kWh and 36.28%. It is also found that CO and HC emissions are lower for the sorghum seeds bioethanol-pertalite blends. Based on the research results, it can be concluded that the sorghum seeds bioethanol-pertalite blends can improve engine performance and reduce exhaust gas emissions. Keywords: bioethanol; pertalite; performance engine; exhaust gas emission; alternatif fuel.


Author(s):  
Sena Mahendra ◽  
Fahmy Fatra ◽  
Akhmad Riszal Riszal ◽  
Didik Rohmantoro

Motorized vehicles with economical fuel, agile, fast, and practical are some of the main factors consumers determine the choice of buying a motorcycle. People who own motorcycles under 2000 have not been equipped with fuel-saving devices, so they are wasteful of fuel and must be smart to save fuel. Many motorcycle manufacturers release the newest fuel-efficient products, but they affect the engine's performance. The price of premium fuel types is Rp. 6,500.00 per liter, petalite Rp. 7,600.00 per liter, firstly Rp. 8,900.00 per liter, and Pertamax turbo Rp. 10,100.00 per liter. High fuel prices encourage researchers to make various fuel-saving innovations. The purpose of this study is to develop an HCS catalyst pipe design double spiral model arranged in series to save fuel above 67% on a 4 stroke motorcycle without affecting the engine performance. The research method uses independent variables with engine speed, pipe length, pipe diameter, and Pertamax volume. Dependent variable by testing engine torque and power, fuel consumption time, temperature, and noise of the 156.7cc Mega Pro motorcycle. The addition of dual HCS catalyst spiral pipes and Pertamax volumes adds to engine performance time. At a length of 500 mm and 2000 ml, the Pertamax volume for the engine speed of 3500 rpm is only able to save fuel by 52.52%. The most optimal HCS double catalyst spiral pipe design is a 500 cm long pipe with a volume of Pertamax 2000 ml. In addition to engine performance time on the catalyst spiral pipe design can increase engine torque and power by 92.3% at 3500 rpm and reduce the temperature by 12.34% at 6000 rpm, and 1.93% noise at 4000 rpm. Increasing the double HSC catalyst spiral pipe and Pertamax volume can increase the hydrocarbon content of fuel entering the combustion chamber supplied from Pertamax vapor. Premium fuel (C8H18) plus Pertamax vapors. This makes the fuel content has a high octane value, greater engine power, and low fuel consumption. A high octane value affects perfect engine combustion, reduced knocking, low engine temperature, and decreased noise.Kendaraan bermotor dengan bahan bakar yang irit, lincah, cepat, dan praktis merupakan salah satu faktor utama konsumen menentukan pilihan membeli sepeda motor. Masyarakat yang memiliki sepeda motor di bawah tahun 2000 belum dilengkapi dengan alat penghemat bahan bakar, sehingga boros bahan bakar dan harus pintar menghemat bahan bakar. Banyak produsen sepeda motor yang mengeluarkan produk terbarunya paling irit bahan bakar, tetapi mempengaruhi performa mesinnya. Harga bahan bakar jenis premium Rp. 6.500,00 per liter, pertalite Rp. 7.600,00 per liter, pertamax Rp. 8.900,00 per liter, dan pertamax turbo Rp. 10.100,00 per liter. Harga bahan bakar yang tinggi mendorong peneliti melakukan berbagai inovasi penghemat bahan bakar.Tujuan penelitian ini mengembangkan desain pipa katalis HCS model spiral ganda yang disusun seri sehingga mampu menghemat bahan bakar diatas 67% pada sepeda motor 4 tak tanpa mempengaruhi performa mesin. Metode penelitian menggunakan variabel bebas dengan putaran mesin, panjang pipa, diameter pipa, dan volume pertamax. Variabel terikat dengan menguji torsi dan daya mesin, waktu konsumsi bahan bakar, temperatur, dan kebisingan sepeda motor Mega Pro 156,7cc. Penambahan pipa spiral katalis HCS ganda dan volume pertamax menambah waktu performa mesin. Pada panjang 500 mm dan 2000 ml volume pertamax untuk kecepatan putaran mesin 3500  rpm hanya mampu menghemat bahan bakar sebesar  52,52%. Desain pipa spiral katalis HCS ganda  yang paling optimal dari yaitu pipa dengan panjang 500 cm dan volume pertamax 2000 ml. Selain waktu performa mesin pada desain pipa spiral katalis ini dapat meningkatkan torsi dan daya mesin sebesar 92,3% pada putaran 3500 rpm serta mengurangi temperatur 12,34% pada putaran 6000 rpm, dan kebisingan 1,93% pada putaran 4000 rpm. Bertambahnya pipa spiral katalis HSC ganda dan volume pertamax dapat meningkatnya kandungan hidrokarbon bahan bakar yang masuk ke ruang pembakaran disuplay dari uap pertamax. Bahan bakar premium (C8H18) di tambah uap pertamax.menjadikan kandungan bahan bakar memiliki nilai oktan tinggi, daya mesin yang lebih besar dan komsumsi bahan bakar rendah. Nilai oktan tinggi mempengaruhi pembakaran mesin sempurna, knocking berkurang, temperatur mesin rendah, dan kebisingan menurun


2020 ◽  
Vol 142 (6) ◽  
Author(s):  
S. Raviteja ◽  
P. A. Ramakrishna ◽  
A. Ramesh

Abstract Nitromethane has a stoichiometric air–fuel ratio of 1.7, which is 8.5 times lower than gasoline. For the same amount of air being drawn by the engine, more amount of nitromethane blends and hence more energy can be added. Methanol was used as a medium to mix nitromethane and gasoline, which are normally immiscible. Engine performance tests were carried out to study the effect of nitromethane addition to the methanol-gasoline blend. A large rise in engine torque and brake thermal efficiency (BTE) was obtained during the investigation. However, the brake specific fuel consumption (BSFC) also increased for the nitromethane blends. The engine parameters like spark timing, equivalence ratio, and compression ratio were optimized to further increase the engine power and also bring down the BSFC. A net torque improvement of 42%, BTE improvement of 35%, and BSFC rise of 9% were obtained by adding nitromethane and methanol in small fractions to gasoline. Combustion analysis was carried out using the cylinder pressure trace. High heat release rate and shorter combustion duration with nitromethane addition were observed. Emission measurements showed decrease in HC and CO emissions with nitromethane addition. However, a drastic rise in NO emissions was observed. Hence, it can be concluded that the specific power of small two-stroke spark ignition (SI) engines can be enhanced using nitromethane as a fuel additive to increase the payload of the unmanned aerial vehicles.


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