The Effects of Backpressure on the Performance of Internal Combustion Engine and Automobile Exhaust Thermoelectric Generator

The maximum generated power of automobile exhaust thermoelectric generator (AETEG) can be enhanced by applying inserted fins to its heat exchanger, for the temperature difference of thermoelectric modules (TEMs) is increased. However, the heat exchanger will result in undesired backpressure, which may deteriorate the performance of the internal combustion engine (ICE). To evaluate the backpressure on the performance of both the ICE and the AETEG, the model of ICE integrated with AETEG was established with the GT-power software and validated with the AETEG test bench. The heat exchangers with chaos shape and fishbone shape were proposed, their pressure drop with different engine speeds was studied, and their effects on the performance of both the AETEG and the ICE were analyzed. The results showed that compared with the fishbone-shaped structure, the pressure drop of chaos-shaped heat exchanger is larger at the same engine speed, which contributes to the increased maximum power and hot side temperature of the AETEG. Moreover, compared with the ICE without heat exchanger, the brake torque, brake power, volumetric efficiency and pumping mean effective pressure of the ICE assembled with chaos-shape and fishbone-shape heat exchanger reduce, and the corresponding brake specific fuel consumption, CO emission and CO2 emission increase because of the raised backpressure caused by the heat exchanger.

Research on Homogeneous Charge Compression Ignition Combustion of Intake Port Exhaust Gas Recirculation Based on Cam Drive Hydraulic Variable Valve Actuation Mechanism

The thermal efficiency of an efficient gasoline engine is only about 40% and it will produce a large number of harmful products. Curbing harmful emissions and enhancing thermal efficiency have always been the goals pursued and emission regulations are also being tightened gradually. As one of the main consumers of fossil fuels, automobile engines must further reduce fuel consumption and emissions to comply with the concept of low-carbon development, which will also help them compete with electric vehicles. Homogeneous charge compression ignition (HCCI) combustion combined with variable valve actuation (VVA) technology is one of the important ways to improve engine emissions and economy. HCCI combustion based on VVA can only be realized at small and medium loads. The actual application on the entire vehicle needs to be combined with spark ignition (SI) combustion to achieve full working condition coverage. Therefore, HCCI combustion needs fast valve response characteristics; however, the valve lift and timing of the existing VVA mechanisms are mostly controlled separately, resulting in poor valve response. In order to solve this problem, the cam driven hydraulic variable valve actuation (CDH-VVA) mechanism was designed. The valve lift and timing can be adjusted at the same time and the switching of valve lift and timing can be completed in 1~2 cycles. A set of combustion mode switching data is selected to show the response characteristics of the CDH-VVA mechanism. When switching from spark ignition (SI) to HCCI, it switches to HCCI combustion after only one combustion cycle and it switches to stable HCCI combustion after two combustion cycles, which proves the fast response characteristics of the CDH-VVA mechanism. At the same time, the CDH-VVA mechanism can form the intake port exhaust gas recirculation (EGR), as one type of internal EGR. This paper studies the HCCI combustion characteristics of the CDH-VVA mechanism in order to optimize it in the future and enable it to realize more forms of HCCI combustion. At 1000 rpm, if the maximum lift of the exhaust valve (MLEV) is higher than 5.0 mm or lower than 1.5 mm, HCCI combustion cannot operate stably, the range of excess air coefficient (λ) is largest when the MLEV is 4.5 mm, ranging from 1.0~1.5. Then, as the MLEV decreases, the range of λ becomes smaller. When the MLEV drops to 1.5 mm, the range of λ shortens to 1.0~1.3. The maximum value of the MLEV remains the same at the three engine speeds (1000 rpm, 1200 rpm and 1400 rpm), which is 5.0 mm. The minimum value of the MLEV gradually climbs as the engine speed increase, 1000 rpm: 1.5 mm, 1200 rpm: 2.0 mm, 1400 rpm: 3.0 mm. With the increase of engine speed, the range of indicated mean effective pressure (IMEP) gradually declines, 3.53~6.31 bar (1000 rpm), 4.11~6.75 bar (1200 rpm), 5.02~6.09 bar (1400 rpm), which proves that the HCCI combustion loads of the intake port EGR are high and cannot be extended to low loads. The cyclic variation of HCCI combustion basically climbs with the decrease of the MLEV and slightly jumps with the increase of the engine speed. At 1000 rpm, when the MLEV is 5.0 mm, the cyclic variation range is 0.94%~1.5%. As the MLEV drops to 1.5 mm, the cyclic variation range rises to 3.5%~4.5%. Taking the maximum value of the MLEV as an example, the cyclic variation range of 1000 rpm is 0.94%~1.5%, 1200 rpm becomes 1.5%~2.3% and 1400 rpm rises to 2.0%~2.5%.

PERBANDINGAN PEMAKAIAN ROCKER ARM KONVENSIONAL DENGAN ROCKER ARM ROLLER BEARING PADA SEPEDA MOTOR

Roller Rocker Arm is important for transmitting signals and determining work efficiency which is the result of technological developments from ordinary rocker arms. The purpose of this study was to compare the use of conventional rocker arm with rocker arm roller on power, torque, exhaust emissions, compression on a motorcycle engine. The research method used is changing the fuel system, ignition system, changing the valve mechanism. The maximum torque on the conventional rocker arm occurs at 2995 rpm with a value of 10.92 Nm. Maximum torque decreases with increasing engine speed. The decrease in power at high speed occurs due to the influence of the volume of the fuel and air mixture which tends to decrease. The highest fuel consumption occurs at 7000 rpm engine speed in a conventional rocker arm of 0.124 kg/kWh, so the rocker arm roller is more efficient than the conventional rocker arm. Fuel consumption rocker arm roller rotation 7000 rpm 0.028 kg/kWh. While the conventional rocker arm fuel consumption at 7000 rpm 0.124 kg/kWh. Exhaust emissions, the rocker arm roller is environmentally friendly compared to the conventional rocker arm CO2 rocker arm roller only produces 5.2%, while the conventional rocker arm test results after the average CO2 value reaches 5.3%. The results of testing the two rocker arms on compression are the same at 90 Psi and 6.2kg/ from the standard size of 10-11kg/

Pengaruh variasi campuran bahan bakar pertamax dan bioetanol 99,9% terhadap torsi mesin bensin 4 langkah Tecquipment TD201

Bioethanol is ethanol made from plants such as cassava, sugarcane, sago, which are processed through hydrolysis, fermentation, distillation and dehydration processes. Lampung Province is one of the largest producers of cassava in Indonesia, with the total productivity of 5,451,312 tons in 2017, and 6,683,758 tons in 2018 or there was an increase of 22,61% compared to 2017. From this data, it is possible to produce bioethanol, where every 1 kg of cassava can produce 0,106 liters of bioethanol. This is what underlies this research to investigate the effect of blending bioethanol of 99% with pertamax and bioethanol on the engine torque. Blending bioethanol of 99% can homogeusly mix. The engine used in this study is a Kohler gasoline engine equipped with a VDAS (Versatile Data Accession System) instrument unit in determining the parameters of engine performance. The blending of bioethanol of 99% as big as 14% (E14) gave the highest value of torque at 1 rotation of dynamometer valve opening and engine speed of 2000 rpm.

Analisis Kerusakan Engine High Blow-By Pressure Pada Mesin SA6D125E-2 UNIT bulldozer D85ESS-2A

Bulldozer merupakan alat berat yang digunakan untuk mendorong material dan untuk pembukaan jalan. Dalam melakukan pekerjaannya, bulldozer banyak menggunakan tenaga mesin sehingga sering terjadi kerusakan pada komponen mesinnya. Kerusakan high blow-by pressure pada mesin bulldozer merupakan hal yang perlu diperhatikan karena dapat menyebabkan kerusakan pada komponen di dalam mesin dan mengakibatkan menurunnya performa mesin. Penelitian ini dilakukan dengan mengidentifikasi data pada technical analysis report, program analisis pelumas, dan hasil overhaul. Technical analysis report dilakukan dengan cara mengukur blow-by pressure dan engine speed untuk mengetahui performa engine. Program analisis pelumas dilakukan dengan mengambil sampel oli pelumas lalu dianalisis di laboratorium untuk mengetahui keausan dan kontaminan pada oli pelumas engine. Dari hasil penelitian, dapat ditarik kesimpulan bahwa penyebab dari kerusakan high blow-by pressure adalah masuknya kontaminan berupa debu kedalam ruang bakar dan menyebabkan gesekan abnormal pada piston, piston ring, dan cylinder liner. Gesekan abnormal ini mengakibatkan celah antara piston, piston ring, dan cylinder liner semakin besar sehingga tekanan hasil pembakaran bocor menuju crankcase melewati celah tersebut. Dampak yang ditimbulkan dari kerusakan high blow-by pressure adalah penurunan tenaga mesin, sehingga unit bulldozer harus dilakukan perbaikan dengan mengganti komponen yang rusak agar unit dapat bekerja dengan optimal.

Design and Dynamic Analysis of an Innovative Axial Shift Valvetrain System (ASVS) for Variable Stroke Engine

A variable valvetrain system is the key part of the variable stroke engine (VSE), which could achieve higher power performance and low-speed torque. An innovative axial shift valvetrain system (ASVS) was put forward to meet the air-charging requirements of a 2/4-stroke engine and complete a changeover within one working cycle. Two sets of intake and exhaust cam profiles for both intake and exhaust sides in the 2/4-stoke mode were designed for 2/4-stoke modes. Furthermore, a simulation model based on ADAMS was established to evaluate the dynamic valve motion and the contact force at different engine speeds. The dynamic simulation results show that the valve motion characteristics meet the challenges at the target engine speed of 3000 r/min. In two-stroke mode, the maximum intake valve lift could achieve 7.3 mm within 78°CaA, and the maximum exhaust valve lift could achieve 7.5 within 82°CaA on the exhaust side. In four-stroke mode, the maximum intake valve lift can achieve 8.8 mm within 140°CaA, and the maximum exhaust valve lift can achieve 8.4 mm within 140°CaA. The valve seating speeds are less than 0.3 m/s in both modes, and the fullness coefficients are more than 0.5 and 0.6 in the 2-stroke and 4-stroke mode, respectively. At the engine speed of 3000 r/min, the contact force on each component is acceptable, and the stress between cam and roller can meet the material requirement.

Combustion Conduct Of A Single-Cylinder Spark-Ignition Affected By Ethanol Fuel Mixtures of Supplement Hydroxy Gas (HHO)

Ethanol is an alternative fuel to replace fossil fuels. Ethanol's high octane value can substitute for power in spark-ignition engines (SI). Gasoline mixed with ethanol will reduce the calorific value generated and intensify the combustion process in the combustion chamber. Through the engine performance test, we can find out the increase in the performance of the SI engine. Several essential variables can improve engine performance, such as gasoline-ethanol variations, iridium spark plugs, and hydroxy gas generators (HHO). This research uses an experimental method by utilizing gasoline (octane-92)-ethanol variations (35%, 45%, and 55% v/v) with the intake of hydroxy gas during the combustion process. The SI automatic transmission engine has a capacity of 124.8 cubic centimeters (one cylinder-four stroke), a compression ratio of 11/1, fuel injection, and iridium spark plugs. Engine performance test using chassis dyno test with engine speed variations of 4000-9000 rpm. This study resulted in optimal performance on a 55% increase in gasoline-ethanol mixture with an intensify in output-power, pressure, and thermal efficiency at an engine-speed of 8000 rpm. It is contrary to the specific fuel consumption has decreased.

Study on the Variable Speed Diesel Generator and Effects on Structure Vibration Behavior in the DC Grid

Global warming and air pollutants are in general major worldwide concerns including for the marine shipping industry. Equipped with new technologies, the onboard DC grid has proven several advantages, including up to 27% reduction in specific fuel consumption with reduced emissions. That can be achieved by installing an optimized variable speed diesel generator. The engine speed is adjusted according to the required power, which allows to always keep the best efficiency of the combustion process. However, it also exposes some changes in the behavior of the structure vibrations. Measurements on an experimental variable speed diesel generator show that vibration increases when trying to slow down the engine for the same load. This behavior is closely related to the resonance in low rev range that usually occurs with general gensets. In other words, we can conclude that the DC grid’s variable speed generator may be beneficial for fuel efficiency, but not for mechanical life and safety. Several measures had been given, of which the alternation of the natural frequency is presented as an economical and efficient solution. The ultimate goal is to maintain operational safety while respecting reduced fuel consumption.

REDUCING FUEL USAGE AND CO2 EMISSIONS FROM TUG BOAT FLEETS: SEA TRIALS AND THEORETICAL MODELLING

Sea trials on a harbour tug have been conducted and are explained. The experimental results for fuel consumption per unit transport effort, under free-running (transiting) conditions, are presented and engine speed-propulsor pitch combinations for improved fuel economy are identified. A simplified analytical approach to predict fuel consumption, including the coupled engine-propulsor-hull system, is described. This rationale is combined with experimental observations and, consequently, performance maps present the complete operating envelopes of the harbour tug under both free-running and towing conditions. This combined approach proved to be effective and can be applied to the study of other tug vessels. As a consequence of this research, the engine control system on the harbour tug was modified to permit it to operate fully within the region of best fuel economy during free-running. The results from the bollard-pull predictions provide insight for the design and operation of harbour tugs in the future.

The effect of replacing standard carburetor with PE-28 carburetor on performance fuel consumption on 2006 Honda Tiger Revo

Carburetors are one of the important components on motorcycles, through modification of replacing Standard Carburetor with Racing Carburetor is one of the ways to improve engine performance. There are several types and sizes of PE, namely PE 24, PE 28, PE 38. PE 28 carburetor is often used on racing motorbikes, both Drag bikes and Roodrace bikes, where this carburetor is able to produce maximum engine performance. By testing the maximum power using a standard carburetor found at 7000 rpm engine speed, which is 11.3 HP, while the maximum power testing using a PE 28 carburetor is found at 7000 rpm engine speed, which is 11.7 HP. For testing the maximum torque using a standard carburetor found at 6000 rpm engine speed, which is 11.7 N.m, while the maximum torque testing using a PE 28 carburetor is found at 7000 rpm engine speed, which is 11.8 N.m. The use of PE 28 carburetor on a 4 stroke motorcycle greatly affects the amount of fuel consumption, it is because the PE 28 carburetor is a racing carburetor that is very suitable for those who want top speed. In addition, the advantage of the PE 28 carburetor is that it is able to improve engine performance because the type of carburetor is different from the standard and there are changes in the dimensions of the venturi hole and intake manifold, so that it can fog up more air and fuel to be brought into the combustion chamber or into the engine cylinder.