Gear Position Research Articles

The Analysis of Exhaust Gas Characterization in Reducing CO and HC Gas Pollution on the EFI Engine of Daihatsu Luxio 1500 CC

Air pollution from highways, particularly in an urban area which density and mobility are already on the verge of solid boundaries, resulting in environmental and human health problems. This is due to the lack of standardization of testing exhaust gas by the governmental body. Accurate results from the test and technology standardization on exhaust system which is one important component for gas pollutant elimination from the vehicle. In the present work, we examined the role of some modified exhausts on the level of pollutant exhaust, i.e. CO, HC, NOx gas. Experimental design for controlled variable is the speed, torque of the wheel, and gear position. Several modifications of exhaust gas were tested were tested, i.e. Standard, 3-way catalytic converter, racing and 2-ways catalytic converter. The data is gained through dynamometer and exhaust gas Analyzer as a speedometer gauges, torque wheels, and levels of exhaust gas that comes out of the tailpipe. Statistical analysis of the results uses one-way ANOVA. The result showed that the order in reducing exhaust gas CO and HC are: (1) two-way exhaust gas and 3 Way Catalytic Converter exhaust gas, (2) standard and (3) modified exhausts. 3 Way catalytic converter was the best to eliminate NOx than other three exhaust gas system

Tooth contact analysis of crossed beveloid gear transmission with parabolic modification

Considering the gear manufacturing and meshing theory, a numerical design approach with parabolic modifications was proposed to improve the mesh behaviors of crossed beveloid gear transmission. The generating procedure with parabolic modifications for the crossed beveloid gears with small shaft angle was proposed. And the analytical mesh model with misalignments of crossed beveloid gear transmission was developed. Then the effects of parabolic modifications on contact path and contact ratio were investigated. Also, the misalignments sensitivity was analyzed for the beveloid gears with and without parabolic modifications. Results show that the design situation with a positive parabola coefficient for the pinion and a negative parabola coefficient for the gear is better than other combinations of the parabola coefficients. Both the offset error and shaft angle error tend to deviate the contact path from the theoretical middle region. The parabolic modifications can reduce the sensitivity of contact path to the offset error and shaft angle error for crossed beveloid gear transmission effectively. Both axial pinion and gear position error has little influence on the mesh behaviors for the crossed beveloid gear pair with and without parabolic modifications.

Assessing acoustic emission in 1055I John Deere combine harvester using statistical and artificial intelligence methods

Agricultural mechanisation is accompanied by several challenges, one of them is the noise pollution caused by machinery. Noise pollution has undesirable effects on humans such as temporary or permanent loss of hearing, decrease in working efficiency and increase in accidents. The aim of this study is to assess noise pollution in the 1055I John Deere combine harvester. The tests were performed at different engine speeds, gear positions and sound measuring locations. The obtained data were analysed in the form of factorial test based on a completely randomised design. An artificial neural network model was created to predict the sound level in the combine. The results of variance analysis for the effects of the main factors on the level of sound were significant at probability level of 1%. The sound intensity reaching the driver's ear based on frequency analysis is equal to 84.16 dB at the frequency of 4000 Hz. The mean square error and the correlation coefficient for the best neural network with ten neurons in the hidden layer were obtained. The permitted time duration of driving the harvester was calculated to be less than 2 h.

Design of Gear Churning Power Loss Measurement Device

To explore the impacts of gear churning power losses, a research was conducted to achieve the internal causes of power losses of churning gear by designing a gear churning power losses measurement device. The gear churning power losses could be influenced by different gear modules, the number of teeth and the axial position of gear. Finally, the impacts of gear churning power losses were discussed by comparing experimental data and theoretical data.

A disassembly-free method for evaluation of spiral bevel gear assembly

The paper presents a novel method for evaluation of assembly of spiral bevel gears. The examination of the approaches to the problem of gear control diagnostics without disassembly has revealed that residual processes in the form of vibrations (or noise) are currently the most suitable to this end. According to the literature, contact pattern is a complex parameter for describing gear position. Therefore, the task is to determine the correlation between contact pattern and gear vibrations. Although the vibration signal contains a great deal of information, it also has a complex spectral structure and contains interferences. For this reason, the proposed method has three variants which determine the effect of preliminary processing of the signal on the results. In Variant 2, stage 1, the vibration signal is subjected to multichannel denoising using a wavelet transform (WT), and in Variant 3 – to a combination of WT and principal component analysis (PCA). This denoising procedure does not occur in Variant 1. Next, we determine the features of the vibration signal in order to focus on information which is crucial regarding the objective of the study. Given the lack of unequivocal premises enabling selection of optimum features, we calculate twenty features, rank them and finally select the appropriate ones using an algorithm. Diagnostic rules were created using artificial neural networks. We investigated the suitability of three network types: multilayer perceptron (MLP), radial basis function (RBF) and support vector machine (SVM).

AMT downshifting strategy design of HEV during regenerative braking process for energy conservation

For hybrid electric vehicles (HEVs), regenerative braking might be the most effective way of energy conservation. However, the braking energy usually cannot be regenerated completely due to the limit of the motor maximum torque. When the braking torque provided by electric motor (EM) cannot meet the driver’s braking demand, the hydraulic brake system should provide extra braking torque, which results in braking energy loss. Therefore, it is meaningful adjusting EM work point to maximize the regenerative energy by transmission downshifting. In this paper, an HEV equipped with an automated manual transmission (AMT) is chosen as the study platform. First, simplified dynamic models of HEV system are built. Then, the process and advantages of AMT downshifting are analyzed and the characteristics of regenerative braking are obtained with different gear positions and different, of which two kinds of downshifting strategy are proposed on basis. At last, hardware-in-loop tests are carried out, and results show that the energy conservation of regenerative braking process with downshifting can be increased by 10.5–32.4% compared to that without downshifting.

On the identification of the angular position of gears for the diagnostics of planetary gearboxes

Generally, in planetary gearbox diagnostics, vibration transducers are placed on the gearbox case near the ring gear. The relative angular position of the planet gears with respect to the transducer is a useful information for the evaluation of vibration signals related to planet/sun gears. This angular position is usually unknown, or it is known with a large tolerance causing serious difficulties in both gears and bearing diagnostics. In fact, noise and spurious component from healthy planets could overhang the informative content about incipient faults. The present work seeks to propose two alternative methods for the identification of the angular position of the planet gears with respect to the transducer. The first one is based on the study of how the power flows inside the Time Synchronous Average of the ring gear, whilst the second method is based on a modified statistical parameter such as the Crest Factor. The effectiveness of these methods is assessed on the basis of actual vibration signals acquired from a faulty planetary gearbox. The knowledge of the exact angular position of the planet gears allows the diagnostics of both gears and bearings, as proven by extensive experimental activities reported in the paper.

Influence of Relative Position of Gears and Casing Wall Shape of Gear Box on Churning Loss under Splash Lubrication Condition—Some New Ideas

ABSTRACTA new rotatable test rig is developed to perform oil churning loss experiments to clarify the influence of the relative position of gears and casing wall shape of gear box under splash lubrication condition. Torque losses are measured and photos are taken using a stroboscope to observe the oil behavior. Based on the test results, it has been confirmed that in addition to the well-known factors, relative position and casing wall shape have significant effects on the churning loss and should be considered in the modeling process, which has been neglected in most previous studies. In this article, the importance of the steady-state oil surface profile (SOSP) is emphasized. New ideas are proposed on how other working conditions such as immersion depth and rotation speed influence the churning loss.

자동화 수동변속기용 건식클러치의 속도기반 Kiss-Point 능동 보상에 관한 연구

Abstract : Clutch torque control is the key to the ride comfort improvement of a vehicle equipped with AMT (automated manual transmission). For such control, the torque transfer starting point, known as the “kiss point,” should be indicated or at least estimated to compensate for the clutch torque. The kiss point changes due to wear, high temperature, and fatigue; as such, it should be estimated while the vehicle is being driven. In this study, the method of kiss point active estimation for an AMT vehicle with a dry-type clutch was devised. The kiss point is learned while the engine is in an idle state and while the transmission is at a neutral gear position. It is determined when the input shaft of the transmission starts to rotate by slowly engaging the clutch. The noise of the shaft speed signal during the slow engagement process is filtered for accurate control. The kiss point estimation at various clutch engagement speeds was analyzed via a vehicle test. Key words : Kiss-Point(키스 포인트), Touch point(접촉점), Automated manual transmission(자동화수동변속기), Dry-type clutch(건식클러치), Estimation(추정), Heavy duty vehicle(중 부하 차량)

Nośność powierzchniowa przekładni zębatych o kołowo-łukowym zarysie zębów typu Nowikowa

Article presents the algorithm for obtaining maximum surface stresses for Novikov gears. Described surface strength calculation method is based on Hertz theory of two bodies being in point contact. What’s more the influence of gear position errors on maximum contact stresses has been presented. Also the comparison of Hertz stresses for Novikov and involute gears has been made.

Phenomenological models of vibration signals for condition monitoring and fault diagnosis of epicyclic gearboxes

Condition monitoring and fault diagnosis of epicyclic gearboxes using vibration signals are not as straightforward as that of fixed-axis gearboxes since epicyclic gearboxes behave quite differently from fixed-axis gearboxes in many aspects, like spectral structures. Aiming to present the spectral structures of vibration signals of epicyclic gearboxes, phenomenological models of vibration signals of epicyclic gearboxes are developed by algebraic equations and spectral structures of these models are deduced using Fourier series analysis. In the phenomenological models, all the possible vibration transfer paths from gear meshing points to a fixed transducer and the effects of angular shifts of planet gears on the spectral structures are considered. Accordingly, time-varying vibration transfer paths from sun-planet/ring-planet gear meshing points to the fixed transducer due to carrier rotation are given by window functions with different amplitudes. And an angular shift in one planet gear position is introduced in the process of modeling. After the theoretical derivations, three experiments are conducted on an epicyclic gearbox test rig and the spectral structures of collected vibration signals are analyzed. As a result, the effects of angular shifts of planet gears are verified, and the phenomenological models of vibration signals when a local fault occurs on the sun gear and the planet gear are validated, respectively. The experiment results demonstrate that the established phenomenological models in this paper are helpful to the condition monitoring and fault diagnosis of epicyclic gearboxes.

神経振動子の同期特性を利用した歯車回転位相角の推定

神経振動子の同期特性を利用した歯車回転位相角の推定

Some Considerations about the Influence of the Stress Intensity Factors KImin, KIImax and Keq in Fatigue Crack Propagation in the Substrate of the Gear Teeth

The values of the stress intensity factor (SIF) KI are almost always negative in the substrate of the gear teeth, due to the compressive stresses field. The more negative values are higher, respectively, the positive values are lower, the crack faces are more compressed, so the probability of crack propagation after the mode I is lower. Thus, the analysis of the factors leading to the minimum KI values may reveal the conditions that favor the fatigue crack propagation by opening mode. Instead, SIF KII is determinant in the growth rate of the fatigue crack by mode II, in terms of compressive stresses field. Thus, the more KII is higher, the propagation speed is higher, so an analysis of the factors that lead to its maximum value is very useful. The equivalent stress intensity factor Keq corresponds to a mixed-mode of loading and take into account the simultaneous influence of both stress intensity factors KI and KII. The variation of this factor can be used as a parameter of the modified Paris law, in order to study the propagation of the fatigue cracks in the case of mixed-mode loading of contact area between teeth flanks. SIFs variations were analyzed according to the state of stresses, position on the pitch line between the gear teeth flanks, position and angle of an initial crack in the gear tooth substrate, residual tensions etc.

Modeling and analysis of engaging process of automated mechanical transmissions

In automated mechanical transmissions, engaging sleeve with clutch gear causes the switches of mechanical coupling modes of engaging-related parts, and impacts may happen to make the part speeds have discrete transitions during the engaging. The two characters make the engaging process exhibit both continuity and discreteness. The aim of the paper is to develop a high-fidelity model to capture the trajectories of the parts in the transmission. We treat the engaging as a two-phase process—sleeve first interacting with synchro ring and then with clutch gear. The part movements under a certain constraint are governed by multibody dynamics, and the speed jumps caused by impacts are described using the Poisson coefficient of restitution. To couple the continuous evolutions and discrete transitions of the states, a hybrid automaton model is developed. This model allows for the characteristic analysis of the engaging process with multiple interaction cases between the engaging-related parts, and it is validated by bench tests. The effects of two key factors—the relative tooth position of sleeve and clutch gear and the shifting force—on engaging duration and impact are studied through numerical simulations.

다축 스핀들 헤드 기반의 전용 공작기계 설계

When many holes on a plane are machined simultaneously, the positional precision and machining efficiency are very important. Multi-spindle heads are typical order making products of which the number of shafts and hole positions vary depending on the size or form of the product. For the automatic design of multi-spindle heads, the design modules for power transmission systems for drive, idle, and spindle shafts were developed, and a design technique the determining the optimum position and number of idle shafts according to gear positions was developed. In addition, for the precise determination of the multi-spindle head, the design methods for the guide planes of columns, and feed mechanisms were devised. In addition, the design modules for accurate clamping and automatic transportation mechanisms were developed. Finally, in order to simplify and standardize the design process, the design analysis and simulation verification modules are integrated.

Fuel-Optimal Cruising Strategy for Road Vehicles With Step-Gear Mechanical Transmission

This paper studies the principles and mechanism of a fuel-optimal strategy in cruising scenarios, i.e., the pulse and glide (PnG) operation, for road vehicles equipped with a step-gear transmission. In the PnG strategy, the control of the engine and the transmission determines the fuel-saving performance, and it is obtained by solving an optimal control problem (OCP). Due to a discrete gear ratio, strong nonlinear engine fuel characteristics, and different dynamics in the pulse/glide mode, the OCP is a switching nonlinear mixed-integer problem. This challenging problem is converted by a knotting technique and the Legendre pseudospectral method to a nonlinear programming problem, which then solves the optimal engine torque and transmission gear position. The optimization results show the significant fuel saving of the PnG operation as compared with the constant-speed cruising strategy. The underlying fuel-saving mechanism of the PnG strategy is explained graphically. For a real-time implementation, a near-optimal practical rule that enables a driver and/or an automatic control system to fast select gear positions and engine torque profile is proposed with only slightly deteriorated fuel saving.

Eco-Departure of Connected Vehicles With V2X Communication at Signalized Intersections

Eco-driving at signalized intersections has significant potential for energy saving. In this paper, we focus on eco-departure operations of connected vehicles equipped with an internal combustion engine and a step-gear automatic transmission. A Bolza-type optimal control problem (OCP) is formulated to minimize engine fuel consumption. Due to the discrete gear ratio, this OCP is a nonlinear mixed-integer problem, which is challenging to handle by most existing optimization methods. The Legendre pseudospectral method combining the knotting technique is employed to convert it into a multistage interconnected nonlinear programming problem, which then solves the optimal engine torque and transmission gear position. The fuel-saving benefit of the optimized eco-departing operation is validated by a passenger car with a five-speed transmission. For real-time implementation, a near-optimal departing strategy is proposed to quickly determine the behavior of the engine and transmission. When a string of vehicles are departing from an intersection, the acceleration of the leading vehicle(s) should be considered to control the following vehicles. This issue is also addressed in this paper.

A visual basic program for predicting optimum gear and throttle position for best fuel economy for 32 kW tractor

A visual basic program was developed to determine the optimum gear and throttle position on the basis of minimum fuel consumption per hectare for ploughing, cultivating and harrowing operations. The program provides an intuitive interfaces by linking database such as tractor, tyre and implement specifications, draft and tractions model constants, fuel consumption model, soil and operating conditions to predict the minimum fuel consumption of selected model. The fuel consumption model was developed by conducting PTO test under variable throttle and load conditions. The coefficient of determination (R2) value for developed model was found close to 0.99. The program was validated with the data collected from the field experiments conducted with a 32kW PTO power 2WD tractor and 2-bottom reversible MB plough under different operating conditions. It was found that the developed program predicted optimum gear as L3 (6.9km/h) at 2066rpm and on an average under predicted slip values by 50–62%, draft by 4–20% and over predicted fuel consumption by −19 to 52% in the depth range of 18–22cm.

Computer simulation for predicting tractor engine overloading for tillage operations

The primary purpose of agricultural tractors, especially those in the middle to high power range, is to perform field work. Tractor manufacturer needs prediction of tractor field performance data in the tractor design stage itself so that they can optimize the transmission with the engine to give better performance. Engine speed prediction model was developed using Budni tractor test data. Developed engine speed prediction model for 10 engine model was compared with actual data of engine speed, it was found that for all engine models R 2 (co-efficient of determination) between predicted and actual engine speed was greater than 0.98. So developed empirical equations can be used in software for predicting engine speed. The field experiments were conducted using a tractor with three different implements viz., 3-bottom mould board plough, 11-tyne cultivator and offset disc harrow. For each operation, the performance parameters such as draft, slip, depth, engine speed and fuel consumption were measured at different combinations of gear and throttle positions. Software in visual basic was developed to predict tractor engine overloading (engine speed drop) for field operations (MB plough, cultivator and disc harrow). The developed software was validated using field data collected in Kanchipuram, Tamil Nadu. For field operation with 2 WD tractor equipped with bias-ply tires and attached with cultivator the deviation of software predicted engine speed (rpm) drop was -16.47 to 26.92 per cent and for draft was -11.07 to 4.65 per cent. For field test with offset disc harrow the deviation of software predicted engine speed (rpm) drop was -17.44 to 15.38 per cent and for draft was -10.98 to 4.76 per cent. For field operation with MB Plough the deviation of software predicted engine speed (rpm) drop was 18.48 to 21.52 per cent and for draft -12.01 to -3.75 per cent.

Measurement of weight transfer in two wheel drive tractor by developed ring transducer

Weight transfer or weight shift is, in fact, reaction transfer or change in the reactions of front and rear wheels of the tractor. Weight transfer because of drawbar loading decreases soil reaction against the front wheels and increases reaction against the rear wheels. A study was done to measure the dynamic front wheel reaction of the tractor and thereby the weight transfer from front to the rear wheel. Developed ring transducer was attached below the tractor's front axle to measure the front wheel reaction. Field experiments were conducted using Ford-3630 tractor with three different implements viz., 3-bottom mould board plough, 9-tyne cultivator and offset disc harrow. For each operation, the parameters such as dynamic front wheel reaction, draft, slip and depth were measured. The instrumented link forces were used to calculate implement draft. Slip was calculated by measuring actual speed in the field at different depths and theoretical speed on a concrete surface in the same gear and throttle position. The dynamic front wheel reaction was measured by using the developed ring transducer and thus, the weight transfer from front to rear was calculated. Also the weight transfer for a given draft was calculated theoretically and compared with the experimentally determined weight transfer. The data indicated that weight transfer increased with increase in draft. The maximum variation between theoretical and experimental values of weight transfer was found to be 12.62 per cent. This variation may be due to some assumptions made in theoretical calculation as well as due to vibration of the front axle while operating the tractor in the field.