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A combined lumped parameter, finite element (FE) and boundary element (BE) model is developed to predict the whine noise from rear axle. The hypoid geared rotor system, including the gear pair, shafts, bearings, engine and load, is represented by a lumped parameter model, in which the dynamic coupling between the engaging gear pair is represented by a gear mesh model condensed from the loaded tooth contact analysis results. The lumped parameter model gives the dynamic bearing forces, and the noise radiated by the gearbox housing vibration due to the dynamic bearing force excitations is calculated using a coupled FE-BE approach. Based on the predicted noise, a new procedure is proposed to tune basic rear axle design parameters for better sound quality purpose. To illustrate the salient features of the proposed method, the whine noise from an example rear axle is predicted and tuned.

Reduction of the drag torque and longevity of the clutch assembly are the most important factors for vehicle transmission improvement. The decreasing trend of the drag torque with speed after its peak is a common characteristic of the clutch assembly. Several theoretical models have been presented by the researchers describing the drag torque characteristics at lower clutch speed. However, very little study has been made on the drag torque behavior at very high clutch speed (6000∼10000+ rpm). The alarming jump of the drag torque at high speed operating condition remains unexplained till date. In this paper, we investigated the possible reasons of torque jump up at high rotation speed and solution to overcome this problem. We presented an analytical correlation of torque jump up with the excessive decrease of local static pressure and assumed that vacuum formation is the possible reason of high speed torque rising and associated vibration.

In this paper the power hop phenomenon is analyzed and important influencing factors are investigated. The results of driving tests on various road surfaces with different types of cars with longitudinal and transversal mounted engines as well as with front and rear wheel drive are presented. In order to understand and quantify the power hop effect the rotational speed of the individual wheels and the engine are measured. Additionally, the drive shaft torque, the engine movement in its bearings and the vertical deflection of the wheel with respect to the chassis are determined to get detailed knowledge about physical dependencies. It is shown that the rotational speed of the driven wheels is not a sufficient indicator to assess the occurrence of power hop by measurements. Alternatively, the measured longitudinal acceleration at the seat rail provides a good quantification.

Free-wheel mechanisms transmit rotary motion in only one direction. They are widely used, for example, in hydraulic transformers, pulsed continuous transmissions, inertial automatic torque transformers, electrical starters for motors, and metal- and wood-working drives. Unfortunately, existing free-wheel mechanisms are insufficiently reliable and durable and in many cases limit the reliability of the drive as a whole. Thus, the insufficient life of free-wheel mechanisms delays the use of inertial automatic continuous transmissions, which have many benefits over existing transmissions. In most known free-wheel mechanism, the whole torque is transmitted through locking elements such as balls, rollers, eccentric wheels, pawls, slide blocks, and wedges, whose operation at large loads may limit the life of the mechanism.

Improved economic growth and infrastructure in India has led to new market trends for commercial vehicles. Customers now expect high levels of comfort from all tactile points in a truck cabin; among them the gearlever knob is frequently used and its reactions greatly influence how a driver perceives gearshift quality (GSQ) and thereby vehicle quality. The importance of the gear shift quality of manual transmissions has increased significantly over the past few years as the refinement of other vehicle systems has increased. In Gearbox, synchroniser is the major component whose performance will affect the peak engagement force to a large extent. Synchroniser mechanism allows gear change to be smooth, noiseless and without vibrations. Since the maximum synchronisation effort vary depending on the rate of the shift actuation, it is difficult to compare synchronisers in different transmissions by force alone.

Stringent diesel emission regulations have been forcing constant reduction in the discharge of particulate matter and nitrogen oxide (NOx). Current state-of-the-art in-cylinder solutions are falling short of achieving these limits. For this reason engine manufacturers are looking at different ways to meet the emission regulations. Selective catalytic reduction (SCR) of oxides of nitrogen with ammonia gas is emerging as preferred technology for meeting stringent NOx emission standards across the world. SCR system designers face several technical challenges, such as avoiding ammonia slip, urea crystallization, low temperature deposits and other potential pitfalls. Simulation can help to develop a deep understanding of these technical challenges and issues, identify root causes of problems and help develop better designs. This paper describes the modeling approach for Urea Water Solution (UWS) spray and its interaction with canister walls and exhaust gases.

The problem of the theory of power transmission to wheels of a vehicle, as part of the theory of cars, has always been in the center of attention of specialists. With the improvement of designs of a vehicle there was a need of thorough scientific review of theoretical and experimental aspects of creating and applying of mechanical, hydrostatic, electrical, and combined transmissions. This has always remained one of the most important questions of the rational allocation of power among drive wheels. In the present paper, it has been done study of different methods of power distribution among the drive wheels of an all-wheel-drive truck, namely: method of partial solution; method of introducing a rigid kinematic connection; method of periodical action; and method of limit of excessive action. Assessment how these methods influence on the performance characteristics of a multi-purpose vehicle has been done.

The Indian automotive sector is experiencing a major shift, focusing predominantly towards the levels of quality, reliability and comfort delivered to the customer. Since the entry of global players into the market, there is a rising demand for timely product launches with utmost priority to reliability. In any vehicle, engine isolation systems play a critical role in isolating the engine vibrations from the vehicle chassis. This project details on how testing can aid in reducing the launch time as well as estimating the reliability of the component when used in a different application/vehicle. It proposes a methodology to formulate a life model for the engine mount considering various combinations of predictor parameters affecting its performance over its design life. In order to maintain good correlation with the field (which considers the loading pattern and the environmental factors), warranty data was analyzed and the predictors were chosen appropriately.

Maximum pressure is an essential parameter determining the degree of environmental impact of pneumatic tractor wheels on soils. The authors of the paper offer a method for determining and adjusting maximum pressure of a pneumatic tractor wheels on the supporting surface. The paper contains an analysis of the variation of maximum pressure on soils for various values of internal tire pressure and vertical load on a wheel. The above method allows parameters for systems of monitoring and adjustment of maximum pressure on soils to be set up by measuring tire flexure and adjusting it through changing the internal air pressure.

This paper demonstrates the use of a system level model that includes torsional models of a Cummins diesel engine and an Allison transmission to study and improve system NVH behavior. The study is a case where the two suppliers of key powertrain components, Cummins Inc. and Allison Transmission Inc., have collaborated to solve an observed NVH problem for a vehicle customer. A common commercial tool, Siemens' AMESim, was used to develop the drivetrain torsional system model. This paper describes a method of modelling and calibration of baseline engine and transmission models to identify the source of vibration. Natural frequencies, modal shapes, and forced response were calculated for each vehicle drive gear ratio to study the torsional vibration. Several parametric studies such as damping, inertia, and stiffness were carried out to understand their impact on torsional vibration of the system.

An electro-hydraulic servo system makes the basis for a mechatronic locomotion module (LM) and for a complex comprising an LM and an undercarriage of a vehicle. The servo system of the wheel module/LM complex is a combination of the information and power channels of the electro-hydraulic wheel drive within the steering system. A combination of the servo systems makes up a complex of servo systems of the steering system of the multi axis wheel mover of the vehicle. Theoretical and experimental studies of the functioning all-wheel steering were aimed on substantiation the rational algorithmic maintenance of the automatic control system. The results of the study allowed formulating the basic principles of designing and calculating the functionality algorithms for the steering system of the complex of mechatronic modules of the multi-axis vehicle.

Recent years have witnessed an increase in the number of electrical loads being driven by semiconductor devices in the body control module (or BCM) rather than by electro-mechanical relays in a typical truck with a 24V vehicle power net. This paper presents the major challenges caused by the higher voltage class of the truck supply and the longer wire harness cables, followed by an analysis of some key issues related to the design of truck BCMs to drive different loads. It offers some general guidance on practical design issues to BCM designers, such as an understanding of the advantages and disadvantages of different BCM architectural topologies, how to make a choice between a relay or a semiconductor driver, knowledge of the requirements of semiconductors used in truck applications etc.

The EU emergency call (eCall) system is used as a vehicle emergency telematic system to reduce the fatalities and save more lives in vehicular incidents. We have designed and implemented the CRC module for the in-vehicle system (IVS) of the EU eCall on an FPGA device. As the CRC is a crucial part of the system to detect bit errors during the transmission, this paper presents the hardware design procedures of the CRC module. The system reads the 1120 serial input bits of the Minimum Set of Data (MSD), calculates the 28-bits of the CRC parity bits, and generates the MSD appended with CRC as the output signal that is consisting of 1148 serial bits. The system is designed in Verilog HDL, compiled, synthesized, and simulated for different MSDs. The results are shown and analyzed for varied applied MSDs. The flowchart of the implemented algorithm is illustrated and discussed.

Internal combustion engines continue to grow more complex every day out of necessity. Legislation and increasing customer demand means that advanced technologies like variable valve actuation (VVA), multi-path exhaust gas recirculation (EGR), advanced boosting, and aftertreatment systems continue to drive ever-expanding requirements for engine control to improve performance, fuel economy, and reduce emissions. Therefore, controller development and implementation are becoming more costly, both in terms of time and the monetary investment in engine hardware. To help reduce these costs, a sophisticated tool chain has been created which allows a real-time, physical, crank-angle resolved one-dimensional (1D) engine model to be implemented on a rapid prototyping engine control unit (ECU) which is then used in the control strategy of a running engine. Model-based controllers have been developed and validated to perform as well as or better than controllers using traditional sensors.

Electrification is a key enabler to reduce emissions levels and noise in commercial vehicles. With electrification, Batteries are being used in commercial hybrid vehicles like city buses and trucks for kinetic energy recovery, boosting and electric driving. A battery management system monitors and controls multiple components of a battery system like cells, relays, sensors, actuators and high voltage loads to optimize the performance of a battery system. This paper deals with the development of modular control architecture for battery management systems in commercial vehicles. The key technical challenges for software development in commercial vehicles are growing complexity, rising number of functional requirements, safety, variant diversity, software quality requirements and reduced development costs. Software architecture is critical to handle some of these challenges early in the development process.

This paper studies the characteristics of fuel consumption and exhaust emission of city transit buses, and analyzes the fuel saving rate and exhaust pollutants reduction effect of LPG-HEV buses relative to LPG buses. The running speed, fuel consumption, exhaust emission and other variables of 3 LPG-HEV buses that aren't plug-in hybrid, and 2 LPG buses were measured by a portable emission measurement system (PEMS) under real driving situations of city transit buses in Guangzhou, China. The test data was analyzed to make a comparison between LPG-HEV and LPG buses. The study results show that the running speed of city buses in real driving modes is mainly distributed in the range of 0 to 35 km/h, and the average value is 18km/h, while the acceleration is distributed in a range from −0.5 to 0.5m/s2 mainly. The average fuel consumption of LPG-HEV buses is 51.02 l/100km, and is 6.23% lower than that of LPG buses.

The use of design of experiment (DoE) and data-driven simulation has become state-of-the-art in engine development and base calibration to cope with the drastically increased complexity of today's engine ECUs (electronic control units). Based on the representation of the engine behavior with a virtual plant model, offline optimizers can be used to find the optimal calibration settings for the engine controller, e.g. with respect to fuel consumption and exhaust gas emissions. This increases the efficiency of the calibration process and reduces the need for expensive test stand runs. The present paper describes the application of Gaussian process regression, a statistical modeling approach with practical benefits in terms of achievable model accuracy and usability. The implementation of the algorithm in a commercial tool framework enables a broad use in series engine calibration.

The relationship between fuel dilution of the crankcase oil and low-speed pre-ignition (LSPI) was studied experimentally with a highly-boosted 1.8L turbocharged gasoline direct injection (TGDI) engine fueled with RON93 gasoline. It was found that properties of oil particles entered the engine cylinder were affected significantly by fuel dilution. The gasoline content in the oil represents those with long carbon chain or heavy species in gasoline, with much lower boiling points and auto ignition temperatures than those for the undiluted engine oil. Thus, dilution of the engine oil by these gasoline species lowers the volatility and the minimum auto ignition temperature of the engine oil. With 15% fuel content in the oil, the flash point and the fire point of the SAE 5W30 oil dropped from 245 °C to 90 °C and from 265 °C to 150 °C, respectively.

The paper describes the measurement of PM emission from an excavator engine under actual operating conditions. The exploration of the relations between the engine operating parameters and its emissions requires measurements under actual conditions of engine operation. The specificity of the emission measurements, PM in particular, requires technologically advanced measuring devices. The situation gets even more complicated when, beside the PM mass. The particle size distribution and number (PN) also need to be measured. An important technical issue is the difficulty in fitting the measurement equipment in/on the vehicle in operation (e.g. excavator), which is why the presented investigations were carried out in a laboratory under simulated operation. The laboratory technicians applied load to the engines through the excavator hydraulic system.

Developing a quiet brake system has been a constant task for OEMs as well as their brake suppliers. As a major component in the brake system, the rotor plays a significant role in brake noise performance. Owning to the cost and damping property advantages, gray iron is still the most widely used material for brake rotor application. When pads/rotor coupling is examined to address noise issues, however, most efforts have been on pads and insulators. Rotor specifications are rather general and the component is typically accepted based on grades defined by mechanical property minimum (mostly in G3000 SAE J431). Nevertheless, we have found that gray iron within a grade can have wide microstructure variations, and the deviation (especially on the rotor friction surface) can critically affect the noise propensity in addition to friction output performance and wear characteristics. In this work, the impact of brake disc material on brake noise and output performance is investigated.