Dynamic Analysis of Automotive Hypoid Gears

Author(s):  
I. Karagiannis ◽  
S. Theodossiades

The dynamics of differentials in rear wheel drive vehicles are of major importance for the automotive industry. Hypoid transmissions — forming the motion transfer mechanism from the driveshaft to the wheels — often suffer from severe vibrations, which could lead to Noise, Vibration and Harshness (NVH) issues. The latter are often attributed to improper mesh between the mating gear flanks due to misalignments, variation of contact load and shifting of the effective mesh position. A new modelling approach on the torsional dynamics of hypoid gear pairs is presented in this work. This is characterised by an alternative expression of the Dynamic Transmission Error (DTE), which accounts for the variation of the effective mesh position. Numerical results indicate the enriched dynamic behaviour that can be predicted using the new formulation. A solution continuation method is employed to follow the response branches over the operating range of the differential under examination. The ensuing parametric studies convey the importance of the main system parameters on the dynamic behaviour of the differential, yielding suggestions for design guidelines.

Author(s):  
S Theodossiades ◽  
M Gnanakumarr ◽  
H Rahnejat

Numerical and experimental investigations shed light on the root causes leading to the emergence and persistence of an acute metallic noise in rear wheel drive light truck drivelines. Sudden demands in engine output torque combined with the presence of lash zones give rise to a phenomenon that is onomatopoeically referred to as clonk. Its multi physics nature requires a comprehensive study, which includes rigid multi-body dynamics, flexible body oscillations, and noise radiation computation. The verification of numerical results is achieved through the design and implementation of a transient dynamic experimental rig, which comprises the complete drivetrain from the engine flywheel to the rear axle. Parametric studies reveal high-frequency contributions in the driveline vibration response of certain structural modes of the driveshaft pieces, which are induced by remote impact of meshing transmission teeth through backlash. The numerically predicted spectrum of vibration is in good qualitative agreement with the experimental measurements. Combined study of the aforementioned results reveals the components that amplify the clonk noise.


Author(s):  
Hugo Heidy Miyasato ◽  
Vinícius Gabriel Segala Simionatto ◽  
Milton Dias Júnior

Powertrain vibrations is a great concern in the automotive industry, once they are related to many Noise, Vibration and Harshness (NVH) phenomena. These are very complex system once their dynamic behaviour, in many cases, involve the interaction between the combustion engine and the remaing components of the powertrain, such as the clutch, transmission, differential, etc. In this work a system approach is used. First, the torque generated by a four cylinder engine is obtained through the thermodynamic equations. Then, these torque curves for each cylinder are combined and used as the excitation of a simplified model of a front wheel drive powertrain. Finally, the influence of ignition angles on the combustion characteristics and on the order content of engine output torque is analyzed. Results show that significant changes may happen on the second and fourth order responses.


2021 ◽  
pp. 85-96
Author(s):  
V.A. Goncharov ◽  
◽  
M.N. Usacheva ◽  
A.V. Khrulkov ◽  
◽  
...  

A transmission shaft is required to transfer power from the engine to the axle and drive wheel in a rear wheel drive vehicle. A composite shaft has many advantages: greater length compared to a metal shaft, improved mechanical properties, less noise, vibration and weight. By adjusting the resin composition and the fiber reinforcement pattern, the mechanical properties of the transmission shaft can be improved. Various options for modifying carbon and fiberglass plastics to improve the characteristics of the shaft are considered.


Author(s):  
Federico Cheli ◽  
Paolo Dellacha` ◽  
Andrea Zorzutti

The potentialities shown by controlled differentials are making the automotive industry to explore this field. While VDC systems can only guarantee a safe behaviour at limit, a controlled differential can also increase the handling performance. The system derives from a rear wheel drive architecture with a semi-active differential, to which has been added a controlled wet clutch that directly connects the front axle and the engine crankshaft. This device allows distributing the drive torque between the two axles, according to the constraints due to kinematics and thermal problems. It can be easily understood that in this device the torque distribution doesn’t depend only from the central clutch action, but also from the engaged gear. Because of that the central clutch controller has to consider the gear position too. The control algorithms development was carried on using a vehicle model which can precisely simulate the handling response, the powertrain dynamic and the actuation system behaviour. A right powertrain response required the development of a customize library in Simulink. The approach chosen to carry on this research was the one used in automotive industry nowadays: an intensive simulation campaign was executed to realize an initial controller design and tuning.


2011 ◽  
Vol 86 ◽  
pp. 762-766
Author(s):  
Jian Jun Hu ◽  
Peng Ge ◽  
Zheng Bin He ◽  
Da Tong Qin

The dynamic models of whole rear-wheel drive vehicle, limited-slip differential, hydraulic control system and electronic throttle were established. Simulations of acceleration course on split-µ road, checkerboard-µ road, low-µ road and step-µ road were carried out combining electronic throttle PI controller and limited-slip differential fuzzy controller. The results show that the Anti-slip Regulation quickly works according to the road adhesion coefficient, effectively inhibits the slip of driving wheels on low adhesion coefficient road, the acceleration performance driving on bad roads was improved obviously, and show a good adaptability.


2021 ◽  
Author(s):  
Sandy Momoe Kawano ◽  
Richard W. Blob

Amphibious fishes and salamanders are valuable functional analogs for vertebrates that spanned the water-to-land transition. However, investigations of walking mechanics have focused on terrestrial salamanders and, thus, may better reflect the capabilities of stem tetrapods that were already terrestrial. The earliest tetrapods were aquatic, so salamanders that are not primarily terrestrial may yield more appropriate data for modelling the incipient stages of terrestrial locomotion. In the present study, locomotor biomechanics were quantified from semi-aquatic Pleurodeles waltl, a salamander that spends most of its adult life in water, and then compared to a primarily terrestrial salamander (Ambystoma tigrinum) and semi-aquatic fish (Periophthalmus barbarus) to evaluate whether walking mechanics show greater similarity between species with ecological versus phylogenetic similarities. Ground reaction forces (GRFs) from individual limbs or fins indicated that the pectoral appendages of each taxon had distinct patterns of force production, but hind limb forces were comparable between the salamanders. The rate of force development ('yank') was sometimes slower in P. waltl but generally comparable between the three species. Finally, medial inclination of the GRF in P. waltl was intermediate between semi-aquatic fish and terrestrial salamanders, potentially elevating bone stresses among more aquatic taxa as they move on land. These data provide a framework for modelling stem tetrapods using an earlier stage of quadrupedal locomotion that was powered primarily by the hind limbs (i.e., "rear-wheel drive"), and reveal mechanisms for appendages to generate propulsion in three locomotor strategies that are presumed to have occurred across the water-to-land transition in vertebrate evolution.


Electronics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 199 ◽  
Author(s):  
Kanwar Bharat Singh

Information about the vehicle sideslip angle is crucial for the successful implementation of advanced stability control systems. In production vehicles, sideslip angle is difficult to measure within the desired accuracy level because of high costs and other associated impracticalities. This paper presents a novel framework for estimation of the vehicle sideslip angle. The proposed algorithm utilizes an adaptive tire model in conjunction with a model-based observer. The proposed adaptive tire model is capable of coping with changes to the tire operating conditions. More specifically, extensions have been made to Pacejka's Magic Formula expressions for the tire cornering stiffness and peak grip level. These model extensions account for variations in the tire inflation pressure, load, tread depth and temperature. The vehicle sideslip estimation algorithm is evaluated through experimental tests done on a rear wheel drive (RWD) vehicle. Detailed experimental results show that the developed system can reliably estimate the vehicle sideslip angle during both steady state and transient maneuvers.


Author(s):  
Jonathan Nadeau ◽  
Philippe Micheau ◽  
Maxime Boisvert

Within the field of electric vehicles, the cooperative control of a dual electro-hydraulic regenerative brake system using the foot brake pedal as the sole input of driver brake requests is a challenging control problem, especially when the electro-hydraulic brake system features on/off solenoid valves which are widely used in the automotive industry. This type of hydraulic actuator is hard to use to perform a fine brake pressure regulation. Thus, this paper focuses on the implementation of a novel controller design for a dual electro-hydraulic regenerative brake system featuring on/off solenoid valves which track an “ideal” brake force distribution. As an improvement to a standard brake force distribution, it can provide the reach of the maximum braking adherence and can improve the energy recovery of a rear-wheel-drive electric vehicle. This improvement in energy recovery is possible with the complete substitution of the rear hydraulic brake force with a regenerative brake force until the reach of the electric powertrain constraints. It is done by performing a proper brake pressure fine regulation through the proposed variable structure control of the on/off solenoid valves provided by the hydraulic platform of the vehicle stability system. Through road tests, the tracking feasibility of the proposed brake force distribution with the mechatronic system developed is validated.


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