Automotive Science and Engineering
Volume:11 Issue: 4, Autumn 2021

This paper experimentally investigates the trafficability of a small tracked vehicle on a slope. An increase in the angle of slope inclination may divert the vehicle from its path. In other words, the deviation of the vehicle is due to a sudden increase in the yaw angle. Also, the tip-over occurs at a specific slope angle. The locomotion of the small tracked vehicle on soils with different terramechanics (such as cohesion, internal friction angle, cohesive modulus, and friction modulus) is also simulated to evaluate its slope-traversing performance. Moreover, the impact of velocity and soil type on traversing a slope is measured. The proposed yaw angle control system is modeled for controlling the yaw angle of the tracked vehicle. This controller is designed through co-simulation. It keeps the tracked vehicle at zero yaw angle to achieve straight locomotion on slopes. It is compared to the PI, PID, and fuzzy controllers. The response of this controller is faster than PI and PID controllers. A Comparison between fuzzy and proposed yaw angle controller yields almost similar responses. The mechanism of the proposed yaw angle controller is also easier to understand. The precision of the controller's performance is measured by simulating over different terrains.

The confluence area cracks is most important durability problems in internal combustion engines. The aim of this article is a thermo-mechanical analysis for exhaust manifold using elasto-viscoplastic chaboche model. The Chaboche model was selected for the elasto-viscoplastic model including a kinematic hardening plastic law coupled with the Norton creep equation. The modeling, meshing and analyzing was performed on a finite element model of the exhaust manifold in ABAQUS software. In order to increase the accuracy of finite element analysis (FEA) results, temperature-dependent of material parameters was considered. The results of mechanical-thermal analysis showed that the temperature maximum and stress is visible in the confluence area. Obtained FEA results proved the manifold gasket leak is another region of critical that has to sustain the expanding and contracting of the heated exhaust manifold metal. The results of the modal analysis proved that the maximum strain energy density and total strain energy exist in the confluence area. The results of the thermo-mechanical analysis are compared with the real sample of the damaged exhaust manifold to evaluate the properly results, and it has been shown that serious identified zones correspond to the failure areas of the real sample.

In this paper, firstly chaotic behavior of the lateral dynamics of vehicle is investigated by the use of numerical tools including Lyapunov exponent and bifurcation diagrams. To this end rout to chaos along with period doubling and quasi-periodic responses are demonstrated in terms of bifurcation diagrams. After chaos analysis, a novel controller commensurate with the chaotic characteristics of the system, in conformity with Poincaré map is represented to suppress the chaotic behavior of lateral movement. The Poincaré map of the system is derived by means of a neuro fuzzy network. A robust Fuzzy system on the basis of nonlinear Ott-Grebogi-Yorke (OGY) method forms the control system. Closed-loop results of the system shows effectiveness of the chaos controller in extreme conditions.

Brakes are a vital, prime, and accident preventive part of any motor vehicle. Brakes help in controlling the vehicle speed when needed by changing the kinetic energy and potential energy into thermal energy. In this work, we have found out temperature distribution, deformation distribution, equivalent stress distribution, and equivalent strain distribution by varying the number of vanes in a ventilated disc brake, considering the coupled thermal and structural field in transient conditions, and compared the results to find out the best possible design. We have considered the disc rotor’s material as grey cast iron and the disc pad’s material as carbon fiber reinforced carbon matrix. It has been found out that with an increase in the number of vanes, there is a reduction in the maximum deformation, maximum stress, and maximum strain and there is a slight increase in the maximum temperature during the whole simulation. A disc rotor with 18 vanes is found to be the best possible design among all 5 designs considered in this paper.

Elastomeric engine mounts are being used in heavy vehicles as well as passenger cars to absorb the vibrations of the engine, carry its weight and reduce its movement while driving. The aim of this research is some studies that have been done to find the components of the elastomeric compound. Moreover, the feasibility study of constructing three different specimens with different percentages of soot and oil has been carried out in order to achieve the desired characteristics in the heavy vehicle engine mount. A rheometric test was then performed to determine the temperature and time of sintering. The tensile strength test has been used to determine the elasticity of the rubber specimens and to achieve high damping coefficients. Also the tensile strength test was performed with the aim of obtaining a specimen with a suitable stress-strain relationship and comparing the results with the reference engine mount. Consequently, the elastomeric compound is used to make the elastomeric engine mount of heavy duty vehicle in the form of rubber and reverse engineering.

Many efforts have been made to increase power and reduce emissions from internal combustion engines. For this purpose, the internal combustion engine subsystems are examined via many studies, and the effective parameters in each of them are analyzed. One of these subsystems is the air inlet and outlet to the combustion chamber, the most important part of which is the manifold. In the present study, using one-dimensional modeling of the OM457 heavy diesel engine in the GT SUITE software environment, the effect of geometric parameters of cylinder runner’s length - cylinder runner’s transverse distance as well as plenum’s depth on the performance and the emissions of this engine has been investigated. During this study, it was concluded that increasing the volume of the plenum not only improves the engine’s output but also reduces the emission of pollutants produced. Also, increasing the length of the cylinder runner increased the engine power. The change in the transverse distance of the cylinder runners did not have a significant effect on the power and pollutants of the sample engine. It was also observed that in similar geometric changes, the effect of changing the input manifold is significantly greater than the output manifold level.