Optimization of the design and experimental study of the stress-strain state of the rear suspension balancer of an all-terrain vehicle

Reducing the curb weight of wheeled vehicles has long been one of the priority areas of work of automotive engineers, since this can significantly improve the operational properties of a wheeled vehicle: improve dynamics, passability, reduce fuel consumption and emissions of harmful sub-stances. A significant proportion of the vehicle's curb weight belongs to highly loaded parts of the frame, transmission and suspension. Therefore, the creation of lightweight, highly loaded parts will make a significant contribution to reducing the curb weight of the whole vehicle. The paper describes the application of the topological optimization method based on finite ele-ment modeling in the design of highly loaded parts of the chassis of vehicle. An example of the syn-thesis of the power circuit of the rear suspension balance bar of an all-terrain vehicle with a descrip-tion of the design model, load modes and interpretation of the results is shown. The optimization problem was solved using a finite element model of varying density. Minimization of the potential energy of deformation was used as an objective function, and the target volume in fractions of the original design space was used as a limitation. A comparative analysis of the obtained design with analogous designs is presented. The formulation and results of an experimental study of the stress-strain state of the optimized balance bar are described. As a result of optimization, it was possible to achieve a reduction in the weight of the balance bar to 49% in comparison with an analogue design while maintaining the required strength. Experi-mental verification of the bearing capacity of the balance bar showed the need for more thorough verification calculations of optimized parts, including taking into account manufacturing and as-sembly errors.

Model for Calculating Average Vehicle Mileage for Different Vehicle Classes Based on Real Data: A Case Study of Croatia

Mileage data collected via surveys based on self-estimation, reports from garages and other sources which use estimations are rough estimates and differ greatly from the actual mileage. Vehicle mileage is a major factor in emission calculations and needs to be as accurate as possible to obtain reliable emission models. Odometer readings are collected annually at the periodic technical inspection in Croatia. Average mileage data were analyzed for vehicles up to 20 years of age in 2017. Vehicles were classified by curb weight and fuel type. Such classification proved to follow driver behavior and the intended purpose of the vehicle. For each vehicle class, the model was applied using the vehicle age and its population size as inputs for calculating average mileage. Real data shows that vehicles in Croatia considerably exceed the estimated mileage in the years following the first registration of the vehicle and that they cannot be compared to data collected in other studies based on estimations. The difference lies in the covered mileage after vehicles reach ten years of age. The outcome of this study has resulted in a model for calculating average vehicle mileage. The model is suitable for use in various analyses for Croatia or for countries with similar driving habits and economic status now and for years to come.

Estimation of appropriate power range extender for battery electric vehicle

The article presents the results of an experimental and theoretical study of the energy consumption of a vehicle under different conditions. The purpose was to determine the power of the auxiliary range extender on board of the electric battery vehicle. Driving is considered both for real road conditions of a large city, and a specific driving cycle. The high validity of the results is ensured by the use of the new driving cycle WLTC. It is shown that in urban traffic conditions 5 kW auxiliary power plant is sufficient for adequate compensation of electricity consumption of a vehicle with a curb weight 2500 kg.

Scaling Trends of Electric Vehicle Performance: Driving Range, Fuel Economy, Peak Power Output, and Temperature Effect

This study investigated scaling trends of commercially available light-duty battery electric vehicles (BEVs) ranging from model year 2011 to 2018. The motivation of this study is to characterize the status of BEV technology with respect to BEV performance parameters to better understand the limitations and potentials of BEV. The raw data was extracted from three main sources: INL (Idaho National Laboratory) website, EPA (Environmental Protection Agency) Fuel Economy website, and the websites BEV manufacturers and internet in general. Excellent scaling trends were found between the EPA driving range per full charge of a battery and the battery capacity normalized by vehicle weight. In addition, a relatively strong correlation was found between EPA city fuel economy and vehicle curb weight, while a weak correlation was found between EPA highway fuel economy and vehicle curb weight. An inverse power correlation was found between 0–60 mph acceleration time and peak power output from battery divided by vehicle curb weight for 10 BEVs investigated at INL. Tests done on the environmentally controlled chamber chassis dynamometer at INL show that fuel economy drops by 19 ± 5% for the summer driving condition with air conditioner on and 47 ± 7% for the winter driving condition.

Measurement and Evaluation of Real-World Speed and Acceleration Activity Envelopes for Light-Duty Vehicles

Accurate estimation of vehicle activity is critically important for the accurate estimation of emissions. To provide a benchmark for estimation of vehicle speed trajectories such as those from traffic simulation models, this paper demonstrates a method for quantifying light-duty vehicle activity envelopes based on real-world activity data for 100 light-duty vehicles, including conventional passenger cars, passenger trucks, and hybrid electric vehicles. The vehicle activity envelope was quanti-fied in the 95% frequency range of acceleration for each of 15 speed bins with intervals of 5 mph and a speed bin for greater than 75 mph. Potential factors affecting the activity envelope were evaluated; these factors included vehicle type, transmission type, road grade, engine displacement, engine horsepower, curb weight, and ratio of horsepower to curb weight. The activity envelope was wider for speeds ranging from 5 to 20 mph and narrowed as speed increased. The latter was consistent with a constraint on maximum achievable engine power demand. The envelope was weakly sensitive to factors such as type of vehicle, type of transmission, road grade, and engine horsepower. The effect of road grade on cycle average emissions rates was evaluated for selected real-word cycles. The measured activity envelope was compared with those of dynamometer driving cycles, such as the federal test procedure, highway fuel economy test, SC03, and US06 cycles. The effect of intervehicle variability on the activity envelope was minor; this factor implied that the envelope could be quantified based on a smaller vehicle sample than used for this study.

Model Research on Energy-Saving Potential of Engine Energy-Saving Technology

Engine energy-saving technology is the key direction of passenger car energy-saving. This paper has built energy-saving potential model, which could forecast the potential of engine energy-saving technology in 2015 and 2020 under such two constraints: overall target requirement of fuel consumption and curb weight range. Afterwards, the model was used to calculate energy-saving potential of narrow sense passenger cars (including basic car + SUV + MPV), which were equipped with single turbo charging technology, single GDI technology and the above two kinds of technologies integration. The research results will provide decision-making support for enterprises’ technology selection and product development.

Parameter Matching and Performance Simulation for a Distributed Power Extended-Range Electric Vehicle

In order to solve the problem of low power-mass-ratio and high curb-weight in existing extended-range electric vehicle, this paper proposed a distributed power design, and calculated the powertrain parameters of this design, which was based on a commercially available extended-range electric vehicle. Through parameter calculation and simulation, this design was proved to significantly lower the curb weight and manufacturing cost of an extended range electric vehicle, and improve the efficiency of regenerative braking at the same time, finally lead to longer mileage.