Road Test Results Research Articles

Electric vehicle ramp recognition based on fusion of vehicle mass estimation

Road slope is the necessary environmental information for intelligent electric vehicles. The accuracy of slope recognition directly determines the control quality of vehicles on the hill. Aiming at the problems that the existing ramp recognition algorithms have poor adaptability to the conditions and are unable to To satisfy the application requirements of mass production vehicles, this paper proposes an electric vehicle slope recognition method based on vehicle mass estimation. Firstly, the vehicle longitudinal dynamics model is established, and the signal characteristics of the acceleration sensor under the actual vehicle conditions are analyzed. The least square vehicle mass estimation strategy with forgetting factor is constructed to obtain the vehicle mass directly under the starting condition. Ramp recognition algorithms are designed for static parking and dynamic driving scenarios. In the static scenario, the filter latch strategy is used to deal with the interference factors such as activities in the vehicle. In the dynamic scenario, the Kalman filter algorithm based on measurement noise adaptation is designed to realize the fusion estimation of dynamic observation and kinematic observation for the slope. The effectiveness of the method is verified by Simulink -CarSim joint simulation. Finally, the real vehicle test is completed on Chery new energy's mass production electric vehicle platform and domain controller. road test results show that the mass estimation error is less than ±10 kg; the static estimation error of the slope is less than 0.001 rad, and the dynamic error is within 0.005 rad. The estimation accuracy and stability are greatly improved, which ensures the environmental adaptability of the intelligent electric vehicles.

Comparison of Tire Rolling Resistance Measuring Methods for Different Surfaces

The rolling resistance of car tires is one of the most important parameters characterizing tires today. This resistance has a very significant contribution to the energy consumption of wheeled vehicles. The climate crisis has forced tire and car manufacturers to place great emphasis on the environmental impact of their products. Paradoxically, the development of electric vehicles has led to an even greater importance of rolling resistance, because in electric vehicles, a large part of the influence of grade resistance and inertial resistance has been eliminated due to re-generative braking, which resulted in rolling resistance and air resistance remain as the most important factors. What is more, electric and hybrid vehicles are usually heavier, so the rolling resistance is increased accordingly. To optimize tires for rolling resistance, representative test methods must exist. Unfortunately, the current standards for measuring rolling resistance assume that tests are carried out in conditions that are far from real road conditions. This article compares the results of rolling resistance tests conducted in road conditions with the results of laboratory tests conducted on roadwheel facilities. The overview of results shows that the results of tests conducted in accordance with ISO and SAE standards on steel drums are very poorly correlated with more objective results of road tests. Significant differences occur both in the Coefficients of Rolling Resistance (CRR) and in the tire ranking. Only covering the drums with replicas of road surfaces leads to a significant improvement in the results obtained. For investigations of rolling resistance in non-steady-state conditions, the flat track testing machine (TTF), equipped with asphalt cassettes, is shown to provide measurement data in agreement with the road test data.

A Kalman Filtering Algorithm for Measurement Interruption Based on Polynomial Interpolation and Taylor Expansion.

Combined SINS/GPS navigation systems have been widely used. However, when the traditional combined SINS/GPS navigation system travels between tall buildings, in the shade of trees, or through tunnels, the GPS encounters frequent signal blocking, which leads to the interruption of GPS signals, and as a result, the combined SINS/GPS-based navigation method degenerates into a pure inertial guidance system, which will lead to the accumulation of navigation errors. In this paper, an adaptive Kalman filtering algorithm based on polynomial fitting and a Taylor expansion is proposed. Through the navigation information output from the inertial guidance system, the polynomial interpolation method is used to construct the velocity equation and position equation of the carrier, and then the Taylor expansion is used to construct the virtual measurement at the moment of the GPS signal interruption, which can make up for the impact of the lack of measurement information on the combined SINS/GPS navigation system when the GPS signal is interrupted. The results of computer simulation experiments and road measurement tests based on the loosely combined SINS/GPS navigation system show that when the carrier faces a GPS signal interruption situation, compared with a combined SINS/GPS navigation algorithm that does not take any rescue measures, our proposed combined SINS/GPS navigation algorithm possesses a higher accuracy in the attitude angle estimation, a higher accuracy in the velocity estimation, and a higher accuracy in the positional localization, and the system possesses higher stability.

Research on noise reduction of drive axle hypoid gear based on tooth surface mismatch modification

In order to reduce the transmission noise of drive axle hypoid gear, a method of tooth surface mismatch modification was proposed. Firstly, on the basis of establishing the grinding mathematical model of hypoid gear with cutter tilt, the theoretical tooth surface equation was derived, and the numerical tooth surface was calculated by dividing the grid points on tooth surface. Secondly, the pinion tooth surface which was full conjugated with gear tooth surface was constructed, and the tooth surface mismatch topography was established and decomposed into the first order and second order mismatch coefficients. According to the modification requirements, the pinion target surface was constructed by modifying the tooth surface mismatch coefficients, and the pinion modified machine setting parameters were acquired by establishing the pinion processing parameters corrected mathematical model. Finally, the loaded tooth contact analysis with finite element simulation and drive axle NVH (Noise, Vibration, Harshness) simulation were carried out for a pair of hypoid gear, therefore the loaded tooth contact areas, transmission errors curves, and noise simulation curves were obtained, and the simulation results show that after modification the tooth contact stress, loaded transmission errors amplitude, and NVH simulation curves value are all reduced. The road test results indicate that the drive axle hypoid gear howling phenomenon under the high speed operation can be eliminated, so the effectiveness of tooth surface modification method and NVH simulation method were verified.

Experimental and simulation study of an automobile cooling system: Performance improvement using passive flow control

The performance of an automobile cooling system has substantial impacts on the engine's efficiency, fuel consumption, and CO2 emission. In this novel experimental and numerical investigation, a combination of full three-dimensional car simulation, and one-dimensional modeling of the radiator along with the results of road tests on two car models, namely Vehicle A (the base car) and Vehicle B, was used to evaluate and compare the performance of the vehicles' cooling systems. The effects of implementing a passive flow control as well as changing the angle and geometry of the air deflectors on the cars' performance were investigated. The simulation utilized the K-epsilon (k-ε) turbulence model, while the experimental section involved standard road cooling tests. The results show that modifying the air deflectors in Vehicle B enables quick cooling of the system by controlling the air flow rate moving toward the radiator, which increased the air mass flow rate through the condenser and the radiator by 13% and 21%, respectively. Also, the radiator inlet water temperature decreased by about 1.9 °C, and the fuel consumption was reduced by approximately 0.5% under the New European Driving Cycle (NEDC) conditions, which decreased the greenhouse gas emissions, namely CO2 by about 0.9%.

Analysis of the Correctness of Mapping the Passage of a Semi-Trailer through a Road Obstacle on a Road Simulator.

Road simulators enable accelerated durability tests under similar-to-real road conditions. However, the road simulator itself generates the signals with the appropriate strength and amplitude that is adequate to the response registered by the sensors during the real run. Therefore, there is a need for verification of the validity of the representation of vehicle runs on a road simulator in terms of the shape of the generated profile and possible sources of uncertainty. The tests in this study were carried out for a multi-axle vehicle passing an obstacle of known shape. Various signals were registered while the vehicle was passing over the obstacle. The MTS (System Corporation) road simulator's response to the signal given by the obstacle was then checked. The results showed a 99% correlation between the simulation and the road test results. A numerical model of the vehicle was developed to verify the quality of representation of the real conditions by the road simulator, especially in terms of forces resulting from the road profile. Interestingly, the input signal generated by the road simulator provided a very good accuracy of the vehicle response, as tested with use of the numerical model.

Reducing the Fuel Consumption of an Hybrid Electric Vehicle With the Use of Model Predictive Control-Case Study

The article presents operational aspects related <p xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">to energy management strategy (EMS) - model predictive control (MPC). The mathematical model showing the synergy of working machines of the hybrid electric vehicle (HEV) was presented. Then the results of road tests have been shown. They were based on the factory control of the above-mentioned system. The results of the operating parameters of the system according to the factory control and the results of the operating parameters according to the MPC with different linear quadratic tracking (LQT) curves were compared. Application of thirteen reference LQT trajectories results in lower fuel consumption of the HEV. It led to changes in the power and the battery state of charge (SOC): for factory control - from 50.1% (the beginning) to 56.1% (the end of course) and for MPC from 50.1% (the beginning) to 59.9% (the end of the course). The applied MPC with 13 reference trajectories (LQT) of power machines of the series-parallel HEV allowed for fuel savings on the level of 4%.

Towards nationwide implementation of 40% biodiesel blend fuel in Indonesia: a comprehensive road test and laboratory evaluation

This research focused on evaluating the technical viability of using biodiesel with a blending ratio of 40% v/v, which is expected to be implemented soon in Indonesia. Two kinds of biodiesel blends were prepared, a blend of 60% diesel fuel and 40% biodiesel (B40) and a blend of 60% diesel fuel, 30% biodiesel, and 10% hydrogenated vegetable oil (HVO) (B30D10). The fuels were tested on EuroII vehicles without any engine modifications through a 50,000 km endurance road test. Laboratory tests were also performed at certain traveled distances to evaluate various engine parameters, including power, fuel economy, exhaust emissions, and used engine oil properties. Engine components were inspected upon the completion of the road test. Cold-start ability was also examined to confirm the suitability of the investigated biofuels at low-temperature operating conditions in Indonesia. The road test results showed that vehicles fuelled with B40 and B30D10 could reach a distance of 50,000 km without encountering any technical issues. The laboratory evaluation during the road test indicated that B30D10 had a higher power and fuel economy than B40, with a maximum difference of 2%. Furthermore, B30D10 emitted lower CO, HC, and PM emissions than B40 throughout the distance traveled, with maximum differences of 11.4%, 14.7%, and 22.6%, respectively, but led to 15% higher NOx. Engine component inspection and used engine oil analysis confirmed the fulfillment of the manufacturer's recommendations for both B40 and B30D10. Finally, B40 and B30D10 were suitable for operating at low ambient temperatures in Indonesia, confirming them as practical options to be implemented in the nationwide 40% biodiesel blend fuel.

Estimation of the Regenerative Braking Process Efficiency in Electric Vehicles

Abstract In electric and hybrid vehicles, it is possible to recover energy from the braking process and reuse it to drive the vehicle using the batteries installed on-board. In the conditions of city traffic, the energy dissipated in the braking process constitutes a very large share of the total resistance to vehicle motion. Efficient use of the energy from the braking process enables a significant reduction of fuel and electricity consumption for hybrid and electric vehicles, respectively. This document presents an original method used to estimate the efficiency of the regenerative braking process for real traffic conditions. In the method, the potential amount of energy available in the braking process was determined on the basis of recorded real traffic conditions of the analysed vehicle. The balance of energy entering and leaving the battery was determined using the on-board electric energy flow recorder. Based on the adopted model of the drive system, the efficiency of the regenerative braking process was determined. The paper presents the results of road tests of three electric vehicles, operated in the same traffic conditions, for whom the regenerative braking efficiency was determined in accordance with the proposed model. During the identification of the operating conditions of the vehicles, a global positioning system (GPS) measuring system supported by the original method of phenomenological signal correction was used to reduce the error of the measured vehicle’s altitude. In the paper, the efficiency of the recuperation process was defined as the ratio of the accumulated energy to the energy available from the braking process and determined for the registered route of the tested vehicle. The obtained results allowed to determine the efficiency of the recuperation process for real traffic conditions. They show that the recuperation system efficiency achieves relatively low values for vehicle No. 1, just 21%, while the highest value was achieved for vehicle No. 3, 77%. Distribution of the results can be directly related to the power of electric motors and battery capacities of the analysed vehicles.

Study of Loads Acting on the Load during the Sudden Braking of a Vehicle

This article presents the results of a study of the braking process in terms of assessing the longitudinal loading condition of transported cargo. The existing methods of securing cargo do not take into consideration the type of vehicle used to transport the cargo. This may result in cargo not being transported in compliance with the principles of proper cargo protection. This paper discusses the differences in maximum deceleration values achieved by different types of vehicles that are structurally suitable for freight transport. As a result of these differences in deceleration values, the values of forces acting on the transported cargo are also different. This paper presents and analyses the results of road tests that entailed the heavy braking of two vehicles structurally suitable for freight transport. One of them was a delivery vehicle, while the other was a semi-trailer truck. The experiment was carried out in six measurement series. Four of them were performed on an asphalt pavement, while the other two on a concrete pavement. One series included ten brake tests. Deceleration values registered during the tests were later used to determine the values of coefficient Cx, which were then compared with standardised values. It has been shown that failure to take into account in the selection process of cargo securing equipment, vehicle category, and type and condition of the pavement can result in cargo displacement and even traffic incidents.

Modeling the fuel consumption by a HEV vehicle – a case study

The article presents a mathematical model demonstrating the synergy of HEV energetic machines in accordance with the model predictive control. Then the results of road tests are presented. They were based on the factory control of the above-mentioned system. The results of the operating parameters of the system according to the factory control and the results of the operating parameters according to the model predictive control were compared. On their basis, it could be concluded that the model predic-tive control contributed to changes in the power and electrochemical charge level of the energy storage system from 50.1% (the beginning) to 56.1% (the end of course) and for MPC from 50.1% (the begin-ning) to 59.9% (the end of the course). The applied MPC with 13 reference trajectories (LQT) of power machines of the series-parallel HEV allowed for fuel savings on the level of 4%.

Robust algorithm of indirect tyre pressure monitoring system based on tyre torsional resonance frequency analysis

• Detects changes in tyre pressure by monitoring changes in tyre resonance frequency. • Eliminating the disturbances of engine and driveline on frequency estimation. • Key parameters for evaluating tyre torsional vibration characteristics is proposed. • Methods proposed to compensate for the effects of road roughness and ambient temperature. • The proposed algorithm improves the robustness of frequency estimation. This paper focuses on an indirect Tyre Pressure Monitoring System (TPMS) algorithm based on frequency analysis of tyre torsional vibration. Tyre vibration is analysed using a tyre structure model, and the tyre resonance frequency is estimated using an Autoregressive (AR) model. The vibration disturbances from the engine and driveline that affect the estimation of the tyre torsional frequency are analysed, and a notch filter is designed to eliminate the disturbances. The torsional vibration of the driveline is identified by the correlation analysis of driving wheel speed. Two qualitative evaluation indexes of tyre torsional vibration characteristics are proposed. The corresponding quantitative parameters are used to determine the tyre torsional vibration state to eliminate the interference of undesirable vibration states on the frequency calculation. A road roughness estimation method is proposed based on tyre vertical vibration information in the wheel speed. The estimated road roughness parameters compensate for the calculated resonance frequency affected by road roughness. Based on the relationship between measured resonance frequency and temperature under a constant tyre pressure condition, the frequency variation value affected by tyre rubber stiffness variation due to temperature variation is calculated using the ambient temperature signal. The calculated resonance frequency is corrected to eliminate the coupling effect of gas stiffness and rubber stiffness, the impact of temperature variation on tyre pressure estimation is compensated. The results of vehicle road tests demonstrate the robustness of the proposed tyre pressure monitoring algorithm.

Multiobjective Optimization of Vehicle Handling and Stability Based on ADAMS

In order to improve the steering characteristics, roll characteristics, and lateral characteristics of heavy commercial vehicles, a multiobjective handling stability comprehensive score optimization model (MHSCS optimization model) was proposed in this study. In this study, the main factors affecting the steering characteristics, roll characteristics, and lateral characteristics are determined by combining the road test method and ADAMS software simulation analysis method. Based on the above road tests and ADAMS software simulation analysis, the MHSCS optimization model was proposed with “understeering degree,” “vehicle roll angle”, and “rearward amplification (RWA)” as evaluation indexes, and the response surface method combined with genetic algorithm was used to carry out multiobjective optimization of heavy commercial vehicle. ADAMS simulation results show that the comprehensive improvement degree of steering characteristics, roll characteristics, and lateral characteristics of a heavy commercial vehicle after optimization is 15.26%. Finally, the field road test results show that the scoring error between the comprehensive scoring optimization model and the real vehicle test was controlled at 0.4%, which proves the accuracy of the optimization model established in this study and effectively improves the handling stability of heavy commercial vehicles.

Selection of child seats in terms of vibration comfort

The article presents the results of laboratory and road tests of the impact of the method of fastening child seats on the vibration comfort of children transported in them. The tested child seats were mounted facing the direction of travel on the rear seat of a passenger vehicle. Two child seats were used in the work, the first (red) was attached to the rear seat behind the driver’s seat using the ISOFIX base. The second child seat (grey) is attached to the rear seat behind the passenger seat with standard seat belts. During the measurements, the child seats were loaded with the mass of 5 kg, 10 kg and 15 kg, simulating the mass of a child fastened in a child seat. The child seats used can be mounted both forward and rearward facing. In the conducted research, they were installed in a passenger vehicle facing the direction of travel. Laboratory and road tests based on registered vertical accelerations showed a negative impact of using the ISOFIX base in terms of vibration comfort.

Field investigation and numerical analysis of an inverted pavement system in Tennessee, USA

Inverted pavement system has been introduced for many years with field investigations, laboratory studies and numerical simulation works. Field investigations of inverted pavement structures have not been widely conducted and are very limited in the USA. This study presents a comprehensive field study on a full-scale inverted pavement as well as a conventional control pavement section constructed in Tennessee, USA. A combination of multiple non-destructive testing (NDT) methods, including ground penetration radar (GPR), Benkelman beam test, 3D road profiling test by laser crack measurement system (LCMS), and falling weight deflectometer (FWD) tests were utilized to assess the actual thickness, structural capacity and surface conditions of the pavement structures. The road surface profiling test results showed that the inverted pavement outperformed the conventional section in roughness, cracking and rutting conditions. Deflection Basin Parameters (DBPs) such as surface curvature index (SCI), base damage index (BDI), base curvature index (BCI) and W7 (7th sensor’s value of FWD) values were compared to study the layers’ condition of the inverted and conventional pavement sections. In addition, a preliminary simulation analysis by a Finite Element Method (FEM) model was conducted to compare the performance of inverted and conventional pavement sections under FWD load. The simulation results showed that the inverted pavement structure could reduce the potential of crack initiation and propagation due to smaller tensile stress at the bottom of the asphalt concrete layer (AC). Also, the smaller deflection was measured at the top of subgrade soil (SG), which reduced the total deflection of the inverted pavement structure. Furthermore, the cement-treated base (CTB)-constrained unbound aggregate base (UAB) acted as a cushion to relieve the tension from CTB and support the AC layer. The stress-dependent property of UAB in the inverted pavement contributed to the performance and ductility of inverted pavement but had little influence on the conventional pavement.

Real-time risk assessment model for hazmat release accident involving tank truck

The main objective of this paper is to develop a real-time risk assessment model for havzmat release accidents involving a tank truck. The proposed model can make full use of multiple real-time data and static data for the purpose of quantifying the risk of hazmat release faced by the tank truck at each moment in the driving process. In order to achieve the above function, we improve the risk quantification method in ARAMIS (Accidental Risk Assessment Methodology for Industries System) for real-time risk assessment. For quantifying the possibility, a fuzzy comprehensive evaluation method based on fuzzy rules is used to synthesize multiple evaluation indicators; For quantifying the intensity and vulnerability, a “potential impact zone” model based on the Gaussian plume model is proposed to describe the influence range of toxic gas leak, and point of interest (POI) data is used to identify critical targets. Through the analysis of the road test results, the effectiveness of the proposed model is verified. The significance of this study is to provide a real-time risk quantification tool for tank trucks, which can be programmed and embedded into various driving auxiliary or safety management systems in the future.

A prototype car converted to solar hybrid: project advances and road tests

A project for upgrading conventional cars to hybrid electric vehicles is presented. The project is carried out by four Italian partners within a EU project financed by the LIFE programme. Hybridisation to a through the road parallel hybrid structure is obtained by integration of wheel motors in rear wheels, the addition of an additional battery, of flexible photovoltaic panels and a Vehicle Management Unit. The technical aspects related to vehicle conversion and the results of test bench and road tests on first prototypes are presented and discussed, as well as the perspectives related to the industrialization of such system.

Optimized 3D printed wheelchair racing gloves

Wheelchair racing gloves are often hand crafted from thermoplastics. The geometries are unique to the individual, often with thumb or finger cavities rendering line-of-sight laser scanning techniques inappropriate for full digital capture. This study describes the use of micro-CT to reverse engineer the bespoke hard gloves of an elite Paralympic athlete, with fabrication via 3D printing. Subsequent design changes, combined with the identification and manipulation of key process parameters during material extrusion, have demonstrated this approach affords enhanced glove performance. Preliminary rolling road test results suggest a competitive advantage for the athlete. The approach is believed transferrable within physical rehabilitation.

Requirements for static and fatigue strength of beams front axle of a truck

Based on the results of road tests of the stress-strain state of the beam of the controlled bridge of a dump truck, recommendations for its design were developed. The most loaded zones of the beam under operating conditions have been identified. The safety margins of the bridge beam in bending and torsion, the ratio of the moments of resistance to bending in the vertical and horizontal planes have been determined. The test mode and the standard of the bench fatigue life of the bridge beam have been established. Keywords: bridge beam, truck, strength, bending, twisting, load, dynamic factor, safety margin, operational requirements

Research on speed estimation of hub-motor vehicle based on multi-sensor information fusion

Accurate acquisition of longitudinal and lateral velocity of the vehicle plays an important role in the modern automobile control system. In this paper, the vehicle speed test system is composed of multiple sensors, data acquisition board (NI cDAQ9137) and LabVIEW software. The real-time acquisition of front-wheel angle, wheel speed, longitudinal acceleration, lateral acceleration, and yaw velocity of the hub-motor vehicle is completed by using the speed measuring system. Based on the real road test results, the vehicle speed estimation is obtained by Kalman filter technology and compared with the reference vehicle dynamics model. The comparison results show that the vehicle speed estimation has high accuracy and can meet the requirements of state parameter estimation. The algorithm has the advantages of simple structure, small computation and easy implementation and can provide more information for the automobile control system.