Car Test Research Articles

The uniqueness of pollutant emission and fuel consumption test results for road vehicles tested on a chassis dynamometer

The article considers the issues of non-repeatability of exhaust emission and fuel consumption test results for road vehicles tested on a chassis dynamometer. Empirical results of passenger car tests on a chassis dynamometer in the WLTC (Worldwide Harmonized Light Vehicles Test Cycle) test were used. Tests were conducted in four repeated sets to assess the repeatability of the test results. The road emission of hydrocarbons, non-methane hydrocarbons, carbon monoxide, nitrogen oxides, particulate matter and carbon dioxide, the road number of particulate matter and operational fuel consumption were determined. The coefficient of variation of the values measured in the four tests was determined, taken as a measure of the repeatability of the test results. The coefficient of variation of the road emission of carbon dioxide and operational fuel consumption is the lowest. No significant differences were found in the values of the measured exhaust emission.

Construction of virtual test scenarios for intelligent car-pedestrian interaction

Aiming at the needs of intelligent car and pedestrian interaction testing under urban conditions, this paper proposes a scenario generation method that comprehensively considers the frequency of scenarios in the real world and the degree of challenge to human-vehicle interaction performance. First, according to the key features of intelligent car and pedestrian interaction, the original scene data of pedestrians crossing the road is extracted from the natural driving dataset; then, according to the needs of accelerated testing, a key scenario extraction method based on importance sampling theory is designed to extract and construct important scenarios for intelligent car-pedestrian interaction testing from the original scenes; finally, by comparing the data distribution of important scenarios with original scenarios, it is shown that this method can effectively screen out scenarios that may challenge safety performance during driving, thereby realizing accelerated testing, while taking into account the statistical characteristics of the test scenarios.

Non-repeatability of the WLTP vehicle test results

The paper presents results of considerations on the repeatability of the passenger car test results obtained in the WLTP procedure on a chassis dynamometer. The research concerned the aspects of exhaust emissions and fuel consumption. Measurements were carried out in the WLTC test with a cold engine start and then in four WLTC (Worldwide harmonized Light vehicles Test Cycle) tests with a hot engine start. The following values were measured: average specific distance emissions of hydrocarbons, non-methane hydrocarbons, carbon monoxide, nitrogen oxides, particulate matter and carbon dioxide, specific distance particulate number, and operational fuel consumption. Thus, it was possible to assess the impact of the engine's thermal state at start-up on the test results and the nature of test results repeatability with the start-up of a hot engine. The repeatability of the test results was assessed based on the coefficient of variation obtained in the individual tests and the relationship of the maximum difference between measurement results values in the individual tests for a hot engine start. The obtained test results turned out to be very diverse for the considered parameters and indicated low repeatability. Values of carbon dioxide emissions and operational fuel consumption were definitely the least varied in individual hot engine start tests. The exhaust emission of particulate matter varied the most in individual test iterations. However, the specific distance particulate number was relatively similar between individual tests, less so than the exhaust emission of other pollutants. In the case of different engine thermal state at start-up, the emitted particulate number varied the most in the test results, while the emission of carbon dioxide and operational fuel consumption varied the least. The repeatability of executing the velocity process in WLTC tests at hot engine and cold engine start-up was also examined as processes determining exhaust emissions and fuel consumption. These tests were much more repeatable than the exhaust emission and fuel consumption.

Conformity Assessment of a Modernised Locomotive Bogie and Body Connection – Type Tests and Results

Referring to the lecture held on 16th Mini-Conference on Vehicle System Dynamics, Identification and Anomalies, Budapest, 5-7 November 2018, the accredited Notified Body started the conformity assessment process of the modernized bogie-locomotive body connection of MÁV-START Class V63 electric locomotives running with Ganz-MÁVAG UFC-type bogies, in 2017. Since the planned modification of the locomotives was delayed, the Conformity Assessment Body could perform the necessary riding quality and noise test in the summer of 2020 instead of September 2018. The study presents the modification carried out on the locomotives, the test procedures, and the test results. The aim and the novelty of the research was to apply the latest developments of the test procedures on a modified, existing rolling stock. The conformity for the new requirement makes challenges for the development of testing even if theoretically a well-known test method is applied. The article gives an example for the application of a classic test method combined with of the new possibilities, that makes unnecessary the use of additional railway test cars.

Teaching Strategies for Automotive Engine Electronic Control System Testing and Maintenance Course under the “1+X” Certificate System

With the continuous development of China’s economy, cars have become the most common means of transportation for people. However, due to this impact, the contradiction between the market demand for after-sales services such as car testing and maintenance and the actual supply of professional technical personnel has become increasingly prominent. Therefore, strengthening the education reform of automotive inspection and maintenance professional technology has become an important task for major vocational colleges. The “1+X” certificate system has become a new norm in vocational education reform in China due to its significant advantages in cultivating students’ professional knowledge and skills to obtain professional skills certificates. Based on this, this article takes the course of automotive engine electronic control system testing and maintenance as an example to explain the practical significance and strategies of course teaching based on the “1+X” certificate system, aiming to further promote professional teaching reform and provide some reference for colleagues.

Field measurement of track vibration induced by full-load and empty-load condition in curve section of underground metro line

In order to compare the differences in vibration before and after wheel re-profiling and assess the vibration impact of train under full-load and empty-load condition, the field vibration measurement was conducted on an underground metro track components (including rail, sleeper, and track-bed) by using a specific testing car. The results indicate that wheel re-profiling is effective in reducing track vibration, within the frequency range of 31.5–1250 Hz, the vibration acceleration levels of the track after wheel re-profiling were notably lower than those prior to re-profiling and the vibration acceleration levels of the rail, sleeper, and track-bed decrease by 4.7 dB, 6.6 dB, and 6.7 dB, respectively. In the frequency domain, the characteristic peak frequencies of the three track components, whether under full load or empty load, align closely with the frequencies associated with track irregularities. Full-load condition primarily affects the vibration acceleration at lower frequencies, with minor influence on higher frequencies. The vibration acceleration levels of all three track components are higher under full load than empty load. Additionally, under full-load condition, the transmission loss from the rail to the sleeper increases, while the transmission loss from the sleeper to the ballast remains nearly constant. The results of vibration acceleration levels obtained from routine vehicle operations validate the limited impact of axle load on track components vibration.

Research on DCT shift strategy for various driving style based on “driver-vehicle-cloud” machine learning

In order to solve the problem that the DCT static shift strategy cannot adapt to the difference in driving style, the driving style identification model based on multi-dimensional data mining and intelligent algorithm heavily depends on vehicle terminal data storage and calculation, an intelligent shift strategy based on “driver-vehicle-cloud” cooperative control is proposed. Firstly, the dynamic model of the DCT vehicle is analyzed, the primary shift schedule is calculated, and a method to adaptively modify the shifting schedule of DCT according to driving style is proposed. Then, many vehicle driving data are collected, cleaned, and reconstructed by wavelet denoising and other methods, and a driving style database with 80-dimensional features is constructed. Five essential features are selected by the ReliefF method, and the driving style recognition model is constructed by combining random forest, support vector machine, naive Bayesian, and other algorithms. Finally, the support vector machine model with the highest precision is selected, and the “driver-vehicle-cloud” collaborative control system is deployed using cloud computing and vehicle-cloud collaborative technology. The experiment car test shows that the system can identify the driver’s driving style in real time and realize the differential shift schedule and driving experience of DCT.

Sim-to-Real Application of Reinforcement Learning Agents for Autonomous, Real Vehicle Drifting

Enhancing the safety of passengers by venturing beyond the limits of a human driver is one of the main ideas behind autonomous vehicles. While drifting is mostly witnessed in motorsports as an advanced driving technique, it could provide many possibilities for improving traffic safety by avoiding accidents in extreme traffic situations. The purpose of the research presented in this article is to provide a machine learning-based solution to autonomous drifting as a proof of concept for vehicle control at the limits of handling. To achieve this, reinforcement learning (RL) agents were trained for the task in a MATLAB/Simulink-based simulation environment, using the state-of-the-art Soft Actor–Critic (SAC) algorithm. The trained agents were tested in reality at the ZalaZONE proving ground on a series production sports car with zero-shot transfer. Based on the test results, the simulation environment was improved through domain randomization, until the agent could perform the task both in simulation and in reality on a real test car.

Braking system analysis with the aid of a dynamic vehicle simulator with nine degrees of freedom

ABSTRACT The braking system is one of the most important vehicle systems, therefore, its optimised operation is essential in the dynamic performance of the automotive project; in addition to ensuring the necessary security of the object of study. Consecutively, the in-depth study on the sizing and performance of the braking system becomes necessary and, using software to assist in the manipulation of the parameters that influence this system, the automotive industry has presented different solutions in recent years, especially due to the use of central electronics such as the brake system module (BSM). In this context, the present work simulates, via a multibody virtual model and the aid of software such as VI-CarRealTime, the dynamic behaviour of a vehicle according to the braking system efficiency loss. With this goal, the virtual model is correlated with a physical test car and the conditions proposed in the AMuS test are executed, where the friction between the pad and the brake disc is changed. Using driver-in-the-loop simulation in a vehicle dynamics simulator with nine degrees of freedom, it was noted, qualitatively, that the loss of brake efficiency through g-force in each braking results in a long time for the vehicle to react according to the driver’s assessment and by telemetry.

Research on the influence of vehicle durability vibration on gap flush of exterior trim parts

Maintaining the newness of a vehicle is currently significant concern for users and vehicle companies. The gap difference between interior and exterior trims plays a crucial role in the overall appearance of vehicles. Over time, the gap and flush parameters of these trims may change due to the movement of components, putting forward higher requirements for the assembly accuracy and reliability design of automotive products. This article presents a study where a test car is subjected to endurance vibration on a wheel-coupled vibration bench. Through measuring the changes in gaps and flushes between the exterior trim parts at different endurance mileage intervals, the variation patterns are obtained. Using dimensional engineering technology, the effects of durable vibration on the gaps and flushes of the vehicle's exterior trim parts were determined. This study provides a foundation for the design of new interior and exterior decoration parts in automobiles. It also offers valuable insights for product design, development, and quality improvement. Problems can be predicted in advance in the early stage of design, and closely coordinate various aspects of production and manufacturing to obtain products with higher standards, requirements, and quality.

DALDet: Depth-Aware Learning Based Object Detection for Autonomous Driving

3D object detection achieves good detection performance in autonomous driving. However, it requires substantial computational resources, which prevents its practical application. 2D object detection has less computational burden but lacks spatial and geometric information embedded in depth. Therefore, we present DALDet, an efficient depth-aware learning based 2D detector, achieving high-performance object detection for autonomous driving. We design an efficient one-stage detection framework and seamlessly integrate depth cues into convolutional neural network by introducing depth-aware convolution and depth-aware average pooling, which effectively improve the detector's ability to perceive 3D space. Moreover, we propose a depth-guided loss function for training DALDet, which effectively improves the localization ability of the detector. Due to the use of depth map, DALDet can also output the distance of the object, which is of great importance for driving applications such as obstacle avoidance. Extensive experiments demonstrate the superiority and efficiency of DALDet. In particular, our DALDet ranks 1st on both KITTI Car and Cyclist 2D detection test leaderboards among all 2D detectors with high efficiency as well as yielding competitive performance among many leading 3D detectors. Code will be available at https://github.com/hukefy/DALDet.

Integration of Skyhook Control in a Quarter Car with Magnetorheological (MR) Damper

Semi-active suspension (SAS) systems attenuate vibrations with minimal power Consumption and is usually paired with magnetorheological (MR) dampers which are a type of variable damper that produces high damping forces with no mechanical movement. This paper presents the analysis of a Skyhook controller in a quarter car test rig equipped with MR damper to reduce vibration peaks when excited by a sinusoidal signal which simulates the unevenness of road surfaces. The viability of Skyhook control in mitigating vibration was examined from the experiments. The study discovered that there was an improvement of 12.72% by Skyhook control when compared to passive damping based on the sprung mass acceleration of both damping modes. The Skyhook controller surpassed passive damping and was deemed a success in vibration control.

The Assessment of PM2.5 and PM10 Immission in Atmospheric Air in a Climate Chamber during Tests of an Electric Car on a Chassis Dynamometer

Electric cars, like internal combustion vehicles, emit particulate pollution from non-exhaust systems, i.e., tires and brakes, which is included in the Euro 7 emission standard planned for implementation. Tests conducted on chassis dynamometers are accompanied by particulate emissions from non-exhaust systems, which are introduced into the ambient air on the test bench. Particulate emissions tests from non-engine systems on chassis dynamometers are mainly aimed at measuring the mass or number of particulates from tires and brakes. In contrast, little attention is paid to the immission of particulate matter from tires and brakes on the dynamometer during tests, which in the case of electric cars include, for example, measurements of energy consumption or range. Therefore, in order to draw attention to the problem of these emissions, the authors carried out measurements of PM2.5 and PM10 immissions into the air in the climatic chamber during tests of an electric car on a chassis dynamometer. The car tests were carried out in accordance with the WLTC (Worldwide harmonized Light duty Test Cycle) and at constant speed. Based on the test results, a model was proposed for the immission of particulate matter in laboratory air from tire and brake abrasion, taking traffic parameters into account. The results and the developed model show that air quality, in terms of particulate content, deteriorates significantly during testing.

THE INFLUENCE OF CAPITAL ADEQUACY (CAR), GROWTH OF THIRD PARTY FUNDS (DPK), NON-PERFORMING CREDIT (NPL) ON CREDIT DISTRIBUTION OF CONVENTIONAL COMMERCIAL BANKS ON THE INDONESIAN STOCK EXCHANGE 2017–2021

Credit distribution carried out by banks is one of the state's income sectors, which in this case is used to maintain economic stability, improve the level of community welfare, help develop MSMEs through capital loans provided by banks, therefore indirectly credit distribution is carried out banking is an effort to increase the level of welfare of citizens, the level of demand for credit has increased from year to year. On the other hand, banks also consider CAR, DPK, NPL obtained from lending, there is a fear that banks will not be able to collect funds, excessive credit distribution will result in risks bad and non-performing loans widened which made banks lose their balance. The aim of this research is to determine empirically the influence of the capital adequacy ratio, growth of third party funds, non-performing loans on the distribution of bank credit registered in BEI for the 2017-2021 period. The population in this research is 46 banks. With this population, banking samples were taken using the method purposive sampling resulted in 26 banks that met the specified criteria. The type and source of data obtained from secondary data sources, the research method used is quantitative using multiple linear regression processed with the SPSS16 program. The results of multiple linear regression analysis and hypothesis testing can be concluded that simultaneously (F test) CAR, DPK Growth, NPL have an effect on banking credit distribution, while the results of partial analysis (T test) CAR, DPK Growth do not have a significant effect on credit distribution due to funds collected by the bank exceeds the reference provided by the IDX so that the bank has funds that are not distributed. It can be said that the amount of CAR, DPK has no influence on credit distribution, while for NPL it has a significant negative effect, which means that if credit distribution increases, the bank will experience The increase in NPL or bad credit, this problem requires banks to limit the distribution of credit funds in order to reduce the level of losses faced by banks.

Energy Management Strategy Based on Model Predictive Control‐Differential Evolution for Hybrid Energy Storage System in Electric Vehicles

This paper addresses challenges related to the short service life and low efficiency of hybrid energy storage systems. A semiactive hybrid energy storage system with an ultracapacitor and a direct current (DC) bus directly connected in parallel is constructed first, and then related models are established for the lithium‐ion battery, system loss, and DC bus. Based on the multiobjective evaluation function, a hybrid energy storage system Model Predictive Control‐Differential Evolution (MPC‐DE) energy management method is proposed. Experiments were conducted under China Light‐Duty Vehicle Test Cycle‐Passenger Car (CLTC‐P) and Highway Fuel Economy Test (HWFET) driving cycles. The experimental results show that compared with other methods, this strategy can effectively reduce the loss of lithium‐ion battery and ultracapacitor hybrid energy storage system and improve the system efficiency.

Modular technological line for assembling and testing car dampers

This publication describes the effects of work on the project no. POIR.01.01.01-00-1029/17-00. Its aim was to develop and demonstrate a technological line for the assembly and testing car dampers. The implementation of the project results took place in the own activities of ELPLC S.A. under Priority Axis I, the Smart Growth Operational Program 2014-2020 - Support for R&D work by enterprises. The commencement of work on the project was also the result of direct experience in the construction of machines and lines for OEM and Tier1 automotive industry clients.

An Enhanced Precise Carrier Phase Positioning Method for Vehicle Navigation

Precise carrier phase positioning is a widely used technique in vehicle navigation, localization, and mapping, which utilizes pseudorange and carrier phase measurements with the extended Kalman filter (EKF) to estimate position, velocity, and ambiguities. For highly accurate vehicle positioning requirements, propagation errors of measurements need to be considered, especially the ionospheric delay, which is the most significant error source. In EKF, a priori information of different error characteristics can be fully utilized as constraints to obtain more precise state estimation results, even when no corrections are available. This paper aims to improve the positioning accuracy for vehicle navigation and proposes a spherical harmonic function (SHF)-based undifferenced and uncombined (UDUC) carrier phase positioning method for vehicles to fit the ionospheric delays of multiple satellites in a single formula and reduce the marginal effect caused by polynomials. Better positioning results are expected compared to traditional UDUC and polynomial fitting approaches. The feasibility of the proposed method is tested on a kinematic dataset from a real-world car test. The experimental results show that the proposed method outperforms the traditional UDUC and polynomial fitting methods, respectively, with a root mean square error of 0.860 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</i> and a standard deviation of 0.579 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</i> when using broadcast ephemeris. In summary, the results demonstrate that the proposed method is highly beneficial for precise vehicle navigation.

Feasibility of a new noise prediction method using vibration speakers to verification of interior noise reduction effects

To effectively reduce interior noise in railway vehicles, the effect of new noise-reduction measures must be pre-estimated before their implementation. We are developing a new method for interior noise prediction, using a vibration speaker to estimate the multiple-input multiple-output transfer functions from the acceleration of interior panels to the sound pressures at the evaluation points. In this paper, we verify the possibility and report on the feasibility of predicting the effect of interior noise reduction in railway vehicles when the vibrations of interior panels are reduced to improve quietness in the cabin. First, we conducted a vibration test using a vibration speaker on a Shinkansen test car to estimate the transfer functions from each interior panel to the noise evaluation point. Then, we conducted another vibration test to simulate the running condition, aiming to reproduce the interior noise. Finally, by assuming that the vibrations of the interior panels are reduced in the second vibration test, we show the feasibility of the proposed method to verify the noise-reduction effect by using it to predict the interior noise with vibration-reduction measures.

A differential-algebraic extended Kalman filter with exact constraint satisfaction

This work proposes an Augmented Manifold Differential-Algebraic Extended Kalman Filter for state and input estimation for multibody systems described by a set of differential algebraic equations. The proposed Kalman Filter allows for exact constraint satisfaction and does not require reformulation of the multibody system equations. The approach consists of two main steps: (i) elimination of the Lagrange multipliers from the system state via a nullspace projection and (ii) an additional correction step that constrains the a-posteriori estimated system state to lie on the constraint manifold. The latter is achieved by solving a constrained optimization problem using a Euclidean descent approach and projection on the constraint manifold, i.e. manifold optimization. The proposed approach is numerically validated on both open and closed kinematic chain rigid multibody models and is shown to be robust and indifferent to the type of kinematic chain being considered. Furthermore, an experimental validation is carried out where the forces and torques acting on the wheel center of a McPherson car suspension test setup are successfully estimated using a flexible multibody model and the proposed Kalman Filter.

Parking behaviour under the influence of alcohol

Real-life driving studies evaluating the impact of alcohol influence on the ability to park a car are rare but necessary to assess a possible impairment to drive a car in the event of prosecution. In this study, 29 test persons (13 m, 16 f) completed three test drives with real cars, each made up of three different parking situations. While four test persons remained sober, the majority drank a previously calculated amount of alcohol before the second drive; the aim was to reach a blood alcohol concentration (BAC) of 1.1 g/kg. The third drive took place about 2 h later without any further ingestion of alcohol. The impact of BAC on the number of accidents, time needed to finish the drive, the amount of correction moves and quality of the final parking position (in the centre of the parking space) were analysed. Furthermore, pressure measuring films were applied to the test cars, measuring the average pressure and load in the areas of the accident impact. A significant increase of accidents could be noted with rising BAC. While a single accident happened to both sober and drivers under the influence of alcohol, more than one accident was only seen in drivers after the ingestion of alcohol (> 0.63 g/kg). The BAC had no impact on the other considered aspects. Concludingly, more than one impact site or accident while parking a car can serve as an indication for alcohol impairment of the driver at the time of the accident.