Passenger Car Research Articles

Objective description of heterogeneous traffic flow patterns of passenger cars and trucks on long downhill sections in Kerner's three-phase traffic theory framework

Objective description of heterogeneous traffic flow patterns of passenger cars and trucks on long downhill sections in Kerner's three-phase traffic theory framework

Bottom-up Analysis for Carbon Emissions from Passenger and Freight Transport Sectors in Xi’an: A City-Level Study Using MOVES and LMDI Models

Abstract Road transportation is identified as one of the primary contributors to urban carbon emissions. This study employed a localized MOVES model, integrating high-resolution urban vehicle data, along with a categorical LMDI decomposition model, to conduct a detailed bottom-up analysis of carbon emissions from passenger and freight vehicles in Xi'an. The MOVES model was utilized to evaluate the inter annual variability of carbon emissions from road transportation sources. The LMDI models assessed the impact of six factors, focusing on microscopic traffic activities such as passenger/freight volume and turnover, vehicle ownership, mileage, carbon emission rate, vehicle types, and fuel types. The research indicates that carbon emissions in Xi'an increased significantly between 2012 and 2021, rising from 21.95 to 51.15 million tons, with an average annual growth rate of 9.9%. Passenger vehicles are the primary contributors to this increase. The emission patterns of passenger and freight vehicles differ notably due to various factors. For passenger transport, which includes passenger cars and school buses accounting for 97% of emissions, per capita vehicle turnover is the primary influencing factor. In contrast, for freight transport, combination long-haul trucks dominate emissions, comprising 65% of total freight emissions, with freight volume being the key influencing factor. By analyzing the factors driving carbon emissions from passenger and freight vehicles, this study provides valuable insights for reducing road traffic emissions in Xi'an and similar regions.

A Study on the Prediction of Long-Term Carbon Absorption by Applying the Renewal Scenario of Forest in Korea

As global warming has emerged as an essential global solution, the role of carbon neutrality is required to respond to rapidly changing environmental policies. Forests are an important means for achieving carbon neutrality as they act as a key carbon sink, and, among them, forest management called afforestation is emerging as a decisive factor. However, although various studies are being conducted to enhance carbon absorption capacity, there are not many long-term research cases on afforestation. In this study, the cumulative carbon absorption for a total of 90 years from 1 January 2020 to 31 December 2100 was set as the baseline. Various changes were made according to the cyclical trend of the species and age classes planted nationwide, and various results were derived through the regeneration scenario. As a result of the study, the difference between the maximum value and the baseline CO2 absorption was approximately 130 million t CO2 when compared with the 90-year cumulative value. When converted into an annual unit, it increased by more than 14 million t CO2. Based on the highest figures, compared with statistics from the Ministry of Environment’s Greenhouse Gas Information Center, it was confirmed that the forest absorption source, which was offset by 6.26 percent in 2019, could be changed by up to 8.74 percent. When analyzing the maximum figures from this study, depending on the method of afforestation, the greenhouse gases emitted by approximately 9.32 million passenger cars per year could be offset. In conclusion, among the carbon neutrality tasks that must be addressed at the national level, it is very important to establish long-term direction decisions and detailed plans for the forest sector, which is the core of carbon sinks, and a strategic approach is essential. Based on this study, it is expected that a more systematic direction can be presented for planning and implementing future afforestation.

Low-Foaming/Aeration and Low-Traction Electric Drivetrain Fluid (EDF) Solutions for High-Speed E-Mobility

The use of electrically driven drivetrains is increasing for passenger cars and light-, medium-, and heavy-duty trucks. Off-the-shelf automatic transmission fluids (ATFs) are still being used as electric drivetrain fluids (EDFs). EDFs are trending toward lower viscosity for better energy efficiency and better heat transfer capacity, while satisfying all the other challenging requirements, such as gear/bearing scuffing/wear protection, oxidative stability, copper corrosion, and coating/seal material compatibility. In this paper, we will highlight the importance of low foaming, low aeration, and low traction coefficient which are critical for the performance of the EDF during high-speed applications, measured using metrics such as energy efficiency, heat transfer capacity, and longer oil drain interval.

Examining Fatal Motorcycle Crashes in Malaysia: Rider Age, Road Attributes and Collision Partner Dynamics

Abstract: - High severity crashes involving motorcycles in Malaysia were analyzed to understand the crash characteristics, crash partner, and crash scenarios. This would involve studying how these variables influence the occurrence and severity of fatal crashes. Based on the examination, countermeasures are emphasized from the perspective of technologies, particularly those available on passenger vehicles. The objective of this study is to identify key risk factors and provide insights for improving road safety policies and intervention strategies. The highest age group involved in motorcycle crashes are among 16-20, followed by 21-25. 62.7% occurred in daylight, 90.5% during good weather and 75.4% occurred in midblock. By comparing the engine capacity to the total industry volume, the highest risk is on motorcycles>250 cc, as the production is only 0.29%, but contributes to 4.55% of fatal crashes. The highest crash partners are passenger cars at 30.84%, followed by trucks at 26.64% and single-vehicle accidents at 19.64%. In single crash accidents, road departure represents 56.7%, and control loss, 43.3%. The mandatory ABS in new motorcycles in Malaysia may help in reducing the number of stability losses during emergency braking. Except for rear-end crashes, passenger cars are the highest collision partner in all crash scenarios. Considering the frequency of crash scenarios and crash compatibility, crash avoidance technologies that could help reduce fatalities include autonomous emergency braking, blind spot detection, and lane-keeping assist.

Real-World Emission Assessment of Diesel Passenger Cars in Urban Traffic: A Comparative Analysis of Compliance with Bharat Stage VI Standards

Urban air pollution, significantly influenced by vehicle emissions, poses severe health risks, particularly in rapidly urbanizing cities. This study investigates real-world emissions from diesel-powered passenger cars under mixed traffic conditions, focusing on compliance with Bharat Stage VI (BS VI) standards. Using Portable Emission Measurement Systems (PEMS), emission factors for Carbon Monoxide (CO), Oxides of Nitrogen (NOx), and the combined mass of Hydrocarbons and Oxides of Nitrogen (THC + NOx) were measured. Results revealed exceedances of 75%, 103.75%, and 40.59% for CO, NOx, and THC + NOx, respectively, underscoring inefficiencies in emission control technologies. Variability in emissions was linked to vehicle age, maintenance, driving behaviors, and challenging road conditions. These findings highlight the critical gap between laboratory-tested and real-world emissions, emphasizing the need for stricter regulations, advanced emission technologies, and public awareness campaigns. The study offers actionable insights for urban air quality improvement and policy development to reduce vehicular pollution.

Investigation into the Prediction of the Service Life of the Electrical Contacting of a Wheel Hub Drive

This article examines contacting by means of ultrasonic welding between a cast aluminum winding and a copper conductor of a wheel hub drive for a passenger car. The effect of thermal stress on the formation and growth of intermetallic phases (IMC) in the contact is analyzed. By using microscopy, the growth constant under the specific load conditions can be identified with the help of the parabolic time law and offer a possibility for predicting the service life of the corresponding contacts. As a result, it can be stated that the increase in electrical resistance of the present contact at load temperatures of 120 °C, 150 °C, and 180 °C does not reach a critical value. The growth rates of the IMC also show no critical tendencies at the usual operating temperatures (120 °C and 150 °C, e.g., at 150 °C = 4.59 × 10−7 μm2/s). The activation energy calculated using the Arrhenius plot of 155 kJ/mol (1.61 eV) can be classified as high in comparison to similar studies. In addition, it was found that future investigations of the IMC growth of corresponding electrical contacts should rather be carried out with electric current. The 180 °C sample series were carried out in the oven and with electric current; the samples in the oven did not show clear IMC, while the samples exposed to electric current already showed IMC under the microscope.

Lubricant Viscosity Impact in Fuel Economy: Experimental Uncertainties Compensation

Climate constraints impose greenhouse gas emissions mitigation, and passenger cars have considerable contributions to contribute to this. To improve the engine efficiency of vehicles equipped with conventional powertrains, many technologies are available but with limited individual contribution. The experimental assessment of some technology regarding fuel economy measurement results is sometimes lower than test uncertainties. This study proposes a methodology to compensate the fuel economy for two test uncertainties: vehicle speed variations and battery recharging. The proposed method can be applied when investigating the effects of different vehicle design changes, including engine power cell design. In this work, the proposed method is demonstrated on the test of two oils: one 5W40, the other 5W20, both without FM. Applying the proposed methodology to experimental results, the expected higher influence of oil viscosity on urban conditions could be observed, and the experimental results presented a much better correlation with the vehicle numerical simulation. Applying the proposed compensation, fuel savings of using the 5W20 in comparison to the 5W40 oil was 3.5% under urban conditions and 2.0% on highways.

Potential of PN Reduction in Passenger Cars with DPF and GPF

Particle number concentration (PN) in vehicle exhaust and ambient air describes the number of ultrafine particles (UFPs) below 500 nm, which are recognized as a toxic and carcinogenic component of pollution and are regulated in several countries. Metal nuclei, ash, and organic matter contribute significantly to the ultrafine particle size fraction and, thus, to the particle number concentration. Exhaust gas filtration is increasingly being used worldwide to significantly reduce this pollution, both on diesel particulate filter (DPF) and gasoline particulate filter (GPF) engines. In recent years, the EU has also funded research projects dealing with the possibilities of retrofitting gasoline vehicles with GPFs. This paper presents the results and compares the PN emissions of different vehicles. An original equipment manufacturer (OEM) diesel car with a DPF is considered as a benchmark. The PN emissions of this car are compared with a CNG car without filtration and with gasoline cars equipped with GPFs. It can be concluded that the currently used GPFs still have some potential to improve their filtration efficiency and that a modern CNG car would still have remarkable possibilities to reduce PN emissions with an improved quality GPF.

A Manikin-Based Study of Particle Dispersion in a Vehicle Cabin

Recently, there has been a growing interest in understanding how respiratory particles spread within passenger cars, especially in light of ongoing challenges posed by infectious diseases. This study experimentally investigates dispersion patterns of respiratory airborne particles (<1 µm) within these confined spaces. The main objective is to introduce a manikin-based method for studying particle dispersion and assessing in-cabin air quality. To achieve this, a respiratory manikin as a particle source has been developed and tested under various use-cases, including variations in source emission (breathing vs. speaking), the HVAC ventilation mode (fresh and recirculation), and the blower level of the HVAC system (low and high). The findings reveal that for an infection source on the first row of the vehicle when cabin airflow originates from the front panel, the seat directly behind the particle source is associated with the highest particle exposure, while the seat adjacent to the source offers the lowest exposure. Among the tested configurations, the recirculation mode with an active HEPA filter and high blower level shows the lowest particle concentration at recipients’ breath levels during both breathing and speaking. These findings can be used to enhance the design of passenger cars to reduce the transmission of potentially pathogen-laden particles.

Using Neural Networks for Pavement Rolling Resistance

All pavements contribute to the rolling resistance of vehicles. For passenger cars, the pavement influence is limited to the surface properties, but heavy trucks are influenced by the deformation, the internal damping, and non-elastic behavior of the pavement materials involved. Previous studies have been addressing the pavement type, the material type and various stages of compaction. Recently, even the effects of curling slabs on rolling resistance was assessed. As sustainable pavements are now becoming a requirement from road authorities, it is important to have access to calculable parameters of energy losses during use, and not only from construction. The present paper addresses some of the input parameters needed to assess rolling resistance losses for pavements in general and rigid pavements in particular, by using neural network techniques. The results can be used for the decision-making in either bidding processes or strategic planning.

Rolling resistance on concrete pavements in The Netherlands

In an effort to reduce fuel consumption and CO2, a measurement program initiated by Rijkswaterstaat and province Gelderland was conducted in 2013 to investigate the variation in rolling resistance of passenger cars tyres on different asphalt road surface types on the Dutch main roads (highways and provincial roads). Complementary to the rolling resistance measurements also texture measurements were performed. In addition to this program rolling resistance and texture measurements have been performed on some concrete road sections for the Cement&BetonCentrum. In total 8 concrete road sections were selected and measured. The measurements were a joint effort by M+P and TU-Gdansk. All the concrete road sections were measured on April 2013. The rolling resistance and texture were measured simultaneously. A temperature correction based on the tyre wall side temperature was applied to all rolling resistance coefficients. Two types of concrete road surfaces were measured: brushed concrete (1 road section) and exposed aggregate concrete (7 road sections of different ages: from 8 to 22 years old pavements!). The difference in average rolling resistance coefficient between brushed concrete and exposed aggregate concrete is 0.9 ± 0.4 kg/t (or 10 ± 4 %). This is a significant difference.

Key Technologies to 50% Brake Thermal Efficiency for Gasoline Engine of Passenger Car

Review Key Technologies to 50% Brake Thermal Efficiency for Gasoline Engine of Passenger Car Xinke Miao, Bingxin Xu, Jun Deng, and Liguang Li * School of Automotive Studies, Tongji University, Shanghai 201804, China * Correspondence: liguang@tongji.edu.cn Received: 13 August 2024; Revised: 6 December 2024; Accepted: 17 December 2024; Published: 20 January 2025 Abstract: As fuel consumption and emissions regulations become increasingly stringent, various advanced strategies have been proposed to achieve higher efficiency in internal combustion engines. This paper reviews the advancements in thermal efficiency of gasoline engines and analyzes the key technological methods to achieve over 50% brake thermal efficiency (BTE). The technological routes proposed for high-efficiency gasoline engine are primarily focused on high compression ratios and lean combustion combined with novel combustion technologies. Supporting technologies mainly include Atkinson/Miller cycles, intake boosting, exhaust gas re-circulation (EGR), water injection, thermal barrier coatings, friction reduction, structural optimization, and combustion diagnostics and control.

Thermoelectric system for cooling and air conditioning in passenger cars

Objective. The aim of the study is to develop a design of a thermoelectric system (TES) for cooling and air conditioning in the passenger compartment of a car, its calculation, analysis of parameters and electrical and thermal characteristics. Method. The study is based on the methods of natural and computational modeling of air conditioning and life support systems in order to find optimal solutions for efficiency, reliability and service life of low-temperature installations, machines and devices. Result. The TES has been calculated and its parameters have been determined. Dependencies describing the main characteristics of the TES and the TEM included in its composition have been obtained. The following dependence graphs have been constructed: changes in the average temperature in the volume of the vehicle cabin, as well as heat exchange systems over time, power, coefficient of performance, TEM supply voltage from the temperature difference between junctions for different values of the supply current, volt-ampere characteristic for different values of the temperature difference between junctions, change in temperature at the cold junction of the TEM from the supply current. The graphs are presented at a temperature of hot junctions of the TEM of 320 K. Conclusions. The parameters of the installation are defined: the number of TEM type TB-199-1.4-1.5 - 18 pcs., the operating power range of a single TEM is from 17 to 40 W with an average temperature difference between the junctions of 50 K, the supply current is from 2 to 6 A with a power consumption of 40 to 130 W, the cooling coefficient is from 0.17 to 0.7.

IMPROVED TECHNIQUES FOR ASSESSING RIDE QUALITY ON CONCRETE PAVEMENTS

Under current procedures used in Australia for testing and interpretation of road profiles it is difficult to identify and isolate pavement sections responsible for unpleasant ride vibration. For the construction of new concrete pavements, in particular, where subsequent correction of profiles is very expensive, there is a need for improved procedures to give early feedback of the ultimate ride quality. To help identify and treat pavement problem areas, numerical models were developed to simulate ride vibration and pavement grinding. The ride and grind simulation models cover four generic vehicle classes – passenger cars, heavy commercial vehicles, offroad recreational and sports utility vehicles and motorcycles – and conventional pavement grinding equipment. A number of vibration response presentation formats were developed to help quantify ride vibration severity, intrinsic unevenness and grind treatment effectiveness. The models and key findings of the study are presented in this paper through contrasting examples of responses from the models to a selection of road profiles before and after virtual (theoretical) remedial grind treatment.

RIDE QUALITY MEASUREMENT AND USER RATINGS: INITIAL ASSESSMENT OF IMPROVED TECHNIQUES

Improved techniques for assessing ride quality have been developed by the authors that closely simulate actual vehicle ride dynamics and the responses of humans to whole-body vibration. Using numerical models to simulate four generic road-user vehicle classes – passenger cars, heavy commercial vehicles (trucks), off-road recreational and sports utility vehicles (SUVs) and motorcycles – fundamental issues associated with current ride quality measurements are addressed leading to more robust and accurate estimates of pavement rideability. Initial field trials and tests of the proposed ride quality model for a passenger car were conducted. To assess the effectiveness of the model as a ride quality predictor, the overall modelled ride responses were compared with actual measured ride vibrations (objective measures) and road-user ride ratings (subjective measures), all taken on the same sections of pavements. For the objective measures of ride quality portable vibration measuring equipment, comprising accelerometers, event markers and a data logger were assembled, customised and tested. In later versions of the equipment, also described in this paper, GPS tracking was incorporated to provide precise time-based recordings of location and speed. Developed specifically for this project, the equipment is small in size, completely self-contained, and is readily adapted for use in both small and large vehicles (motorcycles, cars, SUVs and trucks). The initial study found there was good agreement between the modelled responses, vibration measurements and subjective ratings. A further larger study is planned, which is discussed in this paper.

Carbon emission of urban vehicles based on carbon emission factor correlation analysis

The CO2 emission factor is the basis for analyzing vehicle CO2 emissions. This study establishes a correlation model between the fuel CO2 emission factor and the mileage-based CO2 emission factor using fuel consumption data, then analyzes the fuel consumption and CO2 emission situation of vehicles in Beijing with the established models. The main research conclusions are as follows: The proposed correlation models are effective for analyzing urban vehicle CO2 emissions. Cars can only meet the national standard limit when traveling at an average speed of 42.17 km/h. During rush hours, fuel consumption in most cities in China exceeds national standards, making it urgent to improve urban traffic efficiency. Due to the decline in urban traffic conditions in Beijing in 2023 (average speed decreased from 29.14 km/h to 24.26 km/h), each passenger car consumes an average of 0.282 L more gasoline per day, emitting an additional 619.87 g of CO2. This study is of great significance for energy conservation and emission reduction in road transportation.

Numerical and experimental investigation of vibration of a car chassis and its effect with road gradient on noise and response optimization with factorial design method

This paper delves in to a numerical and experimental investigation of vibration of a car chassis and its effect with road gradient on noise and response optimization. Peak acceleration, peak amplitude as vibration response parameters in vertical motion, internal and pass by noise as a noise response parameters. Vibration parameters obtained numerically by developing a mathematical model of car and equation of motion. Newmark Beta method programmed in MATLAB software used to solve the equation of motion. Experimental investigation of the vibration were carried on a car consist of monocoque chassis, three cylinder engine, Macpherson front suspension and twist beam rear suspension. FFT analyzer and digital sound level meter were used for the data collection. Pass by noise data of vehicle were collected at two locations with gradient 1.15° and 11.31° on state highway (MH SH-44) near Konchi Maharashtra state, India. Comparison between numerical and experimental investigated values of vibration parameters shows minimum error of 0.6035% and average error of 2.81% which validates the car model. Factorial design method was used to optimize the index of response parameters which shows reduction in peak acceleration, peak amplitude, internal noise and pass by noise level by 65.61%, 17.70%, 7.13% and 19.41% respectively. The methodology proposed in this study provides reference to improve the performance of car suspension and passenger comfort.

Lane-changing risk analysis of passenger cars on highways based on the HighD dataset

Lane-changing risk analysis of passenger cars on highways based on the HighD dataset

Aerodynamic Effects of the Backup Tire Arrangement on a Off-Road Type Passenger Car

Aerodynamic Effects of the Backup Tire Arrangement on a Off-Road Type Passenger Car