Automotive Science and Engineering

Enhancing Electric Power Steering Performance: Robust Control Strategies for Noise Suppression and Disturbance Rejection

Morteza Mollajafari

Electric Power Steering (EPS) systems are increasingly being integrated into modern vehicles, offering enhanced fuel efficiency and improved maneuverability. However, these systems are often subject to noise and disturbances, which can significantly impact steering precision and driver comfort. Addressing these challenges requires the implementation of robust control strategies capable of mitigating noise and disturbances in EPS systems. This paper explores advanced methods for achieving robust control in Electric Power Steering systems by reducing noise interference and countering external disturbances. Key techniques involve adaptive control algorithms and robust filtering mechanisms that maintain system stability and performance even under variable operating conditions. Experimental results demonstrate that these robust control approaches effectively minimize noise levels and disturbance impacts, leading to smoother steering response and greater reliability. This study underscores the critical role of robust control in enhancing the functionality and safety of Electric Power Steering systems while highlighting the intricate dynamics between noise, disturbances, and control system robustness in automotive applications.

Numerical simulation of airflow distribution impact on radiator performance in the QUIK automobile

Hojjat Saberinejad

One of the main challenges in designing a vehicle's cooling system, particularly the radiator, is not considering the non-uniform airflow distribution in the radiator's characteristic performance graphs. In this study, a three-dimensional numerical analysis of the airflow passing through a QUIK vehicle and the effect of the cooling system's placement relative to the vehicle's grille in five different cases was conducted. The effect of non-uniform airflow distribution on related radiator parameters such as the Darcy number, particle diameter, and inertial term was examined. The results indicate that the optimal placement range of the vehicle's cooling system for appropriate cooling performance is very limited. Additionally, non-uniform air velocity distribution plays a significant role in the radiator pressure drop. The inertial term is more significant in non-uniform flow conditions. For larger Forchheimer numbers, the change in radiator pressure drop for uniform compared to non-uniform flow distributions is about 22%.

Ethical Decision-Making in Autonomous Vehicles: A Human-Centric Risk Mitigation Approach Using Deep Q-Networks

Abdollah Amirkhani

Ensuring that ethically sound decisions are made under complex, real-world conditions is a central challenge in deploying autonomous vehicles (AVs). This paper introduces a human-centric risk mitigation framework using Deep Q-Networks (DQNs) and a specially designed reward function to minimize the likelihood of fatal injuries, passenger harm, and vehicle damage. The approach uses a comprehensive state representation that captures the AV’s dynamics and its surroundings (including the identification of vulnerable road users), and it explicitly prioritizes human safety in the decision-making process. The proposed DQN policy is evaluated in the CARLA simulator across three ethically challenging scenarios: a malfunctioning traffic signal, a cyclist’s sudden swerve, and a child running into the street. In these scenarios, the DQN-based policy consistently minimizes severe outcomes and prioritizes the protection of vulnerable road users, outperforming a conventional collision-avoidance strategy in terms of safety. These findings demonstrate the feasibility of deep reinforcement learning for ethically aligned decision-making in AVs and point toward a pathway for developing safer and more socially responsible autonomous transportation systems.

Experimental Investigation on Engine Vibration Behavior Caused by Crankshaft Mechanism Under Different Lubricant Type and Temperatures

Ashkan Moosavian

The main objective of this study is to investigate the vibrational behavior of the crankshaft mechanism of an IC engine operated on motoring mode as a function of the lubricant type, oil temperature. This attempt included instrumenting the engine block with accelerometers to measure horizontal and vertical vibration intensity and running the engine on an electromotor test rig in a specific test procedure namely strip-down method. The experiments were conducted with various cranktrain configurations under different engine speeds, lubricant types and oil temperatures. The results showed that vibration intensity of the cranktrain mechanism increases with increasing engine speed. This vibrations level was maximum in the highest speed. Changes in vertical vibrations caused by crankshaft in different conditions were almost similar to horizontal vibration changes. Also, the engine vibration caused by crankshaft were not affected by the oil type and oil temperature at all engine speeds, and increase in the speed had a very slight effect on this vibration. The engine vibrations due to reciprocating masses increased significantly with the speed rise, and altered by changes in oil temperature. Changing the oil type had almost no effect on vertical vibration caused by the movement of the reciprocating masses at any engine speed. But the horizontal vibration caused by them at a constant oil temperature increased by changing the oil type from 20w50 to 10w40. The experimental results showed that the contribution of the reciprocating masses from the vibrations caused by cranktrain mechanism was much higher than that of the crankshaft.

Investigating the effects of the ozone gas injection process on the reduction of exhaust gas emissions

Alireza Asadolahei

This study investigates the effects of ozone gas injection on reducing exhaust emissions in internal combustion engines (ICEs). Ozone (O₃), a highly reactive oxidizing agent, has been widely utilized for air and water purification. Its ability to break down pollutants makes it a promising alternative or supplement to conventional catalytic converters, which require expensive materials and periodic recycling. In this research, ozone gas was generated using the corona discharge method and injected into the combustion system to evaluate its impact on carbon monoxide (CO) emissions. A low-power 12-volt compressor, capable of producing up to 10 bar pressure, was used to ensure proper injection. A five-gas analyzer was employed to measure emission changes before and after ozone injection. Results indicated an average CO reduction of 34–40% across seven tested vehicles, with the highest effectiveness observed at steady-state engine operation and moderate loads. Furthermore, an increase in lambda (λ) values suggested improved air-fuel combustion efficiency. Statistical analysis, including standard deviation (±0.005) and a 95% confidence interval, confirmed the reliability of these findings. The results demonstrate that ozone injection can serve as a cost-effective method to supplement traditional emission control technologies, potentially reducing reliance on catalytic converters.

Measurement and Analysis of Particulate Matter Emitted from Diesel Vehicles Using a Simplified Testing Cycle

Mahdi Keyhanpour

This study develops and validates a simplified testing methodology aligned with UNECE Regulation No. 49 to quantify particle number (PN) emissions from diesel vehicles. A modified World Harmonized Vehicle Cycle (WHVC) was implemented, incorporating steady-state operational segments (urban: 21.3 km/h, rural: 43.6 km/h, motorway: 76.7 km/h), and applied to evaluate 51 Iranian-manufactured diesel vehicles. The tested fleet comprised heavy-duty trucks, buses, and pickup trucks equipped with diverse propulsion systems (e.g., ISF3.8s5154, OM457LA.IV) and after-treatment technologies, including SCR, DOC, and DPF. Results demonstrate that original equipment manufacturer (OEM)-installed DPFs reduced PN emissions by 7000-fold compared to non-DPF-equipped vehicles (2.49 × 10¹⁰ vs. 1.74 × 10¹⁴ particles/km; p < 0.001). Euro VI-compliant vehicles exhibited the lowest emissions (6.01 × 10¹⁰ particles/km), outperforming Euro V and Enhanced Environmentally Friendly Vehicle (EEV) standards. These findings underscore the necessity of adopting OEM-grade filtration systems and enforcing stringent emission regulations, such as Euro VI, to mitigate particulate pollution in urban environments. The methodology provides a replicable framework for emerging markets to align with global emission compliance protocols.