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As environmental problems such as global warming are emerging, regulations on automobile exhaust gas are strengthened and various exhaust gas reduction technologies are being developed in various countries in order to satisfy exhaust emission regulations. Exhaust gas recirculation (EGR) technology is a very effective way to reduce nitrogen oxides (NOx) at high combustion temperatures by using EGR coolers to lower the combustion temperature. This EGR cooler has been mass-produced in stainless steel, but it is expensive and heavy. Recently, high efficiency and compactness are required for the EGR cooler to meet the new emission regulation. If aluminum material is applied to the EGR cooler, heat transfer efficiency and light weight can be improved due to high heat transfer coefficient of aluminum compared to conventional stainless steel, but durability is insufficient. Therefore, the aluminum EGR cooler has been developed to enhance performance and durability.

CO2 emission is more serious in recent years and automobile manufacturers are interested in developing technologies to reduce CO2 emissions. Among various environmental-technologies, the use of solar roof as an electric energy source has been studied extensively. For example, in order to reduce the cabin ambient temperature, automotive manufacturers offer the option of mounting a solar cell on the roof of the vehicle [1]. In this paper, we introduce the semi-transparent solar cell mounted on a curved roof glass and we propose a solar energy management system to efficiently integrate the electricity generated from the solar roof into internal combustion engine (ICE) vehicles. In order to achieve a high efficiency solar system in different driving, we improve the usable power other than peak power of solar roof. Peak power or rated power is measured power (W) in standard test condition (@ 25°C, light intensity of 1000W/m2(=1Sun)).

This paper examines the effect of pulse-and-glide (PnG) driving strategies on the fuel efficiency when applied on parallel HEVs. Several PnG strategies are proposed, and these include the electrical, mechanical, and combined PnG strategies. The electrical PnG strategy denotes the hybrid powertrain control tactics in which the battery is charged or discharged according to the power demanded while maintaining the constant vehicle speed. On the other hand, the mechanical PnG strategy denotes the powertrain control tactics in which the vehicle accelerates or decelerates according to the power load while minimizing the battery usage. The combined PnG strategy involves both electrical and mechanical strategies to find a balanced point in between them. Here, a tradeoff relationship between the fuel efficiency and the vehicle drivability related to the tracking performance of the desired target speed is revealed.

A physics-based model for SCR (Selective Catalytic Reduction) was developed based on five independent SGB (Synthetic Gas Bench) tests. There are NH3 adsorption & desorption test, NO oxidation test, NH3 oxidation test, SCR reaction (NOx & NH3) test and SV (Space Velocity) test. To validate the accuracy of SCR model’s prediction, transient reactor tests were conducted at four different input conditions. A newly developed SCR model showed more than 90% prediction accuracy in transient test conditions in view of cumulative NOx. Validation of SCR model was conducted on 1.6L light duty diesel vehicle in the WLTC (Worldwide Harmonized Light vehicles Test Cycle). Based upon this SCR model, vehicle level SCR calibrations used for urea dosing control were made and validated in the emission test cycles like WLTC.

A study for improving the resistance to fretting corrosion of SCr 420 pinion gear was conducted. Fretting is the damage to contacting surfaces experiencing slight relative reciprocating sliding motion of low amplitude. Fretting corrosion is the fretting damage to unlubricated contacting surfaces accompanied by corrosion, mostly oxidation that occurs if the fretting occurs in air. Two kinds of conventional heat treatment and a newly designed one suggested for improving the resistance to the fretting corrosion of pinion gear were compared each other to find out what is the main factor for generating fretting corrosion phenomenon. Increased carbon potential at both the heating and diffusing zone and reduced time of tempering was found out to be a solution for improving the resistance to fretting corrosion of forged and heat treated gear steel. On the contrary, modified carbo-nitriding using ammonia gas has been getting worse the fretting corrosion problem.

In diesel engine development, the new technology is coming out to meet the stringent exhaust emission regulation. The regulation demands more eco-friendly vehicles. Euro6c demands to meet not only WLTP mode, but also RDE(Real Driving Emission). In order to satisfy RDE mode, the new technology to reduce emissions should cover all operating areas including High Load & High Speed. It is a big challenge to reduce NOx on the RDE mode and a lot of DeNOx technologies are being developed. So the new DeNOx technology is needed to cover widened operating area and strict acceleration / deacceleration. The existing LNT(Lean NOx Trap) and Urea SCR(Selective Catalytic Reduction) is necessary to meet the typical NEDC or WLTP, but the RDE mode demands the powerful DeNOx technology. Therefore, the LNT & Urea SCR on DPF was developed through this study.

Road friction estimation algorithms had been studied for many years because it is very important factor for safety control and fuel efficiency of vehicle. But traditional solutions are hard to adapt in automotive industry because their performance is not sufficient enough and expensive to implement. Therefore, this paper proposes a road friction estimation algorithm based on a trained artificial neural-network which is low cost and robust. The suggested method doesn’t need expensive additional sensors such as optical or lidar sensor, also it shows better performance in real car environment compared to other algorithms based on vehicle dynamics. In this paper, we would describe this algorithm in detail and analyze the test results evaluated in real road conditions.

Recently, as part of the effort to enhance fuel efficiency and reduce costs for eco-friendly vehicles, the R-gearless system has been implemented in the TMED (P)HEV system. Due to the removal of the reverse gear, a distinct backward driving method needs to be developed, allowing the Electronic Motor (e-Motor) system to facilitate backward movement in the TMED (P)HEV system. However, the capability of backward driving with the e-Motor is limited because of partial failure in the high-voltage system of an R-gearless system. Thus, we demonstrate that it is possible to improve backward driving problems by applying a new fail-safe strategy. In the event of a high-voltage battery system failure, backward driving can be achieved using the e-Motor with constant voltage control by the Hybrid Starter Generator (HSG), as proposed in this study.

The electrification of the internal combustion engine is an important subject of future automotive technology. By using a motorized internal combustion engine, it is possible to recover waste energy by regeneration technology and to reduce various losses that deteriorate the efficiency of the internal combustion Engine. This paper summarizes the results of the development of an engine-integrated motor that can be applied to a 48V mild hybrid system for motorization of an internal combustion engine. Like the 48V MHSG-mounted mild hybrid system designed to replace the generator in the auxiliary belt system, the motorized internal combustion engine is designed with the scalability as the top priority to minimize the additional space for the vehicle and to mount the same engine in various models.

Since the fuel efficiency of vehicle has become one of the big issues due to environmental pollution problems, many studies have been conducted on various methods such as improving powertrain performance and aerodynamic performance, reducing the weight of the vehicle and so on. There have been many new attempts to reduce weight but mostly about improving material property. In the case of vehicles sharing the same platform, the weight and cost of vehicle are mainly changed by the exterior styling. But, there is no solution to control the exterior styling in terms of the weight and cost of vehicle, yet. The purpose of this study is to find the way to save the weight and cost of vehicle while achieving the various performance and requirements of vehicle (safety, aerodynamics, driver’s visibility and so on) from exterior styling point of view. We focused on the weight difference of the vehicles that shared the platform and were same overall dimensions.

To improve the fuel efficiency and satisfy the strict emission regulations, the development of internal combustion engine gets more complicated in both hardware and software perspectives, and the margins for durability and NVH quality become narrower, which could result in poor NVH robustness in harsh engine operating conditions. In this paper, we investigate experimentally the camshaft impact noise mechanism relating the valve train and timing chain forces to detailed motion of the camshaft and the chain tensioner. After the initial investigation of identifying the impact timings and specific engine operating points when the noise occurs, the camshaft orbital motion inside of the sliding bearing is measured and visualized with the proximity sensors with calibration after sensor mounting, in addition to the chain tensioner movements.

In order to apply an effective noise reduction treatment determining the contribution of different engine components to the total sound perceived inside the cabin is important. Although accelerometer or laser based vibration tests are usually performed, the sound contributions are not always captured accurately with such approaches. Microphone based methods are strongly influenced by the many reflections and other sound sources inside the engine bay. Recently, it has been shown that engine radiation can be effectively measured using microphones combined with particle velocity sensors while the engine remains mounted in the car [6]. Similar results were obtained as with a dismounted engine in an anechoic room. This paper focusses on the measurement of the transfer path from the engine to the vehicle interior in order to calculate the sound pressure contribution of individual engine sections at the listener's position.

The combustion characteristics of a HSDI diesel engine were analyzed numerically using a reduced chemical kinetics. The reaction mechanism consisting of 26 steps and 17 species including the Zel'dovich NOx mechanism for the higher hydrocarbon fuel was implemented in the KIVA-3V. The characteristic time scale model was adopted to account for the effects of turbulent mixing on the reaction rates. The soot formation and oxidation processes are represented by Hiroyasu's model and NSC's model. The validation cases include the homogenous fuel/air mixture and the spray combustion in a constant volume chamber. After the validation, the present approach was applied to the analysis of the spray combustion processes in a HSDI diesel engine. The present approach reasonably well predicts the ignition delay, combustion processes, and emission characteristics in the high-pressure turbulent spray flame-field encountered in the practical HSDI diesel engines.

Environmental standards concerning Suspended Particulate Matter (SPM) are continuously becoming stricter. The light-duty diesel passenger car market is rapidly increasing due to performance improvements and the economic advantages of the diesel engine. To meet EURO 4 diesel passenger car emission regulations, regeneration experiments of a catalyzed particulate filter (CPF) system have been performed with 2.0L common-rail diesel engine. For effective regeneration of the CPF system, we investigated the effects of various regeneration conditions on the system. Conditions such as exhaust gas temperature, oxygen/hydrocarbon concentrations, gas compositions, etc. were investigated. We found that the regeneration efficiency was improved when the exhaust gas temperature increased to more than 700°C during CPF regeneration using engine post injection. An additional amount of post injection increased the exhaust gas temperature and residual hydrocarbon content.

Thii paper describes Hyundai's research and development work on the dedicated compressed natural gas (CNG) engine, A conventional light duty gasoline engine, a 1.5 liter four cylinder DOHC, has been modified to run on natural gas (NG) by a gas injection system and engine dynamometer test has been performed with emphasis on optimizations of compression ratio and intake port. Also presented are the results on the exhaust emissions characteristic and the purification performance of three-way catalytic converters developed for NG engine. Fuel composition and THC emissions are analyzed quantitatively using gas chromatography devices.

As the carbon neutrality to reduce greenhouse gas emissions has become a global movement, the development of power sources using carbon-free fuels is an essential task for the industry. Accordingly, many companies in various fields that need carbon reduction are striving to develop power sources and build energy value chains using carbon-free or carbon-neutral fuels such as hydrogen and E-fuel. Ammonia, which is also a carbon-free fuel, stands as an efficient energy vector delivering high energy density and flexibility in transportation and storage, capable of mitigating hydrogen’s key drawbacks. However, difficulty of controlling combustion of ammonia due to its fuel characteristics limited the development of internal combustion engines using ammonia to the basic research stage in the limited operating conditions. Hyundai Motor Company presents the development of ammonia fueled 4-cylinder SI engine using direct injection strategy, designed based on 2.5L LPG T-DI engine.

The success of improved fuel economy is the proper integration of thermal management components which are appropriately performed to reduce friction and wasted energy. The thermal management systems of vehicle are able to balance the multiple needs such as heating, cooling, or appropriate operation within specified temperature ranges of propulsion systems. Since the propulsion systems of vehicle have changed from a single energy source based on conventional internal combustion engine to hybrid system including more electrical system such as full type of hybrid electric vehicle or plug-in hybrid electric vehicles, a new transition associated with vehicle thermal management arises. More efficient thermal management systems are required to improve the fuel economy in the hybrid electric vehicles because of the driving of electric traction motor and the increase of engine off time. The decrease of engine operation time may not sustain the proper temperature ranges of engine and gearbox.

The use of light-weight materials in automotive engine components has increased in order to achieve better fuel efficiency and engine performance. In this study, Al alloy (AI5056) valve spring retainer can reduce a weight by 63% in comparison to steel and improve the upper limit of engine speed by about 500rpm. The Al valve spring retainer was fabricated by cold forging and coated with hard anodizing, DLC (diamond like coating), cold spray and thermal spray for better wear resistance and durability. We conclude that among these materials the DLC coating improves the wear resistance of Al valve spring retainer and has a sufficient durability after endurance testing.

Improved Lean NOx Trap (LNT) catalysts with enhanced NH3 generation feature were developed for the small diesel engine. The next generation LNT system needs to perform good NOx conversions over the wide temperature range including below 200°C for urban driving and above 400°C for motorway of real road driving. However, the extended use of BaO, a component of LNT known to be very effective for high temperature NOx storage, results in the decrease of low temperature NOx conversion due to the degradation of NO oxidation associating with sulfur over time. The improvement of the low-temperature LNT performance is a key requirement for the real driving emission control as the best operation temperature for urea-SCR is above ~250°C. In this study, our next generation LNT with new washcoat architecture has demonstrated improved NOx removal efficiencies under the wider operation temperature window than the current production technology.

Various polymer-based coatings are applied on piston skirt to reduce friction loss between the piston skirt and cylinder bore which is one of main factors of energy loss in an automotive engine system. These coatings generally consist of polymer binder (PAI) and solid lubricants (graphite or MoS₂) for low friction property. On the other hand, the present study found that PTFE as a solid lubricant and nano diamond as hard particles can be used to improve the low friction and wear resistance simultaneously. In the process of producing coating material, diamond particles pulverized to a nano size tend to agglomerate. To prevent this, silane (silicon coupling agent) treatment was applied. The inorganic functional groups of silane are attached to the nano diamond surface, which keep the diamond particles are apart.