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This paper proposes a new returnless LPG fuel supply system designed to increase the efficiency of current LPG engines. With a conventional engine fuel supply system, the fuel pump is driven at a certain speed to pressurize the fuel to an excessive level, and excess fuel that is discharged from the fuel pump but not injected from the injector is returned to the fuel tank via a pressure regulator and a return line. This arrangement keeps the pressure in the fuel supply line at a constant level. Accordingly, during engine idling, fuel cut-off or other times when very little or no fuel is injected from the injector, nearly all the fuel discharged from the fuel pump is returned to the fuel tank via the pressure regulator and return line. Therefore, the energy (electric power) applied to drive the fuel pump is wastefully consumed. Moreover, returning a large amount of excess fuel to the fuel tank can raise the fuel temperature in the tank, causing the fuel to evaporate.

In the port injected Spark Ignition (SI) engine, the single greatest part load efficiency reducing factor are energy losses over the throttle valve. The need for this throttle valve arises from the fact that engine power is controlled by the amount of air in the cylinders, since combustion occurs stoichiometrically in this type of engine. In WEDACS (Waste Energy Driven Air Conditioning System), a technology patented by the Eindhoven University of Technology, the throttle valve is replaced by a turbine-generator combination. The turbine is used to control engine power. Throttling losses are recovered by the turbine and converted to electrical energy. Additionally, when air expands in the turbine, its temperature decreases and it can be used to cool air conditioning fluid. As a result, load of the alternator and air conditioning compressor on the engine is decreased or even eliminated, which increases overall engine efficiency.

This paper demonstrates that the implementation of Flash Gas Bypass method can improve the performance of conventional direct expansion R134a mobile air-conditioning system with a microchannel evaporator. This method uses flash gas tank after expansion valve to separate and bypass flash refrigerant vapor around the evaporator, and feed the evaporator with only liquid refrigerant. Pressure drop is reduced and refrigerant distribution is significantly improved, resulting in higher evaporator effectiveness and evaporation pressure. Both lower pressure drop and lifted evaporation pressure allows the compressor to work with lower pressure ratio, saving required compressor work. An experimental comparison of the direct expansion system shows that Flash Gas Bypass method increases the cooling capacity and COP at the same time by up to 16% and 11%, respectively.

Axiomatic design is utilized to identify the design characteristics of an On-Line Electric Vehicle and to manage the design information. The On-Line Electric Vehicle, which is being developed at the Korea Advanced Institute of Science and Technology, is a different concept of an electric vehicle from conventional electric vehicles which use the electric power of a charged battery(s). It is operated by an electric power supplied by the contactless power transmission technique between the roadway side and the vehicle. In other words, the power is transmitted based on the principle of an electric transformer. The On-Line Electric Vehicle can overcome the limitations of conventional electric vehicles such as the weight of the battery and driving distance problems. Because designers have little experience and knowledge about the On-Line Electric Vehicle in the developmental stage, an appropriate design guide is needed. The axiomatic approach is employed for the design process.

The present production General Motors 2-Mode Hybrid system for full-size SUVs and pickup trucks integrates truck utility functions with a full hybrid system. The 2-mode hybrid system incorporates two electro-mechanical power-split operating modes with four fixed-gear ratios. The combination provides fuel savings from electric assist, regenerative braking and low-speed electric vehicle operation. The combination of two power-split modes reduces the amount of mechanical power that is converted to electric power for continuously variable transmission operation, meeting the utility required for SUVs and trucks. This paper describes how fuel economy functionality was blended with full-size truck utility functions. Truck functions described include: Manual Range Select, Cruise Control, 4WD-Low and continuous high load operation.

The wear of thrust 51100 rolling bearings was investigated and their dissipative responses in a bench test rig were associated to their heating, elastic energy of mechanical vibration and Sound Pressure Level [dB], regarding two greases, both from the same supplier, being one with graphite and the other with Molybdenum Disulfide. The samples were commercially acquired and submitted to a normal load of 450±5N and 3100±30 CPM, determined after the screening tests. Four variables were measured: temperature [K], electrical power [W], global velocity vibration [mm/s] and Sound Pressure Level [dB]. After 106 cycles, the tracks were analyzed by Optical Microscopy. The bearings lubricated with the grease with graphite showed different responses in relation to the ones lubricated with MoS2 thrust bearings. The signal of the signatures and the damage morphology are presented and discussed.

Electrically Powered Hydraulic Steering (EPHS) has provided value in passenger car applications by reducing power consumption at engine idle, providing only the required power during high speed lane-keeping, and allowing engine-off operation of vehicles with alternative power sources. This work discusses the design modifications made to use EPHS for medium duty commercial vehicle applications. Configuration options along with communication and diagnostic interface are discussed. Bench tests show the steady-state performance of the system. Experiments are done on a medium duty truck with the EPHS as the sole source of steering power to determine the speed of steer at various vehicle speeds. Finally, the power consumption for the EPHS system is compared to a conventional engine driven pump.

The subject addressed by this work, currently discussed in Europe following an European Commission inquiry, is the evaluation of the possibility to prevent the MAC (Mobile Air Conditioning) use below 18°C and its benefits in terms of CO2 emissions saving. This strategy, while providing an uncertain fuel consumption saving, has to be faced with basic safety and cabin comfort conditions. The OEMs (Original Equipment Manufacturers) may evaluate to address these concerns by controlling the cabin absolute humidity content. In order to maintain safety it should be acceptable to turn the AC on based on other inputs, such as air distribution modes (defrost or floor/defrost), windshield wiper usage, rear defroster usage, etc. FGA (FIAT Group Automobiles) exploited our proprietary prediction tool to assessing the yearly fuel efficiency that can be achieved in real use by means of the testing results of representative vehicles.

The performance of an organic Rankine cycle (ORC) used to recover waste heat from the exhaust of a diesel and a spark ignition engine for electric power generation was modeled. The design elements of the ORC incorporated into the thermodynamic model were based on an experimental study performed at Oak Ridge National Laboratory in which a regenerative organic Rankine cycle system was designed, assembled and integrated into the exhaust of a 1.9 liter 4-cylinder automotive turbo-diesel. This engine was operated at a single fixed-load point at which Rankine cycle state point temperatures as well as the electrical power output of an electric generator coupled to a turbine that expanded R245fa refrigerant were measured. These data were used for model calibration.

Multiple-ribbed V belts have been widely used in automotive accessory drive systems to transmit power from crankshaft to power steering pump, alternator, and air conditioning (A/C) compressor. Overload under severe environmental conditions can lead to excessive slippage in the belt pulley interface in poorly designed accessory drive systems. This can lead to undesirable noise that increases warranty cost substantially. The mechanisms of this tribology phenomenon, noise features and system response are of utmost interest to the accessory drive system engineers. As accessory belt systems are usually used in ambient condition, the presence of water or moisture on belt is unavoidable under rainy or highly humid conditions. It has been found that the wet friction with negative coefficient of friction (cof)-velocity slope can lead to self-excited vibrations and squeal noise.

The performance of energy flow management strategies is essential for the success of hybrid electric vehicles (HEVs), which are considered amongst the most promising solutions for improving fuel economy as well as reducing exhaust emissions. The heavy duty HEVs engaged in cycles characterized by start-stop configuration has attracted widely interests, especially in off-road applications. In this paper, a fuzzy equivalent consumption minimization strategy (F-ECMS) is proposed as an intelligent real-time energy management solution for heavy duty HEVs. The online optimization problem is formulated as minimizing a cost function, in terms of weighted fuel power and electrical power. A fuzzy rule-based approach is applied on the weight tuning within the cost function, with respect to the variations of the battery state-of-charge (SOC) and elapsed time.

In the automobile industries, weight reduction has been investigated to improve fuel efficiency together with reduction of CO2 emission. In such circumstance, it becomes necessity to make an electric power steering (EPS) more compact and lightweight. In this study, we aimed to have a smaller and lighter EPS gear size by focusing on an impact load caused at steering end. In order to increase the shock absorption energy without increase of stopper bush size, we propose new theory of impact energy absorption by not only spring function but also friction, and a new stopper bush was designed on the basis of the theory. The profile of the new stopper bush is cylinder form with wedge-shaped grooves, and when the new stopper bush is compressed by the end of rack and the gear housing at steering end, it enables to expand the external diameter and produce friction. In this study, we considered the durability in the proposed profile.

This paper will discuss the stress reduction of the worm wheel for an electric power steering (EPS) system. The research discussed in this paper focused on the worm wheel, the EPS component that determines the maximum diameter of the system. If the stress of the worm wheel could be reduced without increasing in size, it would be possible to reduce the size of the worm wheel and EPS system. In order to reduce the stress of the worm wheel, the conventional design method has extended the line-of-action toward outside of the worm wheel to increase the contact ratio of the gears and these method lead to an increase in the outer diameter. In order to address this issue, past research proposes the basic concept to extend line-of-action toward the inside of the worm wheel. And this new meshing theory was named MUB (Meshing Under Base-circle) theory. In this paper, characteristics of meshing of the gear formed by MUB theory are determined in more detail.

The fuel prices are increasing every day and so are the pollution caused by vehicles using fossil fuels. Moreover, in a car with an internal combustion engine, we get on average 25% efficiency, the other 75% is wasted, mostly through friction and heat. One important loss is the dissipation of vibration energy by shock absorbers in the vehicle suspension under the excitation of road irregularity and vehicle acceleration or deceleration. In this paper we design, manufacture and test a regenerative coil-over strut that is compact, simple in design and more economical. Since our strut is a modification of an existing strut design, it would be much more feasible to implement. We tested our prototype strut using a TATA Indica car under city road conditions. The damping characteristics and output voltage of the strut were recorded and compared with a normal coil over strut. Based on the test data, it was found that the strut was able to recover about 8-10 watts of electricity at 20kmph.

The operation of air conditioning (A/C) systems is a significant contributor to the total amount of fuel used by light-and heavy-duty vehicles. Therefore, continued improvement of the efficiency of these mobile A/C systems is important. Numerical simulation has been used to reduce the system development time and to improve the electronic controls, but numerical models that include highly detailed physics run slower than desired for carrying out vehicle-focused drive cycle-based system optimization. Therefore, faster models are needed even if some accuracy is sacrificed. In this study, a validated model with highly detailed physics, the “Fully-Detailed” model, and two models with different levels of simplification, the “Quasi-Transient” and the “Mapped-Component” models, are compared. The Quasi-Transient model applies some simplifications compared to the Fully-Detailed model to allow faster model execution speeds.

Traditional vehicle air conditioning systems condition the entire cabin to a comfortable range of temperature and humidity regardless of the number of passengers in the vehicle. The A/C system is designed to have enough capacity to provide comfort for transient periods when cooling down a soaked car. Similarly for heating, the entire cabin is typically warmed up to achieve comfort. Localized heating and cooling, on the other hand, focuses on keeping the passenger comfortable by forming a micro climate around the passenger. This is more energy efficient since the system only needs to cool the person instead of the entire cabin space and cabin thermal mass. It also provides accelerated comfort for the passenger during the cooling down periods of soaked cars. Additionally, the system adapts to the number of passengers in the car, so as to not purposely condition areas that are not occupied.

The paper presents a semi-empirical model to predict refrigerant and lubricant inventory in both evaporator and condenser of an automotive air conditioning (MAC) system. In the model, heat exchanger is discretized into small volumes. Temperature, pressure and mass inventory are calculated by applying heat transfer, pressure drop and void fraction correlations to these volumes respectively. Refrigerant and lubricant are treated as a zeotropic mixture with a temperature glide. As refrigerant evaporates or condenses, thermophysical properties are evaluated accordingly with the change of lubricant concentration. Experimental data is used to validate the model. As a result, refrigerant and lubricant mass is predicted within 20% in the evaporator. However, in the condenser, lubricant mass was consistently under-predicted while refrigerant mass was predicted within 15% error. Moreover, the lubricant under-prediction becomes more significant at higher Oil Circulation Ratio (OCR).

Conventional crank-based engines are limited by mechanical, thermal, and combustion inefficiencies. The free piston of a linear engine generator reduces frictional losses by avoiding the rotational motion and crankshaft linkages. Instead, electrical power is generated by the oscillation of a translator through a linear stator. Because the free piston is not geometrically constrained, dead center positions are not specifically known. This results in a struggle against adverse events like misfire, stall, over-fueling, or rapid load changes. It is the belief that incorporating springs will have the dual benefit of increasing frequency and providing a restoring force to aid in greater cycle to cycle stability. For dual free piston linear engines the addition of springs has not been fully explored, despite growing interest and literature.

This work is based on a current project related to auxiliary power unit (APU) exhaust silencing technology development, specifically an active exhaust noise cancellation technology. The overriding technical challenge is identified as development of a frequency and amplitude controllable noise source that can survive in a hot and corrosive exhaust environment. Installation of an APU enables vehicle platforms to turn off the main engine and still utilize auxiliary equipment that requires electrical power. An APU with a small engine potentially consumes much less fuel than a main engine at low power levels. However, past APU integrations have resulted in unacceptable noise levels, often times louder than the main engine at the equivalent operating point. Exhaust tones created by combustion pose a unique challenge to external acoustic reduction because they generally occur at low frequency, often less than 100 Hz.

The idea of grid friendly charging is to use electricity from the grid to charge batteries when electricity is available in surplus and cheap. The goal is twofold: to avoid putting additional load on the electricity grid and to reduce the cost to the consumer. To achieve this, a smart meter and a tariff with variable electricity prices has to be in place. In Day Ahead tariff (DA), prices are announced in advance for the next day, and this information can be used to select the cheapest times to charge the battery by the required amount. The optimization method is very simple, and it only has to be run once per day. However, the balance of supply and demand is not fully known in advance. Therefore Real Time Pricing (RTP) tariff supplies electricity at spot market rate depending on the current balance.