• Journal of Biosystems Engineering
• /
• 제11권2호
• /
• pp.23-30
• /
• 1986

A waste heat recovery system for an internal combustion engine for agriculture was developed. The system is for recovering both of exhaust heat and cooling heat of an engine and is so simple in its structure that can be used in rural area easily. A series of experiment was carried out to the experiment which will be discussed later on, collect data for the performance of the system at various operating conditions of the system and an engine and to determine a range of coolant temperature in which performance of an engine is not affected by the heat recovery system incorporated. The obtained experimental data is not only useful to materialize performance of the system at the experimental conditions but also to construct a mathematical model of the system to predict the system variables beyond the scope of

• Special Issue of the Society of Naval Architects of Korea
• /
• 대한조선학회 2013년도 특별논문집
• /
• pp.103-109
• /
• 2013

The Present work focuses on application of Organic Rankine Cycle - Waste heat Recovery System (ORC-WHRS) for marine diesel engine. ORC and its combined cycle with the engine were simulated and its performance was estimated theoretically under the various engine operation conditions and cooling water conditions. The working fluid, R245fa, was selected for the consideration of the heat source temperature, system efficiency and safety issues. According to the thermodynamic analysis, ~13.1% of system efficiency of the cycle was performed and it is about 4% of the mechanical power output of the considering Marine Diesel Engine. Also, addition of evaporator and pre-heater were studied to maximize output power of Organic Rankine Cycle as a waste heat recovery system of the marine diesel engine.

• Journal of Biosystems Engineering
• /
• 제12권1호
• /
• pp.6-13
• /
• 1987

A mathematical model for the waste heat recovery system for an engine was developed. The model based on the experimental data reported before was validated and was used to predict the waste heat recovery and recoverable heat of the engine at various operating conditions of the engine and the system. The model was also used to determine flow rates of the circulating water in the system for a certain temperature increment of the water at various operating conditions of the engine to give basic data to design the system. Stability of the system performance was tested on subjects of vapor lock problem, thermal characteristics of the thermostatic valve, and temperature variation of the circulating water in the engine and fuel consumption of the engine during each mode of the system operation and its change into the other. The test showed that the system operation was stable enough. Temperature profile in the thermal energy storage (TES) was observed during storing thermal energy, and thermal stratification in the TES was well formed acceptable to be used in the system. Finally a scheme to automatize the system was suggested.

• Transactions of the Korean Society of Automotive Engineers
• /
• 제19권5호
• /
• pp.58-66
• /
• 2011

A 2-loop waste heat recovery system with Rankine steam cycles for the improvement of fuel efficiency of gasoline vehicles has been investigated. A high temperature loop(HT loop) is a system to recover the waste heat from the exhaust gas, a low temperature loop(LT loop) is for heat recovery from the engine coolant cold relatively. This paper has dealt with a layout of a LT loop system, the review of the working fluids, and the design of the cycle. The design point and the target heat recovery of the LT boiler, a core part of a LT loop, has been presented and analytically investigated. Considering the characteristics of the cycle, the basic concept of the LT boiler has been determined as a shell-and tube type counterflow heat exchanger, the performance characteristics for various design parameters were investigated.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• 제14권3호
• /
• pp.1022-1026
• /
• 2013

Recently, the waste heat recovery technique using thermoelectric generator (TEG) in automotive engine has emerged to improve thermal efficiency in commercial vehicle. It is not difficult to recognize the numerous attempts that have been made to develop the TEG simulation model, but it is hard to find the model in conjunction with a particular heat engine system. In this study, 1-D commercial software AMESim was used to develop a computational model that can assess waste heat recovery from a diesel engine exhaust using TEG. The developed TEG simulation model can be used for evaluating the TEG performance of various types of TE module, and the diesel engine model can simulate any type of on and off-road diesel engines. The simulation results demonstrated that approximately 544.75W could be recovered from the engine exhaust and 40.4W could be directly converted into electricity using one TE module. The models developed in this study can be easily coupled with each other in the same computational program; thus, the models are expected to provide a viable tool for developing and optimizing a TEG waste heat recovery system in an automotive diesel engine.

• Transactions of the Korean Society of Automotive Engineers
• /
• 제20권4호
• /
• pp.25-32
• /
• 2012

Cold start driving cycles exhibit an increases in friction losses due to the low temperatures of metal components and media compared to the normal operating engine conditions. These friction losses are adversely affected to fuel economy. Therefore, in recent years, various techniques for the improvement of fuel economy at cold start driving cycles have been introduced. The main techniques are the upward control of coolant temperature and the fast warm-up techniques. In particular, the fast warm-up techniques are implemented with the coolant flow-controlled water pump and the WHRS (waste heat recovery system). This paper deals with an effect of fast ATF (automatic transmission fluid) warm-up on fuel economy using a recovery system of EGR gas waste heat in a diesel engine. On a conventional diesel engine, two ATF coolers have been connected in series, i.e., an air-cooled ATF cooler is placed in front of the condenser of air conditioning system and a water-cooled one is embedded into the radiator header. However, the new system consists of only a water-cooled heat exchanger that has been changed into the integrated structure with an EGR cooler to have the engine coolant directly from the EGR cooler. The ATF cooler becomes the ATF warmer and cooler, i.e., it plays a role of an ATF warmer if the temperature of ATF is lower than that of coolant, and plays a role of an ATF cooler otherwise. Chassis dynamometer experiments demonstrated the fuel economy improvement of over 2.5% with rapid increase in the ATF temperature.

• Transactions of the Korean Society of Automotive Engineers
• /
• 제10권1호
• /
• pp.99-105
• /
• 2002

About 70% of energy input to internal combustion engine is rejected to atmosphere by heat. By utilizing this waste heat, a plenty of energy can be conserved in nationwide. One of possible ways is the thermoelectric generation to utilize engine's waste heat to provide auxiliary electric power. Under th is concept, we have been developing the thermoelectric generation system to replace the alternator by converting the waste heat in the engine's exhaust directly to electricity This system may reduce the shaft horse power of the engine, then improves the vehicle fuel economy and the exhaust emissions. In the present study, the characteristics of the electric energy and exhaust heal energy in city and highway mode driving conditions are analysed by using a gasoline passenger car. These results would be used to determine the optimum design parameters of the thermoelectric generation system.

• Transactions of the Korean Society of Automotive Engineers
• /
• 제19권6호
• /
• pp.53-60
• /
• 2011

The effect of exhaust heat recovery system can be evaluated by two well known method. First method is to measure the time duration from engine start under cold coolant temperature till coolant get warmed. By this methodology coolant warming duration can be index of warm-up effect. Second method is to analyze heat balance of the engine during warm-up phase under steady engine operation so that wasted energy by losses such as cooling and exhaust can be index of warm-up effect. This study focused on evaluation of warming-up effect by both methodology above mentioned using 2L SI engine under from idle to 2000rpm steady condition. Results, idle operation showed low heat recovery efficiency but under higher engine speed condition, remarkable heat recovery efficiency improvement was observed. In 2000rpm steady condition, warm-up duration of engine is decreased by exhaust heat recovery system.

• Transactions of the Korean Society of Automotive Engineers
• /
• 제20권4호
• /
• pp.76-81
• /
• 2012

In recent, there are tremendous efforts to apply co-generation concept in automobile to improve its thermal efficiency. The co-generation is basically a simple Rankine Cycle that uses the waste heat from the engine exhaust and coolant for heat source. In spite of developed nano technology and advance material science, the bulky co-generation system is still a big concern in automotive application. Therefore, the system should be effectively designed not to add much weight on the vehicle, but the capacity of the waste heat recovery should be still large. With such a goal in mind, the system thermal efficiency was investigated in terms of the system operation condition and working fluid. This paper provides a direction for the optimal design of the automotive co-generation system.

• Journal of Energy Engineering
• /
• 제21권4호
• /
• pp.402-410
• /
• 2012

A two-loop Rankine cycle for engine waste heat recovery of gasoline vehicle has been investigated. Water-steam cycle as a high-temperature (HT) loop for exhaust gas heat recovery and R-134a cycle as a low-temperature (LT) loop for both heat recovery of the engine coolant and the residual heat from the HT loop were considered. Energy and exergy analysis was performed to investigate the performance of the system. Because two volumetric expanders are used for the HT and LT loop, the sizes of two expanders are very important for the optimization of the system. The effects of pressure ratio of the HT loop, considering the size of the HT expander, and the condensation temperature of LT loop on the performance of the system at a target engine condition were investigated. This study shows that about 20% of additional power from the engine waste heat recovery can be obtained at the target engine condition.