Improvement of piston engine operation efficiency by direct conversion of the heat of exhaust gases into electric energy

Abstract

A promising new way of direct conversion of the heat of piston engine exhaust gases into electric energy is investigated. An original design of a thermoelectric converter with various surface reliefs (smooth, spher ical peaks, spherical dimples) is developed. The engine operation and the flow in the heat exchanger of the ther moelectric generator are modeled. Based on the results of 3D modeling of convective heat transfer, it has been determined that the surface with heat transfer intensifiers in the form of spherical dimples is the most efficient.

Building a technological model of the exhaust gas energy recovery device for the diesel engine on a small­sized vessel

“…Determining exhaust gas temperature. Temperature Т g of the gas released from the diesel engine cylinders depends on the engine load and, according to study [15], is within 700-800 K. The corresponding mean Т g is 750 K. Due to dynamic cooling, the average temperature of the gas coming from the collector to TEG (Т 1 in Fig. 2…”

“…The degree of an increase is determined by the percentage portion of oxygen combustion based on the coefficient of excess air α (the air and fuel ratio in a combustible mixture) according to the technical parameters of the engine. The thresholds of the coefficient α for different types of engines, according to work [15], are given in Table 2. The average value of those given in Table 2 equals two (α=2).…”

“…To calculate the specific heat capacity of exhaust gas, we used the average heat capacity of its components. For α=2 and gas temperature in the range from 0 to 700 °C, Table 3 from work [15] gives the average values of specific heat capacity μ•С р (μ -the molar mass of gas).…”

“…where D is the ship displacement, K n is the power consumption factor depending on the speed of movement. Ship displacement equals , T D S L B = ⋅ ⋅ ⋅ρ (15) where S T is the coefficient of complete ship displacement, L is the length of a vessel, B -its width, ρ is the density of water that depends on its composition. With a vessel length L=12 m (a yacht or a small fishing vessel) and the corresponding width B=3.5 m, the recommended value S T =0.5 [18].…”

Improving the energy efficiency of a piston engine based on the use of a numerical method for forming the laws of motion of gas distribution valves

“…Its characteristics determine the quality of filling and cleaning of the cylinders in various operating modes, the loss of power for gas exchange and, consequently, the indicator and effective indicators of the engine. Indeed, the valve gap is the main source of aerodynamic resistances in the channels of the cylinder head: it accounts for up to 75-90% of the total channel resistance [1].…”