Problem statement. Starting internal combustion engines for a large car fleet at ambient temperature of less than 5 ºС requires considerable time; it leads to increased wear of the components of the connected engine pairs, increased fuel consumption during start-up and warm-up and increased emissions of harmful substances into the atmosphere with exhaust fumes. Therefore, prestart warming up of car engines is given great attention.
Actual scientific researches and issues analysis
Recently, this problem has been solved by using heat accumulators, moreover, heat accumulators with heat storage material of a phase transition are given preference.
The engine exhaust gases (temperature 600-700 ºС) or the engine cooling liquid (water, tosol cooling agent) are used as a heat transfer agent. Given the negative impact of high temperatures on the heat storage material, the metal of the heat storage structure and overheating (boiling) of the engine coolant, the first way has certain disadvantages. In this regard, we consider it more promising to use a liquid cooling engine as a coolant for a heat accumulator. High temperatures have no positive affect on the heat storage material, the metal of the heat storage structure and these are a cause for boiling a coolant –cooler of the engine. In this regard, we consider more promising to use a cooling fluid of the heat accumulator as a heat transfer agent.
The aim of this work is to develop a new design of a heat accumulator for pre-starting warming up of a car engine, to make the experimental installation to research its work and conducting researches in order to find the time of charging and discharging of the heat accumulator, to construct operating modes during charging and discharging, to determine the necessary mass of the heat-accumulating material and the battery size.
Base material
The experimental installation was a closed system: the heat accumulator — a passage of the VAZ 2109 car engine cooling system. Taking into account the work peculiarities of the heat accumulator in the cooling system of the car engine, unlike other areas where all mass of the heat storage material constantly is in contact with the substance which the heat storage material giving up heat, in our case, the engine cooling liquid is located in the heat accumulator and in the cooling jacket. They mixes before starting the engine, while its temperature decreases. The time of charging and staying of the heat accumulator in the charged state has been determined, the operating modes during charging and discharging have been constructed, the necessary mass of the heat-accumulating material and the battery size has been determined.
Conclusions
The experimental model of the heat accumulator of the pre-starting system of worming up of the engine of the car has been developed. This experimental model is included in a closed circuit with engine cooling system. On the model the researches of charging and discharging process of the heat accumulator have been conducted. The required time for these processes has been determined and on this basis the modes of operation of the heat accumulator - engine cooling system have been constructed. The temperatures of tosol cooling agent in the cooling system were calculated and it allowed finding mass (volume) of heat storage material of the heat accumulator and it served as the basis for determining the size of the heat accumulator.
Establishment of a computerized control system on/off control of the heat accumulator in order to maintain the desired temperature of the engine coolant liquid using of heat storage material of phase transition and controlling this system using supplements to phones.
Effects of LLC Flow Characteristics and Surface Roughnesses on Nucleate Boiling Heat Transfer Mechanisms in IC Engine Cooling System