Обоснована математическая модель физико-химических процессов, протекающих в оригинальном устройстве. Предложено устройство, позволяющее запасать тепловую энергию отработавших газов в аккумуляторе при работе двигателя пожарного автомобиля на полной мощности и отдавать ее каталитическому нейтрализатору при работе двигателя на средних и малых нагрузках. Показано, что в процессе отдачи тепла обеспечивается поддержание оптимальной температуры нейтрализатора и, как следствие, высокой эффективности процесса катализа. Приведены результаты испытаний и расчетов устройства, разработанного для пожарных автомобилей с двигателями Акционерного общества “Камский автомобильный завод”, подтверждающие эффективность работы нейтрализатора и адекватность математической модели возможности применения для оценки конструктивных параметров устройства.
There are two actual technical tasks for the engines of the fire trucks which are used in the Arctic zone. The first one is the utilization of heat and the second one is the increase of the efficiency of catalytic neutralization of the exhaust pollutants. The device combining catalytic converter (CC) and mineral heat storage system (MHSS) elaborated for fire trucks may help to solve such problems. The device is supposed to be built in the exhaust system of the engine of the fire truck instead of the noise muffler. It allows to storage the thermal energy of the exhaust gas with the use of heat-retaining substance when the engine operates at full capacity, and to deliver the heat back to the catalytic converter when the engine of the fire truck operates at idling mode. The reverse heat delivery allows maintaining the optimum temperature for the effective catalytic neutralization of exhaust pollutants. The process of the excess heat taking, when the engine operates at a forced mode, may contribute to the increase of the operational life and to the decrease of the risk of inflammation of the engine. Physically and mathematically this process may be described with the use of the thermal balance methodical approach. At the same time, the exothermic process of neutralization may be formalized using the classical Arrhenius kinetics approach, which we previously adjusted for the block-designed catalytic converters. The validity of the mathematical model is confirmed with the test of the fire truck AC 4-40 (43202) equipped with the engine KamAZ-740/10 (8CN 12/12). The experiments have shown that the efficiency of the catalyst at idling operation may be increased from 4 to 74 % with respect to the CH neutralization and from 10 to 86 % in respect to the CO neutralization. The results of calculations have confirmed that the use of the elaborated salt heat storage system with the heatexchange surface 1.58 m2 and the length 400 mm, which can be easily built in the exhaust system of the fire truck instead of the noise muffler, allows to solve the problem of the utilization of the excess heat and the increase of efficiency of catalytic neutralization of the exhaust pollutants of the engines of the fire trucks used in the Arctic zone.
The authors declare that there are no conflicts of interest present.