# Promising Approaches for Heat Utilization in Agricultural Machinery Engines
## 2 Presentation of the Main Material
### Research Results
The device works as follows [45]. When the internal combustion engine 6 is running with fuel from the combustion chamber, the exhaust gases flow to the turbine 7, which is rigidly mounted on one shaft with the compressor 2, which injects air into the combustion chamber of the internal combustion engine 6. After the combustion engine 6 has been heated up and discharged from the water tank 5 with the help of the feed pump 4 to the nominal operating power (the temperature of the exhaust gases is about 925 K), the water is pumped to the boiler 3, where the water begins to turn into saturated steam due to heating from the exhaust gases. The saturated water vapor formed is fed to the turbine 7 and is thus combined with the exhaust gases coming from the combustion chamber of the internal combustion engine 6. At the same time, the compressor 2, which is rigidly mounted on one shaft by the turbine 7, begins to rotate at an additional increased speed and pumps a larger amount air into the combustion chamber of the internal combustion engine 6. Due to the excess power of the turbine 7, it transmits the torque of the drive shaft of the reducer 1, to the driven shaft of the reducer 1, which is connected to the crankshaft of the internal combustion engine, through the overtaking clutch 8. The mathematical model for determining the effect of the specified recycling scheme on the economic and performance indicators of the engine showed that the temperature of the exhaust gases of the internal combustion engine before the turbocharger at the rated power mode is approximately 925 K. The temperature of gases Tg\({}_{2}\) after expansion in the turbine can be determined as follows:  
\[SPP=\frac{I_{\mathrm{R}}}{R-OE},\ \mathrm{h}, \tag{6}\]1  
where \(T_{g1}\) is the temperature of exhaust gases in front of the turbine, K;  
\(\Delta T_{ad}\)--is the adiabatic temperature drop in the turbine, K;  
\(\eta_{T}\) is the efficiency factor of the turbine. The decrease in temperature during the adiabatic expansion of gases is:  
\[SPP=\frac{I_{\mathrm{R}}}{R-OE},\ \mathrm{h}, \tag{6}\]2  
where \(T_{ad}\) is the gas temperature at the exit from the turbine during adiabatic expansion, K;\(l_{ad}\)--specific work of expansion, J/kg;  
\(k\) is the adiabatic coefficient;  
\(R\) is the specific gas constant, J/(kg\(\cdot\)K). The maximum value of the specific work of expansion in one stage of the turbine is 300 kJ/kg. Under such conditions, the temperature of the gas during expansion decreases by about 263 K.  
In real internal combustion engines, the expansion of gases in the turbine is not complete. Then, the temperature of the gases after the turbine is:  
\[SPP=\frac{I_{\mathrm{R}}}{R-OE},\ \mathrm{h}, \tag{6}\]3  
where \(P_{1}\), \(P_{2}\) are gas pressure before and after the turbine, respectively;  
\(n\)--coefficient of polytropy;  
\(\pi_{T}\) is the degree of pressure reduction in the turbine. Let us consider the processes of producing steam, injecting it into the turbine and expansion along with gases. Steam is produced in the recovery boiler. Let us determine the temperatures at the nodal points. The temperature of the mixture of exhaust gases and steam in front of the turbine is determined from the equation:  
\[SPP=\frac{I_{\mathrm{R}}}{R-OE},\ \mathrm{h}, \tag{6}\]4  
where \(Ts\) is the temperature of saturated water vapor, K;  
\(Cp\), \(Cps\)--specific isobaric heat capacity of exhaust gases and steam, respectively, kJ/(kg\(\cdot\)K);  
\(Gv\), \(Gg\)--consumption, respectively, of steam and waste gases, kg/s;  
\(Tm\) is the temperature of the steam-gas mixture, K.  
Specific isobaric heat capacities of steam and gases differ by a factor of almost two. Then, the desired value of the temperature of the steam-gas mixture will be:  
\[SPP=\frac{I_{\mathrm{R}}}{R-OE},\ \mathrm{h}, \tag{6}\]5  
Let us determine the amount of steam that can be obtained in the utilization boiler. The heat balance of its production is described by the following equations.