Thermodynamic analysis of an engine for tractor application

Objective:

       To perform Thermodynamic analysis of an engine for tractor application with following targets:

• Power 75 HP
• bsfc targets- min 210 g/kWh and max 225 g/kWh
• cooled EGR configuration

Model Specification:

Tractor model Sonalika Worldtrac 75 has been taken for analysis with following engine specification:

Case 1: Engine without EGR

Model:

                               Fig: 4 cylinder engine model without EGR

Case Setup:

    Total 2 cases has been ran with 5 parameters namely Engine RPM,Compressor output Preasure, Turbine inlet preasure,fuel injection,Air to Fuel Ratio.

• Consider rated speed as 2200 rpm and intermediate speed as 1300 rpm.
• Consider rated A/F ratio as 25 and intermediate A/F ratio as 22.

Result:

Engine Geometry and operating condition:

Engine Performace Prediction:

Energy Performance:

Cylinder Performance prediction:

 Result Discusion:

Brake power = 77.5 Hp and Brake Torque =279.8 Nm

BSFC's value are 223.9g/kWh (max) and 221.2 g/kWh (min) which are in specified limits.

Case 2: Engine with EGR

Exhaust gas recirculation (EGR):

     Exhaust gas recirculation (EGR) is an emission control technology allowing significant NOx  emission reductions from most types of diesel engines: from light-duty engines through  medium- and heavy-duty engine applications right up to low-speed, two-stroke marine engines. While the application of EGR for NOx reduction is the most common reason for applying EGR to modern commercial diesel engines, its potential application extents to other purposes as well. Some of these include: imparting knock resistance and reducing the need for high load fuel enrichment in SI engines, aiding vaporization of liquid fuels in SI engines as an enabler for closed cycle diesel engines, for improving the ignition quality of difficult-to-ignite fuels in diesel engines or for improving the performance of SCR catalysts.  While NOx reductions had been reported with EGR as early as 1940, the first engine experiments to investigate the NOx reduction potential of EGR appeared to be carried out in the late 1950s in SI engines. By the 1970s, EGR was being seriously considered as a NOx control measure for diesel engines.

Model:

                                     Fig: 4 cylinder engine model with EGR

Engine Geometry and  Firing order:

stroke and bore for engine is 100 mm and 118mm respectivaly with compresion ratio of 16.5.

Firing order for 4 cylinder engine is 1-3-4-2 with firing interval of 180 degree.

Case setup:

   Total 2 cases has been ran with 5 parameters namely Engine RPM,Compressor output Preasure, Turbine inlet preasure,fuel injection,Air to Fuel Ratio.

Result:

Engine Geometry and operating condition:

Energy Performance:

Cylinder Performance prediction:

Result Discusion:

Brake power = 77.5 Hp and Brake Torque =279.8 Nm

BSFC's value are 223.4 g/kWh (max) and 220.9 g/kWh (min) which are in specified limits.

Conclusion:

• Air flow rate is more for engine with EGR.
• Value of CO2 in ppm is found less for engine with EGR.