Turbocharger inlet temperature observer model for diesel internal

Day by day while customers are expecting better performance and lower fuel consumption from their vehicles, emission regulations are being made more stringent to reduce the environmental impact of exhaust gases. On the other hand, vehicle manufacturers have to produce vehicles that provide high performance, low fuel consumption and legal emission limits that will provide both customer and regulatory requirements. In order to meet these challenging targets, advanced vehicle and exhaust aftertreatment control systems are needed. The importance of model based motor control is increasing, with the use of advanced control systems, as system response is fast and vehicle production costs are reduced. Exhaust manifold gas temperature is an important parameter for vehicle, engine and exhaust aftertreatment control systems, and affects engine performance and aftertreatment system selection. Some cases where the exhaust gas temperature is important can be listed; the exhaust gas is bypassed in fixed geometry turbocharged engines to provide exhaust gas transfer at higher temperatures to the aftertreatment systems.The EGR system is an effective system for reducing NOx emission values. The exhaust gas temperature is an important parameter in the control of the EGR system and in high pressure EGR engines, it is also effective both the intake manifold temperature and the EGR gas cooler operating points determination. The throttling of intake air is usually used for "engine regen mode", for cleaning diesel particulate filter (DPF). The manifold pressure is reduced by intake throttling thus reducing the amount of air taken into the engine. In this case, the engine will have a richer air-fuel mixture and the engine exhaust gas temperatures will increase and high temperature exhaust gas is used to clean the DPF. Another function of the engine control unit, where the exhaust gas temperature is important, is the function of turbocharger and engine protection. The exhaust gas temperature is used to prevent the turbocharger system from exceeding the maximum operating temperature, so that the system is not damaged in hardware. In addition, high exhaust gas temperatures that may occur after combustion can cause piston scuff to prevent this adverse condition exhaust gas temperature is also used in engine protection functions. In general, the exhaust gas temperature can be considered as an important parameter for functions such as performance, emission and engine hardware protection in internal combustion engines. Many academic studies have been carried out to model the exhaust gas temperature, which is an important parameter for internal combustion engines. In these studies in order to model the exhaust gas temperature, system models related to vehicle driving, models using in-cylinder pressure values, models using artificial neural network, mathematical and thermodynamic models and exhaust gas temperature observer models were used. This thesis study aims at predicting the modeled exhaust gas temperature value with higher accuracy by taking advantage of the exhaust gas observer model study. This model contains; obtaining open-loop exhaust temperature (T3) value by regression model using data collected from steady state speed-torque points, providing the turbocharger outlet temperature value generated by adiabatic expansion using the obtained T3 value, calculating catalyst inlet temperature using heat loss formulas between turbocharger outlet and catalayst inlet. It is aimed to compare the modeled T4 temperature values with the sensor values and to predict the T4 temperature with using Kalman Filter so that the modeled T3 temperature value converges to the measured T3 temperature value. The obtained T3 model was validated at both steady-state and transient maneuvers. In order to obtain the open loop exhaust temperature by regression method, test measurements were taken at steady-state engine speed-torque points in the engine dynamometer at 1000rpm-4500rpm at different engine coolant temperatures. Before taking the Diesel engine to the engine test room, necessary instrumentation such as pressure, temperature, turbine shaft speed was made and taken to the dynamometer pallet. Engine tests were run in the test chamber which contains, dynamometer to create counter-load for engine, engine inlet air conditioner, engine coolant conditioner, intercooler conditioner, oil conditioner, fuel conditioning and flow meter, in-cylinder pressure meter, blow-by meter and the emission devices. Using the obtained test data, the T3 temperature value is modeled as an open loop using variables affecting the exhaust gas temperature. Besides T3 model, turbocharger efficiency and turbocharger shaft speed were modeled by regression method. In the next step, the turbocharger outlet gas temperature value is calculated from the equation of work done by adiabatic expansion of the turbocharger system using T3 temperature data estimated by the regression method. During this calculation, the turbocharger efficiency values obtained by both the regression method and the instrumentation data calculation can be used. Using the temperature value obtained from the turbocharging isentropic expansion equations, the heat losses up to the pre-catalyst fraction were calculated and the catalyst inlet temperature (T4) value was obtained. The calculated T4 temperature is compared to the T4 temperature sensor value required to drive the emission regulation and control of the exhaust aftertreatment systems. With using Kalman Filter, T4 temperature value is predicted then compared with the measured T4 temperature value. T4 differences is added to the open loop temperature T3 to minimize the T3 error. When we compare the temperature data obtained by using Kalman Filter, which is generated by the data received at the steady state speed-torque points, the error amount of the modeled T3 value decreases compared with the open loop regression model.