<p>The aim of this master's thesis is to implement and evaluate a method for estimating the indicated engine torque. The method is developed by IAV GmbH, Fraunhofer-Institut and Audi AG. The determination of the indicated torque is based on high resolution engine speed measurements. The engine speed is measured with a hall sensor, which receives the signal from the transmitterwheel mounted on the crankshaft. A transmitterwheel compensation is done to compensate for the partition defects that arises in the production and thus enable a more precise calculation of the angular velocity. The crankshaft angle, angular velocity and angular acceleration are estimated and the helpvariable effective torque is calculated using these signals as input. Through a relationship between effective torque and the indicated pressure the indicated pressure is extracted from a map. The indicated torque is then calculated from the pressure. </p><p>The method is validated with data from an engine test bed. Because of the low obtainable sample rate at the test bed, 4MHz, quantisation errors arises at engine speeds over 1000 rpm. Therefore the model is validated for low engine speeds and the result is promising.</p>

<p>The importance of control systems and diagnostics in vehicles are increasing and has resulted in several new methods to calculate better control signals. The performance can be increased by calculating these signals close to optimum, but that also require more and precise information regarding the system.</p><p>One of the wanted control signals are the crankshaft torque and the thesis presents two different methods to estimate this torque using engine speed variations. These methods are Modeling of the Crankshaft and Frequency Analysis. The methods are evaluated and implemented on for a four cylinder SAAB engine. Measurements are made in an engine test cell as well as a vehicle.</p><p>The results show that the Modeling of the Crankshaft method does not produce a satisfying estimation, with a difference of about 200% between estimated and calculated torque. On the other hand, the Frequency Analysis provides an accurate estimation of both mean and instantaneous indicated torque, with a maximum difference of ±20% between estimated and calculated torque.</p>

The aim of this master's thesis is to implement and evaluate a method for estimating the indicated engine torque. The method is developed by IAV GmbH, Fraunhofer-Institut and Audi AG. The determination of the indicated torque is based on high resolution engine speed measurements. The engine speed is measured with a hall sensor, which receives the signal from the transmitterwheel mounted on the crankshaft. A transmitterwheel compensation is done to compensate for the partition defects that arises in the production and thus enable a more precise calculation of the angular velocity. The crankshaft angle, angular velocity and angular acceleration are estimated and the helpvariable effective torque is calculated using these signals as input. Through a relationship between effective torque and the indicated pressure the indicated pressure is extracted from a map. The indicated torque is then calculated from the pressure. The method is validated with data from an engine test bed. Because of the low obtainable sample rate at the test bed, 4MHz, quantisation errors arises at engine speeds over 1000 rpm. Therefore the model is validated for low engine speeds and the result is promising.

The importance of control systems and diagnostics in vehicles are increasing and has resulted in several new methods to calculate better control signals. The performance can be increased by calculating these signals close to optimum, but that also require more and precise information regarding the system. One of the wanted control signals are the crankshaft torque and the thesis presents two different methods to estimate this torque using engine speed variations. These methods are Modeling of the Crankshaft and Frequency Analysis. The methods are evaluated and implemented on for a four cylinder SAAB engine. Measurements are made in an engine test cell as well as a vehicle. The results show that the Modeling of the Crankshaft method does not produce a satisfying estimation, with a difference of about 200% between estimated and calculated torque. On the other hand, the Frequency Analysis provides an accurate estimation of both mean and instantaneous indicated torque, with a maximum difference of ±20% between estimated and calculated torque.