The concept of downsizing has proved to be a succesful method to improve engine efficiency. The engine key component is the turbocharging system that use excess energy in the exhaust gases to compress air into the cylinder. There are different types of supercharging systems, in the thesis a serial turbo system is modeled together with a complete six cylinder engine. A model-based controller is developed that regulates the intake pressure to a certain reference. The controller operates in modes that are defined by the engine operating point. To control the turbochargers it is necessary to have knowledge about the energy in the exhaust gases. A dynamic temperature model has therefore been analyzed, which has led to surprising results regarding the temperature measurements made in the test cells. This is analyzed and improvements are suggested.The engine model is validated and the system, including controller, is evaluated in certain simulations. The serial turbo concept is compared to a VGT turbo system, which gives a hint of the possible advantages of serial turbo charging. / Konceptet downsizing är bevisligen en mycket kapabel lösning för att höja en motors verkningsgrad. Nyckelkomponenten är turbosystemet som använder överskottsenergi i avgaserna för att komprimera in luft till cylindern. Det finns olika typer av turbosystem, i denna uppsats modelleras en seriell turbostruktur tillsammans med en komplett sexcylindrig motor. En modellbaserad regulator utvecklas för att reglera insugstrycket. Regulatorn arbetar i moder som definieras av motorns arbetspunkt. För att styra turboladdningen på ett bra sätt är det viktigt att ha vetskap om energin i motorns avgaser, varpå mer dynamik har införts i befintlig temperaturmodell. Temperaturmätningar har lett till förvånande och teoretiskt motstridiga resultat. Detta har undersökts och förslag på förbättringar tas fram.Motormodellen har validerats och systemet tillsammans med regulatorn har utvärderats i simuleringsexperiment. Det seriella turbosystemet jämförs med ett VGT-system, varpå potentiella fördelar hos en seriell dubbelturbo diskuteras.

<p>Stronger environmental awareness as well as actual and future legislations increase</p><p>the demands on diagnosis and supervision of any vehicle with a combustion engine.</p><p>Particularly this concerns heavy duty trucks, where it is common with long driving</p><p>distances and large engines. Model based diagnosis is an often used method in</p><p>these applications, since it does not require any hardware redundancy.</p><p>Undesired changes in the intake manifold pressure can cause increased emissions.</p><p>In this thesis a diagnosis system for supervision of the intake manifold</p><p>pressure is constructed and evaluated. The diagnosis system is based on a Mean</p><p>Value Engine Model (MVEM) of the intake manifold pressure in a diesel engine</p><p>with Exhaust Gas Recirculation (EGR) and Variable Geometry Turbine (VGT).</p><p>The observer-based residual generator is a comparison between the measured intake</p><p>manifold pressure and the observer based estimation of this pressure. The</p><p>generated residual is then post treated in the CUSUM algorithm based diagnosis</p><p>test.</p><p>When constructing the diagnosis system, robustness is an important aspect. To</p><p>achieve a robust system design, four different observer approaches are evaluated.</p><p>The four approaches are extended Kalman filter, high-gain, sliding mode and an</p><p>adaption of the open model. The conclusion of this evaluation is that a sliding</p><p>mode approach is the best alternative to get a robust diagnosis system in this</p><p>application. The CUSUM algorithm in the diagnosis test improves the properties</p><p>of the diagnosis system further.</p>

Stronger environmental awareness as well as actual and future legislations increase the demands on diagnosis and supervision of any vehicle with a combustion engine. Particularly this concerns heavy duty trucks, where it is common with long driving distances and large engines. Model based diagnosis is an often used method in these applications, since it does not require any hardware redundancy. Undesired changes in the intake manifold pressure can cause increased emissions. In this thesis a diagnosis system for supervision of the intake manifold pressure is constructed and evaluated. The diagnosis system is based on a Mean Value Engine Model (MVEM) of the intake manifold pressure in a diesel engine with Exhaust Gas Recirculation (EGR) and Variable Geometry Turbine (VGT). The observer-based residual generator is a comparison between the measured intake manifold pressure and the observer based estimation of this pressure. The generated residual is then post treated in the CUSUM algorithm based diagnosis test. When constructing the diagnosis system, robustness is an important aspect. To achieve a robust system design, four different observer approaches are evaluated. The four approaches are extended Kalman filter, high-gain, sliding mode and an adaption of the open model. The conclusion of this evaluation is that a sliding mode approach is the best alternative to get a robust diagnosis system in this application. The CUSUM algorithm in the diagnosis test improves the properties of the diagnosis system further.

<p>The SAAB variable compression engine is a new engine concept that enables the fuel consumption to be radically cut by varying the compression ratio. A challenge with this new engine concept is that the compression ratio has a direct influence on the output torque, which means that a change in compression ratio also leads to a change in the torque. A torque change may be felt as a jerk in the movement of the car, and this is an undesirable effect since the driver has no control over the compression ratio. </p><p>The aim of this master's thesis work is to develop a torque control strategy for the SAAB variable compression engine. Where the main control objective is to make the output torque behave in a desirable way despite the influence of compression ratio changes. </p><p>The controller is developed using a design method called Internal Model Control, which is a straightforward way of both configuring a controller and determining its parameters. The controller has been implemented and evaluated in a real engine, and has proved to be able to reduce the effect of compression ratio disturbance.</p>

A turbo system is driven by the excess energy in the exhaust gases.  As a result, variation in exhaust temperature cause variations in  boost pressure. By using the information about the available exhaust  energy in the turbo controller directly through a feedforward  controller, an unexpected variation in turbo boost can be avoided. A  model based controller is developed that calculates the desired  turbine power from the boost pressure reference and then, by  observing the available exhaust energy, controls the generated  turbine power to match the desired power. A Mean Value Engine Model  has been used to make simulation with the developed controller  implemented. Steps between different boost pressure references are  used to evaluate controller performance. Tests in a car have also  been made to make sure the simulation results are consistent in a  real environment. / Turbosystem drivs av överskottsenergin i motorns avgaser. Dettainnebär att temperaturvariationer i avgaserna orsakar variationer igenererad turbineffekt och därmed ökat laddtryck från turbosystemet.Används informationen om den tillgängliga energin i avgaserna när manstyr turbinen så kan man motverka oväntade laddtrycksförändringar. Idenna rapport har en modellbaserad turboregulator med en framkopplingsom beräknar en önskad turbineffekt från givet referenstryckutvecklats. Sedan tas en styrsignal fram till turbinen som, genom attanvända informationen om den observerade energin i avgaserna, matcharden önskade turbineffekten. En model av en medelvärdesmotor haranvänds för att validera prestandan i regulatorn via stegsvar mellanolika referenstryck. Det har även utförts tester i bil för att avgöraom resultatet blir detsamma under verkliga förhållanden.

The SAAB variable compression engine is a new engine concept that enables the fuel consumption to be radically cut by varying the compression ratio. A challenge with this new engine concept is that the compression ratio has a direct influence on the output torque, which means that a change in compression ratio also leads to a change in the torque. A torque change may be felt as a jerk in the movement of the car, and this is an undesirable effect since the driver has no control over the compression ratio. The aim of this master's thesis work is to develop a torque control strategy for the SAAB variable compression engine. Where the main control objective is to make the output torque behave in a desirable way despite the influence of compression ratio changes. The controller is developed using a design method called Internal Model Control, which is a straightforward way of both configuring a controller and determining its parameters. The controller has been implemented and evaluated in a real engine, and has proved to be able to reduce the effect of compression ratio disturbance.