Man vill på Scania korta utvecklingstiden på sina produkter för att fortsatt kunna vara en av de främsta tillverkarna av lastbilar i världen. För att lyckas med detta måste man hitta nya hjälpmedel och vägar för att öka kunskapen och snabba på utvecklingsarbetet. Oljeflödet i växellådan är ett sådant område där man nu undersökt möjligheterna till att öka kunskaperna genom datorsimuleringar. I detta examensarbete har en modell för datorsimuleringar av oljeflödet genom axlarna i växellådan tagits fram i GT-Suite, som är ett modulbaserat simuleringsprogram i 1D. Modellen kan simulera flödet från oljepumpen, ända bak till solhjulet i planetväxeln och däremellan flödet till lager och synkar. Tanken är att den ska kunna användas vid vidareutveckling av dagens växellådor och i framtiden utvecklingen av nya växellådor. Simuleringarna har validerats mot mätningar som genomförts där flödet till solhjulet har mätts för olika varvtal och uppställningar av växellådan. Simuleringarna har kunnat efterlikna mätningarna på ett tillfredsställande sätt. Det finns goda möjligheter att simulera flödet i GT-Suite och använda programmet som referens vid förändringar och nyutveckling av växellådor. Simuleringar har även för vissa delkomponenter validerats mot CFD-simuleringar i 3D. Fördelen med CFD-simuleringar är att mer kunskap om flödet kan utvinnas även för komplicerade geometrier. Nackdelen är att komplexiteten vid simulering av hela systemet blir för stor varför mestadels delsystem måste studeras. I framtiden kommer säkerligen arbete i form av nya mätningar och simuleringar i CFD-program behövas för att ytterligare förbättra och utveckla modellen. Men redan nu har resultat från simuleringar kunnat öka kunskapen om flödet i växellådan. Detta har i sin tur kunnat hjälpa konstruktörer att lösa utmaningar man haft, samt upptäcka nya som skulle kunna lösas genom att simulera och undersöka vilka förändringar som krävs. / At Scania they want to shorten the development time on their products in order to continue being one of the top manufacturers of trucks in the world. To do this they have find new ways and new tools to increase the knowledge and speed up the development of new products. The oil flow in the gearbox is such an area in which they have examined the possibilities to increase the knowledge with the aid of computer simulations. In this thesis work a model for computer simulations of the oil flow through the shafts of the gearbox has been developed in GT-Suite, a module based simulation program in 1D. The model can simulate the flow of oil from the oil pump in the front of the gearbox, all the way back to the sun wheel in the planetary gear and in between the flow to bearings and synchronizers. The aim is to be able to use the model during further development of todays gearboxes and in the future development of new gearboxes. The simulations have been validated against measurements which have been performed in which the oil flow to the sun wheel have been measured for various speeds an configurations of the gearbox. The simulations have been able to replicate the measurements in many ways adequately. GT-Suite is well suited for simulations and to use as a reference when making adjustments to the gearbox and in the future when developing new gearboxes. The result from simulations in GT-Suite have also been validate against CFD-simulations in 3D for some specific components. The advantage of CFD-simulations is that more knowledge of the flow can be obtained even for complicated geometries. The disadvantage is that the complexity when simulating the entire system makes it almost impossible, so mostly subsystems must be studied. In the future more work in form of new measurements and simulations in CFD-programs will be necessary to further improve the model. But already now the results of simulations have been able to increase the knowledge of the oil flow in the gearbox. And this in turn have helped designers to solve some challenges they have had, but also discovered new ones that could be solved by simulations and examine what changes are required.

The vast majority of trucks in the European Union are reliant on fossil fuels as their primary mode of propulsion. In efforts to decarbonise the truck transport sector manufacturers are developing electrified trucks. An electrification may serve to reduce the tailpipe emissions of trucks, but it introduces a new challenge to supply the cabin with energy. This energy is primarily used to maintain a comfortable cabin climate for the driver and passenger. In order to maximise the range of an electric truck the cabin energy requirement needs to be minimised. This thesis evaluates the current energy performance of a Scania S20H cabin through experimental testing as well as simulations using the simulation software GT-SUITE. Based on the results from the tests and the models, energy saving concepts were generated and their performance was evaluated. The experimental tests were performed on a truck in a climate chamber where the ambient temperatures, HVAC system fan speeds, air recirculation rate and inlet air temperatures were varied. The test data was used to build a one-dimensional simulation model in GT-ISE as well as a three-dimensional model in GT-TAITherm. The one-dimensional model was calibrated against 10 experimental tests and yielded an average relative error for the chosen temperature calibration parameters between 0.05% and 0.43%. The one-dimensional model showed that the largest energy loss was through air evacuation and air leakage, accounting for 70-90% of the input energy. The structural energy losses were primarily through the windshield and the side windows, accounting for 32% and 23% of the total structural losses respectively. Energy saving concepts in the form of low emissivity window glazing, double pane windows, xenon filled gas panel insulation and low levels of air recirculation were simulated. The best and most plausible combination of the aforementioned concepts yielded an average input energy decrease of 31.6%, air loss decrease of 32.9% and a structural loss decrease of 27.6% compared to the simulated base cases. The three-dimensional model was calibrated against one test case and yielded an average relative error of 0.15% for the chosen temperature calibration parameter. One energy saving concept in the form of double pane side windows in conjunction with low emissivity glazing on all windows was simulated. This concept had a slight impact in raising the average cabin air temperature and the interior surface temperatures of the windows. The surface temperature change resulted in a decrease of cold downdraught from the top roof window and the driver side window. In conclusion, the models work as intended providing a time efficient way of evaluating the energy performance of structural changes. In order to improve the performance, usefulness and accuracy of the models the initial values should be more exact. This can be achieved by standardised testing procedures as well as data collection with wind speed.

The vast majority of trucks in the European Union are reliant on fossil fuels as their primary mode of propulsion. In efforts to decarbonise the truck transport sector manufacturers are developing electrified trucks. An electrification may serve to reduce the tailpipe emissions of trucks, but it introduces a new challenge to supply the cabin with energy. This energy is primarily used to maintain a comfortable cabin climate for the driver and passenger. In order to maximise the range of an electric truck the cabin energy requirement needs to be minimised. This thesis evaluates the current energy performance of a Scania S20H cabin through experimental testing as well as simulations using the simulation software GT-SUITE. Based on the results from the tests and the models, energy saving concepts were generated and their performance was evaluated. The experimental tests were performed on a truck in a climate chamber where the ambient temperatures, HVAC system fan speeds, air recirculation rate and inlet air temperatures were varied. The test data was used to build a one-dimensional simulation model in GT-ISE as well as a three-dimensional model in GT-TAITherm. The one-dimensional model was calibrated against 10 experimental tests and yielded an average relative error for the chosen temperature calibration parameters between 0.05% and 0.43%. The one-dimensional model showed that the largest energy loss was through air evacuation and air leakage, accounting for 70-90% of the input energy. The structural energy losses were primarily through the windshield and the side windows, accounting for 32% and 23% of the total structural losses respectively. Energy saving concepts in the form of low emissivity window glazing, double pane windows, xenon filled gas panel insulation and low levels of air recirculation were simulated. The best and most plausible combination of the aforementioned concepts yielded an average input energy decrease of 31.6%, air loss decrease of 32.9% and a structural loss decrease of 27.6% compared to the simulated base cases. The three-dimensional model was calibrated against one test case and yielded an average relative error of 0.15% for the chosen temperature calibration parameter. One energy saving concept in the form of double pane side windows in conjunction with low emissivity glazing on all windows was simulated. This concept had a slight impact in raising the average cabin air temperature and the interior surface temperatures of the windows. The surface temperature change resulted in a decrease of cold downdraught from the top roof window and the driver side window. In conclusion, the models work as intended providing a time efficient way of evaluating the energy performance of structural changes. In order to improve the performance, usefulness and accuracy of the models the initial values should be more exact. This can be achieved by standardised testing procedures as well as data collection with wind speed.

Driven by the goal of decreasing emissions and pollutants towards a more sustainable future, the automotive industry is undergoing a rapid transition towards battery-powered electric vehicles. This shift to sustainable transport is fast-paced, and new technical solutions are being offered on a regular basis to fulfil the future needs for electric vehicles, including battery-electric trucks. This continuously necessitates a fast development of the battery-electric truck, along with the cooling system. To validate the cooling system, Scania's preferred approaches are testing and 3D simulations. However, these approaches are time-consuming and cannot match the pace of the design or the development. This thesis addresses the implementation of using 1D Simulations (GT-Suite) to carry out coolant filling simulations as a more efficient approach by studying the filling of the battery cooling system in an electric truck and, later, validating the results obtained with a test rig. In this thesis, different cases were defined, each adding more complexity to the circuit, and the parameters studied were the filling times and the location of air traps. Finally, a case with a closed circuit and running a coolant pump was developed to study the possibilities of devising quicker deaeration techniques for the circuit. The work completed in this thesis may be used as an example of how filling simulations can be performed with GT-Suite. This thesis is a good starting point, exploring a vast potential in using 1D Simulations to simulate the coolant-air interaction in a cooling system. Nonetheless, the findings revealed that GT-Suite v2020 and v2021 lack a robust model to properly simulate the interaction of coolant and air in certain sections of the circuit. In addition, the simulation model failed to obtain a steady-state solution in some cases resulting in discrepancies between the results from the test rig and the simulations. In conclusion, it was found that 1D simulations are not an ideal way forward when individual components of the cooling circuit are being considered, for example, the cooling plates, but are much quicker and seem to be a promising method to get an overview on a system level. / Fordonsindustrin drivs av målet att minska utsläppen och föroreningarna mot en mer hållbar framtid och genomgår en snabb omställning mot batteridrivna elfordon. Övergången till hållbara transporter går snabbt och nya tekniska lösningar erbjuds regelbundet för att möta de framtida behoven av elfordon, inklusive batteridrivna lastbilar. Detta kräver kontinuerligt en snabb utveckling av den batteri-elektriska lastbilen, tillsammans med kylsystemet. För att validera kylsystemet är Scanias föredragna metoder testning och 3D-simuleringar. Dessa tillvägagångssätt är dock tidskrävande och kan inte matcha takten i designen eller utvecklingen. Denna avhandling behandlar implementeringen av att använda 1D-simuleringar (GT-Suite) för att utföra kylvätskefyllningssimuleringar som ett effektivare tillvägagångssätt genom att studera fyllningen av batterikylsystemet i en elektrisk lastbil och senare validera resultaten som erhållits med en testrigg. I denna avhandling definierades olika fall, var och en lägga till mer komplexitet till kretsen, och de undersökta parametrarna var påfyllningstiderna och platsen för luftfällor. Slutligen utvecklades ett fall med en sluten krets och kör en kylvätskepump för att studera möjligheterna att utforma snabbare deaerationstekniker för kretsen. Arbetet i denna avhandling kan användas som ett exempel på hur fyllningssimuleringar kan utföras med GT-Suite. Denna avhandling är en bra utgångspunkt och utforskar en enorm potential i att använda 1D-simuleringar för att simulera kylvätske-luftinteraktionen i ett kylsystem. Resultaten visade dock att GT-Suite v2020 och v2021 saknar en robust modell för att korrekt simulera interaktionen mellan kylvätska och luft i vissa delar av kretsen. Dessutom kunde simuleringsmodellen inte få en steady state-lösning i vissa fall vilket resulterade i skillnader mellan resultaten från testriggen och simuleringarna. Sammanfattningsvis konstaterades det att 1D-simuleringar inte är en idealisk väg framåt när enskilda komponenter i kylkretsen övervägs, till exempel kylplattorna, men är mycket snabbare och verkar vara en lovande metod för att få en översikt på systemnivå.

The ability to control engine valve timing has the potential to alter the engine performance over the entire operating range. The outcome of valve timing technology enables the possibility to increase efficiency, lowering emissions, increase engine torque, etc. One of the simplest ways to obtain a variable valve timing is to use cam phasers. The dynamics of a hydraulic cam phaser has been studied, three concepts with the purpose to control such an element has been developed using simulation driven product development. Focus have been on robustness, simplicity and implementation. A final concept using on/off solenoids to control a torque driven cam phaser has been designed and simulated in GT-SUITE which validated its performance and functionality. A dynamic model was built in Simulink which simulated the behaviour of the cam phaser and provided tools for optimizing the rotor design. By combining the knowledge of mechanical- and control engineering at Scania, the development process of such machine elements was effective. The outcome of this thesis has given a new perspective in understanding these components and their potentials.

Load sensing pumps in hydraulic system of wheel loaders helps in increasing the energy efficiency of wheel loaders. Present day machines have hydro mechanical load sensing system. After the advent of hydro mechanical load sensing concept, over the years, lots of research has been carried out relevant to electro hydraulic load sensing, trying to control the pump electronically. Currently, Volvo Construction Equipments (VCE) is interested in investigating the possibility of implementing electro hydraulic load sensing system in the wheel loaders. Research works has shown existence of several configurations of electro hydraulic load sensing pumps. Successful simulation results of an electro hydraulic load sensing pump configuration would provide a backing for the proposal of building and testing that configuration of electro hydraulic load sensing pump prototype. Also, the thesis work aims in benchmarking hydraulic system simulation capabilities of AMESim and GT- Suite by simulating the existing hydro mechanical load sensing system in both in both the simulation packages. / The thesis work has been carried out at Virtual Product Development (VPD) division of Volvo Construction Equipments (VCE), Eskilstuna, Sweden.

The demands on heavy duty vehicles is constantly raising with government legislations on CO2 emissions becoming stricter and increasing customer demands. A continuous search for new methods and tools is a crucial element in finding more performance and lower emissions, which are prerequisites for heavy duty vehicles of the future. This thesis is conducted at Scania CV AB and aims at proposing a co-simulation setup which implements the engine management system, EMS, for turbocharger control, into engine simulation models that the company uses to simulate the behaviour of their combustion engines. The EMS software for turbocharger control is modelled in a MATLAB Simulink model and the engine simulation model is modelled in GT-SUITE. The thesis is also suggesting improvements to a turbine model that is modelled within the given EMS software. The results suggest a co-simulation setup that enables the engine simulation models to utilize the EMS software for turbocharger control which thereby enhances their ability to predict engine behaviour. The setup can also be used as a tool during the development process for other part of the EMS and could ease the need for physical engine tests in test cell. The suggested improvements to the turbine model revolves around building a model capturing the aspects of a so called twin scroll turbine and also to implement a better estimation of the turbine efficiency. The improvements to the turbine model ultimately leads to improving the response behaviour of the EMS turbocharger control system.

The deployment of electric vehicles has speeded up during the past ten years. As heavy-duty trucks are a significant source of GHG emissions, electrification is an encouraging way to lead to sustainability beyond doubt. However, some constraints regarding electric vehicles have emerged. Range extension is a primary challenge of the development of electric vehicles, where thermal conditioning systems can have a considerable impact. Some researches have been done on electric passenger vehicles. However, studies regarding the energy consumption for the thermal conditioning system of heavy-duty electric vehicles are scarcely provided.This study therefore focuses on estimating the energy consumption for the auxiliary heating/cooling and studying the influence of the ambient temperature, vehicle velocity, payload, and driving cycles. A designed integrated thermal conditioning system model was constructed in GT-SUITE, with three subsystems to provide thermal comfort for the truck cabin, meet the operative temperature for battery packs and condition the power electronics and the electric machine. Calibrations were done and yielded acceptable relative errors less than 10%, regarding the cabin and battery heaters.The study shows that the thermal conditioning system consumes the most energy during extremely cold weather, reaching up to 10 kW when the ambient temperature is lower than -20℃. Moreover, the energy consumption during heating/cooling will increase if the vehicle velocity increases. However, it remains stable during mild weather. Payload has different impacts on the energy consumption for heating and cooling. As higher payload results in higher waste heat from the electric machine and batteries, it alleviates the heating while burdens the cooling. Four different driving cycles were simulated, and the result reveals that despite the cycle with the lowest average speed has the highest energy consumption/km, however has the lowest average power.

The master’s thesis deals with modelling of various architectures of hybrid powertrains for three vehicle sizes in GT-SUITE and compares them in daily commuting operating mode. On top of making of the hybrid vehicle simulation models, control algorithms had to be created to manage the energy split between the internal combustion engine and the electric motor for each of the architectures. Routes to work and back were logged using the GPS and postprocessed to obtain the speed and the road grade profiles. Resulting data was used as an input in simulations of daily commuting. To compare all hybrid powertrain architectures, fuel economy and electricity consumption were evaluated for WLTP and daily commuting operating modes. Finally, the environmental impact of each topology was assessed based on an estimation of corresponding well-to-wheel emissions.

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