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This study has been performed at Powertrain Engineering Sweden AB (PES), a fully owned subsidiary of Volvo Cars Group, which is constantly working to develop and improve internal combustion engines. As part of this work, durability tests are performed to analyse the impact of wear on the engines. At present, there is a strong focus on visual inspections after the engines have undergone durability tests. PES wants to develop a method where collected data from these tests can be used to explain how the phenomenon of knocking and the control of lambda changes over time. The study analyses one specific durability test and investigates the methodology of data analysis by using the open-source software platform Sympathy for Data, with an add-on developed by Volvo Cars Group, for data management, visualisation and analysis. To execute the analysis, engine parameters that affect these systems as well as parameters suitable to use as response variables are identified through literature studies of internal combustion engine fundamentalsas well as internal material, and knowledge acquired at the company. The result is presented in the form of an analysis generated by the node for partial least squares regression (PLSR) which is pre-programmed in Sympathy for Data as well as the images and graphs obtained as output. For knock, the signal for the final ignition angle was found to be suitable to use as the response variable in the PLSR. A suitable response variable for lambda was more difficult to identify, this is why both signals for the measured lambda and lambda adaptation are analysed. Studies of the internal material and knowledge highlighted the fact that several engine subsystems are highly dependent on each other and that even deeper research would be necessary to fully understand the process and identify the primary cause for the variations observed in the generated models. However, partial least squares regression was performed using parameters derived from literature, Denna studie är utförd hos Powertrain Engineering Sweden AB (PES), vilka är ett helägt dotterbolag till Volvo Cars Group, som arbetar med att ta fram och förbättra förbränningsmotorer. En del i detta arbete är att genomföra långtidstest för att analysera hur motorernas egenskaper ändras vid förslitning över tid. I nuläget ligger stort fokus på visuella inspektioner efter att motorerna genomgått långtidstester. PES önskar utveckla en metod där redan insamlad data som registrerats i dessa tester kan förklara hur fenomenet knack och regleringen för lambda förändras över tid. Studien är genomförd i form av en fallstudie av ett specifikt långtidstest där den öppna programvaran Sympathy for Data, tillsammans med det av Volvo Cars Group utvecklade tillägget, används för datahantering, visualisering och analys. Studien undersöker också metodiken för dataanalys med nämnd programvara. För att genomföra detta identifieras motorparametrar som påverkar de undersökta systemen samt parametrar som lämpar sig att användas som responsvariabler i en regressionsmodell. Dessa parametrar togs fram genom litteraturstudier om de fundamentala delarna i en förbränningsmotor samt från företaget förvärvad intern kunskap kring systemen. Resultatet presenteras i form av en analys genomförd med den, i Sympathy for Data, förprogrammerade noden för partial least squares regression(PLSR) samt de bilder och grafer som erhålls. För knack visade det sig att den slutliga tändningsvinkeln var lämplig att använda som respons i PLSR-modellen. En lämplig responsvariabel för lambda var mer svåridentifierad, detta förklarar varför signalerna för uppmätt lambda och lambda adaption analyseras. Inläsning av internt material och grundläggande information om förbränningsmotorer visade att delsystem i ottomotorn är beroende och påverkas av varandra vilket innebär att mer ingående studier i dessa delsystem är nödvändigt för att förstå hela processen och hitta grundorsakerna till variationerna som påvisas för respons

This study present the performance optimization of a spark ignition (SI) engine using gasoline fuels with variations of research octane number (88, 92, and 98) with 40 volume % of bioethanol. The optimization is done by setting the spark ignition time (2° CA advanced) and fuel injection duration (10% reduction) of the engine control module. The engine was tested using an engine dynamometer test to obtain the performance data at the shaft speed of 1000, 1500, 2000, and 2500 RPM and wide-open throttle conditions. From the results of this study, we conclude that optimizing the engine control strategy can lead to the improvement of engine power, torque, and specific fuel consumption which are more significant with the usage of fuels with higher octane number.

This study has been performed at Powertrain Engineering Sweden AB (PES), a fully owned subsidiary of Volvo Cars Group, which is constantly working to develop and improve internal combustion engines. As part of this work, durability tests are performed to analyse the impact of wear on the engines. At present, there is a strong focus on visual inspections after the engines have undergone durability tests. PES wants to develop a method where collected data from these tests can be used to explain how the phenomenon of knocking and the control of lambda changes over time. The study analyses one specific durability test and investigates the methodology of data analysis by using the open-source software platform Sympathy for Data, with an add-on developed by Volvo Cars Group, for data management, visualisation and analysis. To execute the analysis, engine parameters that affect these systems as well as parameters suitable to use as response variables are identified through literature studies of internal combustion engine fundamentalsas well as internal material, and knowledge acquired at the company. The result is presented in the form of an analysis generated by the node for partial least squares regression (PLSR) which is pre-programmed in Sympathy for Data as well as the images and graphs obtained as output. For knock, the signal for the final ignition angle was found to be suitable to use as the response variable in the PLSR. A suitable response variable for lambda was more difficult to identify, this is why both signals for the measured lambda and lambda adaptation are analysed. Studies of the internal material and knowledge highlighted the fact that several engine subsystems are highly dependent on each other and that even deeper research would be necessary to fully understand the process and identify the primary cause for the variations observed in the generated models. However, partial least squares regression was performed using parameters derived from literature, Denna studie är utförd hos Powertrain Engineering Sweden AB (PES), vilka är ett helägt dotterbolag till Volvo Cars Group, som arbetar med att ta fram och förbättra förbränningsmotorer. En del i detta arbete är att genomföra långtidstest för att analysera hur motorernas egenskaper ändras vid förslitning över tid. I nuläget ligger stort fokus på visuella inspektioner efter att motorerna genomgått långtidstester. PES önskar utveckla en metod där redan insamlad data som registrerats i dessa tester kan förklara hur fenomenet knack och regleringen för lambda förändras över tid. Studien är genomförd i form av en fallstudie av ett specifikt långtidstest där den öppna programvaran Sympathy for Data, tillsammans med det av Volvo Cars Group utvecklade tillägget, används för datahantering, visualisering och analys. Studien undersöker också metodiken för dataanalys med nämnd programvara. För att genomföra detta identifieras motorparametrar som påverkar de undersökta systemen samt parametrar som lämpar sig att användas som responsvariabler i en regressionsmodell. Dessa parametrar togs fram genom litteraturstudier om de fundamentala delarna i en förbränningsmotor samt från företaget förvärvad intern kunskap kring systemen. Resultatet presenteras i form av en analys genomförd med den, i Sympathy for Data, förprogrammerade noden för partial least squares regression(PLSR) samt de bilder och grafer som erhålls. För knack visade det sig att den slutliga tändningsvinkeln var lämplig att använda som respons i PLSR-modellen. En lämplig responsvariabel för lambda var mer svåridentifierad, detta förklarar varför signalerna för uppmätt lambda och lambda adaption analyseras. Inläsning av internt material och grundläggande information om förbränningsmotorer visade att delsystem i ottomotorn är beroende och påverkas av varandra vilket innebär att mer ingående studier i dessa delsystem är nödvändigt för att förstå hela processen och hitta grundorsakerna till variationerna som påvisas för respons

As an alternative to second generation ethanol, valeric esters can be produced from lignocellulose through levulinic acid. While some data on these fuels are available, only few experiments have been performed to analyze their combustion characteristics under engine conditions. Using a traditional spark ignition engine converted to mono-cylinder operation, we have investigated the engine performances and emissions of methyl and ethyl valerates. This paper compares the experimental results for pure valeric esters and for blends of 20% of esters in PRF95, with PRF95 as the reference fuel. The esters propagate faster than PRF95 which requires a slight change of ignition timing to optimise the work output. However, both the performances and the emissions are not significantly changed compared to the reference. Accordingly, methyl and ethyl valerate represent very good alternatives as biofuels for SI engines. Future studies will focus on testing these esters in real application engines and performing endurance tests. Copyright © 2013 SAE International.

Combustion simulation in two-stroke engines becomes necessary not only for engine performance prediction but also for scavenge evaluation, since in-cylinder pressure and temperature are highly influenced by combustion process evolution. Combustion simulation by using a Wiebe function is appropriate to be included in a 1D engine code for providing design criteria with fast and accurate calculations; the main drawback is the determination of the four Wiebe parameters needed to build up the in-cylinder heat release. This paper deals with a detailed methodology for heat release determination in two-stroke engines under a wide range of running conditions; obtained empirical data will serve for building ad-hoc Wiebe functions, whose four parameters will be finally correlated with engine related parameters derived from 1D simulations. Two different engines, with three exhaust systems each, varying engine speed and spark-ignition timing were used to obtain correlations far from particular situations. A multiple regression analysis stated that charge density, residual gas fraction, spark timing and mean piston speed were the significant engine parameters that influence on Wiebe parameters. Finally, two scenarios were considered regarding Wiebe parameters: (a) specific correlations different for each engine gave coefficient of multiple determination values higher than 98% when predicting indicated mean effective pressure, (b) a global correlation used for both engines provided R2 values of 93% in the 50 cc and 91% in the 125 cc engine. © 2010 Elsevier Ltd. All rights reserved.

Combustion simulation in two-stroke engines becomes necessary not only for engine performance prediction but also for scavenge evaluation, since in-cylinder pressure and temperature are highly influenced by combustion process evolution. Combustion simulation by using a Wiebe function is appropriate to be included in a 1D engine code for providing design criteria with fast and accurate calculations; the main drawback is the determination of the four Wiebe parameters needed to build up the in-cylinder heat release. This paper deals with a detailed methodology for heat release determination in two-stroke engines under a wide range of running conditions; obtained empirical data will serve for building ad-hoc Wiebe functions, whose four parameters will be finally correlated with engine related parameters derived from 1D simulations. Two different engines, with three exhaust systems each, varying engine speed and spark-ignition timing were used to obtain correlations far from particular situations. A multiple regression analysis stated that charge density, residual gas fraction, spark timing and mean piston speed were the significant engine parameters that influence on Wiebe parameters. Finally, two scenarios were considered regarding Wiebe parameters: (a) specific correlations different for each engine gave coefficient of multiple determination values higher than 98% when predicting indicated mean effective pressure, (b) a global correlation used for both engines provided R2 values of 93% in the 50 cc and 91% in the 125 cc engine. © 2010 Elsevier Ltd. All rights reserved.

Two virtual sensors are proposed that use the spark-plug based ion current sensor for combustion engine control. The first sensor estimates combustion variability for the purpose of controlling exhaust gas recirculation (EGR) and the second sensor estimates the pressure peak position for control of ignition timing. Use of EGR in engines is important because the technique can reduce fuel consumption and NOx emissions, but recirculating too much can have the adverse effect with e.g. increased fuel consumption and poor driveability of the vehicle. Since EGR also affects the phasing of the combustion (because of the diluted gas mixture with slower combustion) it is also necessary to control ignition timing otherwise efficiency will be lost. The combustion variability sensor is demonstrated in a closed-loop control experiment of EGR on the highway and the pressure peak sensor is shown to handle both normal and an EGR condition., Sponsors, the International Association of Science and Technology for Development (IASTED), Technical Committee on Modelling and Simulation, Technical Committee on Control, World Modelling and Simulation Forum (WMSF)

Two virtual sensors are proposed that use the spark-plug based ion current sensor for combustion engine control. The first sensor estimates combustion variability for the purpose of controlling exhaust gas recirculation (EGR) and the second sensor estimates the pressure peak position for control of ignition timing. Use of EGR in engines is important because the technique can reduce fuel consumption and NOx emissions, but recirculating too much can have the adverse effect with e.g. increased fuel consumption and poor driveability of the vehicle. Since EGR also affects the phasing of the combustion (because of the diluted gas mixture with slower combustion) it is also necessary to control ignition timing otherwise efficiency will be lost. The combustion variability sensor is demonstrated in a closed-loop control experiment of EGR on the highway and the pressure peak sensor is shown to handle both normal and an EGR condition., Sponsors, the International Association of Science and Technology for Development (IASTED), Technical Committee on Modelling and Simulation, Technical Committee on Control, World Modelling and Simulation Forum (WMSF)

Two virtual sensors are proposed that use the spark-plug based ion current sensor for combustion engine control. The first sensor estimates combustion variability for the purpose of controlling exhaust gas recirculation (EGR) and the second sensor estimates the pressure peak position for control of ignition timing. Use of EGR in engines is important because the technique can reduce fuel consumption and NOx emissions, but recirculating too much can have the adverse effect with e.g. increased fuel consumption and poor driveability of the vehicle. Since EGR also affects the phasing of the combustion (because of the diluted gas mixture with slower combustion) it is also necessary to control ignition timing otherwise efficiency will be lost. The combustion variability sensor is demonstrated in a closed-loop control experiment of EGR on the highway and the pressure peak sensor is shown to handle both normal and an EGR condition., Sponsors, the International Association of Science and Technology for Development (IASTED), Technical Committee on Modelling and Simulation, Technical Committee on Control, World Modelling and Simulation Forum (WMSF)

Two virtual sensors are proposed that use the spark-plug based ion current sensor for combustion engine control. The first sensor estimates combustion variability for the purpose of controlling exhaust gas recirculation (EGR) and the second sensor estimates the pressure peak position for control of ignition timing. Use of EGR in engines is important because the technique can reduce fuel consumption and NOx emissions, but recirculating too much can have the adverse effect with e.g. increased fuel consumption and poor driveability of the vehicle. Since EGR also affects the phasing of the combustion (because of the diluted gas mixture with slower combustion) it is also necessary to control ignition timing otherwise efficiency will be lost. The combustion variability sensor is demonstrated in a closed-loop control experiment of EGR on the highway and the pressure peak sensor is shown to handle both normal and an EGR condition., Sponsors, the International Association of Science and Technology for Development (IASTED), Technical Committee on Modelling and Simulation, Technical Committee on Control, World Modelling and Simulation Forum (WMSF)

Two virtual sensors are proposed that use the spark-plug based ion current sensor for combustion engine control. The first sensor estimates combustion variability for the purpose of controlling exhaust gas recirculation (EGR) and the second sensor estimates the pressure peak position for control of ignition timing. Use of EGR in engines is important because the technique can reduce fuel consumption and NOx emissions, but recirculating too much can have the adverse effect with e.g. increased fuel consumption and poor driveability of the vehicle. Since EGR also affects the phasing of the combustion (because of the diluted gas mixture with slower combustion) it is also necessary to control ignition timing otherwise efficiency will be lost. The combustion variability sensor is demonstrated in a closed-loop control experiment of EGR on the highway and the pressure peak sensor is shown to handle both normal and an EGR condition., Sponsors, the International Association of Science and Technology for Development (IASTED), Technical Committee on Modelling and Simulation, Technical Committee on Control, World Modelling and Simulation Forum (WMSF)

Two virtual sensors are proposed that use the spark-plug based ion current sensor for combustion engine control. The first sensor estimates combustion variability for the purpose of controlling exhaust gas recirculation (EGR) and the second sensor estimates the pressure peak position for control of ignition timing. Use of EGR in engines is important because the technique can reduce fuel consumption and NOx emissions, but recirculating too much can have the adverse effect with e.g. increased fuel consumption and poor driveability of the vehicle. Since EGR also affects the phasing of the combustion (because of the diluted gas mixture with slower combustion) it is also necessary to control ignition timing otherwise efficiency will be lost. The combustion variability sensor is demonstrated in a closed-loop control experiment of EGR on the highway and the pressure peak sensor is shown to handle both normal and an EGR condition., Sponsors, the International Association of Science and Technology for Development (IASTED), Technical Committee on Modelling and Simulation, Technical Committee on Control, World Modelling and Simulation Forum (WMSF)

This masters thesis investigates the possibility to estimate the ethanol content in the fuel using ion currents. Flexible fuel cars can be run on gasoline-ethanol blends with an ethanol content from0 to 85 percentage. It is important for the engine control system to have information about the fuel. In todays cars the measurements of the fuel blend are done by a sensor. If it is possible to do this with ion currents this can be used to detect if the sensor is broken, and then estimate the ethanol content until the sensor gets fixed. The benefit of using ion currents is that the signal is measured directly from the spark plug and therefore no extra hardware is needed. To be able to see how the ethanol ratio affects the ion currents, the dependencies of the operating point have been investigated. This has been done by a literature review and by measurements in a Saab 9-3. Engine speed, load, ignition timing, lambda and spark plugs effects on the ion currents are especially studied. A black box model for the ion currents dependence on operating point is developed. This model describes the engine speed, load and ignition timing dependencies well, but it can not be used to estimate the ethanol ratio.

Adjusting a proportion of two fuels with different ignition properties is an effective technique for controlling the ignition timing in HCCI combustion. This research newly proposes an HCCI combustion engine system fuelled with dimethyl ether (DME) having a high cetane number and methanol-reformed gas (MRG) having a high anti-knock property. In the system, both DME and MRG are to be produced from methanol by onboard reformers utilising the exhaust heat from the engine. Because the reactions producing DME and MRG are endothermic, a part of exhaust heat energy can be recovered during the fuel reforming process. This research experimentally investigated characteristics of combustion, exhaust emissions, engine efficiency and overall thermal efficiency including the waste heat recovery through the fuel reforming in the HCCI combustion engine system. Because MRG consists of hydrogen and carbon monoxide, effects of the two on the autoignition of DME were also analysed.

This masters thesis investigates the possibility to estimate the ethanol content in the fuel using ion currents. Flexible fuel cars can be run on gasoline-ethanol blends with an ethanol content from0 to 85 percentage. It is important for the engine control system to have information about the fuel. In todays cars the measurements of the fuel blend are done by a sensor. If it is possible to do this with ion currents this can be used to detect if the sensor is broken, and then estimate the ethanol content until the sensor gets fixed. The benefit of using ion currents is that the signal is measured directly from the spark plug and therefore no extra hardware is needed. To be able to see how the ethanol ratio affects the ion currents, the dependencies of the operating point have been investigated. This has been done by a literature review and by measurements in a Saab 9-3. Engine speed, load, ignition timing, lambda and spark plugs effects on the ion currents are especially studied. A black box model for the ion currents dependence on operating point is developed. This model describes the engine speed, load and ignition timing dependencies well, but it can not be used to estimate the ethanol ratio.

Adjusting a proportion of two fuels with different ignition properties is an effective technique for controlling the ignition timing in HCCI combustion. This research newly proposes an HCCI combustion engine system fuelled with dimethyl ether (DME) having a high cetane number and methanol-reformed gas (MRG) having a high anti-knock property. In the system, both DME and MRG are to be produced from methanol by onboard reformers utilising the exhaust heat from the engine. Because the reactions producing DME and MRG are endothermic, a part of exhaust heat energy can be recovered during the fuel reforming process. This research experimentally investigated characteristics of combustion, exhaust emissions, engine efficiency and overall thermal efficiency including the waste heat recovery through the fuel reforming in the HCCI combustion engine system. Because MRG consists of hydrogen and carbon monoxide, effects of the two on the autoignition of DME were also analysed.

The location of the peak pressure can serve as a control parameter to adjust ignition timing and optimize engine performance. The ionization sensor, an electrical probe for combustion diagnostics, can provide information about the peak pressure location. However, the reliability of such information is rather poor. In-cylinder gas flow at the electrodes may be one reason for this. We present results from an investigation of the relationship between ionization sensor current and pressure under various gas flow conditions. The gas flow velocity in the vicinity of the electrode gap was measured by LDA. From the results one may infer how the in-cylinder gas flow affects the reliability of the prediction of pressure peak location from the ionization sensor signal. One finding is that high bulk gas flow impairs the precision of the prediction in certain configurations.