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- Hellgren, Jonas, 1974, et al.
(författare)
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A Systematic Way of Choosing Driveline Confriguration and Sizing Components in Hybrid Vehicles
- 2000
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Ingår i: 2000 Future Transportation Technology Conference, August 21-23, 2000, in Costa Mesa, California, USA, 2000.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Energy saving in general and less polluting vehicles in specific, become more and more urgent topics. One reason is that, in a world where the demand for fast transportation is increasing, the risk of global warming is a fact. Hybrid Vehicles (HV:s) are proposed as a more environmentally friendly candidate than conventional vehicles. Nowadays, there are numerous different types of HV:s and the components can, in theory, be sized in infinite ways. There is no simple answer to how to choose driveline configuration and size components in a HV. This paper describes one method, Driveline Synthesis (DS), that systematically presents a suitable driveline, on the basis of demands and conditions. Examples of demands are driving cycle and emission free zones. Some conditions are fuel price, tax on pollution and discount rate. The most suitable driveline is defined as the most cost effective. Total cost is defined as the sum of: cost of components, fuel cost, cost of external energy and cost of pollution. Genetic algorithms are used as an optimization method.Two major types of drivelines are compared in a case study, a conventional bus with a diesel engine and automatic transmission versus a series hybrid bus with different types of primary power units (diesel engine or fuel cell) and storage devices (super capacitor or NiMH battery). DS gives reasonable answers but needs further validation and development. One conclusion from the work is that the most suitable driveline configuration depends very much on demands, conditions and present technology, i.e. HV:s are only preferable to conventional vehicles under special circumstances.
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- Jacobson, Bengt J H, 1962, et al.
(författare)
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Gearshift Sequence Optimisation for Vehicles with Automated Non-Powershifting Transmissions
- 2003
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Ingår i: International Journal of Vehicle Design. - 0143-3369. ; 32:3/4, s. 187-207
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Tidskriftsartikel (refereegranskat)abstract
- Vehicle powertrains are increasingly automated. The gearshift strategy that is built into an automated manual (non-powershifting) transmission (AMT) has to determine when to shift and to which gear. AMT has the potential to reduce environmental impact and improve vehicle performance. However, the gearshift strategy is far from obvious, especially for heavy-duty trucks with many gears. This paper presents an analytic tool for finding the ultimate gearshift sequence for any given vehicle and driving situation. The paper includes some case studies that show credible results. These studies addressuphill acceleration and engine torque down control. The optimisation criterion used is minimum acceleration time. The tool is based on a trajectory optimisation method called dynamic programming. The cost function is formulated using simulations results from a dynamic system model, which can be implemented in Simulink. Comparisons with measurements secure a reasonably good practical relevance.
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- Jacobson, Bengt J H, 1962
(författare)
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Outline of a New Control Concept for Power Shifting of Fixed Step Ratio Automotive Transmissions
- 2001
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. - 2041-2991 .- 0954-4070. ; 215:5, s. 613-624
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Tidskriftsartikel (refereegranskat)abstract
- Power shifting transmissions, e.g. automatic transmissions, are traditionally shifted from gear A to B by disengaging a clutch belonging to gear A and engaging a clutch belonging to gear B. This paper tries out the idea of employing a third clutch. In practice, such a third clutch can be one of the clutches which is traditionally used only for other gears. This means that the new concept can be used with only a control software update in an ordinary gearbox. The trade-off between comfort and wear, which is experienced in the traditional control concept, becomes less troublesome. The wear, or the discomfort, can be reduced to roughly half of that corresponding to a traditionally controlled upshift. The work finds the largest potential in using an extra clutch which belongs to a gear higher than the high gear in an upshift. The theoretical study is carried out with a general and simple model, but a simulation example is added using a more detailed model of an existing gearbox.
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- Jacobson, Bengt J H, 1962
(författare)
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Potential of electric wheel motors as new chassis actuators for vehicle manoeuvring
- 2002
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Ingår i: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering. - 2041-2991 .- 0954-4070. ; 2016:8, s. 631-640
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Tidskriftsartikel (refereegranskat)abstract
- The stability and yaw control systems in today's vehicles are increasingly appreciated for active safety. They use individual wheel braking to obtain an extra yaw moment. Adding individual traction, e.g. through electric wheel motors, would increase the available extra yaw moment. The present work investigates the manoeuvrability potential of such a concept. A passenger car employing electric wheel motors at the rear axle is compared with the same vehicle using only brake intervention. The potential, or ultimate limits, are investigated for two driving situations. The time delay in yaw speed change when entering a curve is estimated. A reduction of some 10-30 per cent is found, the highest gains being at low longitudinal speed. For pure lateral translation, the maximum initial lateral acceleration is estimated and a 40 per cent increase is predicted. The investigation is based on mathematical analysis employing a modified version of the common bicycle model. The feasibility of introducing these solutions in series-produced vehicles is discussed briefly. Cost aspects are not considered in any great detail, but it is emphasized that such aspects must be weighed not only against improved manoeuvrability but also against reduced environmental impact and improved longitudinal driveability, all of which are attainable with electric propulsion.
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