Todays vehicle industry is converging more and more to electrification of vehicles, introducing electrical architectures to cooperate side by side with the combustion engine. This paper investigates the potential of using an electric turbocharger in a long haulage application during highway driving. A charge sustainable control strategy is developed, implemented, tuned, and evaluated on a heavy duty truck model. The benefits of using an electrical turbocharger on a heavy duty diesel truck, from a long haulage perspective, are evaluated. By calibrating the implemented controller, long haulage driving routes can be charge sustainable and consume less fuel than a conventional truck with fix turbine geometry, the fuel savings for the simulated case is 0.9%. (C) 2017, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

The diesel engine remains one of the key components in the global economy, transporting most of the worlds goods. To cope with stricter regulations and the continuous demand for lower fuel consumption, optimization is a key method. To enable mathematical optimization of the diesel engine, appropriate models need to be developed. These are preferably continuously differentiable, in order to be used with a gradient-based optimization solver. Demonstration of the optimization-based methodology is also necessary in order for the industry to adapt it. The paper presents a complete mean value engine model structure, tailored for optimization and simulation purposes. The model is validated using measurements on a heavyduty diesel engine. The validated model is used to study the transient performance during a time-optimal tip-in, the results validate that the model is suitable for simulation and optimization studies.

The pursuit of lower fuel consumption and stricter emission legislation has made a simulation- and optimization-based development methodology important to the automotive industry. The keystone in the methodology, is the system model. But for the results obtained using a model to be credible, the model has to be validated. The paper validates an open-source, meanvalue engine model of a 13 liter CI inline 6 cylinder heavyduty engine, and releases it as open-source.

Vehicle speed planning for heavy duty vehicles is a powerful tool to reduce the fuel consumption, and thereby the emissions released from the vehicle. By optimizing a driving mission for lowest possible fuel consumption, while still fulfilling the mission deadlines, the fuel consumption could be reduced over that specific mission. If the vehicle is driven by a combustion engine, the engine efficiency will be dependent on the load and speed requirements from the vehicle. By having a gearbox between the engine and the wheels, the engine operating points could be selected by choosing the appropriate gear. When optimizing gear changes, different model complexities can be used. To solve a gear change problem during acceleration, some key aspects needs to be taken into account, for example the loss of propulsion power when disengaging the clutch, how much clutch slip should be allowed, the time it takes for the gearbox to change the gear. The paper presents a method how to formulate and solve a fuel optimal acceleration of a vehicle, where the gear selections are in focus. The method is used to find which gears that should be used to perform a fuel optimal acceleration to a predefined vehicle speed. (C) 2019, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

Reducing the fuel consumption is important and much development work is on engine optimization for best stationary fuel consumption. Here, a solution is developed for the transient operation to get fuel optimal accelerations, considering the actuation of fuel injection, wastegate control and gear utilization. The transient acceleration scenario studied is; a truck is approaching a red light at slow rolling speed, the light turns green and the truck shall be accelerated to 50 km/h with minimum fuel. Optimal control is used to find the fuel optimal control strategies. By using a dynamic engine model, taking the turbocharger dynamics into consideration, the engine air fuel ratio is taken into account. The differences and similarities between a stiff and flexible driveline model, are analyzed. The results show that the most dominating effect is the turbocharger dynamics of the engine. The two drivelines have similar gear changing strategies while the finer details differ due to the additional degrees of freedom that are present in the flexible driveline.

A combustion engine-driven vehicle can be made more fuel efficient over some drive cycles by, for example, introducing electric machines and solutions for electrical energy storage within the vehicles driveline architecture. The possible benefits of different hybridization concepts depend on the architecture, i.e., the type of energy storage, and the placement and sizing of the different driveline components. This paper examines a diesel electric plug-in hybrid truck, where the powertrain includes a diesel engine supported with two electric motors, one supporting the crank shaft and one the turbocharger. Numerical optimal control was used to find energy-optimal control strategies during two different accelerations; the trade-off between using electrical energy and diesel fuel was evaluated using a simulation platform. Fixed-gear acceleration was performed to evaluate the contribution from the two electric motors in co-operation, and individual operation. A second acceleration test case from 8 to 80 km/h was performed to evaluate the resulting optimal control behavior when taking gear changes into account. A cost factor was used to relate the cost of diesel fuel to electrical energy. The selection of the cost factor relates to the allowed usage of electrical energy: a high cost factor results in a high amplification from electrical energy input to total system energy savings, whereas a low cost factor results in an increased usage of electrical energy for propulsion. The difference between fixed-gear and full acceleration is mainly the utilization of the electric crank shaft motor. For the mid-range of the cost factors examined, the crank shaft electric motor is used at the end of the fixed-gear acceleration, but the control sequence is not repeated for each gear during the full acceleration. The electric motor supporting the turbocharger is used for higher cost factors than the crank shaft motor, and the amplification from electrical energy input to total energy savings is also the highest.