Fast Optimal Energy Management with Engine On/Off Decisions for Plug-in Hybrid Electric Vehicles

In this paper we demonstrate a novel alternating direction method of multipliers (ADMM) algorithm for the solution of the hybrid vehicle energy management problem considering both power split and engine on/off decisions. The solution of a convex relaxation of the problem is used to initialize the optimization, which is necessarily nonconvex, and whilst only local convergence can be guaranteed, it is demonstrated that the algorithm will terminate with the optimal power split for the given engine switching sequence. The algorithm is compared in simulation against a charge-depleting/charge-sustaining (CDCS) strategy and dynamic programming (DP) using real world driver behaviour data, and it is demonstrated that the algorithm achieves 90\% of the fuel savings obtained using DP with a 3000-fold reduction in computational time

Advanced continuously variable transmissions for electric and hybrid vehicles

A brief survey of past and present continuously variable transmissions (CVT) which are potentially suitable for application with electric and hybrid vehicles is presented. Discussion of general transmission requirements and benefits attainable with a CVT for electric vehicle use is given. The arrangement and function of several specific CVT concepts are cited along with their current development status. Lastly, the results of preliminary design studies conducted under a NASA contract for DOE on four CVT concepts for use in advanced electric vehicles are reviewed

Modeling and Control Strategy for Hybrid Electrical Vehicle

This chapter reviews the developments and configurations of hybrid electrical vehicles. A classic model for a parallel hybrid electrical vehicle is chosen and modeled. Model predictive controllers and simulations for this vehicle model are applied to control the vehicle speed and power to check the ability of the system to handle the transitional period for the automatic clutch engagement from the electrical driving to the internal combustion engine (ICE) driving. The chapter produces potential model predictive control considerations to achieve the optimal real-time control actions subject to the vehicle physical constraints. The new system can be applied for electronic control units in real hybrid vehicle powertrains

Realization of a dual clutch transmission hydraulic and thermal model for HIL applications

Depleting oil resources and global warming has led to a continual search in the automotive field to find a cost-effective solution to develop more and more fuel efficient vehicles. In the last years the number of electric and hybrid vehicles have rapidly increase thanks to pollution standards and their high efficiency. It is possible to define three main categories, based mainly on the power of the electric motor and the capacity of the batteries. In "mild" hybrids, a small unit takes the place of the alternator and starter motor, and is connected to the main engine with a belt. When it slows down, it recharges a battery, while the energy flow is reversed, and the current motor "helps" the thermal one. The "full" hybrids have instead more powerful electric motors that are integrated with the rest of the vehicles : they are often part of the transmission. The "plug-ins" are "full" equipped with much larger batteries, which allow a range of tens of kilometers without using fuel; to be able to charge them to the maximum, however, it is necessary to connect them to the electric network through a cable. Otherwise, these cars behave like "full" hybrids: the accumulators are filled by the inertia of the vehicle when it slows down. As a result of this, new concepts called hybrid dual clutch transmission (HDCT) have been developed. These new type of transmission are suitable for multiple hybridisation topologies, as the e-machine can be connected to the transmission by different methods in order to obtain a more efficient interaction of the internal combustion engine and the e-machine. Compared to an automatic transmission based on planetary gearsets or to continuous variable transmissions (CVT), further optimisation potentials can be achieved thanks to the flexible hybridisation concept. This thesis aims to realize a model to calculate the heat generated by an hybrid dual clutch transmission in real-time without a great amount of computing power

Eliminating the torque hole: Using a mild hybrid EV architecture to deliver better driveability

© 2016 IEEE. Hybrid vehicle engineering has traditionally and dominantly focused on fuel economy benefits and emissions reductions. Although the transient power delivery benefits of hybrid powertrains are well-understood, these are not a primary focus of the majority of research and development efforts, with some exceptions. Our approach to this problem is to deliver a low-cost, low-tech mild-hybrid powertrain, with unique power delivery features designed to appeal to price-sensitive, but aspirational consumers. The powertrain is a simple post-transmission parallel hybrid configuration. It utilizes a low-powered four-cylinder engine coupled to a four-speed manual transmission through a robotically-actuated clutch. A low-voltage BLDC motor is directly connected to the transmission output shaft, before the final drive. Our research focuses on bringing the benefits of HEV architecture to the world's developing cities, where, it can be confidently argued, local emissions reductions are needed the most. Crucial to the success of this research is the understanding that compared to an equivalent ICE-powered vehicle, an HEV competes at a price disadvantage, no matter how cost-effective the solution is. This disadvantage is amplified in regions of low-middle income, where price sensitivity is greatest. It must, therefore, present better value than an equivalent conventional vehicle if it is to be commercially successful in these particularly price-sensitive markets. We discuss the extent to which control can be used to deliver transient power delivery gains in such a setup, and offer an example powertrain for simulation. To validate the concept, simulation of this research is performed in MATLAB and Simulink. The prototype is based on a generic engine and a BLDC motor. The results mainly focus on the electric drive and comparison of the transient response of drivetrains

Design of Power Split Hybrid Powertrains with Multiple Planetary Gears and Clutches.

Fuel economy standards for automobiles have become much tighter in many countries in the past decades. Hybrid electric vehicles (HEVs), as one of the most promising solutions to take on these challenging standards, have been successful in the US market. In the last few years, an observed trend is to use multiple planetary gears with multiple operating modes to further improve vehicle fuel economy and driving performance. Most work in existing literature on HEV design and optimization has been based on specific configurations, rather than exhaustively searching through all possible configurations. This limitation arises from the large size of the design space–millions to trillions of possible topological candidates. In this dissertation, a systematic design methodology is presented, which enables the exhaustive search of multi-mode powertrain systems. As a first step, a systematic analysis has been performed for all 12 single PG configurations with multiple operating modes enabled by clutch operation. The Dynamic Programming (DP) technique is used to solve the optimal energy management problems for each design candidate. For multi-mode HEVs with multiple PGs, an automated modeling and mode classification methodology is developed, which makes it possible to exhaustively search all possible designs. General mode shift mechanisms are studied, while mode shift cost is evaluated using Dijkstra’s algorithm, which identifies the optimal mode shift path. For each candidate, the optimal control problem needs to be solved so that all designs can be compared based on their best possible execution. A fast and near-optimal energy management strategy is proposed. The comparison results show that it is up to 10,000 times faster than DP while achieving similar performance. To ensure acceptable launching performance of the design candidates, a fast and optimal acceleration performance test procedure is developed, which can be used to determine optimal control inputs and mode shift schedule. Combining all proposed methodologies produces a systematic and optimal design procedure. Optimization results show that the exhaustive search design method is able to identify dozens of better designs than the production hybrid vehicle models available in today’s market.PhDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/116659/1/xiaowuz_1.pd

Traction and Launch Control for a Rear-Wheel-Drive Parallel-Series Plug-In Hybrid Electric Vehicle

Hybrid vehicles are becoming the future of automobiles leading into the all-electric generation of vehicles. Electric vehicles come with a great increase in torque at lower RPM resulting in the issue of transferring this torque to the ground effectively. In this thesis, a method is presented for limiting wheel slip and targeting the ideal slip ratio for dry asphalt and low friction surfaces at every given time step. A launch control system is developed to further reduce wheel slip on initial acceleration from standstill furthering acceleration rates to sixty miles per hour. A MATLAB Simulink model was built of the powertrain as well as a six degree of freedom vehicle model that has been validated with real testing data from the car. This model was utilized to provide a reliable platform for optimizing control strategies without having to have access to the physical vehicle, thus reducing physical testing. A nine percent increase has been achieved by utilizing traction control and launch control for initial vehicle movement to sixty miles per hour

A low-cost and novel approach in gearshift control for a mild-hybrid powertrain

© 2017 IEEE. A novel, the low-cost mild hybrid powertrain is described. It relies on a manual, or robotized manual transmission together with a BLDC motor coupled at the output for filling the torque hole between gear changes. In order to keep manufacturing cost low and improve commercial attractiveness, it incorporates gearshift strategies that deliver high-quality gear shifts. A deliberate downsizing of componentry is implemented as far as possible to reduce cost, and control strategies are employed to exploit the maximum potential of the architecture using methods including torque-fill, ICE-assist, and ICE start-stop. The architecture is developed in simulation using an existing conventional platform to investigate system properties and their effect on performance. In particular, we discuss the gear-shift control algorithm design. Until the cost of full hybrids and fuel cell vehicles is significantly reduced, such a mild hybrid may have the potential to provide the right cost-benefit balance to achieve strong market penetration

Co-Optimization of Adaptive Cruise Control and Hybrid Electric Vehicle Energy Management via Model Predictive Mixed Integer Control

In this paper, a model predictive mixed integer control method for BYD Qin Plus DM-i (Dual Model intelligent) plug-in hybrid electric vehicle (PHEV) is proposed for co-optimization to reduce fuel consumption during car following. First, the adaptive cruise control (ACC) model for energy-saving driving is established. Then, a control-oriented energy management strategy (EMS) model considering the clutch engagement and disengagement is constructed. Finally, the co-optimization structure by integrating ACC model and EMS model is created and is converted to the mixed integer nonlinear programming (MINLP). The results show that this modeling method can be applied to EMS based on the model predictive control (MPC) framework and verify that co-optimization can achieve a 5.1$\%$ reduction in fuel consumption compared to sequential optimization with the guarantee of ACC performance