Vehicle Propulsion System Research Articles

Guest Editorial Special Issue on Electric Machine Drives and Converters for Automotive Applications

The automotive industry is in the midst of a historically disruptive revolution. The electrification of the vehicle propulsion system was initiated by the shared global need to address climate change and the pace of this revolution has picked up speed as customers become more aware and costs decrease. Whether it be through hybridization or full electrification, all types and segments of automobiles are expected to shift primarily to electrified products within the next 10 to 20 years. With this growth, the automobile industry will foreseeably become one of the largest producers and users of electric machines, power electronic converters, and related components. Besides the primary propulsion of the vehicle (electric machines and drives), an even greater opportunity for innovation exists in the auxiliary systems that either enable (chargers, dc/dc converters, etc.) or are enabled (autonomy, accessory systems, V2X exportable power, etc.) by electrification. This broad application is expected to drive significant amounts of innovation and cost reduction that will have farreaching impacts on other power electronic applications.

Comprehensive Review on Electric Propulsion System of Unmanned Aerial Vehicles

In recent years, electric unmanned areal vehicles (UAVs) are gaining popularity due to their capabilities in civil and military applications. The rationale is that UAVs can do more complex and risky tasks while maintaining mobility, safety, and cheap cost. UAVs are generally used for inspection and monitoring, search and rescue operation, delivery, precision agriculture, hobbyist applications, and many more. Due to a broad spectrum of applications, UAVs of various sizes and weights have evolved. UAVs have developed with the hybrid architecture of power supply incorporating batteries, fuel cells, solar photovoltaic systems, and supercapacitors for extended endurance and improved performance. The electric propulsion system is the central part of UAVs, which generates thrust to control and hover the UAVs in the air. The propulsion system includes an electric motor, electronic speed controller, power sources, and an energy management system for efficient operation. This paper presents an extensive and critical evaluation of state of the art on classifications, components of the electric propulsion system, the control strategy of electric motor, hybridization of power sources, and energy management system to identify research gaps and give insights exhortations for future research.

A method for verifying the model of tank operational pressurization process during development of propellant supply system in liquid rocket engines of launch vehicle propulsion systems

During development of propulsion systems for launch vehicles, in order to verify the design results, standalone developmental tests of propellant supply system components were run in specially designed test setups outfitted with the required instrumentation. As an example of such work, this paper describes the experience of standalone developmental testing of operational pressurization of propellant tanks. During tests in the constructed test setups, heat and mass exchange processes were tried out with simulation of design modes of operational pressurization of propellant tanks filled with oxygen and hydrogen. As a result of these tests, a rationale was provided for selection of working mediums as the pressurization gas, design and characteristics of gas injection into propellant tanks, a method for evaluating the efficiency of the pressurization process. Empirical dependences were obtained that were used as the boundary conditions in the models for practical calculations for refining the modes and evaluating the efficiency of the propellant supply subsystem of propulsion systems. The paper calls attention to the need to use for the purpose of development of the propellant supply systems that involves computer simulations the results of such earlier work when designing advanced rocket propulsion systems. Key words: propulsion system, propellant supply system, development of pressurization process, test setup, pressurization gas, propellant components, heat and mass transfer intensity, process efficiency, liquid surface sloshing, computer simulations.

Convexification in energy optimization of a hybrid electric propulsion system for aerial vehicles

This paper concerns the energy management of a hybrid electric propulsion system for aerial vehicles, using convex optimization. The main contribution of this paper is the proposal of a new convexification, which simplifies the formation of the convexified problem, and the proof of equality between the original problem and the convexified problem. The primary energy management is formulated from first principles and using experimental data. The convexity of the original problem is clarified via investigating the approximation to the experimental data. Then, change of variables and equality relaxation are implemented to convexify the concave constraints. The introduced variable—battery internal energy, is proposed to convexify the battery model. The relaxation of a non-affine equality yields to new convex inequality constraints. Numerical examples and forward simulations were carried out to validate the convexified problem. The first test case verifies that the convex relaxation does not sacrifice the optimality of the solution nor does the variable change lose the original bounds. Also, the optimal control from convex optimization is demonstrated to be robust to a disturbance in power demand. Comparison with the benchmark optimization—dynamic programming, shows that convex optimization achieves a minimal objective value with less fluctuation of the optimal control value. Most significant is that the convexification reduces the optimization computation time to a level compatible with implementation in practical application.

An Adaptive Dendrite-HDMR Metamodeling Technique for High-Dimensional Problems

Abstract High-dimensional model representation (HDMR), decomposing the high-dimensional problem into summands of different order component terms, has been widely researched to work out the dilemma of “curse-of-dimensionality” when using surrogate techniques to approximate high-dimensional problems in engineering design. However, the available one-metamodel-based HDMRs usually encounter the predicament of prediction uncertainty, while current multi-metamodels-based HDMRs cannot provide simple explicit expressions for black-box problems, and have high computational complexity in terms of constructing the model by the explored points and predicting the responses of unobserved locations. Therefore, aimed at such problems, a new stand-alone HDMR metamodeling technique, termed as Dendrite-HDMR, is proposed in this study based on the hierarchical Cut-HDMR and the white-box machine learning algorithm, Dendrite Net. The proposed Dendrite-HDMR not only provides succinct and explicit expressions in the form of Taylor expansion but also has relatively higher accuracy and stronger stability for most mathematical functions than other classical HDMRs with the assistance of the proposed adaptive sampling strategy, named KKMC, in which k-means clustering algorithm, k-Nearest Neighbor classification algorithm and the maximum curvature information of the provided expression are utilized to sample new points to refine the model. Finally, the Dendrite-HDMR technique is applied to solve the design optimization problem of the solid launch vehicle propulsion system with the purpose of improving the impulse-weight ratio, which represents the design level of the propulsion system.

Revisiting the dewar design for liquid oxygen storage in fuel cell energy systems

Dewars are used to store liquid oxygen (LOX) in a fuel cell-driven Air Independent Propulsion (AIP) system for subsea vehicles. The dewar should have good storability to reduce snorkeling frequency. It is a double-walled vessel in which the two vessels are held together with a support system. The annular space contains the insulation. Heat flows from the ambient into the LOX through the insulation and support systems. Many types of dewar are available commercially; however, there exist no design guidelines in the open literature. Heat inleak is one of the primary concerns in the dewar design. For the first time, a comprehensive study is presented in this paper to highlight the relative importance of the support system and the insulation in dictating the heat inleak into the dewar. We determined the effects of heat inleak on the dewar design. The study revealed that the heat inleak through the support is considerably larger than that through the insulation. The results clearly emphasize the importance of the support system design in improving the storability of the LOX dewars in a fuel cell system.

Study of Hybrid Propulsion Systems for Lower Emissions and Fuel Saving on Merchant Ship during Voyage

The hybrid propulsion system is a vehicle propulsion system with two or more sources of propulsion such as diesel, batteries, and other renewable energy. The use of hybrid propulsion systems is not new, and they have been adopted worldwide. There are many applications for hybrid propulsion systems, from powering land-based vehicles to marine vessels. With the success of hybrid propulsion systems, many large vessels still rely on two-stroke engines for power generation. In this paper, the benefits and feasibility of using battery systems or hybridizing existing conventional two-stroke engines onboard large intercontinental vessels is studied and simulated. The merchant ship, a bulk carrier with 82,000 deadweight tonnage capacity, is used. The model vessel travels along a simulated route of up to 4000 nautical miles using weather routing software to generate data for estimating emissions with the help of widely adopted empirical formulas. A reduction of up to 3.4 tonnes of emissions and fuel consumption of not more than 1 tonne per kWh from peak shaving and boosting applications for a 12-day voyage were observed.

One for the Road

Choosing a single supplier for an electric commercial vehicle propulsion system offers the benefit of a highly engineered, purpose-built solution

One for the Road

Choosing a single supplier for an electric commercial vehicle propulsion system offers the benefit of a highly engineered, purpose-built solution

Numerical and Experimental Analyses of Track Shoe Patterns for Vehicle on Sandy Terrain

A track is a vehicle propulsion system that consists of a continuous band of chains connected with track shoes or may be entirely made of rubber. The track system is still commonly used on various vehicles, including bulldozers, excavators, tanks, and tractors, and has recently been used in lunar expedition vehicles. A tracked vehicle is mainly designed to provide better mobility in rough, uneven, or slippery terrain. The main component of the track system is track shoes or so-called grousers. This track shoe geometry will determine the tractive performance of the vehicle. If an incorrect shape is used, the excavator will most likely slip. The previous study approached this traction problem by using the semi-empirical method. However, until now, the track geometry and traction relation are still unclear. This research focuses on the effects of track shoe geometry on tractive performance and vehicle climbing ability. The analysis was mainly conducted with a DEM (Discrete Element Method) simulation. The result from the experimental test is also confirmed using a small-scale RC prototype on simulated terrain with different slope variations. It is proven that the grouser height directly affects the climbing performance of tracked vehicles. A higher grouser height proves to be better at a higher inclination slope. However, for a low inclination angle, the flattened track was better. The traction result from the EDEM simulation also yields a similar result. However, higher usable traction means more friction is generated; therefore, the track with higher traction also takes more energy to cover the same distance.

Selection of the optimum configuration and calculation studies of the parameters of a cryogenic propulsion system for an unmanned aerial vehicle

A computational study of the parameters of a propulsion system of an unmanned aerial vehicle operating on a cryogenic working medium has been carried out. Liquid nitrogen was selected as the cryogenic working fluid. Two alternative configurations of a cryogenic propulsion system for an unmanned aerial vehicle are presented. The first one is a scheme of an air-heated cryogenic propulsion system of an unmanned aerial vehicle in which air acts as the heat source at an ambient temperature at an altitude of 2000 m. The second one is a scheme wherein the working fluid is heated due to solar energy, in this case solar energy acts as the source of heat. A computational study of a cryogenic propulsion system operating on the open Rankine cycle was carried out, as well as computational studies of possible cryogenic propulsion system configurations. As a result of the studies a comparative analysis of the data obtained was made and a suitable cryogenic propulsion system configuration for an unmanned aerial vehicle with the required parameters was selected.

Collaborative Control of Novel Uninterrupted Propulsion System for All-Climate Electric Vehicles

Collaborative Control of Novel Uninterrupted Propulsion System for All-Climate Electric Vehicles

Preliminary Evaluation of Induction Switched Reluctance Machine (ISRM) for Electric Vehicle Application

In this paper, a novel electric machine, Induction Switched Reluctance Machine (US patent-US20170370296A1) is introduced, and its preliminary performance is evaluated. The innovation is based on placing windings on the rotor, in order to create short magnetic flux paths in the rotor and stator core of the electric machine. As a result, a higher torque with lower copper and iron losses is generated. Like other ideas, there are unknown aspects of this electric machine, such as thermal and mechanical properties, that should be studied. A comprehensive research program is required to analyze and design an Induction Switched Reluctance Machine with an optimized configuration. This electric machine could be designed with different pole numbers and various winding strategies, and it is not possible to consider all configurations and aspects of it in this paper. Moreover, the size and the rated power of the machine can affect its properties. The purpose of this paper is to introduce, simulate and prototype a simple Induction Switched Reluctance Machine. This electric machine has an excellent potential to be implemented in the propulsion system of electric vehicles.

Evaluation of Effectiveness of Waterjet Propulsor for a Small Underwater Vehicle

Abstract The goal of the project described is to replace the existing propulsion system of a small underwater vehicle with a solution less prone to mechanical damage and ensuring a lower risk of the entanglement of fibrous objects suspended in the body of water. Four typical marine screws are utilised in the current design of the vehicle. One possible solution of the problem is the application of waterjet propulsors located inside the body of the vehicle instead. The general condition of the application of the new solution was to secure at least the same motion control capabilities of the vehicle while the basic capability is its propulsion effectiveness at the required speed. Specific features of the considered waterjet propulsor, when compared with their application in surface vessel propulsion, are the lack of the head losses and the low significance of cavitation issues. One of the difficulties in the considered case is the small diameter of the propulsor in comparison to commercially available waterjet units, which have diameters between 0.1 [m] and 1.0 [m]. There is very little data regarding the design and performance of devices in the 0.02 to 0.05 [m] range. Methods utilised to forecast the performance of the new propulsion system are presented and results compared. These were semi-empirical calculations, numerical calculations and tests of real devices. The algorithm that is based on semi-empirical calculations is of particular interest while it offers possibility quick assessment of performance of a propulsor composed of several well defined components. The results indicate the feasibility of modification of the propulsion system for the considered vehicle if all the existing circumstances are taken into account.

Novel Graphene Allocating Carbon–Copper Ratio Method for the Rail Vehicle Propulsion System Ground Carbon Brush

This study proposed graphene allocating carbon−copper ratio (GACCR) for the grounding carbon brush of rail vehicle propulsion systems. The proposed GACCR is the key component of grounding apparatuses, and the system effectiveness can be enhanced by increasing the electro-conductive efficiency of the grounding carbon brush. The proposed GACCR applies physical vapor deposition, which uses a sputtering system to control the vacuum and temperature, thereby adjusting the copper to carbon ratio, and fabricate optimized graphene. This study employed an energy dispersive spectrometer to observe the graphite flake corrugated stack architecture on the surface of grounding carbon brush, and analyze the composition. A four−point probe was used to measure the impedance characteristic. The characteristics of graphite film were detected using a Raman spectrometer. The G peak of 1580 cm-1 and the 2D peak at 2750 cm-1 formed the two−dimensional structure of graphite film. Finally, this study took the underground rail vehicle as an example. The grounding carbon brush with the proposed GACCR was compared with traditional graphite grounding carbon brush to assess the economic benefit of periodically changing the grounding carbon brush of rail vehicles every three years. The proposed GACCR can save 112000 USD (35% compared to the original replacement grounding carbon brush cost) for Taiwan Metro, proving its significant cost−benefit effect.

Comparative numerical evaluation of ECE-EUDC cycle performances of a hypothetical car equipped with three types of propulsion systems: conventional, series hybrid and parallel hybrid

This publication refers to the studies which were made to a compact car model to observe the behavior of the three drivetrain versions that the car can be equipped with: the version in which the vehicle model is equipped only with a Diesel engine (classic), a plug-in hybrid version with the combustion engine placed in a series circuit (pSHEV) and a second plug-in hybrid variant, where the thermal engine is arranged in parallel (pPHEV) with the electric motor (EM). The study emphasizes the behavior of three different vehicle propulsion systems equipped on the compact car on a standardized road cycle condition defined by the Urban Driving Cycle (UDC) referred as ECE 15 cycle combined with the Extra-Urban Driving Cycle (EUDC). The scope is to set up the three different powertrain systems through numerical modeling and to generate the conclusions based on the simulations results obtained in ADvanced VehIcle SimulatOR (ADVISOR).

Design Issues of a Rotating to Linear Motion Magnetic Converter for Short-Distance Transport Applications

This paper discusses some design issues of a magnetic rotating to linear motion converter (RLMC), suitable for the propulsion system of a short-distance low-capacity vehicle. It basically operates like a magnetic rack, which executes the contactless conversion of the motor torque into a propulsion thrust, deriving from the interaction of on-board permanent magnet (PM) modules and stationary ferromagnetic steel pieces. A design procedure is set up that deals with both the PM module arrangement and the geometric shape of the steel pieces to optimize different performance aspects. A simplified modeling based on 2D transient finite element analyses is carried out to determine the thrust profile and the RLMC losses, which are essential to assess its practical feasibility. Finally, the characteristics as functions of the load angle and speed are determined to enable the prediction of the dynamic power exchange and then of the net energy demand useful to size the on-board source.

Innovative Energy-Saving Propulsion System for Low-Speed Biomimetic Underwater Vehicles

This article covers research on an innovative propulsion system design for a Biomimetic Unmanned Underwater Vehicle (BUUV) operating at low speeds. The experiment was conducted on a laboratory test water tunnel equipped with specialised sensor equipment to assess the Fluid-Structure Interaction (FSI) and energy consumption of two different types of propulsion systems. The experimental data contrast the undulating with the drag-based propulsion system. The additional joint in the drag-based propulsion system is intended to increase thrust and decrease energy input. The tests were conducted at a variety of fins oscillation frequencies and fluid velocities. The experiments demonstrate that, in the region of low-speed forward movement, the efficiency of the propulsion system with the additional joint is greater.

A Review of Compressed Air Engine in the Vehicle Propulsion System

Abstract Engines powered by compressed air as a source of propulsion are known for many years. Nevertheless, this type of drive is not commonly used. The main reason for not using commonly is the problem with the low energy density of the compressed air. They offer a number of advantages, primarily focusing on the possibility of significantly lowering the emissions of the engine. Their emissivity mainly depends on the method of obtaining compressed air. This also has an impact on the economic aspects of the drive. Currently there are only a few, ready to implement, compressed air powered engine solutions available on the market. A major advantage is the ability to convert internal combustion engines to run with compressed air. The study provides a literature review of solutions, focusing on a multifaceted analysis of pneumatic drives. Increasing vehicle approval requirements relating to their emissions performance are encouraging for the search of alternative power sources. This creates an opportunity for the development of unpopular propulsion systems, including pneumatic engines. Analysing the works of some researchers, it is possible to notice a significant increase in the efficiency of the drive, which may contribute to its popularisation.

Artificial neural networks applied on induction motor drive for an electric vehicle propulsion system

Artificial neural networks applied on induction motor drive for an electric vehicle propulsion system