Vehicle Acceleration Performance Research Articles

Rapid Decision-Making Tool for Electric Powertrain Sizing for Motorcycles during New Product Development

As part of the intergovernmental and public interventions to reduce carbon dioxide emissions, there are no existing regulations to ban the sale of petrol motorcycles (PM), but it is expected that motorcycle regulations will follow car regulations with several years of delay. There is an emerging trend in motorcycle uptake, which will lead to new development projects with existing brands, and new brands, and will clearly increase the need for development tools that satisfies design challenges specific to electric motorcycles (EM) and electric powertrains. There is significant importance in motorcycle design to quantify the vehicle-level performance indicators and specifications, which are not limited to total vehicle mass, range, acceleration performance, and top speed. Those performance indicators should be quantified for different powertrain configurations and component selections to identify the most suitable configuration for the specific motorcycle development. In this paper, an innovative powertrain sizing approach is proposed to provide solutions for EMs against the design challenges specific to electric motorcycles. The innovative approach is to apply the practice of design space exploration (DSE) in resilient system design (RSD) to EM development. As a proof of concept, a case study of battery sizing is presented, in which a powertrain sizing tool is used to identify battery pack sizing requirements using requirement-based design (RBD), sensitivity analysis and DSE. The case study shows that the RBD approach allows EM product developers to identify a single solution, while DSE clearly demonstrates the trade-off between different configurations, taking multiple design variables into account. The tool prioritises high accessibility and high confidence with limited information at the early phases of electric motorcycle powertrain component sizing and selection.

A compact hydro-mechanical transmission solution to wheel loader propulsion system and its control strategy

Given the need for high efficiency to wheel loader powertrain, hydro-mechanical transmission is a promising solution to wheel loader propulsion system since it enables efficient engine operations owing to its continuously variable transmission function. The current hydro-mechanical transmission consists of planetary gear set and two hydrostatic units, making it bulky and complex in controls. This study proposes a simple and compact hydro-mechanical transmission solution to wheel loader powertrain. It improves vehicle acceleration performance by providing hydraulic torque assistance at low vehicle speed. The steady-state characteristics of the proposed hydro-mechanical transmission are analyzed, and the mathematical models of proposed wheel loader powertrain are constructed. An optimization strategy is developed as a reference for the design of an engine-speed based control strategy. The simulation results of the key components of proposed powertrain are analyzed. Furthermore, the engine-speed based control strategy is evaluated by the optimization strategy in different forms of the loading cycles. The results demonstrate the effectiveness of proposed wheel loader powertrain and its control strategy.

Vehicle design for terrain mobility: A modeling technique of powertrain power conversion and realization

Vehicle terrain mobility characteristics, provided by the powertrain and running gear, are realized in dynamic interactions between the wheels and terrain. Approaches to modeling and simulation of vehicle-terrain interaction and mobility characteristics as well as engineering approaches to design powertrain sub-systems together pre-determine a vehicle’s technical success or failure before it touches the ground. This article develops a vehicle mobility design technique, applicable to both manned and unmanned platforms, concerned with powertrain power conversion and realization in tire-terrain interactions. The modeling component is based on multi-drive-wheel vehicle longitudinal dynamics combined with terramechanics and powertrain characteristics. The approach advances the conventional dynamic factor by introducing the conjoint effect of the engine, transmission, and driveline system on vehicle traction and acceleration performance in terrain conditions where circumferential wheel forces and tire slippages may differ from each other. The vehicle design component of the proposed technique introduces drivetrain, driveline, and powertrain design factors that assess the influence of the drivetrain and driveline systems on traction, acceleration performance, power conversion, and realization at the wheels. The vehicle-design-for-mobility technique is completed by examining indices of mobility margins and performance. An analysis of several 8x8 armored personal carriers and 4x4 off-road vehicles illustrates the proposed technique.

Acceleration‐based wheel slip control realized with decentralised electric drivetrain systems

Traction control is one of the most important functions in vehicle drivetrain systems. When a vehicle is driven on a low-friction road surface, loss of traction force can cause the driven wheels to spin. This reduces vehicle acceleration performance and can even cause the driver to lose control of the vehicle. The high bandwidth of electric machine control in electric vehicles gives more possibilities to regulate driving torque on wheels and prevent wheel spin. An acceleration-based wheel slip control is designed and investigated. Compared to traditional slip-based traction control, the proposed method does not depend on the estimation of the vehicle speed and only relies on the driven wheel rotational acceleration. The control method is verified using the simulation of an electric vehicle with a decentralised electric drivetrain system. The vehicle and the electric drive are modelled in CarMaker and PLECS, respectively. The simulation results show that the proposed method is able to prevent the driven wheel from spinning when the vehicle is accelerated on an ice road. In addition, the control is fast enough and requires only half a second to reduce the wheel acceleration to a normal range.

A Critical Review on Lightweight Design of Battery Pack Enclosure for Electric Vehicles

An electric vehicle battery pack which is a gathering of battery modules which subsequently comprised of the battery cell is a primary source of control transmission for an Electric Vehicle (EV). The inappropriate design of the battery enclosure will cause many genuine issues, such as cracking, causing noise, or battery harm. At the same time, the weight of the battery enclosure is huge; in order to get better the driving range of the electric vehicle and diminish the influence of the battery on the vehicle dynamic performance and acceleration performance, it is essential to carry out the lightweight design of the battery enclosure. This paper reviews the multi-material battery enclosure design optimization, the multi- technologies, and a proficient Battery Management System (BMS) for compact battery pack design used to lightweight battery pack enclosure design; the multi-objective optimization approach for distinctive parameters of battery pack enclosure design optimization by diverse manufacturing techniques.

Acceleration, Drive Cycle Efficiency, and Cost Tradeoffs for Scaled Electric Vehicle Drive System

This article investigates and quantifies, for varying drive system ratings (0.5–2.0 times the rating of a small and large reference system), the tradeoff relations between the electric vehicle acceleration performance and energy consumption during a wide range of drive cycles, using detailed load-dependent loss models. Additionally, the results are related to estimated drive system cost by transparently determined scalable electric motor and inverter cost models. When reducing the system rating to half, the cost is 83% of the small reference system and 76% of the large. The acceleration time (0–100 km/h) decreases nonlinearly with increasing system rating. Interestingly, the drive cycle energy consumption generally decreases with decreasing drive system rating, and most cycles show a minimum consumption with a downscaled drive system. For the small system, the strongest impact was noted for the HWFET cycle where the energy consumption is reduced 2% when downscaling the drive system by 0.5 relative to the reference system. For the large system, NYCC shows the largest reduction in energy consumption: 4% when scaled by 1.6 relative to the reference system.

Numerical Investigation of 48 V Electrification Potential in Terms of Fuel Economy and Vehicle Performance for a Lambda-1 Gasoline Passenger Car

Real Driving Emissions (RDE) regulations require the adoption of stoichiometric operation across the entire engine map for downsized turbocharged gasoline engines, which have been so far generally exploiting spark timing retard and mixture enrichment for knock mitigation. However, stoichiometric operation has a detrimental effect on engine and vehicle performances if no countermeasures are taken, such as alternative approaches for knock mitigation, as the exploitation of Miller cycle and/or powertrain electrification to improve vehicle acceleration performance. This research activity aims, therefore, to assess the potential of 48 V electrification and of the adoption of Miller cycle for a downsized and stoichiometric turbocharged gasoline engine. An integrated vehicle and powertrain model was developed for a reference passenger car, equipped with a EU5 gasoline turbocharged engine. Afterwards, two different 48 V electrified powertrain concepts, one featuring a Belt Starter Generator (BSG) mild-hybrid architecture, the other featuring, in addition to the BSG, a Miller cycle engine combined with an e-supercharger were developed and investigated. Vehicle performances were evaluated both in terms of elasticity maneuvers and of CO2 emissions for type approval and RDE driving cycles. Numerical simulations highlighted potential improvements up to 16% CO2 reduction on RDE driving cycle of a 48 V electrified vehicle featuring a high efficiency powertrain with respect to a EU5 engine and more than 10% of transient performance improvement.

Development of a new traction control system using ant colony optimization

An advanced traction control system can help limit wheel rotation and enhance vehicle stability. This article presents a new traction control system under complicated situations, including the low slippery road surface and split-µ road surface. First, a 15-degree-of-freedom nonlinear vehicle dynamics simulation model is established. Then, the driving wheel speed is regulated by adjusting the engine torque and the wheel brake pressure. The engine torque regulation is based on a proportional–integral–derivative plus ant colony optimization controller, and the wheel brake pressure regulation is based on a proportional–integral plus ant colony optimization controller. Finally, the proposed strategies are applied to simulation and road tests. Results indicate that the algorithm exhibits high control accuracy and robust performance. Compared with the traditional proportional–integral–derivative controller, the proposed strategies improve vehicle acceleration performance and stability.

A New Supercapacitor and Li-ion Battery Hybrid System for Electric Vehicle in ADVISOR

The supercapacitor (SC) and Li-ion battery(BT) hybrid energy storage system(HESS) electric vehicle(EV) is gaining universal attention. The topology is of importance for the SC/BT HESS. A new SC/BT topology HESS with a rule-based energy management strategy for EV was proposed. The BT pack is connected directly to the DC link via a controlled switch. The SC pack is connected to the DC link via a controlled switch. A uni-directional DC/DC converter is connected between the SC pack and the BT pack. The braking regeneration energy is all harvested by the SC pack. The output power of BT pack is limited. The different SC/BT configurations with varied BT maximum Ah capacity factor and SC maximum capacity factor are simulated in ADVISOR. Simulation results show that BT maximum Ah capacity factor has little impact on vehicle acceleration performance and maximum speed. SC maximum capacity factor has significant impact on vehicle acceleration performance and maximum speed. The fuel economy isn’t affected.

Comparisons of draft gear damping mechanisms

ABSTRACTThis paper compared three types of draft gears with different damping mechanisms: friction, polymer and friction–polymer. Impact characteristics, frequency responses, in-train characteristics and fatigue damage for these draft gears were compared. Wagon impact simulations show that the friction draft gear, polymer draft gear and the friction–polymer draft gear can withstand impact speeds of 9, 12 and 11 km/h, respectively. Comparisons of frequency responses show that the friction draft gear has higher stiffness at lower working velocities, while the polymer draft gear has lower stiffness at lower working velocities. The response of the friction–polymer draft gear is less sensitive to the working velocities as it blends the friction and polymer damping mechanisms and offsets their influences on draft gear forces. Train dynamics simulations show that the in-train characteristics of friction draft gears and polymer draft gears are similar to their static characteristics and very different from their impact characteristics. The in-train characteristics of the polymer draft gears have lower stiffness and lower damping abilities than the other two types of draft gears. The friction–polymer draft gears achieved better vehicle acceleration performance than the friction draft gears. The polymer draft gears achieved similar maximum accelerations throughout the train and the maximum accelerations were significantly lower than that of the other two types of draft gears. The polymer draft gears achieved 23.4% less fatigue damage than the friction draft gears; the fatigue damage of the friction–polymer case is only half that of the friction case.

The Sliding Mode Control about ASR of Vehicle with Four Independently Driven In-Wheel Motors Based on the Exponent Approach Law

Acceleration slip regulation control system is a new active safety technology. In this paper, through the research of the four-wheel independent drive electric vehicle, a sliding mode variable structure control algorithm based on exponent approach law is proposed, which is applied to the ASR system. This paper establishes a seven DOFs vehicle dynamics model, tests whether the ASR control strategy is efficient on the poor condition road. The simulation results show that the vehicle acceleration performance improvement rate increases by 43.5% and 58.5% with the control strategy. During the two simulation processes, the results indicate that the sliding mode variable structure control algorithm applied to ASR system has a good adaptation to good and slippery roads. The algorithm can greatly improve the four-wheel independent drive electric vehicle's acceleration performance.

Design of Acceleration Slip Regulation System Based on Vehicle Test Platform

In order to improve vehicle acceleration performance on low adhesion roads, an acceleration slip regulation (ASR) is designed with combination control of engine throttle and braking interference based on vehicle platform and fuzzy control algorithm. The principle of ASR system and control logic are described in detail, and the vehicle tests have been carried out. The results show that the controller can effectively prevent excessive spinning of driving wheels on low adhesion roads, and greatly improve the vehicle acceleration performance. It provides a test platform to further study of vehicle active safety control.

Traction Control Method of Hybrid Electric Vehicle based on Multi-Objective Dynamic Coordination Control

The control method of the conventional traction control system on split-μsurfaces improves vehicle acceleration performance, but influences its stability performance. To solve this problem, a hierarchical traction control system for ISG hybrid electric vehicles based on multi-objective dynamic coordination control (MHEVTCS) is proposed. In the upper level controller, a target driving torque calculating strategy based on dynamical sliding mode control is developed. In the lower level controller, such strategies as multi-objective dynamic coordination control strategy, brake torque control strategy based on an inverse model, target engine torque design strategy and torque dynamic coordinate control strategy are proposed. Detailed simulation and hardware-in-loop experiment results show that slipping wheels are controlled quickly, accurately and smoothly by MEHVTCS. MHEVTCS solves the problem of merely pursuing acceleration performance and neglecting stability performance of conventional traction control system.

The working regime analysis of a track-type tractor

The estimation of the vehicle acceleration performance plays an important role in the assessment of the vehicle mobility. The estimation becomes difficult in the case of tracked vehicles owing to the complexity of their power pack (consisting mainly of the engine and the hydromechanical transmission) and also because of the tracked running gear. Because of that, this case was taken into investigation and an algorithm was proposed. The algorithm is focused on the estimation of the acceleration performances. The accuracy of the proposed algorithm is compared with the experimental data resulted from the testing of a 50 tonnes tracked vehicle running up to 60 km/h, concluding that the model-based data are in good agreement with the experimental results.

Start and acceleration optimization of a parallel hybrid electric vehicle

The main issues relating to hybrid electric vehicle (HEV) emissions are starting and transient air-fuel ratio (AFR) control. The idle-cancelling function of an HEV will postpone the catalyst activation at cold start. So it is vital to confine the start emission to a much lower level. The conventional transient fuel also dramatically deteriorates emissions. The start and transient acceleration control strategies were developed on a uni-axis integrated starter–generator (ISG) parallel HEV. The optimization of each stage of the start process was realized. The start parameters of the engine controller (ECU) and vehicle controller (VCU) were determined by analysing unsuccessful starts. The results show that the engine starts smoothly without much speed overshoot. The AFR is superior to that of the prototype vehicle. At warming-up start and hot start there is also a smooth transition from ambient oxygen ratio to stoichiometric AFR. The concept is introduced of ‘fast’ and ‘slow’ torque to ISG boost acceleration. The conventional engine fuel wetting effect is overcome by ISG boost. The engine transient fuel and acceleration fuel compensation (AFC) for vehicle acceleration were replaced by ISG transient torque and continuous torque. The ISG boost acceleration calibration was completed and validated the result that the transient AFR was optimized without sacrificing vehicle drivability or acceleration performance. Both ISG start and ISG boost acceleration are effective approaches to solve the problem of HEV emission.

Dual-mode Operation of a Rocket-Ramjet Combined Cycle Engine

One-dimensional evaluation of Ramjet-mode operation was carried out on a rocket-ramjet combined cycle engine model. For simplicity, instantaneous mixing between the airflow and rocket exhaust, instantaneous heat release, and pressure recovery by a normal-shock wave were assumed. Shock wave location was so decided that the heat release at the injection (heat addition) location was to thermally-choke the combustion gas flow. By changing the injection location, it was shown that a further downstream injection resulted in a further thrust production and a further fuel flow rate requirement for choking, and a lesser specific impulse. Balancing the thrust production and the specific impulse in terms of the launch vehicle acceleration performance should be pursued. The total pressure loss within the engine model was dominated by the shock wave location, not depended on injection location and fuel flow rate, so that having shock wave penetration to further upstream location was beneficial both for thrust production in the engine and at the external nozzle.

Project Sabre: A Close-Spaced Direct Injection 3-Cylinder Engine with Synergistic Technologies to Achieve Low CO2 Output

The paper describes the design and development of 'Sabre', a 3-cylinder engine encompassing a combination of technologies to realise low CO2 in a practical automotive application while retaining driving pleasure (vehicle acceleration performance). This project is a partnership with Continental Automotive, in which Lotus Engineering is responsible for the base engine and combustion system. The decision process that led to a close-spaced direct injection combustion system that does not target high BMEP as the chief route to low fuel consumption is described. Instead of pursuing an approach in which specific power is maximized in order to reduce throttling losses at part load, mild downsizing coupled with throttling loss reduction and turbulence manipulation enabled by a switching valve train is employed. This approach, together with the use of an integrated exhaust manifold, enables cylinder head packaging benefits together with improved driveability and reduced high-load fuel consumption as a result of a lower boost requirement. The interaction of spray and air motion in the resulting homogeneous combustion system is briefly discussed. The rationale behind the choice of a 3-cylinder layout is also discussed which, in addition to reducing friction and engine mass, also contributes towards knock control by removing blowdown pulse interaction between the cylinders. Friction reduction methods are discussed which centre around the use of laser-deposition bores and roller bearings on the balance shaft. The balance shaft helps to address the NVH issues expected from the layout, together with the very low CoV of IMEP afforded by the combustion process. The technology under-pinning the integrated exhaust manifold is also discussed. This simultaneously improves thermal management and reduces mass and bill-of-material (BOM) costs in this integrated engine concept.

An efficient powertrain simulation model for vehicle performance

It is well established that interaction between powertrain and vehicle dynamics contributes significantly to the vehicle handling and ride response. This paper proposes a simple and efficient powertrain model for a Front-Wheel-Drive (FWD) vehicle to support vehicle design studies. This model captures the major interactions that impact vehicle ride and handling and is capable of real-time execution. A detailed description of the model is provided as well as how it is coupled to the vehicle model. Simulation results are presented for an example vehicle. The ability to predict vehicle acceleration performance is demonstrated. The model is also used to investigate dynamic responses in throttle tip-in events and for road disturbance.

Subjective evaluation of engine acceleration sound with driving simulator

The vehicle acceleration performance, the accelerator pedal controllability etc. have influence on the engine sound evaluation besides the sound level and quality. Subjective evaluation of the engine sound by the design of experiments was conducted with a driving simulator. As a result, the effects of the vehicle performance and the accelerator pedal controllability for the engine sound evaluation were measured quantitatively. It became clear that these factors could improve both “quiet feeling” and “sporty feeling” which show the evaluation of engine sound.

On the Beneficial Effects of Anti-Squat in Rear Suspension Design of a Drag Racing Motorcycle

In the drag racing environment, maximizing tractive effort is essential to competitive performance. Anti-squat is a transient vehicle suspension parameter which can dramatically affect tractive effort available at the motorcycle drive tire. This paper addresses the design of a four-link rear suspension for a drag racing motorcycle to provide anti-squat, which increases rear tire traction, thereby improving vehicle acceleration performance. Utilizing PC based CAD, finite element analysis and dynamic system analysis software, a motorcycle rear suspension system was designed, built and tested under actual racing conditions. Parametric studies using dynamic theoretical models were conducted for both unsuspended and four-link equipped versions of the same vehicle. Based on the results, it is shown that the four-link suspension, when applied to a drag racing motorcycle, does provide opportunity for improving tractive effort at the beginning of a race which will improve overall drag racing performance.