Traditional Powertrain Research Articles

Optimal energy management strategy of a novel hybrid dual-motor transmission system for electric vehicles

To improve the performance of powertrain configuration and heuristic strategy used in electric commercial vehicles currently for complex traffic scenarios, we propose a blended optimal rule extraction method for a novel hybrid dual-motor transmission (hDMT) system. Dynamic programming (DP) is applied to determine the optimal working points on the real-world cycles. However, it is challenging to extract online rules in real-time due to overlapping working points induced by compound running conditions. To create a trade-off between optimum and practicability, a novel blended optimal rule extraction method of energy management strategy is proposed for the integrated powertrain system. To be specific, DP is applied offline to find optimal working points from compound running scenarios. Then, a self-organizing feature map (SOM) is utilized to classify overlapped working points with reference to the characteristics of sample points. To solve the over-classification issue, the recursive k-means method is used to cluster the best matching unit generated by SOM. Based on the above, the optimal strategy is developed systematically and implemented online. Furthermore, the hardware-in-the-loop experiments and simulation results demonstrate that the proposed powertrain configuration and method can improve the economic performance of EVs. The online performance of the blended optimal strategy is highly consistent with the simulation, which can reduce energy consumption by 29.02% compared to the preliminary strategy. Compared with traditional powertrain configuration, the hDMT system also has better energy-saving potential.

Effects of Individualized Versus Traditional Power Training on Strength, Power, Jump Performances, and Body Composition in Young Male Nordic Athletes.

This study aimed to examine the effects of individualized-load power training (IPT) versus traditional moderate-load power training (TPT) on strength, power, jump performance, and body composition in elite young Nordic athletes. In a randomized crossover design, 10 young male athletes (ski jumpers, Nordic combined athletes) age 17.5 (0.6) years (biological maturity status: +3.5y postpeak height velocity) who competed on a national or international level performed 5weeks of IPT (4 × 5 repetitions at 49%-72% 1-repetiton maximum [RM]) and TPT (5 × 5 repetitions at 50%-60% 1-RM) in addition to their regular training. Testing before, between, and after both training blocks comprised the assessment of muscle strength (loaded back squat 3-RM), power (maximal loaded back squat power), jump performance (eg,drop-jump height, reactive strength index), and body composition (eg,skeletal muscle mass). Significant, large-size main effects for time were found for muscle strength (P < .01; g = 2.7), reactive strength index (P = .03; g = 1.6), and drop-jump height (P = .02; g = 1.9) irrespective of the training condition (IPT, TPT). No significant time-by-condition interactions were observed. For measures of body composition, no significant main effects of condition and time or time-by-condition interactions were found. Our findings demonstrate that short-term IPT and TPT at moderate loads in addition to regular training were equally effective in improving measures of muscle strength (loaded back squat 3-RM) and vertical-jump performance (reactive strength index, drop jump, and height) in young Nordic athletes.

Numerical Performance Investigation of a Hybrid eCVT Specialized Agricultural Tractor

The need for highly efficient agricultural machineries is increasing the interest of the research community and of industrial manufacturers towards the use of integrated electric systems in combination with traditional powertrain elements. In this work, a hybrid electric tractor with electric continuously variable transmission (eCVT) capabilities was studied to investigate their performance in comparison with that of traditional diesel-powered tractor designs. This hybrid electric configuration can be classified as a power-split architecture that aims to combine the best characteristics of both the simpler parallel and the series hybrid layout while minimizing their main drawbacks. An eCVT configuration can allow for optimizing the diesel operating point with respect to the current working conditions, and achieving peak power performance and energy saving with relatively small electric machines. The proposed hybrid eCVT (HeCVT) tractor architecture was studied using a numerical model that allowed for developing two different control strategies: a charge depleting mode enabling the driver to use full power for the most power-intensive scenarios and a charge sustaining mode developed to optimize efficiency and battery use along an entire work day. To test the proposed architecture, several tasks derived from experimental field measurements on a specialized agricultural tractor were used. HeCVT results were compared with a numerical model of the traditional tractor validated by these experimental data. The HeCVT tractor showed good performance in terms of peak power capabilities using a downsized diesel engine, and consistent fuel savings were obtained according to typical daily working scenarios.

DESIGN AND PERFORMANCE ANALYSIS OF AN IN-WHEEL HUB REDUCER

In order to reduce the greenhouse effect caused by CO2 emissions, a lot of car manufacturers are developing battery electric vehicles (BEVs). Almost all of these vehicles have a traditional powertrain layout with the drive unit located in the car body. However, in recent years, a new technology called in-wheel motors has appeared. It significantly improves handling and manoeuvrability of vehicles but it also presents a challenge for both researchers and manufacturers. Since the motors are fitted into a limited space, they must provide high torque and high efficiency. When a reducer is used, the amount of torque needed is decreased several times, hence the overall dimensions of the motor are reduced. This paper studies a number of issues such as the basic concepts of the in-wheel hub drive systems, traction balance, preliminary gear ratio and possible design solutions for reducers used in in-wheel hub drive units. Characteristics of single-stage planetary and cycloidal reducers are analysed in detail. The results show that planetary reducers have an advantage if a lower gear ratio is needed.

A Model-Based Design Approach for a Parallel Hybrid Electric Tractor Energy Management Strategy Using Hardware in the Loop Technique

Recent developments in emissions regulations are pushing Non-Road Mobile Machineries manufacturers towards the adoption of more efficient solutions to reduce the amount of pollutants per unit of work performed. Electrification can be a reasonable alternative to traditional powertrain to achieve this goal. The higher complexity of working machines architectures requires, now more than ever, better design and testing methodologies to better integrate electric systems into mechanical and hydraulic layouts. In this work, the attention focused on the use of a Hardware in the Loop (HIL) approach to test performance of an energy management strategy (called load observer) developed specifically for an orchard tractor starting from field characterization. The HIL bench was designed to replicate a scaled architecture of a parallel hybrid electric tractor at mechanical and electrical level. The vehicle behavior was simulated with a personal computer connected on the CAN BUS network designed for the HIL system. Several tasks were simulated starting from data gathered during field measurements of a daily use of the machine. Results showed good performance in terms of load split between the two power sources and stability of the speed control although the variability of the applied load.

Global Insights on Future Trends of Hybrid/EV Driveline Lubrication and Thermal Management

Revised Abstract Global automotive industries have recently switched development trends from the traditional powertrain mechanical components into the digital transformation of the electrification components in advanced propulsion vehicles. This industrial impact on global development trend into automotive electrification designs has created an emerging technology for new propulsion systems such as hybrid electrical vehicles (HEV) or electrical vehicles (EV). Advanced propulsion systems resulting from global regulations are intended to improve vehicle fuel efficiency and reduce transportation-related emissions of greenhouse gases and other pollutants. In many HEV or EV advanced system designs, automotive lubri¬cants such as drivetrain fluids or thermal coolants have contact with the integrated electric motor (e-motor) and thermal management devices, which requires electrical and thermal properties to be consi¬dered in addition to conventional lubricant properties. The introduction of electrification components has been targeted for energy efficiency and long-term durability. Automotive industries have requested the adoption of the dedicated automotive lubricants or driveline fluids to meet appropriate thermal cooling requirements, offer bearing protection, ensure corrosion protection, and provide oxidation and sludge control. This review paper will provide with global insights on future automotive electrification development trends related to advanced driveline lubricants and thermal cooling fluids used in Hybrid/EV vehicles. Future research activities in advanced driveline fluids will be focused on minimizing friction loss and maximizing hybrid component durability. The major objective of this paper is to highlight the future electrification development trends and the required lubricants for advanced Hybrid/EV vehicles. The major section of this paper will be focused on the most important progress of automotive lubrication in the areas of energy efficiency, driveline reliability, cooling system design and thermal management requirements. In this review paper, new developments in thermal management fluids have been described to help promote the high-performance cooling system on electrical batteries, motors, and power electronics. In addition, global research activities using novel nanofluids for thermal cooling have the high potential for application to EV/Hybrid technologies. This paper has reviewed the state-of-art thermal management technology used for extending driving range and durability of EV/Hybrid vehicles. .

An Edge Computing Framework for Powertrain Control System Optimization of Intelligent and Connected Vehicles Based on Curiosity-Driven Deep Reinforcement Learning

For the ongoing revolution in developing intelligent and connected vehicles (ICVs), there is a lack of research for powertrain control systems using the latest artificial intelligence and vehicle-to-everything technology that have already been widely adopted in the autonomous driving systems. In this context, recent development of deep reinforcement learning (DRL) and one of the latest computing frameworks are coupled to facilitate an onboard-based intelligent powertrain control. Taking the boost control of a diesel engine equipped with variable geometry turbocharger as an example, the results show that the final control behavior indicated by the cumulated rewards is improved by 50.43% and the learning efficiency is improved by 74.29% for the proposed curiosity-driven DRL algorithm, compared with the same structure DRL algorithm with classic random exploration policy. In addition, unlike most of the DRL-based powertrain optimization algorithms, which have only been applied to single-machine architecture, this work manages the proposed DRL algorithm in parallel and, more importantly, from an edge computing perspective. This, in addition to greatly speeding up the algorithm training, can also realize a good balance of control accuracy and generality depending upon the selected training scenario. Moreover, unlike most of the cloud computing frameworks, which require low network latency, the proposed architecture can achieve a similar final control performance even if good network communication is not allowed. Compared with other existing powertrain control methods, the proposed algorithm is able to approximate a global powertrain control optimization autonomously in a connected manner, making it attractive to current ICVs with advanced automated driving and traditional powertrain control.

Simulation based feasibility confirmation of using hybrid powertrain system in unmanned dump trucks

The use of medium-duty vehicles (up to 50 tons) with a simultaneous reduction in technological and operational downtime, which is achieved by automated traffic control and loading and unloading systems, as well as optimization of technological maintenance modes, can be considered a new trend in the development of mining transport. The solution that meets the requirements and current development trends is the use of medium-duty unmanned dump trucks (UDT) in the interests of the Russian coal industry. An assessment of the most important performance characteristics of UDT, such as energy efficiency indicators, is considered in this research. The purpose of the research is to confirm the feasibility of using hybrid power system (HPS) in the construction of UDT. A series HPS is considered, characterized by the use of two traction electric motors: one drives the wheels of the front axle, the second drives the wheels of the rear bogie axle. The feasibility confirmation is carried out by comparing the energy efficiency and mobility of the studied vehicle with similar, equipped with other types of powertrains by simulation methods. The presented simulation results show the efficiency of HPS application in comparison with a traditional powertrain and a mechanical transmission for UDT when driving in drive cycles similar to a given one. The use of HPS allows reducing energy consumption for motion by 20-25% due to the recovery of braking energy.

Effects of Resisted Sprint Training and Traditional Power Training on Sprint, Jump, and Balance Performance in Healthy Young Adults: A Randomized Controlled Trial.

Power training programs have proved to be effective in improving components of physical fitness such as speed. According to the concept of training specificity, it was postulated that exercises must attempt to closely mimic the demands of the respective activity. When transferring this idea to speed development, the purpose of the present study was to examine the effects of resisted sprint (RST) vs. traditional power training (TPT) on physical fitness in healthy young adults. Thirty-five healthy, physically active adults were randomly assigned to a RST (n = 10, 23 ± 3 years), a TPT (n = 9, 23 ± 3 years), or a passive control group (n = 16, 23 ± 2 years). RST and TPT exercised for 6 weeks with three training sessions/week each lasting 45–60 min. RST comprised frontal and lateral sprint exercises using an expander system with increasing levels of resistance that was attached to a treadmill (h/p/cosmos). TPT included ballistic strength training at 40% of the one-repetition-maximum for the lower limbs (e.g., leg press, knee extensions). Before and after training, sprint (20-m sprint), change-of-direction speed (T-agility test), jump (drop, countermovement jump), and balance performances (Y balance test) were assessed. ANCOVA statistics revealed large main effects of group for 20-m sprint velocity and ground contact time (0.81 ≤ d ≤ 1.00). Post-hoc tests showed higher sprint velocity following RST and TPT (0.69 ≤ d ≤ 0.82) when compared to the control group, but no difference between RST and TPT. Pre-to-post changes amounted to 4.5% for RST [90%CI: (−1.1%;10.1%), d = 1.23] and 2.6% for TPT [90%CI: (0.4%;4.8%), d = 1.59]. Additionally, ground contact times during sprinting were shorter following RST and TPT (0.68 ≤ d ≤ 1.09) compared to the control group, but no difference between RST and TPT. Pre-to-post changes amounted to −6.3% for RST [90%CI: (−11.4%;−1.1%), d = 1.45) and −2.7% for TPT [90%CI: (−4.2%;−1.2%), d = 2.36]. Finally, effects for change-of-direction speed, jump, and balance performance varied from small-to-large. The present findings indicate that 6 weeks of RST and TPT produced similar effects on 20-m sprint performance compared with a passive control in healthy and physically active, young adults. However, no training-related effects were found for change-of-direction speed, jump and balance performance. We conclude that both training regimes can be applied for speed development.

The effects of training with loads that maximise power output and individualised repetitions vs. traditional power training.

BackgroundIt has been suggested that strength training effects (i.e. neural or structural) vary, depending on the total repetitions performed and velocity loss in each training set.PurposeThe aim of this study is to compare the effects of two training programmes (i.e. one with loads that maximise power output and individualised repetitions, and the other following traditional power training).MethodsTwenty-five males were divided into three groups (optimum power [OP = 10], traditional training [TT = 9] and control group [CG = 6]). The training load used for OP was individualised using loads that maximised power output (41.7% ± 5.8 of one repetition maximum [1RM]) and repetitions at maximum power (4 to 9 repetitions, or ‘reps’). Volume (sets x repetitions) was the same for both experimental groups, while intensity for TT was that needed to perform only 50% of the maximum number of possible repetitions (i.e. 61.1%–66.6% of 1RM). The training programme ran over 11 weeks (2 sessions per week; 4–5 sets per session; 3-minute rests between sets), with pre-, intermediate and post-tests which included: anthropometry, 1RM, peak power output (PPO) with 30%, 40% and 50% of 1RM in the bench press throw, and salivary testosterone (ST) and cortisol (SC) concentrations. Rate of perceived exertion (RPE) and power output were recorded in all sessions.ResultsFollowing the intermediate test, PPO was increased in the OP group for each load (10.9%–13.2%). Following the post-test, both experimental groups had increased 1RM (11.8%–13.8%) and PPO for each load (14.1%–19.6%). Significant decreases in PPO were found for the TT group during all sets (4.9%–15.4%), along with significantly higher RPE (37%).ConclusionOP appears to be a more efficient method of training, with less neuromuscular fatigue and lower RPE.

Yaw moment Lyapunov based control for In-Wheel-Motor-Drive Electric Vehicle

The new generation of electric vehicles, also called in-wheel-motor-drive electric vehicles (IWM-EVs), will replace the traditional power-train by on-hub motors. Consequently, it will offer new options and flexibilities in motion control due to its structural merits, i.e the longitudinal force of each wheel could be controlled independently. This paper proposes an advanced direct yaw moment control strategy to improve IWM-EV steerability and stability. The proposed integrated control involves two coordinated standalone Lyapunov model-based controllers. Coordination is ensured according to the vehicle dynamic states evolution in the phase plane defined by the body sideslip angle and its rate. The control objective in the linear driving zone is to enhance the vehicle steering response by tracking a certain reference yaw rate. However, when the vehicle reaches the handling limits, the primary objective becomes to stabilize the vehicle while reducing a vehicle stability index. The yaw moment generated to provide control goals is then converted into four torque inputs of the four in-wheel motors. An algorithm is proposed for an effective torques distribution to maintain vehicle longitudinal velocity. Simulation results carried out on a full nonlinear IWM-EV model confirm the ability of the developed control scheme to improve vehicle handling and directional stability.

Improvement of powertrain efficiency through energy breakdown analysis

A vehicular powertrain can be thought as an energy conversion chain, each component being characterized by its efficiency. Significant global efficiency improvements can be achieved once is identified the system energy breakdown, individuating the losses connected to each powertrain component; it is then possible to carry out the most appropriate interventions.This paper presents a simulation study of a diesel-fuelled commercial vehicle powertrain based on the above summarized point of view. The work aims at individuating the energy flows involved in the system during different missions, proposing an intelligent combination of technical solutions which minimize fuel consumption. Through a validated Matlab–Simulink model, able to indicate the powertrain energy breakdown, simulations are carried out to evaluate the fuel saving associated to a series of powertrain management logics which lead to the minimization of engine losses, the recovery of reverse power in deceleration and braking, the elimination of useless engine cycles.Tests were performed for different real missions (urban, extra-urban and highway).The results obtained point out a –23% fuel consumption (average value for urban, extra-urban and highway missions) compared to the traditional powertrain. Clearly, such result affects positively the CO2 emission.

Recursive least squares with forgetting for online estimation of vehicle mass and road grade: theory and experiments

Good estimates of vehicle mass and road grade are important in automation of heavy duty vehicles, vehicle following manoeuvres or traditional powertrain control schemes. Recursive least square (RLS) with multiple forgetting factors accounts for different rates of change for different parameters and thus, enables simultaneous estimation of the time-varying grade and the piece-wise constant mass. An ad hoc modification of the update law for the gain in the RLS scheme is proposed and used in simulation and experiments. We demonstrate that the proposed scheme estimates mass within 5% of its actual value and tracks grade with good accuracy provided that inputs are persistently exciting. The experimental setups, signals, their source and their accuracy are discussed. Issues like lack of persistent excitations in certain parts of the run or difficulties of parameter tracking during gear shift are explained and suggestions to bypass these problems are made.