Two-Scale Command Shaping for Reducing Powertrain Vibration During Engine Restart

Author(s):  
J. Justin Wilbanks ◽  
Michael J. Leamy

This paper introduces a two-scale command shaping strategy for reducing vibrations in conventional and hybrid electric vehicle (HEV) powertrains during engine restart. The approach introduces no additional system components and thus few additional costs. The torque profile from an electric machine (EM) is tailored to start the internal combustion engine (ICE) while minimizing residual vibrations. It is shown that the tailored EM torque profile, composed of a linear combination of constant and time-varying components, results in significant mitigation of powertrain vibrations and smoother ICE startup. The time-varying EM torque component is calculated using an analytical ICE model and a perturbation technique for separating scales, which isolates the ICE nonlinear response. Command shaping is then applied to the linear problem at the remaining scale. Simulation results suggest a promising and straightforward technique for reducing vibrations and improving drivability during ICE restart. Furthermore, two-scale command shaping may also be useful in mitigating other HEV-related drivability issues associated with powertrain mode changes (e.g., blending of hybrid power sources, engaging and disengaging of clutches, etc.).

Author(s):  
J. Justin Wilbanks ◽  
Michael J. Leamy

This paper analyzes the robustness of a two-scale command shaping strategy for reducing vibrations in hybrid electric vehicle (HEV) powertrains during engine restart. Propagation of HEVs through the automobile market depends on their perceived quality and performance. In this work, a two-scale command shaping strategy addresses the drivability of the vehicle by focusing on the reduction of noise, vibration, and harshness (NVH) issues associated with restarting the internal combustion engine (ICE) during a mode transition. The strategy tailors the electric machine (EM) torque profile, which consists of a linear and time-varying component, to significantly mitigate the powertrain and chassis vibrations for a smoother ICE startup. The time-varying EM torque component is calculated by applying a perturbation technique for separating the scales of an analytical ICE model, which isolates the ICE nonlinear response. Command shaping is then applied to the linear problem governed by the remaining scale. Simulations confirm that the two-scale command shaping strategy is a straightforward technique for reducing powertrain and chassis vibrations during ICE restart. In real-time implementation, inaccuracies or variations in system parameters and initial conditions arising from the operating condition or from general wear during a vehicle’s life cycle will occur. Therefore, successful implementation of the two-scale command shaping strategy relies upon the robustness of the perturbation technique and command shaping to these variations. This paper validates the perturbation technique’s robustness to variations in the ICE parameters and initial conditions. Robust command shaping methods are also explored to decrease the impact of system parameter variations on the efficacy of command shaping. Improving the overall robustness of the two-scale command shaping strategy will increase the applicability to consumer HEVs by ensuring its performance under variations in system parameters.


In recent days, the demand for petroleum and emission of pollutant gases continuously increase. This necessitates the electrification power train which replaces Internal Combustion Engine (ICE). Despite pure electric vehicles or Battery Electric Vehicle (EV) reduce the greenhouse gas emissions, there are some major hurdles for EVs to overcome before they totally relieve ICE vehicles form transport sector such as range anxiety, battery storage, economic fall down due to automobile industries, etc. This necessitates Hybrid Electric vehicle (HEV) which combines two different power sources to propel the vehicle. One of the challenges in HEV is how to control the power coming from the two different sources such as battery and ICE. The prime goal of an Energy Management Strategy (EMS) is to manage energy flow such that fuel consumption and emissions are minimized without affecting the vehicle’s performance. In this paper, the different structures of power train and energy management strategies are analysed.


Author(s):  
J. Justin Wilbanks ◽  
Michael J. Leamy

This paper develops recursive least-squares (RLS) and extended Kalman filtering (EKF) approaches for estimating uncertain engine friction (and other) parameters necessary for successful implementation of a two-scale command shaping (TSCS) engine restart strategy. The TSCS strategy has been developed for mitigating vibrations in conventional and hybrid electric vehicle (HEV) powertrains during internal combustion engine (ICE) restart. Implementing the TSCS strategy increases the drivability of a HEV by reducing noise, vibration, and harshness (NVH) issues associated with ICE restart during a powertrain mode transition. This is accomplished primarily, by modifying the electric machine (EM) torque profile with linear and time-varying components over multiple time scales. For full implementation, the TSCS strategy requires input parameters characterizing the ICE which may be a) difficult to quantify, and/or b) uncertain due to their dependence on engine operating temperature and other environmental considerations. RLS and EKF algorithms tailored to TSCS are presented herein for estimating these parameters. It is shown that both the RLS and EKF algorithms can be used to estimate the necessary ICE parameters and increase effectiveness of the TSCS strategy. The EKF algorithm, in particular, estimates uncertain ICE parameters with minimal measurement requirements, giving it an advantage over the presented RLS algorithm.


Author(s):  
Charbel R Ghanem ◽  
Elio N Gereige ◽  
Wissam S Bou Nader ◽  
Charbel J Mansour

There have been many studies conducted to replace the conventional internal combustion engine (ICE) with a more efficient engine, due to increasing regulations over vehicles’ emissions. Throughout the years, several external combustion engines were considered as alternatives to these traditional ICEs for their intrinsic benefits, among which are Stirling machines. These were formerly utilized in conventional powertrains; however, they were not implemented in hybrid vehicles. The purpose of this study is to investigate the possibility of implementing a Stirling engine in a series hybrid electric vehicle (SHEV) to substitute the ICE. Exergy analysis was conducted on a mathematical model, which was developed based on a real simple Stirling, to pinpoint the room for improvements. Then, based on this analysis, other configurations were retrieved to reduce exergy losses. Consequently, a Stirling-SHEV was modeled, to be integrated as auxiliary power unit (APU). Hereafter, through an exergo-technological detailed selection, the best configuration was found to be the Regenerative Reheat two stages serial Stirling (RRe-n2-S), offering the best efficiency and power combination. Then, this configuration was compared with the Regenerative Stirling (R-S) and the ICE in terms of fuel consumption, in the developed SHEV on the WLTC. This was performed using an Energy Management Strategy (EMS) consisting of a bi-level optimization technique, combining the Non-dominated Sorting Genetic Algorithm (NSGA) with the Dynamic Programming (DP). This arrangement is used to diminish the fuel consumption, while considering the reduction of the APU’s ON/OFF switching times, avoiding technical issues. Results prioritized the RRe-n2-S presenting 12.1% fuel savings compared to the ICE and 14.1% savings compared to the R-S.


2013 ◽  
Vol 288 ◽  
pp. 142-147 ◽  
Author(s):  
Shang An Gao ◽  
Xi Ming Wang ◽  
Hong Wen He ◽  
Hong Qiang Guo ◽  
Heng Lu Tang

Fuel cell hybrid electric vehicle (FCHEV) is one of the most efficient technologies to solve the problems of the energy shortage and the air pollution caused by the internal-combustion engine vehicles, and its performance strongly depends on the powertrains’ matching and its energy control strategy. The theoretic matching method only based on the theoretical equation of kinetic equilibrium, which is a traditional method, could not take fully use of the advantages of FCHEV under a certain driving cycle because it doesn’t consider the target driving cycle. In order to match the powertrain that operates more efficiently under the target driving cycle, the matching method based on driving cycle is studied. The powertrain of a fuel cell hybrid electric bus (FCHEB) is matched, modeled and simulated on the AVL CRUISE. The simulation results show that the FCHEB has remarkable power performance and fuel economy.


2016 ◽  
Vol 78 (6) ◽  
Author(s):  
Mohd Sabirin Rahmat ◽  
Fauzi Ahmad ◽  
Ahmad Kamal Mat Yamin ◽  
Noreffendy Tamaldin ◽  
Vimal Rau Aparow ◽  
...  

This paper provided a validated modeling and a simulation of a 6 degree freedom vehicle longitudinal model and drive-train component in a series hybrid electric vehicle. The 6-DOF vehicle dynamics model consisted of tire subsystems, permanent magnet synchronous motor which acted as the prime mover coupled with an automatic transmission, hydraulic brake subsystem, battery subsystem, alternator subsystem and internal combustion engine to supply the rotational input to the alternator. A speed and torque tracking control systems of the electric power train were developed to make sure that the power train was able to produce the desired throttle torque in accelerating the vehicle. A human-in-the-loop-simulation was utilized as a mechanism to evaluate the effectiveness of the proposed hybrid electric vehicle. The proposed simulation was used as the preliminary result in identifying the capability of the vehicle in terms of the maximum speed produced by the vehicle and the capability of the alternator to recharge the battery. Several tests had been done during the simulation, namely sudden acceleration, acceleration and braking test and unbounded motion. The results of the simulation showed that the proposed hybrid electric vehicle can produce a speed of up to 70 km/h with a reasonable charging rate to the battery. The findings from this study can be considered in terms of design, optimization and implementation in a real vehicle.


2020 ◽  
Vol 10 (16) ◽  
pp. 5467
Author(s):  
Po-Tuan Chen ◽  
Cheng-Jung Yang ◽  
Kuohsiu David Huang

To avoid unnecessary power loss during switching between the various power sources of a composite electric vehicle while achieving smooth operation, this study focuses on the development and dynamic simulation analysis of a control system for the power of a parallel composite vehicle. This system includes a power integration and distribution mechanism, which enables the two power sources of the internal combustion engine and electric motor to operate independently or in coordination to meet the different power-output requirements. The integration of the electric motor and battery-charging engine reduces the system complexity. To verify the working efficiency of the energy control strategy for the power system, the NEDC2000 cycle is used for the vehicle driving test, a fuzzy logic controller is established using Matlab/Simulink, and the speed and torque analysis of the components related to power system performance are conducted. Through a dynamic simulation, it is revealed that this fuzzy logic controller can adjust the two power sources (the motor and internal combustion engine) appropriately. The internal combustion engine can be maintained in the optimal operating region with low, medium, and high driving speeds.


Author(s):  
F. Zhang ◽  
B. J. Gilmore ◽  
A. Sinha

Abstract Tolerance allocation standards do not exist for mechanical systems whose response are time varying and are subjected to discontinuous forcing functions. Previous approaches based on optimization and numerical integration of the dynamic equations of motion encounter difficulty with determining sensitivities around the force discontinuity. The Alternating Frequency/Time approach is applied here to capture the effect of the discontinuity. The effective link length model is used to model the system and to account for the uncertainties in the link length, radial clearance and pin location. Since the effective link length model is applied, the equations of motion for the nominal system can be applied for the entire analysis. Optimization procedure is applied to the problem where the objective is to minimize the manufacturing costs and satisfy the constraints imposed on mechanical errors and design variables. Examples of tolerance allocation are presented for a single cylinder internal combustion engine.


The hybrid power train is a complex system. It consists of mechanical and electrical components, and each of them is important. The evolution of the Hybrid Electric Vehicle (HEV) power trains is presented from the historical point of view. This chapter discusses the selected review of the hybrid power train’s architectural engineering. It includes the development of the hybrid vehicle power train’s construction from the simple series and parallel drives to the planetary gear hybrid power trains. The fuel consumption difference between the pure Internal Combustion Engine (ICE) drive and the hybrid drive is especially emphasized. Generally, there are two main hybrid drive types that are possible to define. Both these hybrid drive types are not mainly differentiated by their power train architecture. The first is the “full hybrid” drive, which is a power train equipped with a relatively low capacity battery that is not rechargeable from an external current source, and whose battery energy balance—its State-Of-Charge (SOC)—has to be obtained. The second one is the “plug in hybrid,” which means the necessity of recharging the battery by plugging into the grid when the final State-Of-Charge (SOC) of the battery is not acceptable. Additionally, the chapter focuses on the fuel cell series hybrid power train, which is only shown because its operation and design are beyond the scope of this book.


Electronics ◽  
2018 ◽  
Vol 7 (11) ◽  
pp. 287 ◽  
Author(s):  
Seok-Min Kim ◽  
Ho-Sung Kang ◽  
Kyo-Beum Lee

This paper presents the design and control methods of a single-phase bidirectional on-board charger (OBC) using a hybrid starter generator (HSG) and an inverter in a hybrid electric vehicle (HEV). In an HEV, there are a number of components, including the combustion engine, transmission, traction motor, motor controller, OBC, and HSG system. The proposed design reconfigures the HSG system to provide battery-charging capability instead of a conventional OBC based on the use of additional power relays. As a result, the number of power converters is effectively reduced through the replacement of the conventional OBC, and, thus, the power density is increased. This paper also proposes a control method for enabling not only battery charging but also a reactive power support depending on the grid command. Compared with a conventional reactive power compensation method, the proposed method has an advantage because it is located near the principal reactive power source. The simulation and experimental results verify the validity and feasibility of the proposed bidirectional OBC design and its control methods.


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