• 한국자동차공학회논문집
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• 제19권6호
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• pp.97-106
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• 2011

Both an optimal design of the engine operating strategy and fuel economy prediction technique for a HEV under the vehicle driving condition are very crucial for the development of vehicle fuel economy performance. Thus, in this study, engine operating characteristics of PRIUS III were analyzed with vehicle running conditions and the correlations between vehicle tractive power and fuel consumption were introduced. As a result, fuel economy performance of PRIUS III with various test modes were predicted and verified. Errors of predicted fuel economy were between -5% and -1%.

• 한국기계가공학회지
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• 제18권7호
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• pp.29-35
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• 2019

In this paper, the component loss models of the electric vehicle(EV) and the internal combustion engine vehicle(ICEV) are developed to analyze the losses and efficiencies of these two types of vehicles. The EV powertrain efficiency decreases as the vehicle velocity increases over most of the vehicle velocity range because the battery efficiency decreases. Especially, the EV powertrain efficiency decreases significantly when the battery SOC is low. But the ICEV powertrain efficiency increases as the vehicle velocity increases. This is because the efficiencies of both the transmission and engine increases.

• 한국자동차공학회논문집
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• 제23권5호
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• pp.508-514
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• 2015

In this paper, the powertrain efficiency is analyzed for the input split type hybrid electric vehicle. For considering the powertrain loss, the power loss models of planetary gear and motor are applied. And, the mathematic equations of powertrain speed and torque are found by using the lever analogy. With the above models and equations, the powertrain efficiency is analyzed for the 0 to 180 km/h vehicle velocity range. From the analysis results, it is found that the transmission efficiency with the power loss of planetary gear is smaller maximum 2.1% than the transmission efficiency without the power loss of planetary gear.

• 한국기계가공학회지
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• 제19권5호
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• pp.8-13
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• 2020

In this paper, the electric vehicle (EV) and internal combustion engine vehicle (ICEV) are compared for different driving cases. The EV exhibits a lower powertrain efficiency when driven on the aggressive driving cycle than when driven on the moderate cycle. In particular, EV powertrain efficiency is low when the battery state of charge (SOC) is low, but ICEV efficiency increases when the driving cycle changes from the moderate cycle to the aggressive cycle. Based on these results, attempts can be made to increase EV powertrain efficiency. EV charging before the battery power drops to a low charging state can reduce energy consumption by 2.7% for an urban area. Furthermore, ECO driving has a more significant effect on EVs than on ICEVs.

• 한국자동차공학회논문집
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• 제9권2호
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• pp.185-191
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• 2001

In many papers, the powertrain system generally has been madeled as one-dimensional torque model. One-dimensional powertrain model may calculate the torque correctly but it does not consider the non-rotational degrees-of-freedom of the powertrain components and the interaction of these degrees-of-freedom with the vehicle body frame and suspension. To consider the non-rotational degrees of freedom, the differential is modeled as a three-dimensional rigid body in this paper. A constant velocity joint is newly formulated and a relative constraint is also formulated to model the motion transfer due to gear ratio of the differential. Implementing the proposed powertrain system in the multibody model, more detail dynamic responses can be obtained. Obtained outputs such as reaction torques on the constant velocity joint and reaction forces on the rack can be useful data in the design of a powertrain.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.684-689
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• 2000

In this paper, the equations of motion about vehicle, powertrain and brake system were derived. The vehicle has eight degrees of freedom with nonlinear tire model and the powertrain has two degrees of freedom containing engine, torque converter and four speed automatic transmission. The brake system has two states about front and rear brake line pressures. The transient tire model with first order time lag is also subjoined for low speed or stop-and-go simulation. The modeling was derived considering two points - the fidelity and the simplicity. The simulation using this model is similar with real vehicle dynamic behavior and the model is made as simple as possible far fast simulation. It is validated that the derived vehicle model can be applicable to the real time simulation.

• 한국자동차공학회논문집
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• 제23권6호
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• pp.591-600
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• 2015

The efficiency of a powertrain system of hybrid vehicle is highly dependent on the design and control of the hybrid powertrain system. In other words, the optimal design of the powertrain systems is coupled with optimal control of the powertrain system. Therefore, the solution of an optimal design problem for hybrid vehicles is computationally and timely very expensive. For example, dynamic programming, which is a recursive optimization method, is usually used to evaluate the best fuel economy of certain hybrid vehicle design, and, thus, the evaluation takes tens of minutes to several hours. This research aims to accelerate the speed of efficiency evaluation of hybrid vehicles. We suggest a mathematical treat and a methodological treat to reduce the computational load. The mathematical treat is that the dynamics of system is discretized with sparse sampling time without loss of energy balance. The methodological treat is that the efficiency of the hybrid vehicle is inferred by characteristic loss evaluation that is computationally inexpensive. With the suggested methodology, evaluating a design candidate of hybrid powertrain system is taken few minutes, which was taken several hours when dynamic programming is used.

• 전자공학회논문지SC
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• 제48권6호
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• pp.71-81
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• 2011

일반적인 내연기관 자동차와는 달리, 전기자동차는 파워트레인을 구성하는 배터리, 인버터, 모터 등의 전기 동력 시스템들이 차량의 주행성능과 동역학 특성에 직접적인 영향을 준다. 따라서 전기 차량의 최종 운동 및 동특성을 예측하기 위해서, 기계 및 전기전자 복합 시스템을 세부적으로 모델링하고 이를 통한 전체 파워트레인의 해석이 필요하다. 본 논문에서는 전기자동차의 최종 출력 성능을 예측하고 분석하기 위한 전기자동차의 파워트레인 시스템의 동적 모델을 유도하였다. 전기적인 신호로부터 최종 기계 동력 시스템으로 전달되는 입출력 변수의 상관관계를 수학적으로 모델링하여 개발하였다. 또한, 전기자동차의 동특성을 시뮬레이션 할 수 있는 기준모델을 Matlab/Simulink 플랫폼 기반으로 개발하였으며, 이를 이용하여 유도된 수학적 분석 모델을 검증하였다. 이를 통하여 속도, 가속도, 추진력 등의 주요 차량 주행성능을 비교 분석하였다.

• International Journal of Automotive Technology
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• 제7권4호
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• pp.459-468
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• 2006

The objective of this paper is the development of the forward-looking dynamic simulation model of a hybrid electric vehicle(HEV) for a fuel economy study. The specification of the vehicle is determined based on two factors, engine peak power to curb weight ratio and specific engine power. The steady state efficiency models of the powertrain components are explained in detail. These include a spark ignition direct injection(SIDI) engine, an integrated starter alternator(ISA), and an infinitely variable transmission(IVT). The paper describes the integration of these models into a forward facing dynamic simulation diagram using the AMESim environment. Appropriate vehicle and driver models have been added and described. The controller was designed in Simulink and was combined with the physical powertrain model by the co-simulation interface. Finally, the simulation results of the HEV are compared with those of a baseline vehicle in order to demonstrate the fuel economy potential. Results for the vehicle speed error and the fuel economy over standard driving cycles are illustrated.

• 동력기계공학회지
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• 제14권3호
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• pp.33-38
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• 2010

Technology of vehicle industry has been developing and it is required a better vehicle performance than before. Therefore, the consumers are asking not only an economic efficiency, functionality, polished design, ride comfort and silence but also a driving stability. The ride comfort, silence and driving stability are influenced by the size of vehicle and various facilities. But the principal factor is a room noise and vibration sensed by a driver and passenger. Thus, the NVH of vehicle has been raised and used as a principal factor for evaluation of vehicle performance. The primary objective of this study is an optimized design of powertrain mounting system. To optimized design was applied MSC.Nastran optimization modules. Results of dynamic analysis for powertrain mounting system was investigated. By theses results, design variables was applied 12 dynamic spring constant. And the weighting factor according to translational displacement and rotational displacement applied 3 cases. The objective function was applied to minimize displacement of powertrain. And the design variable constraint was imposed dynamic spring constant ratio. The constraint of design variable for objective function was imposed bounce displacement for powertrain.