Hierarchical control of the Zero Inertia powertrain

Abstract:What is the best number of gear steps for parallel type hybrid electric vehicles (HEVs) and what are the pros and cons of the power split type HEV compared to the parallel type have been interesting issues in the development of HEVs. In this study, a comparative analysis was performed to evaluate the fuel economy potential of a parallel HEV and a power split type HEV. First, the fuel economy potential of the parallel HEV was investigated for the number of gear steps. Four-speed, six-speed, and eight-speed automatic transmissions (ATs) and a continuously variable transmission (CVT) were selected, and their drivetrain losses were considered in the dynamic programming (DP). It was found from DP results that the power electronics system (PE) loss decreased because the magnitude of the motor load leveling power decreased as the number of gear steps increased. On the other hand, the drivetrain losses including the electric oil pump (EOP) loss increased with increasing gear step. The improvement rate from the 4-speed to the 6-speed was the greatest, while it decreased for the higher gear step. The fuel economy of the CVT HEV was rather low due to the large EOP loss in spite of the reduced PE loss. In addition, the powertrain characteristics of the parallel HEV were compared with the power split type HEV. In the power split type HEV, the PE loss was almost double compared to that of the parallel HEV because two large capacity motor-generators were used. However, the drivetrain loss and EOP loss of the power split type HEV were found to be much smaller due to its relatively simple architecture. It is expected that the power characteristics of the parallel and power split type HEVs obtained from the DP results can be used in the development of HEV systems.

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“…ω is the rotational speed. [18]. Figure 3b shows the CVT mechanical efficiency map from the literature [18].…”

Section: Transmissionmentioning

confidence: 99%

“…[18]. Figure 3b shows the CVT mechanical efficiency map from the literature [18]. The CVT efficiency is determined by the CVT ratio, input speed, and torque.…”

Section: Motor-generatormentioning

confidence: 99%

A Study on the Fuel Economy Potential of Parallel and Power Split Type Hybrid Electric Vehicles

Kim

Yoo

et al. 2018

Energies

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“…This results in that the engine often delivers less power than its maximum. A torque assisting system [7][8][9][10][11][12][13], which provides an additional power, not only reduces the engine size significantly but also enables intermittent engine operation [14] (or Start-Stop operation [13]). On the basis of this point, the hybrid electric/mechanical powertrain (HEV) has attracted serious attention as it is expected to save over 10% of fuel consumption [15].…”

Section: %mentioning

confidence: 99%

“…The current paper contributes to the fuel economy research by proposing a concept for an IdleStop and Go (SG) system utilizing a zero inertia (ZI) powertrain [11][12][13][24][25][26]. The proposed system switches the engine off when the vehicle comes to a standstill.…”

Section: %mentioning

confidence: 99%

“…The powertrain comprises an internal combustion engine driven by wire, a torque converter including a lockup clutch C l , a Van Doorne type metal push-belt CVT, having a DNR (drive-neutral-reverse) set with a drive clutch C d and a reverse clutch C r , a final reduction gear set and a differential. Besides, in parallel to the CVT, a steel flywheel of the ZI powertrain is connected through an additional planetary gear set [13,24,26]. The planetary gear set operates as a power-split device, dividing the power to and from the flywheel via the primary and secondary pulleys whenever the ratio of the CVT is changed.…”

Section: Modelling and Analysismentioning

confidence: 99%

See 1 more Smart Citation

IdleStop and Go: a way to improve fuel economy

Shen

Vroemen

Veldpaus

2006

Vehicle System Dynamics

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This paper proposes a mechanical solution to save fuel by shutting down an internal combustion engine whenever it is unnecessary for propulsion, e.g., when a vehicle is waiting for traffic lights. The engine and vehicle are restarted using the energy that is stored in a flywheel. Two additional clutches are needed to enable appropriate power flow from the flywheel to the engine and vehicle. This complicates the powertrain dynamics in that the number of degrees of freedom changes due to clutch operations. Therefore, a hybrid control strategy, which is treated as a top-level controller, is introduced to deal with this finite-state mechanical system. At the lower level, the engine and clutches are controlled in a coordinated manner such that the vehicle is launched according to the driver's demands. Using a comprehensive powertrain simulation package, the proposed controller is evaluated numerically.

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Optimal engine operation by shift speed control of a CVT

Lee

Kim

2002

KSME International Journal

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Hierarchical control of the Zero Inertia powertrain

Cited by 32 publications

References 0 publications

A Study on the Fuel Economy Potential of Parallel and Power Split Type Hybrid Electric Vehicles

A Study on the Fuel Economy Potential of Parallel and Power Split Type Hybrid Electric Vehicles

IdleStop and Go: a way to improve fuel economy

Optimal engine operation by shift speed control of a CVT

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