Optimum shape design of a BLDC motor for electric continuous variable valve timing system considering efficiency and torque characteristics

The development of a hydrogen-fueled engine using an external mixture (e.g., using port or manifold fuel injection) with high efficiency and high power is dependent on the control of backfire. This work has developed a method to control backfire by reducing the valve overlap period while maintaining or improving engine performance. For this goal, a single-cylinder hydrogen-fueled research engine with a mechanical continuous variable valve timing system was developed. This facility provides a wide range of valve overlap periods that can be continuously and independently varied during firing operation. By using this research engine, the behavior of backfire occurrence and engine performance are determined as functions of the valve overlap period for fuel-air equivalence ratios between 0.3 and 1.2. The results showed that the developed hydrogen-fueled research engine with the mechanical continuous variable valve timing system has similar performance to a conventional engine with fixed valve timings, and is especially effective in controlling the valve overlap period. Backfire occurrence is reduced with a decrease of the valve overlap period, and is also significantly decreased even under operating conditions with the same volumetric efficiency. These results demonstrate that decreasing the valve overlap period may be one of the methods for controlling backfire in a hydrogen-fueled engine while maintaining or improving performance.

Download Full-text

Controlling Backfire for a Hydrogen-Fueled Engine Using External Mixture Injection

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.2940353 ◽

2008 ◽

Vol 130 (6) ◽

Cited By ~ 13

Author(s):

T. C. Huynh ◽

J. K. Kang ◽

K. C. Noh ◽

Jong T. Lee ◽

J. A. Caton

Keyword(s):

High Efficiency ◽

Engine Performance ◽

Continuous Variable ◽

Operating Conditions ◽

Variable Valve Timing ◽

Valve Timing ◽

Wide Range ◽

Timing System ◽

Variable Valve ◽

Valve Overlap

The development of a hydrogen-fueled engine using external mixture injection (e.g., using port or manifold fuel injection) with high efficiency and high power is dependent on the control of backfire. This work has developed a method to control backfire by reducing the valve overlap period while maintaining or improving engine performance. For this goal, a single-cylinder hydrogen-fueled research engine with a mechanical continuous variable valve timing system was developed. This facility provides a wide range of valve overlap periods that can be continuously and independently varied during firing operation. By using this research engine, the behavior of backfire occurrence and engine performance are determined as functions of the valve overlap period for fuel-air equivalence ratios between 0.3 and 1.2. The results showed that the developed hydrogen-fueled research engine with the mechanical continuous variable valve timing system has similar performance to a conventional engine with fixed valve timings, and is especially effective in controlling the valve overlap period. Backfire occurrence is reduced with a decrease in the valve overlap period, and is also significantly decreased even under operating conditions with the same volumetric efficiency. These results demonstrate that decreasing the valve overlap period may be one of the methods for controlling backfire in a hydrogen-fueled engine while maintaining or improving performance.

Download Full-text

Optimum Design of a BLDC Motor for Electric Continuous Variable Valve Timing System

ASME 2017 Conference on Information Storage and Processing Systems ◽

10.1115/isps2017-5417 ◽

2017 ◽

Author(s):

Soo-Whang Baek

Keyword(s):

Optimum Design ◽

Design Process ◽

Internal Combustion Engines ◽

Continuous Variable ◽

Variable Valve Timing ◽

Bldc Motor ◽

Valve Timing ◽

Maximum Torque ◽

Cogging Torque ◽

Variable Valve

In order to save resources and prevent global warming, it has been urgently needed to reduce CO2 emissions and decrease automobile fuel consumption in recent years. The trend in automotive applications are being studied to improve fuel efficiency and to reduce volume and weight. For these reasons, the mechanical parts of the automobile are being replaced by electric components. This paper deals with the optimum design process for a small Brushless DC (BLDC) motor used in Electric-Continuous Variable Valve Timing (E-CVVT) system in automobiles with internal combustion engines. It is also proposed to improve the rated efficiency and the maximum torque and reduce the cogging torque to improve the characteristics of the BLDC motor. To maximize the maximum torque as well as to maintain the rated efficiency, the radial basis function based on latin hypercube sampling and genetic algorithm are utilized. The design variables, objective functions, and constraints are selected for the optimum design of the BLDC motor, which is divided into three steps. Step I and step II are calculated to improve the rated efficiency and the maximum torque respectively, while step III utilizes to reduce cogging torque. To verify the proposed optimum design process, the improvement of characteristic is suggested with FE-analysis.

Download Full-text