排序方式: 共有72条查询结果,搜索用时 296 毫秒
31.
Myeong Jae Han Chul Hyung Lee Tae Won Park Jung Min Park Sung Min Son 《International Journal of Automotive Technology》2017,18(6):1027-1035
In vehicle braking systems, the non-uniform contact pressure distribution on the brake pad is a major cause of uneven wear. The experimental approach of the wear phenomenon is the time consuming and costly. For this reason, a threedimensional finite element (FE) model of a brake system is presented for numerical simulation in this paper. A coupled thermo-mechanical analysis is carried out to confirm the non-uniform contact pressure distribution. A correlation between the non-uniform contact pressure and uneven wear is confirmed by measuring the amount of wear in the brake pad. The shape optimization of the brake pad is performed to reduce the uneven wear. In addition, the simulation results, such as natural frequency and temperature, are compared to experimental results. 相似文献
32.
B. J. Moon H. G. Jung S. G. Lee D. H. Kim 《International Journal of Automotive Technology》2014,15(3):483-494
This paper describes a parallel model-based fault detection algorithm for an electronic parking brake (EPB) system, which consists of an electronic control unit with built-in current sensor and braking force sensor. For the EPB system to supply sufficient parking force to a vehicle, the parking force sensor is of utmost importance. If a fault occurs in this sensor, sufficient parking force may not be supplied, thereby seriously threatening the safety of the vehicle. Thus, a fault detection method is required for the parking force sensor of the EPB system to improve the safety of vehicles. For this purpose, a highly reliable fault detection method is needed to detect abnormal fault signals, which cannot be detected by the existing on-line sensor monitoring fault detection methods. This paper proposes a novel parallel model-based fault detection algorithm for the EPB system, which compares the physical sensor data with the mathematical model, the fuzzy model, and the neural network model at the same time. In order to reduce false alarms, the magnitude of thresholds and the operation counts are changed adaptively. When the proposed parallel model-based fault detection algorithm detects severe failures of the force sensor, it warns the driver in advance to prevent accidents due to the failures. The proposed algorithm is verified by hardware-in-theloop simulations in various situations. 相似文献
33.
W. M. Choi J. S. Kim H. S. Jung T. S. Kwon 《International Journal of Automotive Technology》2011,12(3):383-389
As a crash energy absorber, a tube-type crash element (expansion tube) dissipates kinetic energy through the internal deformation
energy of the tube and through frictional energy. In this paper, the effects of the variation of punch angles on the energy-absorbing
characteristics of expansion tubes were studied by quasi-static tests using three punch angles (15°, 30°, and 45°). A finite
element analysis of the tube expanding process (m = τ
max
/K) was performed using a shear friction model to confirm the variation of the shear friction factor with respect to punch angles
using the inverse method. Additional analyses were performed using angles of 20°, 25°, 35°, and 40° to study the effect of
the punch angles on the internal deformation energy, frictional energy, and expansion ratio of the tubes. The results of the
experiment and finite element analysis showed that the shear friction factor was inversely proportional to the punch angles,
and a specific punch angle existed at which the absorbed energy and expansion ratio remained constant. 相似文献
34.
J. -K. Kim E. S. Yim C. H. Jeon C. -S. Jung B. H. Han 《International Journal of Automotive Technology》2012,13(2):293-300
This study examines the cold performance of biodiesel blends in a passenger car and a light duty truck at −16 °C and −20 °C.
Six different types of biodiesels derived from soybean oil, waste cooking oil, rapeseed oil, cottonseed oil, palm oil and
jatropha oil were blended with different volume ratios (B5 (5 vol. % biodiesel — 95 vol. % diesel), B10 and B20). The cold
filter plugging point (CFPP) and the cloud point had an effect on the startability and driveability of both the passenger
car and the light duty truck. The startability and driveability of the passenger car with all biodiesel blends (B5) were generally
good at −20 °C. In the light duty truck, biodiesel blends (B10 and B20) of soybean, waste cooking, rapeseed and jatropha tended
to be good at −20 °C in the startability and driveability tests than the biodiesel blends (B10 and B20) of cottonseed and
palm. In particular, the palm biodiesel blend (B10) failed at −20 °C, and the palm biodiesel blend (B20) also failed at −16
°C in the startability test. The cold flow properties of biodiesel dictate that the length of the hydrocarbon chains and the
presence of unsaturated structures significantly affect the low temperature properties of biodiesel. 相似文献
35.
As driver assistant systems (DAS) and active safety vehicles (ASV) with various functions become popular, it is not uncommon
for multiple systems to be installed on a vehicle. If each function uses its own sensors and processing unit, it will make
installation difficult and raise the cost of the vehicle. As a countermeasure, research integrating multiple functions into
a single system has been pursued and is expected to make installation easier, decrease power consumption, and reduce vehicle
pricing. This paper proposes a novel side/rear safety system using only one scanning laser radar, which is installed in the
rear corner of the driver’s side. Our proposed system, ISRSS (integrated side/rear safety system), integrates and implements
four system functions: BSD (blind spot detection), RCWS (rear collision warning system), semi-automatic perpendicular parking,
and semi-automatic parallel parking. BSD and RCWS, which operate while the vehicle is running, share a common signal processing
result. The target position designation for perpendicular parking and parallel parking situations is based on the same signal
processing. Furthermore, as system functions during running and those during automatic parking operate in exclusive situations,
they can share common sensors and processing units efficiently. BSD and RCWS system functions were proved with 13025 and 2319
frames, respectively. The target position designation for perpendicular and parallel parking situations was evaluated with
112 and 52 situations and shows a success rate of 98.2% and 92.3%, respectively. 相似文献
36.
In this paper, a numerical procedure to estimate the performance of the high power pretensioner used in the seatbelt of a
passenger vehicle is presented. The data on the gas explosion pressure in a 10-cc volume and the data on the displacement
of the rack according to time were applied to the numerical procedure. The procedure was implemented using MATLAB. The testing
device, which met the automobile industry standards, was created. Experiments were carried out seven times under the same
conditions, and the mean values of the web retraction and belt load were used as the representative data. By comparing the
simulation results to the test results, the numerical procedure presented in this paper was verified. 相似文献
37.
S. P. Jung K. J. Jun T. W. Park J. H. Yoon 《International Journal of Automotive Technology》2008,9(1):45-51
It is quite challenging to estimate the braking performance of a vehicle because the brake system is comprised of many parts,
including a booster, master cylinder, and caliper. Calculation of characteristics such as braking force through vehicle tests
requires much time and money. Therefore, the development of a method to estimate the braking performance of a vehicle using
qualitative methods is beneficial. In this study, a program that can analyze the braking capabilities of a vehicle such as
pressure, efficiency, and pedal travel is presented. The increase in disc temperature during braking as well as the properties
of various boosters can be calculated using the proposed program. Dynamic characteristics of a vehicle equipped with a Load
Sensing Proportional Valve (LSPV) were computed more precisely by obtaining the change in valve pressure according to the
displacement of a suspension system. Since all input and output files are composed in the Microsoft Excel format, both design
data management and database construction can easily completed. 相似文献
38.
D. Jung W. L. Wang A. Knafl T. J. Jacobs S. J. Hu D. N. Assanis 《International Journal of Automotive Technology》2008,9(1):9-15
The effects of the Abrasive Flow Machining (AFM) process on a direct injection (DI) Diesel engine fuel injector nozzle are
studied. Geometry characterization techniques were developed to measure the microscopic variations inside the nozzle before
and after the process. This paper also provides empirically-based correlations of the nozzle geometry changes due to the AFM
process. The resulting impact of the process on the engine performance and emissions are also assessed with a DI Diesel engine
test setup. This study shows that properly AFM-processed injectors can enhance engine performance and improve emissions due
to the improved quality of the nozzle characteristics. However, an extended process can also cause enlargement of the nozzle
hole as a side effect, which can adversely affect emissions. Emission measurements show the trade-off for the minimum levels
as the process proceeds. Since the enlargement of the hole during the AFM process is not avoidable and must be minimized,
strict control over the process is required. This control can be enforced by either limiting the AFM processing period, or
by properly preparing the initial hole diameter so as to accommodate the inevitable changes in the nozzle geometry. 相似文献
39.
J. W. Lee Y. I. Jeong M. W. Jung K. O. Cha S. I. Kwon J. C. Kim S. Park 《International Journal of Automotive Technology》2008,9(4):397-403
In recent years, particle number emissions rather than particulate mass emissions in automotive engines have become the subject
with controversial discussions. Recent results from studies of health effects imply that it is possible that particulate mass
does not properly correlate with the variety of health effects attributed to engine exhaust. The concern is now focusing on
nano-sized particles emitted from I. C. engines. In this study, particulate mass and particle number concentration emitted
from light-duty vehicles were investigated for a better understanding of the characteristics of the engine PM from different
types of fuels, such as gasoline and diesel fuel. Engine nano-particle mass and size distributions of four test vehicles were
measured by a condensation particle counter system, which is recommended by the particle measurement program in Europe (PMP),
at the end of a dilution tunnel along a NEDC test mode on a chassis dynamometer. We found that particle number concentrations
of diesel passenger vehicles with DPF system are lower than gasoline passenger vehicles, but PM mass has some similar values.
However, in diesel vehicles with DPF system, PM mass and particle number concentrations were greatly influenced by PM regeneration.
Particle emissions in light-duty vehicles emitted about 90% at the ECE15 cycle in NEDC test mode, regardless of vehicle fuel
type. Particle emissions at the early cold condition of engine were highly emitted in the test mode. 相似文献
40.
Some gears in an automobile transmission have to be mounted by being press-fitted on a shaft instead of splines. The torque capacity of the press-fitted gear will be proportional to the radial interference. The excessive interference, however, will increase the gear radial deformation. In this paper, the press- and shrink-fit and the subsequent torque capacity test were investigated by finite element analysis, theoretically and experimentally. The static and dynamic coefficient of friction were determined. 相似文献