Engine Hood Research Articles

Development of Bicycle Throw Distance Estimation Model Based on Akaike Information Criterion Statistical Method

As the number of bicyclists is gradually increased, it is important to develop more accurate accident reconstruction model to response bicycle accidents with vehicles. There have been research works to reconstruct bicycle accident by using estimated vehicle impact speed and simulation methods. However, there are limitations that the models do not consider other significant factors that may affect bicycle throw distance including road friction, vehicle gross weight, engine hood types, and other factors. This study aims to develop the improved reconstruction model to estimate vehicle impact speed better. The results that utilize the statistical analysis and real accident data show that the road friction needs to be considered with vehicle impact speed to reconstruct the accident more accurately.

A Numerical Investigation of a Novel Hood Design for Pedestrian Protection

Currently the use of new materials is becoming even more prevalent in vehicle industry for the lightweight design purpose. The design of engine hood is very important for pedestrian’s safety during a vehicle-pedestrian accident. In order to improve the pedestrian protection performance of the new material engine hood, the radial stiffening rib structure and trapezium sandwich structure engine hoods were proposed in this paper. And an energy-absorbing structure has been designed on the strengthening hinge plate to reduce the pedestrian head injury further more. The simulation results indicate that with new structures, the new material engine hoods have more uniform rigidity and better energy absorbing ability, which would effectively reduce the engine hood intrusion and pedestrian head injuries.

Procedure for hydraulic oil heat exchanger performance improvement through integrated CFD analysis

Present and future constraints on the layout of hydraulic circuits onboard mobile machinery will require more and more compact components with improved efficiency. The need to use IC engines complying with new standards on emissions will introduce new components into the engine hood, like Exhaust Gas Recirculation (EGR), Selective Catalytic Reduction (SCR), Dust Particulate Filter (DPF) and more, reducing the space available for components where traditionally the ratio between dimension and performance was not considered a ‘hard boundary’ to the design space. One of the components of the hydraulic circuit affected by the general tendency to an increase of the operating temperatures due to the new-generation engines introduction is the heat exchanger. The need to design properly tailored, efficient and compact heat exchangers is therefore one of the first priority targets in machine design. Accurate and reliable estimate of the performance at the design stage is a priority as well.This paper shows how the ...

Research of Front-End Modeling Design for a SUV Based on Self-Piercing Riveting Anti-Fatigue Design

By analyzing the modeling characteristic of ground and front-end impact areas, the modeling control strategy is proposed with regard to ventilation cover plate, engine hood, engine hood leading edge, fender and radiator grille, front bumper. The Riveting point support area concept is presented accordingly. Furthermore, the optimal position relationship of bumper modeling support area is obtained using the ADMAD under a given stiffness of bumper components. The result indicates that the optimized modeling can control the manipulation easily and helps to improve performance of driver assistance.

G1810103 信号なし交差点における歩行者事故防止のためのドライバから歩行者への意思伝達支援の研究([G181-01]交通事故の予防)

Recently, the percentage of a number of pedestrian fatalities to that of road traffic fatalities is the most in Japan. It is pointed out that these accidents are deeply related to the mismatch of recognition on traffic situation between pedestrians and vehicle drivers. Although many on-board devices designed to prevent injury or accidents are developed, there are few devices providing mutual understanding between pedestrians and vehicle drivers. In this paper, we studied attentive actions of pedestrians to vehicle on intersection with no traffic lights in order to design the systems providing the information about the vehicle condition (e.g., running direction, speed) from vehicles to pedestrians. We measured a gaze point of pedestrians who intend to cross a road. The positions of the gaze point on the approaching vehicle were determined by the panels attached to several places on the vehicle (e.g., an engine hood, a windshield). On these panels a random combination of a number and an alphabet is written. In the experiment, participants were required to answer the panel that they looked at in the fixed time (1 [s]). From the measurements, we found that the panels attached to an emblem and an engine hood were looked at with high frequency regardless of individual difference. Furthermore, the position of gaze points moved from the inside to the outside of the front of the approaching vehicle.

2408 低コストポップアップエンジンフードシステムの開発(D&Sコンテスト2,DC0 D&Sコンテスト口頭発表)

2408 低コストポップアップエンジンフードシステムの開発(D&Sコンテスト2,DC0 D&Sコンテスト口頭発表)

Research on Lifting Technology of Engine Hood for Protecting the Head of Pedestrian

In the pedestrian and vehicle collision accident, head injury is the first factor of causing death, so studying the mechanism and protective measures are very important. In this paper, based on the theory of multi-rigid-body system dynamics, used ADAMS software for simulation tools, established human body model and car mode to follow the national standard. Finally put forward a new hood lift technology. The simulation results show that the technology can effectively reduce the collision impact on pedestrian head in the traffic accident.

Structure Analysis and Quality Prediction of DP Steel Engine Hood in the Process of Hot Stamping

Due to its good formability characteristics, such as high strength, high initial work hardening rate, as well as continuous yielding, thin-walled DP steel possesses great advantages of weight loss and security, and has been used to replace ordinary steel for automotive parts manufacturing by a lot of automotive industry. But along with the improvement of the performance of the strength, the high strength steels formability is worsened dramatically, and failure and fracture often occurs in its cold stamping process. So, hot stamping technology must be adopted to make the formability available. In the paper, it took the hot stamping process of DP steel engine hood for example and took DP800 as object of research. The forming limit, variation of major strain, minor strain and thickness, as well as the potential equality defects were analyzed by using eta/DYNAFORM software. The research results show that duplex steel plate can meet the performance requirements of car engine dumping plank forming, which offers theory basis for the production of similar parts.

Engine Hood Lightweight Optimization Design Based on Overall Satisfaction

CAE analysis on engine hood is conducted under five common working conditions in this paper. Considering lightweight material application status at present, three material substitution plans are determined. To make full use of material properties, draw up size optimization scheme based on volume target and displacement and frequency constraints. Determine the optimum thickness by conducting size optimization on engine hood with optimization tool-Optistruct, so as to realize lightweight design.Based on the introduction of a evaluation method for lightweight scheme selection based on overall satisfaction and taking the factors of weight, cost and performance into consideration, at last, determine the best lightweight scheme.

Research on Noise Control of Wheel Loader and Frequency Spectrum Analysis

The tested wheel loader machinery noise was 110dB and driver position was 108dB, more than Chinese earth-moving machinery standard. Engine noise is the main noise, so thirty-five test points were arranged around the cab and engine to analyze and find the main noise points. The frequency spectrogram show that the main frequency band for the engine and exterior cab are 120Hz and 216Hz, and the interior cab noise was caused by the vibration of the power train passed through the frame result in resonance. Analyzed and calculated the main frequency concludes that the main noise resources are engine exhaust noise and cooling fan noise. To decrease the noise, proper damping materials were affixed to the engine hood and interior cab, the metal pieces were tightened and the cooling fan and shock absorber were replaced with new ones that match the main noise frequency.

Far-field extrapolation of Maximum Noise Levels produced by individual vehicles

This paper describes a combination of analytical and experimental investigations for the identification of the drivers responsible for the generation of Maximum Noise Levels (MNL) and the prediction of the extrapolated levels to the far-field positions where the receiver is situated. An on-board acquisition system composed of two microphones situated inside the engine hood and close to the right back tyre respectively provides a measurement of rolling and power-train noise. This electro-acoustic system has been shown to be able to discriminate the noisiest vehicles in different environments and for different driving behaviours. Based on this estimation of the near-field levels, we have developed a complete procedure for extrapolating the noise up to the receiver positions with a combination of analytical predictions and experimental measurements. The corrections for the extrapolated levels are due to atmospheric factors, to the spherical wave divergence term and to the absorbing conditions of the propagating surface that have been determined experimentally. For the microphone situated close to the engine we also need to characterise the acoustic properties of the engine hood. Both noise levels are extrapolated independently to the far-field position, where a comparison between prediction and measurements is performed to confirm that the methodology is reliable to estimate the remote impact of traffic noise.

Analysis for the Impact of an Engine Hood to a Radiator Support Frame in a Car Body Structure

The dynamic behavior of a radiator support frame impacted by a free-falling engine hood was studied with the use of the 3-D finite element simulations. The engine room including an engine hood, a radiator support frame, and a hood ledge was modeled first. Taking computing efficiency and accuracy into account, approaches for selecting element size, cleaning up complicated features of CAD files were then studied. In order to make the simulations more efficient, the contact spot weld model was adopted. To further reduce the computing time, a theoretical model was also proposed in the present study to calculate the instantaneous angular velocity of the engine hood at the incipient impact to the radiator support frame. The engine hood free-falling tests were also conducted to validate the finite element simulations. The consistency between the experimental data and the simulation results confirms the validity of the finite element model constructed in the present study.

Modal Analysis of a Lightweight Engine Hood Design Considering Stamping Effects

Modal frequency distribution of automotive structures or sub-structures is an important factor affecting the NVH performance. During lightweight optimizations of a part, the modal characteristics of the new design is often kept the same as those of the reference design to ensure that the NVH performance is not degraded. However, the effects of the part manufacturing process on the modal parameters are usually ignored in the design stage. In this study, four alternative designs of replacing the original steel hood of a passenger car with lightweight aluminum material are proposed. The stamping process (drawing, trimming and springback) of the inner and outer panels of the hood with both steel and aluminum designs is simulated in DYNAFORM. Once the residual stress, residual strain and thickness change of the panels during the stamping process are identified, a modal analysis is conducted on the four alternative designs. The obtained natural frequency data are compared with the natural frequencies of the body-in-white as well as the common excitation frequencies of the engine. It is shown that, due to parameter changes in the stamping process, the modal frequencies of the final manufactured part drift away from the original design before stamping. It is thus critical to take stamping effects into account when determining the optimal lightweight design of the hood.

Design Research of Car Engine Hood of Robot Rimming Fixture

Connection of internal and external board of automobile body‘s door cover is usually stamped by traditional mold and pressing machine, Because outer edge outline should be changed according to the change of car body outline and edge angles along the outline are also different, it’s very difficult to edge the area with sharp edge transition and too big edge angle. Robot edge fixture, the new design technology of internal and external board connection, is composed of seven parts, including edge mold, platform, lifting mechanism, testing institution, clamping unit, logic gas and electric control system, which overcomes shortcomings of traditional stamping edge mold, such as covering much area, costing high and having poor flexibility, shortens development cycle and of automobile and enhances the competitiveness of products.

Key Technology Research on Rimming Fixture Design

The role the rimming fixture is to ensure the models and the front cover having no relative motion in rolling process, and quality of fixture layout can influence if the cover edge has quality defects such as undulated in rimming process. First, this paper analyzes composition of the rimming bottom die and positioning clamping mechanism in rimming fixture, and obtains stressed situation of front cover edge under the action of rimming and stamping by the roll head by using the result of finite element analysis to the rimming process of front cover, combining with the design requirement of processing datum graph, the production program of engine hood, production class system and actuating rate 、failure rate and production rhythm of production lines, establishes distribution points of rimming fixture and finally designs the rimming fixture of engine hood. The fixture is currently used in actual production with stable and reliable performance.

Performance Improvement and Lightweight of Engine Hood Structure

Engine Hood is an important part of a whole auto body panels, Structural stiffness and vibration modal always are considered while designing. After structure analysis of original engine hood, some defects were found. Based on the theories of topology optimization , topography optimization and size optimization, some constraints for the displacement, the modal, the volumetric fraction were set up, firstly, minimum strain energy was set up for the optimization objective; secondly, the minimum mass was set up for the objective. After computation, an optimized shape and material distribution for the structure was shown. Then, the structure was redesigned, and then it was computed with method of size optimization. The results of recomputation showed that the engine hood structure capability was superior to the original and the new hood weight was also reduced.

Optimization of Hood Thickness Based on the Multi-Objective

Head injury of pedestrian is the most common and fatal cause of mortality in vehicle-to-pedestrian crash. And the engine hood is most likely to cause harm to pedestrian head. Efforts to improve engine hood design, which minimize the head injury of pedestrian in vehicle-to-pedestrian crash, are becoming more and more important. In this study, an approximate model of hood thickness for three targets: HIC, mass and modality, is established. In order to meet the requirements of lightweight and reducing vibration and noise, approximate models iterate by the NSGA-II genetic optimization algorithm, and select the Pareto optimal solutions for thickness optimization. At last the study re-simulates the collision between pedestrian head and hood to verify the reliability of the obtained optimization results.

Optimization of the Engine Hood to Reduce the Head Injury during the Vehicle-Human Collision

Effect of hard point of the engine hood on the head injury during the vehicle-human collision was studied to improve the design of engine hood. Firstly, the current common model of the engine hood was established with three-dimensional finite element modeling software, and 20 areas were divided, also a standard head finite element model was imported, secondly, each area of the engine hood was clashed by the standard head model, then the impact on the head injure was analyzed and the hard point of the hood area was achieved, thirdly, the optimization of the inside and outside panel materials and the plate structure were carried out to reduce the head damage. The simulation results show that the engine hood after optimization gave less damage to the head, which means the research carried out here is of a good reference to the engine hood optimization design for human protection

Study on Optimal Design of Light-Weight Composite Hood

In this paper, the traditional steel engine hood is analyzed using finite element method firstly, and then the basic performance requirements of the hood is obtained. Based on the principle of equal stiffness, the design process is executed on carbon fiber composite hood. Afterwards according to the property of this composite, the whole optimization process of composite hood from conceptual design to detailed design is accomplished by ways of free size optimization, parameters optimization and stacking sequence optimization. The optimal structure of carbon fiber composite engine hood can be obtained by comparing the results of optimization design. Carbon fiber can put lightweight into practice , and the developing time of composite hood can be sharply reduced .

Design Optimization Method about the Spring Stiffness Used in Active Engine Hood of Pedestrian Protection

Among the car accident casualties, Pedestrian occupied a large proportion of the injuries. Pedestrian protection became a key problem of vehicle safety. The engine hood was the most possible zone impacted by the head of pedestrian. The pedestrian protection of engine hood was an important performance of vehicle. The active engine hood was used to improve the pedestrian protection performance of vehicle and to meet the regulations. In the lifting system of active engine hood, springs were used to improve the pedestrian protection performance. A design optimization method about the spring stiffness used in active engine hood was developed in this research. The spring stiffness of K was set as design variable, and its interval was set 1~50 N/mm. The impacting zones of engine hood where HIC values of original engine hood were higher than the mean values of corresponding child and adult zones were selected as the cases of optimization. The objective was to minimize the sum of HIC values of those selected zones. The first type of constraints was that the HIC values of child zones were less than the mean HIC value of child zones. The second type of constraints was that the HIC values of adult zones were less than the mean HIC value of adult zones. The spring stiffness optimization model about active hood based on pedestrian protection was constructed and solved. The results of optimization indicated that the obtained spring stiffness by this method improved the pedestrian protection performance of engine hood.