[YesAuto Safety Technology] Mention of the three words muscle car, many people will think of those American sports cars with tough appearance and matching large displacement and high horsepower engines in the 1960s and 1970s, but with With the increasingly stringent emission regulations and the outbreak of the oil crisis in the 1970s, traditional muscle cars are slowly moving away from people's sight. At the beginning of this century, with the emergence of pony cars such as Ford Mustang, Chevrolet Camaro and Dodge Challenger that returned to the market, people gradually became accustomed to calling such high-performance two-door “muscle cars” Small sports car.
The muscle car culture has been deeply imprinted in the American car culture. When traveling by car in the United States, many people often choose to rent a “muscle car” to become their own car, and experience this kind of inexpensive and powerful car. . While these “muscle cars” are pursuing the faster the better in terms of speed, can the safety performance of these vehicles be able to protect the owner from injury in an emergency when there is a danger? Not long ago, IIHS took the three most representative “muscle cars”: Ford Mustang, Chevrolet Camaro and Dodge Challenger for crash tests, but the results were not satisfactory. None of these three cars got the Top The honor of Safety Pick (the highest safety rating).
If you look carefully through the IIHS test records over the years, you will find that there are some rules: standard models with a starting price of more than 60,000 US dollars, they rarely conduct crash tests (currently the most expensive model tested by IIHS is Maserati's Ghibli); Models with too small sales may not necessarily be tested; but if it is a best-selling model and the price is not expensive, IIHS will definitely test. So if it is a car that is affordable and popular on the market after a long time, the IIHS will not test it, there must be a reason behind it.
Chevrolet Camaro has a similar situation: Camaro is based on the General Motors Alpha platform, and the first to adopt this platform was Cadillac ATS. After so many years, other models of the same level as the ATS have been tested, but IIHS has never tested the ATS (or tested it, but did not publish the results). It was not until last year that IIHS finally released the test results of CTS, showing that in addition to the 40% frontal offset collision results are good, the performance of the other test items CTS is very average compared with the same level of models.
The lack of ATS test results, coupled with the new Chevrolet Camaro is likely to be the last model to adopt the Alpha platform, which led to a speculation in the car fan circle: the passive safety of the Alpha platform is inherently lacking in design , Which also prompted GM to quickly develop an updated Omega platform (which has already begun to be used on CT6) to replace it. This speculation is that the IIHS has not heard from the new Chevrolet Camaro nearly half a year after it went on the market. After all, the IIHS is generally very fast for the popular models, and it is not common to wait for such a long time. Now that the IIHS has finally announced the results and data, all suspicions have finally come to light. Everyone will look at the following analysis to make it clear.
Ford Mustang, IIHS has tested two sporadically (40% frontal offset collision and side collision); Dodge Challenger, although IIHS has never tested it, but IIHS has tested its vest model Dodge Charger on the same platform. Drive a four-door sedan).
Among these three cars, Chevrolet Camaro and Ford Mustang are both new platforms designed after 2009; Dodge Challenger is relatively old. The Chrysler LC platform it is based on actually shortens the wheelbase of the LX platform, which is the product of the early 21st century. At that time, Chrysler and Mercedes-Benz were one family, so the LX/LC platform incorporated some Mercedes-Benz designs. For example, its front suspension was derived from the previous generation (W220) of the S-Class, and the rear suspension was derived from the previous generation (W211). Class E. In order to meet the increasingly strict collision safety, Dodge has made some enhancements to the Challenger's body structure from the 2015 model.
Let's analyze the crash test results of these three muscle cars. The “deformation value” referred to in the IIHS frontal offset crash test uses the measurement method of taking the residual amount of displacement, so the readings at some measuring points may appear negative. A negative value does not mean that it does not collapse after the collision but expands outward.
■ 40% frontal offset crash test
In this project, the challenger occupies an absolute advantage. The deformation at several measuring points in the foot space is only 2-3 cm. The center console and A-pillar are all zero deformation, which is close to or even reaching the Audi A6/BMW 5 series. / Mercedes-Benz E-class cars. But this is not surprising, because the LC platform is made up of the early S-level and E-levels, and the solidity is still very secure.
The Chevrolet Camaro is also very good. The deformation of the foot space at several measurement points hovered between 3-6 cm. The center console and A-pillar also have zero deformation. This performance is not only worse than the Dodge Challenger, but even better than the same platform. The Cadillac CTS is also bad, but it can still barely enter the first-class camp. What is the approximate level of this performance? ——Slightly better than the Ford Fusion (US Mondeo), one of the best-selling mid-size cars in the United States. The Alpha platform widely used aluminum in the front of the car is relatively successful, which can reduce weight and has no impact on collision energy absorption.
Ford Mustang's results are very interesting. At first glance, the center console/steering wheel/A-pillar all have zero deformation, which seems very powerful; but at the first glance, the foot space deformation is immediately dumbfounded. The dense deformation of more than ten centimeters, the deformation of the central position even reaches 16 centimeters, and it falls out. The “excellent” limit defined by IIHS (≤ 15 cm) is reached. In this part of the performance of the foot space, the new Ford Mustang is even far behind the previous generation models. This shows that the structural design of the new Ford Mustang has not been handled properly; although the frame girder is arranged with a special force transmission path and high-strength steel is used in key parts, the actual results show that the effect is not ideal. But why is the Ford Mustang still able to get “excellent” results in this set of tests in the end? That's because of the IIHS regulations, as long as “most” of the measured values fall within the “excellent” range.
■ 25% frontal offset crash test
Compared with the 40% frontal offset crash test, this test car factory has much more room to play. The root cause is: For 40% frontal offset crash test, it is difficult for you to not let the car not bear the force of frontal impact; but for 25% frontal offset crash test, the car factory can completely design the shape of the front part to make the front of the car. After contacting the collision object, it easily “slides away” so that the frame does not have a frontal collision.
This is indeed a solution, and from the results, it does have the effect of protecting the safety of the occupants in the car; but on the other hand, we cannot measure the energy absorption level of the car and the strength of the cabin structure through this test. More importantly: What if the friction between the road surface and the wheels is so great that the car will not “slip” when there is an actual accident? At this time, it really depends on the firmness of the crew cabin to harden it. Therefore, the current mainstream practices in the industry are still focused on improving the energy absorption, conduction, and strength capabilities of the corresponding parts of the front of the car. For these three “muscle cars”, they also adopt a similar routine.
The difference in the performance of these three models in this project cannot be simply said to be caused by the frame structure or material. Judging from the structure diagrams of Mustang and Challenger, they both have energy absorption/force transmission structures that can cope with the 25% frontal offset crash test, and this type of design does make some models (such as the 2017 Audi A4) achieve good results. . Therefore, there are many factors that determine the performance of the 25% frontal bias crash test.
Compared with models with horizontal engines, the 25% frontal offset crash test poses a greater threat to models with vertical engines like muscle cars, because in the engine compartment of such models, the front of the vehicle has two longitudinal lines in order to install the engine. The spacing of the load-bearing beams is generally narrower than that of models with horizontal engines.
The side member is one of the strongest and most important load-bearing components in a car. Whether it participates in energy absorption during a collision will have a great impact on the results of the crash test. Since the longitudinal beams of most longitudinal engine models are closer to the center axis of the vehicle body, the longitudinal beams will basically not touch the collision object during the 25% frontal offset crash test, and cannot help absorb energy. The transverse engine models are different. For many models of transverse engine models, the longitudinal beams fall within the collision zone, which can help absorb energy. Therefore, in this collision project, the transverse engine models have a part of the advantage. In this way, it can explain why in a batch of models tested when IIHS suddenly launched a 25% frontal offset crash test in 2012, why many luxury cars with vertical engines have poor performance, while the low-cost engine layout is adopted. The performance of the car is obviously better for one grade.
■ Side impact test
From the performance point of view, the side impact test results of these three cars are particularly good. Except for the Dodge Challenger who received a good evaluation in the sub-item, all the other sub-items are excellent. But in fact, the results of the side impact test are not of great reference to the two-door coupe, because the moving collision object adopted by the IIHS is not a large plane, but a part of the back contracting plane on both sides. Therefore, the plane that touches the vehicle at the time of the collision is not very large. For a four-door car, the B-pillar will be within this plane range, but for a two-door coupe, because the front doors are generally relatively long, the B-pillar is located very far behind, beyond the coverage of this plane, so their B The column is hit by the rearwardly retracting plane after the deformable obstacle has collided with the door. And because the IIHS test process stipulates that the moving collision object will start the brake after it leaves the drive for one second. Therefore, for the two-door coupe, the door becomes the most important energy-absorbing component during the side impact test, and the impact force of the B-pillar will be much less. The common situation of the two-door coupe is that the door collapses inward. More serious than the B-pillar. The data for detecting the results of side collisions is collected by sensors installed on the vehicle's B-pillar. The residual displacement calculated by these sensors is the displacement of the vehicle's B-pillar after the collision, not the most severely collapsed door part, so IIHS The current method of measuring and displaying side impact test results has certain limitations for this type of vehicle.
The factors that affect the performance of the side crash test are quite complicated. Even if the vehicle is essentially the same platform, the engine and interior configuration are different (meaning different vehicle weights), and the suspension is different in hardness (standard suspension and sports suspension) The difference), and even the different gripping capabilities of the tires, etc., will greatly affect the side impact test results. For example, the current Volkswagen Golf and Audi A3 are actually built on the same architecture, but the Golf’s side impact test results are much better than the Audi A3.
■ Roof Strength Test
The evaluation of this test item, IIHS is based on whether the roof can withstand the weight of the car itself when the car is overturned, that is to say, the ratio of the maximum load to the weight of the car. So if the car is relatively light, then the maximum load-bearing value of its roof is not high, but as long as the ratio of the two is high enough, it can still be well received.
From a horizontal perspective, what is the level of roof stiffness of these three muscle cars? In terms of absolute performance, they are roughly equivalent to the current level of ordinary mobility cars in the North American market (that is, such as Honda Civic / Accord, Toyota Camry, Ford Fusion, etc.), which are in the range of 15,000-17,000 pounds. Of course, Chevrolet Camaro's £13,641 result is a bit regrettable. In fact, in addition to the protection of the roof hardness after the vehicle itself rolls over, another purpose is to protect the passenger compartment when foreign objects roll over. Therefore, just looking at the ratio of the maximum load to the weight of the vehicle to assess the degree of safety, this evaluation method may not be perfect.
■ Active Collision Prevention System
Judging from the test results, the scores of these three cars in proactive collision prevention are not satisfactory. This is not because manufacturers do not have the ability to equip them with active collision prevention systems, but because these three muscle cars are sports-oriented performance cars, the use of too many driver assistance systems will inevitably limit the limits of the vehicle. Make the vehicle “rational and docile”. Therefore, the manufacturer's stinginess in the active collision prevention system may also be a targeted trade-off between driving pleasure and driving assistance systems, in exchange for more driving pleasure by reducing driving assistance systems.
|Comparison of the performance of the three models|
|Model||US starting price (USD)||25% frontal offset collision||40% frontal offset collision||Side collision||Roof strength||New platform|
From the detailed crash test results of these three muscle cars, we can see that the focus of the car manufacturer's research and development is still the tradition of American muscle cars: to provide models with the highest possible horsepower at the lowest possible cost. Therefore, although the solidity of the car body structure and passive safety are one of the concerns, it is certainly not the top priority. The Chevrolet Camaro and Dodge Challenger of these three cars are not specially designed platforms, so the collision results of these two cars inherit the advantages and disadvantages of the same platform models. The advantage of this approach is that it can save development costs and resources while ensuring a certain level of passive safety for the frame. In contrast, Ford Mustang is a specially developed exclusive platform (Ford S550 platform), and R&D/manufacturing costs are difficult to share with other models. The consequences of this constraint can also be clearly seen from the crash test results. In the two most important front-offset crash tests, Mustang's performance is not ideal.
Although none of these three cars won the Top Safety Pick honor, this does not mean that the safety performance of these muscle cars is not enough to protect the drivers and passengers. Ford Mustang and Chevrolet Camaro performed well in the crash test, and both received four excellent and one good evaluations. However, the Dodge Challenger has not undergone major design changes due to its early launch and in recent years. Therefore, the safety performance is still at the level of the earlier period. Therefore, the poor performance of the collision is also due to the cause. It is believed that the safety performance will be greatly improved when the new model is changed or replaced.