Original link: https://www.latepost.com/news/dj_detail?id=1735
Ideal sales soared. In the first half of the year, 138,500 vehicles were delivered, exceeding the total of last year. The delivery volume in June exceeded 30,000 for the first time, and has reached the supply limit of 7,500 vehicles per week. Li Xiang, the founder and CEO of Ideal Auto, said that the production capacity will be raised to 8,000 vehicles in the second week of July.
At the same time, doubts about the ideal car have never subsided. Recently, the ideal L9 has sparked controversy. Some voices pointed out that the chassis of the ideal L9 is reverse-developed, resulting in a disproportionate length and space utilization; it is a rare 6-seater car with floating caliper brakes in its class, and it is easy to generate heat after intense driving. Attenuation, affects braking distance, etc.
In this regard, today’s ideal car responded, saying that the interior space of the car has not been affected. In terms of safety, it has shown the results of the third-party test of the 100-kilometer brake and the results of the China Insurance Research Institute and C-NCAP authoritative tests.
Since Ford built the first car, automobile research and development has a history of 100 years, but there has been no major innovation for a long time since then. After the development of new energy vehicles, automakers have launched an arms race in terms of power systems and software capabilities. At the same time, they have continued to improve acceleration performance and NVH (noise, vibration, etc.) according to the characteristics of electric vehicles. Safety should also be the primary concern of car manufacturers.
“Later Auto” interviewed three auto technicians (Yu Gong and Gao Gong are the chassis engineers of Lixiang Auto), and talked about some topics related to reverse development, braking distance and chassis evolution:
Reverse development does not meet the requirements
Late Auto: Is reverse development a common phenomenon in China’s auto industry?
Yu Gong: Reverse engineering is a common phenomenon in the initial stage of the Chinese auto industry. Everyone has no experience in building cars, and the performance requirements are not high, so they will go to the market to find suitable competing cars for reverse development. All from Volkswagen and Honda and Toyota.
At this stage, with the development of the automobile industry, users have higher and higher requirements for performance, personalization, and extreme driving space, and any reverse-engineering car cannot meet the above requirements. So we have to develop positively, but it does not mean that we are going to create a new type of chassis suspension. If you look closely at the current market, many domestic cars or new power models will have the shadow of luxury cars, such as BBA, Land Rover, Porsche, etc., everyone has more or less learned from the mature experience of the industry.
Later Auto: New car companies do not have technology accumulation, how to develop a chassis from 0 to 1?
Yu Gong: Starting from scratch, it is only for car companies. The people it recruits are not novices, they must be relatively experienced engineers in the auto industry, and they all have experience. In the course of a century of automobiles, the form of chassis suspension has been relatively mature, but the most important thing is matching, such as how to better integrate K&C features such as suspension roll center, anti-nodding, and pitch center. As long as the market positioning is determined, we can tailor a chassis structure suitable for the company’s positioning according to our own needs.
Later Auto: How do you see someone saying that the ideal chassis is made by reverse development?
Yu Gong: I don’t think the so-called reverse engineering is accurate. There are only a few types of suspension and chassis of the car. Now that there are so many cars, how can there be no similarities. For example, the suspension, the front suspension is a McPherson, a double wishbone. The main suspension of the rear suspension is three-link, four-link and five-link. Basically, they are modified according to these structures, and there are no more than seven or eight forms in total.
To develop a model, you will definitely encounter some more or less headaches. If you don’t have a good idea, the best solution is to learn from the structural layout of other car companies. But you said that it is impossible to completely copy this car. Because the proportions of your powertrain and car are different. If you copy it down, the performance of this car must be a mess.
With floating tongs, the braking distance can also be made within 38 meters
Later Auto: What is the difference between floating caliper brakes and fixed caliper brakes? Why did Ideal choose the former?
Gao Gong: There is no essential difference between fixed tongs and floating tongs. They both use hydraulic pressure to push the piston cylinder to clamp the brake disc to generate braking force. The equivalent cylinder diameter of the fixed tongs used by the BMW X7 is 59.5mm, and the equivalent bore of the floating tongs used by the GLS is 65mm. From the point of view of performance alone, the performance of X7’s four-cylinder fixed tongs is not better than that of GLS’s two-cylinder floating tongs.
The fixed pliers industry is the first to be an Italian supplier, and its “high appearance” is an important factor for its popularity; in the limited rim space, the fixed pliers are more flexible in layout; through the increase in the number of cylinders, the pressure distribution of the caliper is relatively uniform . The above advantages have nothing to do with the braking performance and do not affect the braking distance.
Ideal Auto chose a double-cylinder floating caliper. Through system matching and performance adjustment, a braking distance of 37-38 meters per 100 kilometers was achieved. The Mercedes-Benz GLS also chose the double-cylinder floating caliper; Tesla’s remodeled models are also gradually turning to the floating caliper route.
Qian Gong: Generally speaking, the floating caliper brake is simpler and cheaper than the fixed caliper, and the cost is doubled. Floating pliers require only one piston and fewer parts, making them less expensive to manufacture. Fixed pliers require multiple pistons, a more complex structure and more parts.
Fixed calipers are generally considered to have better brake feel. Due to the use of multiple pistons in the design, and the arrangement of the piston positions is more uniform, it can provide a more direct and sensitive braking response and a more linear braking force output. This makes it easier for the driver to feel and control the braking force, thus providing better handling and driving experience.
The floating caliper may have some limitations in terms of braking performance, but for general passenger cars, it is enough to meet the normal driving and braking needs. And the floating tongs can be driven independently by an external motor structure, and can be clamped to realize the EPB (electronic parking brake) function when parking.
Fixed pliers are more commonly found on high performance cars or race cars. At present, most models on the market choose the brake arrangement scheme of “front solid and rear floating”. But there are exceptions. For example, Toyota chooses the layout of front floating and rear floating in most models, and the electric models of Volkswagen MEB platform choose the layout of front solid and rear drum.
Ideal L series and Lexus have floating clamps at the front and rear, while Tesla Model 3, Weilai ET7 and most mid-to-high-end cars have fixed front and floating rear.
Late Auto: Would using fixed calipers help shorten stopping distances?
Gao Gong: Based on the condition that the basic braking system is reasonably matched, the braking distance has little to do with the type of caliper. The braking distance mainly depends on the ABS calibration and the longitudinal adhesion coefficient of the tire.
Qian Gong: Fixed caliper brakes usually provide better braking effect and shorter stopping distance. They are designed to distribute braking force more evenly and to better control brake rotor heat.
The floating caliper is easier to reach thermal decay earlier than the fixed caliper. For example, the test floating caliper stops at 100 kilometers, and the thermal decay occurs after 5 times, and the braking distance begins to become longer. Then the clamp may appear after 8 times.
Thermal decay is not only determined by the clamp/floating clamp. The diameter of the brake disc, whether the brake disc is perforated and lined, etc. all have an impact. Although the GLS is also a floating caliper, its brake disc diameter is larger and the weight of the car is lighter.
Later Auto: What performance do the elk test, body torsional stiffness, and 100km/h braking performance reflect?
Qiang Gong: The elk test simulates an emergency avoidance action. The vehicle needs to turn quickly to avoid sudden obstacles. It can evaluate the vehicle’s suspension system, suspension adjustment, chassis stability, etc. Usually a car with excellent handling and stability can successfully pass the test at a speed of 70-80km/h.
The torsional stiffness of the vehicle body refers to the torsional resistance of the vehicle body during dynamic driving such as turning or sudden braking. Higher body torsional rigidity can reduce body roll, and the body dynamics are more stable, providing better balance and handling performance. In addition, the higher the torsional rigidity of the body, the better the NVH performance will be in theory. As a part of the vehicle body, the battery of an electric vehicle can directly improve the torsional rigidity of the vehicle body to a large extent, which is an “inherent” advantage.
The braking distance per 100 kilometers per hour refers to the braking distance required for the vehicle to stop completely from a speed of 100 kilometers per hour, and is used to evaluate the braking performance of the vehicle. It depends on factors such as the design of the brake system, the material of the brake disc and brake pad, the adhesion of the tire, and the quality of the vehicle. From the perspective of the original car, the braking distance below 35m is excellent, 35-38m is good, 38-41m is average, and above 41m is relatively poor.
Most car companies do not announce the stopping distance of 100 kilometers. General automotive media or safety testing agencies will conduct tests. There are many factors affecting the braking distance per 100 kilometers, including the design of the braking system, the material of the brake disc and pad, the type of tire, the quality of the vehicle, and the road conditions and so on.
The configurations are the same, and the final difference is the integration ability
Auto later: Ideal current chassis, where else can we continue to upgrade?
Yu Gong: No matter what you do, it can only be said that at that stage it met or exceeded expectations. Because it is impossible to achieve the ultimate product in a limited time, there must be some regrets, or balance is required. Future products must deal with regrets.
In order to meet the diverse needs of users and continuously improve the user experience, Ideal will carry out product development and layout in rear wheel steering, dual-chamber air suspension, dual-valve CDC shock absorber, steer-by-wire, brake-by-wire, etc. With the development of vehicle intelligence, the self-development of the chassis electronic control system seems to be bound to become a development trend.
Later Auto: Electric vehicles are all being rolled up, how is the chassis rolled up, and how to widen the gap with competitors?
Yu Gong: Like air springs, we have achieved the highest assembly rate in China and are successful in the market. Domestic friends are also looking for two suppliers, Konghui and Baolong, for development. happy with this.
In the same price range, if you don’t make air springs, the product will not be competitive; today you use single-chamber air springs, and see others use dual-chamber air springs. People don’t care what dual-chamber and single-chamber air springs bring to the car. Even if it is equal, you will feel that the double chamber has one more chamber than others, and the performance is better, so it is rolled up. In 2025, 2026, things like rear-wheel steering are definitely going to roll up.
From a structural point of view, it is basically impossible to jump out of this range. What can eventually open up the gap reflects the integration ability, that is, whether you can maximize the product in the existing space and provide greater convenience to passengers. In terms of performance, everyone uses the same thing. Can your team develop and adjust the integration and performance of the chassis to reach the top of the industry. Also, can the development and calibration of your software give full play to its product performance.
Late Auto: Are automakers investing enough money and people to improve safety?
Yu Gong: Safety is our bottom line. Whether it is collision safety or driving safety, every car manufacturer should spare no effort to improve performance regardless of cost.
Title picture: The ideal car chassis, from the ideal car official website.
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