Analysis and Development of Factors Affecting the Brake Pedal Feeling of Sedans
1、 Development of the automotive industry
The automotive industry not only requires large investment and high economies of scale, but also has close connections with many sectors of the national economy. Moreover, the proportion of intermediate inputs and value transfer is significant. Therefore, the development of the automotive industry depends not only on many industrial sectors, but also has a great driving effect on the overall development of the industry.
According to relevant data from several developed countries that are major automobile producers, the value-added rate of the automobile industry is much lower than that of the entire manufacturing industry. The value-added rate of the Japanese automotive industry is less than 30%, and the value-added rate of the German and French automotive industries is only about 30%, while the value-added rate of other manufacturing sectors is generally 40% -50%. That is to say, even in developed industries with high levels of industrial technology and added value, about 70% of the output value in the automotive industry is transferred during the consumption of products from other sectors. This is the fundamental reason why the automotive industry has a strong driving effect on other industries, especially the industrial sector.
The added value rate of China's automobile industry is relatively low, with 21.5% in 1995 and 22.3% in 1997. The high proportion of intermediate investment plays a significant driving role in the development of China's automobile industry and related industrial sectors.
The industrial sectors with high demand in the automotive industry mainly include steel, non electronic machinery, electronic machinery, metal products, plastic products, rubber products, non-ferrous metals, textiles, clothing, leather, glass products, chemical industry, and power industry, among which the top six industries have a high demand proportion. The development of the automotive parts industry has had a significant demand driving effect on the above industrial sectors.
According to relevant data calculations, in developed countries such as the United States, Germany, Japan, and France, the ratio of pre investment in the automotive industry to total pre investment in major related industries is approximately 1:1 (except for Japan in some years), and in France, the ratio of total pre investment in major related industries to pre investment in the automotive industry is also about 1.5 times. That is to say, due to the driving effect of the development of the automotive industry on the main related industries, the investment in the entire industry is doubled compared to the investment in the automotive industry itself. Or in other words, the input-output of the automotive industry will have a double driving effect on the overall development of the industry.
2、 Analysis of Factors Influencing Brake Pedal Sensation in Sedans
The braking performance of a vehicle is an important evaluation indicator of its driving performance, and the pedal feel of a sedan is one of the important evaluation directions in the evaluation of vehicle braking performance. According to relevant research, the reflection of pedal feel in cars mainly focuses on issues such as insufficient braking force, soft braking, and insufficient brake sensitivity. To improve the pedal feel of cars, it is necessary to summarize and analyze the various factors that affect the pedal feel of cars, and through detailed theoretical analysis and data comparison, find reasonable methods.
（1） Analysis of Factors Affecting the Pedal Feeling of Sedans
1. What is the feeling of a car brake pedal
In the hydraulic braking system of a sedan, the brake pedal is connected to the vacuum booster and brake master cylinder through a lever mechanism to form the sedan braking system. When braking a sedan, the driver steps on the car pedal bracket; During the process, while overcoming the clearance and resistance of the brake pedal mechanism, the vacuum booster is driven to control the brake master cylinder, causing the pipeline oil pressure to increase and push the brake cylinder, thereby generating braking torque between the friction plate and the brake disc, increasing the friction between the tire and the road surface, and achieving deceleration of the car. In this complete set of brake control, the feeling of the car brake pedal displacement and pedal force obtained by the driver when stepping on the car brake pedal, combined with the vehicle's braking deceleration and dynamic operation during the braking process, constitute the car brake pedal sensation.
2. Analysis of Factors Affecting the Feeling of Car Brake Pedals
There are several factors that affect the feeling of the car brake pedal in the hydraulic brake system of a sedan, including:
(1) The efficiency of the car braking system should be well matched in the design process of the car braking system. Only when the overall braking efficiency of the car meets the braking needs of the vehicle can it have a good brake pedal feel. To achieve good braking performance of sedans, it is necessary to design a matching system for the overall braking system of the vehicle. (2) The vacuum degree has an important impact on the feel of the car brake pedal in the car brake system. The vacuum degree of the vacuum booster can only exert good braking performance under the condition of good vacuum degree. Currently, some engines cannot provide the vacuum source required by the car brake system due to design defects or other reasons, which affects the feel of the car brake pedal. In addition, some key parameters of the vacuum booster are also important factors affecting the feel of the car brake pedal. (3) The longer braking stroke and variable displacement in the car braking system can also have an impact on the feel of the car brake pedal.
