China's automotive core components lightweight technology roadmap

[China Aluminum Industry Network] Automotive is a complex mechanical system that optimizes lightweight components such as high-strength steels, aluminum/magnesium alloys, carbon fiber composite materials, and advanced manufacturing processes. It is estimated that by 2030, lightweight components represented by carbon fiber hybrid vehicles will account for 40% of the market.

Engine and Drive System Core Components Technical Route

The technical route of the core components of the engine and transmission system is shown in Figure 1.

1. Passenger car engine head and exhaust manifold modular design

The modular design of the engine is an important means of achieving lightweighting of the engine. In turbocharged gasoline engines, the modular design of the cylinder head and exhaust manifold of the engine can cool the exhaust manifold on the one hand, improve the economy, and solve the reliability problem of excessively high exhaust temperatures. It can reduce the size of exhaust pipe flanges, bolts, and other connected parts, and can greatly reduce the quality of the whole machine. For 2L petrol turbocharged engines can reduce the quality of 2 - 3kg, is one of the important ways to reduce weight.

2. Passenger car engine block

Cast iron cylinder block to ensure the casting wall thickness, reduce the wall thickness tolerance, optimize the local structure of the method, combined with the improvement of the casting process to reduce weight. Optimize the main bearing wall, cylinder skirt, upper and lower flange surface structure, can reduce the weight of 2% -3%; optimize the main bearing cap structure through topology analysis, the weight drop 1% -3%; cast aluminum cylinder block is preferred The technical solution of die-casting aluminum cylinders. In the case of ensuring the strength of the structure, the structure can be made lighter. The main work content is to solve the design process problems of cast aluminum cylinder structure design, die casting process, and then expand the application.

3 crankshaft

The engine crankshaft mainly uses the casting crankshaft of the main shaft and the connecting rod journal hollow structure to achieve the purpose of lightweight. In the structure, the weight optimization design can be adopted by optimizing the number of weights, external dimensions, crank shape and other measures. The high-strength ductile iron is used to roll the crankshaft on the material instead of the existing forged steel crankshaft.

4. Camshaft

Assembled hollow camshaft is a very mature camshaft lightweight technology, which can achieve a weight reduction of more than 30%. It has been widely used in foreign engines.

5. Transmission shaft

When the length of the transmission shaft is long, the conventional steel shaft tube can only be made into two sections due to the low modality and the inability to meet the NVH requirements. The carbon fiber shaft tube has a high modality, and only one segment is required. This saves one universal joint, bearing, and intermediate support. The structure is greatly simplified and the weight is significantly reduced. The carbon fiber transmission shaft can be reduced by about 50% as compared with the conventional steel transmission shaft.

Body core components lightweight technology roadmap

For the load-carrying body, one direction of the lightweight technology line is the aluminum body, the second direction is the steel-aluminum hybrid car body, and the third direction is the carbon fiber-based multi-material hybrid car body. The problems that need to be solved are the manufacture of aluminum alloy materials, performance testing and evaluation of aluminum/composite materials, simulation of properties (strength and safety, etc.) of aluminum/carbon fiber bodies, manufacturing techniques of molds, and connection technologies of different materials.

For the non-bearing body body, one of the directions of the lightweight technology is the carbon fiber body and the outer cover of the plastic body, and the second direction is the use of an aluminum frame. The weight reduction technology roadmap of the body and body core components is shown in Figure 2.

The use of high-strength steels, aluminum/magnesium alloys, and carbon fiber composites is a major application for lightweight materials. High-strength steels are mainly used for inner and outer panels and body structures. The deformed aluminum alloys develop rapidly in the application of body parts and structural parts, such as aluminum alloy trunk lids, hoods, back doors and bumpers that are increasingly widely used. Beams and so on. Magnesium alloys are currently mainly used in the body of the steering wheel skeleton, dashboard skeleton, seat skeleton, etc. From the comprehensive consideration of cost and performance, the composite materials that can be used for body structure parts are preferably resin-based carbon fiber reinforced composite materials. Carbon fiber composite materials are mainly used in automobiles, such as hoods, fenders, roofs, trunks, door panels, and chassis.

In the advanced technology, the main use of hot forming technology, laser tailored welded plate technology, unequal thickness rolling plate / poor thick plate technology, roll forming technology. Thermoforming technology has the advantages of high forming precision, good forming performance, etc. It has been widely used to produce high-strength automotive bumpers, door anti-collision rods, A-pillars, B-pillars, C-pillars, and roof frames, middle passages, and other safety components. And structural parts. Tailored laser blanking plate technology can be applied to the body side frame, door inner panel, windshield frame/window frame, wheel cover plate, floor, middle column (B-pillar), etc. The thick plate can replace the laser tailor-welded plate. It is more suitable for the manufacture of beam components such as channel stiffeners, front floor stringers, rear bumper beams, rear floor beams, etc. Roll forming technology can reasonably design the geometric section of the profile, improve the bearing capacity, and reduce the weight of the parts.

Chassis System Core Components Technology Roadmap

The chassis of the car is divided into four major parts: the suspension system, the driving system, the steering system and the braking system. The technical route of its core components is shown in Figure 3.

1. Suspension system

Suspension system control arm is mainly used cast aluminum, forged aluminum or carbon fiber composite material control arm to achieve lightweight; Horizontal stabilizer bar is mainly hollow or carbon fiber composite material to achieve the goal of lightweight stabilizer; spiral spring is mainly used high strength steel hollow spiral spring Or carbon fiber composite coil springs to achieve lightweight.

2. Driving system

The driving system wheels are mainly made of cast aluminum alloy, aluminum alloy forging, magnesium alloy forging or carbon fiber composite material wheels to achieve lightweight.

3. Steering system

The steering system mainly uses electric power steering systems and steer-by-wire systems to achieve lightweighting. The use of cast iron knuckles can be achieved by optimising the structural design topology and reducing the weight of the knuckles, or using cast aluminum, wrought aluminum and carbon fiber composite knuckles to achieve lighter weight.

4. Braking system

The integration of braking systems is the direction of future lightweight braking systems. It can take the form of a conventional vacuum booster, ESP, vacuum pump (under vacuum) combination brake system or traditional vacuum booster, ESP, vacuum pump combination. A few models use hydraulic booster system without vacuum pump, or further Braking system with integrated ESP and hydraulic booster. The brake disc is mainly composed of a combined brake disc to achieve light weight, such as a steel cap or aluminum cap + ceramic friction ring brake disc. The brake caliper is mainly made of aluminum brake calipers to reduce the weight.