(I) Global Market Overview
North American market: For about 20 years, traditional stepped automatic transmissions have always dominated the market, and AT technology has an absolute advantage. In the North American market, dynamic performance is critical, and people prefer large cars with high comfort.
On compact models, CVT will gradually increase in number, and compact cars will have a dominant role in Japan and South Korea. The first DCT will be introduced into the North American market around 2010, but no AMT will enter the market.
The general situation in the European market is that manual transmissions dominate the market and the market share of AMT declines. In 2003, Volkswagen began to apply DCT in the European market. Now it is the transition phase between MT and AMT to DCT. In the Western European market, DCT technology is very important, people have a stronger awareness of environmental protection and fuel consumption; Eastern European markets do not have special high-tech, the market tends to traditional stepped automatic transmission.
In the Japanese market, automatic transmissions dominated the market, and CVTs showed significant growth; in 2008, DCT was introduced into the market (Mitsubishi EVO10 generation), but in the future, AMT will not enter the market.
In the Chinese market, the technology of vehicles is relatively uncomplicated. Manufacturers' research and development and technology investment are mostly market-oriented; representative market representations, cars and heavy trucks are still traditional models, and have specific vehicle comfort requirements. The Chinese market has grown rapidly, but without the traditional car culture, the Chinese market has brought together technologies and processes from Europe, Asia, and North America. Competition and cost pressures are even worse. There will be a DCT listing in 2011.
(b) The advantages and disadvantages of dual clutch
From the six latitudes of comfort, performance, fuel economy, cost, weight, and hybrid matching, DCT scored equally on both cost and weight, and was recognized at the other four latitudes. It is worth highlighting: DCT is the best technology for pre-precursor applications.
Advantages and Disadvantages of DCT by Addition and Subtraction
+ Very quick shift time (with sportiness)
+ Power transmission without interruption
+ Gear ratio can be flexibly adjusted
+ can be set to drive in manual or automatic mode
+ Same response characteristics as MT (direct connection, accelerator pedal to wheels)
+ Very flexible handling; characteristics of automatic transmissions
+ Lower fuel consumption and weight (relative to AT), close to MT's efficiency
+ Good compatibility with hybrid vehicles
- Oil pump required, but can be replaced with advanced design of backlog
- If the volume of production is not high, the production cost is higher than both MT and AMT
(c) Cost considerations for DCT
DCT is a new technology, because it is a new technology, so its cost reduction space is greater than AT technology; In addition, the manufacture of DCT does not require a large number of new equipment; the first time into the market, the core components of dual clutch and electronic mechanical control devices, etc. Single-supplier supply is more costly, and if more suppliers participate in the future, the cost of components will be reduced.
From the actual production point of view, the production of DCT requires the use of ordinary straight/helical gear manufacturing technology, rather than the planetary gear manufacturing technology of the AT transmission; the DCT can share the manufacturing technology and supplier information of MT components, including shafts, gears, bearings, Synchronizers, seals and many other components; key components (dual clutch, mechatronics, hydraulic pumps and TCU) can be supplied by professional suppliers.
(IV) Work Contents Related to DCT Design and Verification
Benchmarking, design speed ratios, load spectrum development, form factor, transmission design, system integration, supplier selection, circuit layout, prototyping, software development, bench and vehicle calibration, transmission testing.
The comparative products we have involved include VWDQ200, VWDQ250, GIFDCT, and GFT6DCT450.
In this step of transmission design, the design criteria include serialization (maximum versatility of parts), weight, noise, shift force, oil leakage, and durability.
The supplier selection step is a system supplier that is jointly appointed by Giff and the customer, and Gifford makes recommendations based on technology, quality, and timing. The selection of suppliers will have a huge impact on DCT's current design and final product, total cost and time schedule. We recommend that suppliers should be involved early in the DCT project. OEMs/transmission manufacturers should make full use of the expertise of suppliers, train suppliers to provide the concept of high-quality products, and completely serialize the transmission (such as diesel, gasoline, Torque type, etc.)