tailieunhanh - Understanding Automotive Electronics 5 Part 14

Tham khảo tài liệu 'understanding automotive electronics 5 part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | FUTURE AUTOMOTIVE ELECTRONIC SYSTEMS 11 Electronic control of an automotive transmission could provide maximum performance by matching engine controls and transmission gear ratios. ratio. The quantity of fuel required for a given mass air flow rate increases as the alcohol content increases. For neat methanol 100 methanol the fuel flow rate is roughly double that for neat gasoline. Figure is a schematic of an FFV system. This system configuration is virtually identical to the fuel control system explained in Chapters 6 and 7. The only significant difference is the alcohol sensor and the need for stainless steel fuel delivery hardware . Transmission Control The automatic transmission is another important part of the drivetrain that must be controlled. Traditionally the automatic transmission control system has been hydraulic and pneumatic. However there are some potential benefits to the electronic control of the automatic transmission. The engine and transmission work together as a unit to provide the variable torque needed to move the car. If the transmission were under control of the electronic engine control system then optimum performance for the Figure FFV System UNDERSTANDING AUTOMOTIVE ELECTRONICS 379 11 FUTURE AUTOMOTIVE ELECTRONIC SYSTEMS entire drivetrain could be obtained by coordinating the engine controls and transmission gear ratio. Continuously Variable Transmission One concept having great potential for integrated engine power train control involves the use of a continuously variable transmission. Instead of being limited to three four or five gear ratios this transmission configuration has a continuous range of gear ratios from a minimum value to a maximum value as determined by the design parameters for the transmission. The continuously variable transmission CVT is an alternative to the present automatic transmission. It is being developed presently and will likely see considerable commercial use in production cars. The principle of the