Page 392 - Understanding Automotive Electronics

2735 | CH 11 Page 379 Tuesday, March 10, 1998 1:30 PM

FUTURE AUTOMOTIVE ELECTRONIC SYSTEMS 11

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 11.9 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

Electronic control of an The automatic transmission is another important part of the drivetrain
automotive transmis- that must be controlled. Traditionally, the automatic transmission control
sion could provide maxi- system has been hydraulic and pneumatic. However, there are some potential
mum performance by benefits to the electronic control of the automatic transmission.
matching engine con- The engine and transmission work together as a unit to provide the
trols and transmission variable torque needed to move the car. If the transmission were under control
gear ratios. of the electronic engine control system, then optimum performance for the

Figure 11.9
FFV System
FPO

UNDERSTANDING AUTOMOTIVE ELECTRONICS 379