Now Electronic Fuel Injection
Page 78
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AN electronically controlled system of fuel injection has been developed in America by the Bendix Aviation Corporation. The units employed consist of an electronic modulator, a fuelinjection distributing commutator. fuel-injection breaker points and fuelinjection nozzles. Asthe timing, sensing and actuating elements automatically control the flow of fuel to the engine under all operating conditions, no special drive from the engine is required.
On the throttle body is an electronic pressure sensor, together with an electronic switch to " sense " and signal the need for a proper fuel mixture according to whether the engine is idling or accelerating. Also on the throttle body i3 an automatic cut-off switch which has the effect of preventing smoke in the exhaust gases.
Located in the water jacket is a thcrmistor which is sensitive to temperature changes in the coaling system. Such variations are passed on to the electronic modulator to assist in starting and warming up.
Fuel is metered by pressure variations in the intake manifold, and controlled automatically by the sensor on the throttle unit to provide for the precise quantity of fuel at the correct time.
Another interesting feature of the system is its distributor-breaker, which can be installed on any conventional distributor. It consists of a commutator and breaker points.
The electronic modulator is equipped with a transistor which is a semi: conductor that replaces a thermionic valve and has the advantage that it does not require any power supply. Timed signals from the distributor-breaker are passed on to the modulator, which co-ordinates the signals with information from the electronic devices which sense engine operating conditions.
The modulator regulates the amount of fuel injected by signals to the injectors. Optional features of the system include a device to compensate for ambient temperature conditions, as well as an automatic compensator for variations in barometric pressure at varying altitudes.
Advantages claimed for the system are far reaching and include a greater power output at lower engine speeds, increased m.p.g., wider latitude in the selection of fuel, and better acceleration.