A potentiometer is a satisfactory way for non-critical applications such as volume control on a radio, but as it has a wiper contact rubbing against a resistance element, and dirt and wear between the wiper and the resistor can cause erratic readings. There are two primary types of throttle position sensors: a potentiometer or a Hall Effect sensor (magnetic device). Then, if due to dirt build up in the throttle bore or a damaged TPS a signal is sent from the TPS to the ECU, the ECU can make appropriate adjustments to compensate, though it might result in surging, hesitation or uneven idle. Most if not all current ETC systems have a closed loop system whereby the ECU tells the throttle to open a certain amount according to an algorithm based on the geometry of the throttle. But just moving the throttle by sending a signal to the motor is an open loop condition and leads to poor control. However, with the ETC, the movement is all done by electronic controls moving an electric motor. Occasionally after servicing or repair, the wire or cable between the accelerator and throttle would not be correctly reinstalled causing sudden acceleration.
#Control synonym driver#
Failure modesīefore drive by wire technology was introduced, if a throttle stuck open a driver could generally put a toe under the accelerator and lift up. Such technology has recently been extended to other vehicle systems to include features like brake assist and electronic steering control, but these systems are much less common, also requiring careful design to ensure appropriate back-up and fail-safe modes.
#Control synonym software#
Most ETC systems have sensor and controller redundancy, even as complex as independent microprocessors with independently written software within a control module whose calculations are compared to check for possible errors and faults.Īnti-lock braking (ABS) is a similar safety critical technology, whilst not completely 'by-wire', it has the ability to electronically intervene contrary to the driver's demand. Much of the engineering involved with drive-by-wire technologies including ETC deals with failure and fault management.
#Control synonym drivers#
Nowadays, the vast majority of drivers have no idea how much intervention is happening. ETC provides only a very limited benefit in areas such as air-fuel ratio control, exhaust emissions and fuel consumption reduction, working in concert with other technologies such as gasoline direct injection.Ī criticism of the very early ETC implementations was that they were "overruling" driver decisions.
The ETC is also working 'behind the scenes' to dramatically improve the ease with which the driver can execute gear changes and deal with the dramatic torque changes associated with rapid accelerations and decelerations.ĮTC facilitates the integration of features such as cruise control, traction control, stability control, and precrash systems and others that require torque management, since the throttle can be moved irrespective of the position of the driver's accelerator pedal. However, acceleration response may occasionally be slower than with cable-driven throttle.
The benefits of ETC are largely unnoticed by most drivers because the aim is to make the vehicle power-train characteristics seamlessly consistent irrespective of prevailing conditions, such as engine temperature, altitude, accessory loads etc. The electric motor within the ETC is then driven to the required position via a closed-loop control algorithm within the ECU.
Instead, the electronic control unit (ECU) determines the required throttle position by calculations from data measured by other sensors such as an accelerator pedal position sensor, engine speed sensor, vehicle speed sensor etc. An ETC-equipped vehicle has no such cable. Most automobiles already use a throttle position sensor (TPS) to provide input to traction control, antilock brakes, fuel injection, and other systems, but use a bowden cable to directly connect the pedal with the throttle. (May 2008)Įlectronic throttle control (ETC) is an automobile technology which severs the mechanical link between the accelerator pedal and the throttle. Unsourced material may be challenged and removed. Please help improve this article by adding citations to reliable sources. This article does not cite any references or sources.
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