How Electronic Throttle Control Systems Work

How Electronic Throttle Control Systems Work

Before the late 1980s, the majority of automobiles featured relatively simple throttle controls. When you pressed the accelerator pedal, the throttle opened and air poured into the engine, where it combusted with the fuel. This burning fuel propelled the car’s wheels along the road. If you pressed down harder on the accelerator, the throttle would open wider, giving the vehicle additional power.

Nevertheless, electronic throttle control, often known as drive-by-wire, uses electronic signals rather than mechanical ones to operate the throttle. This means that when you step on the gas pedal of your vehicle, rather than opening the throttle, you activate an accelerator pedal module that turns the pressure you provide to the pedal into an electronic signal. This signal is then transmitted to an electronic control unit, which considers your inputs as well as external variables in order to open the throttle for optimal efficiency and performance.

It is a complicated system with numerous advantages for engine wear, performance, and efficiency. Yet, as with any complicated system, it is imperfect, and drivers have highlighted numerous concerns. Can signals from the outside interact with the ETC? What safeguards are in place if such intervention occurs? Continue reading for the answers.

Benefits of Electronic Throttle Control

Electrical throttle control systems may appear quite absurd. If a mechanical throttle control system is effective, why make it more complex?

While it is true that electronic throttle control adds complexity, it also provides a number of advantages. The first is reduced maintenance costs. Mechanical throttle systems are vulnerable to a great deal of wear because they consist of numerous moving parts. Throughout the vehicle’s lifetime, numerous components may deteriorate. Comparatively, an electronic throttle control system has comparatively less moving parts, as it transmits signals via electric impulse rather than through the use of moving parts. This decreases the system’s wear and maintenance requirements.

Since 2009, electronic throttle control systems have been in the news due to a massive recall of Toyota automobiles for acceleration control issues. With the terrible press electronic throttle control systems have gotten, it may come as a surprise that electronic throttle controls offer several safety advantages over mechanical ones. In a mechanical system, the throttle position is determined only by the driver’s input. The main control unit of an electronic throttle control system not only reads input from the driver’s foot on the accelerator, but also examines input from wheels that are slipping, wheels that have grip, the steering system, and the brakes, helping to correct driver error and maintain vehicle control. In other words, a throttle control system may balance multiple parameters that influence the speed and direction of a vehicle, not simply the pedal position. In addition, electronic throttle control is an integral part of the majority of cruise control systems.

Electronic throttle control may be a sophisticated system, but it makes driving a vehicle simpler, safer, and more convenient, and it can save maintenance costs. Nonetheless, one of the concerns expressed during the 2009-2010 Toyota recall was whether or not external signals can interfere with electronic throttle control. Continue reading to discover whether this is true.

ETC Systems and Outside Signals

How Electronic Throttle Control Systems Work

Imagine going along your typical route to work when your vehicle suddenly begins to surge past traffic. Some drivers say that this has occurred to them, with some blaming the vehicle’s electronic throttle control system.

According to several drivers who have experienced unintended acceleration as well as some automotive engineering specialists, electromagnetic interference can lead to malfunctioning electronic throttle control systems. In certain instances, interference from cell phones and power lines has been attributed to a short circuit in the electronic throttle control, resulting in unexpected, unwanted acceleration.

Professor David Gilbert, an engineering professor at Southern Illinois University, demonstrated on ABC news how he was able to create a short circuit in a Toyota Avalon that caused the engine to rev, thereby accelerating the vehicle without driver input — and despite the application of the brakes [source: Ross].

Toyota and other experts responded that Gilbert’s example was fabricated and unlikely to occur in reality. According to Gilbert’s criticism, he had to disconnect and reconnect a number of wires in the system, which is exceedingly improbable to occur in a routinely operated vehicle [source: Toyota].

Theoretically, a short circuit may cause an electronic throttle control to open the throttle and rev the engine. However, many experts assert that the systems are enough insulated to prevent electromagnetic interference from compromising the system.

Yet, the fact that short circuits and interference are improbable does not mean that manufacturers have overlooked their possibility. Continue reading to discover the failsafes and backups built into electronic throttle control systems.

ETC Failsafe Modes

How Electronic Throttle Control Systems Work

As with the majority of complex systems, electronic throttle control systems include multiple failsafes. They are designed as redundancies and backups to keep the system operational or enable a safe shutdown in the event of a malfunction.

The majority of electronic throttle controls are designed to close the throttle and return to idle at the first sign of a malfunction. Hence, if the engine control unit senses a sensor failure, the system reverts to idle, preventing the throttle from opening.

Similarly, the system contains a number of redundant components. For instance, many sensors are employed to detect driver inputs and other parameters. Each sensor position is equipped with two sensors. If a sensor fails or if the two sensors in a particular position produce different readings, the system closes the throttle, causing the engine to idle.

What about interference from the outside that causes power spikes or short circuits? Most systems employ an intelligent throttle motor. The throttle motor is the final gatekeeper that throttle signals must pass through prior to the throttle moving. If the throttle motor senses voltage or signals not generated by the engine control module, it is programmed to shut down the engine. If electromagnetic interference were powerful enough to disrupt electronic throttle controls, the throttle control system would be designed to shut down, not accelerate.

It is not to suggest that electronic throttle control systems are error-free; rather, they have been designed with a variety of failsafes that, if functioning properly, should avoid engine surges and acceleration that are not anticipated.

Yet, as a result of heightened consumer awareness regarding accidental acceleration and doubts regarding electronic throttle controls, automakers are incorporating an additional failsafe: brake overrides. These systems, which are already available on a variety of automobiles from German manufacturers, allow the throttle mechanism to be overridden by driver input. So, if the mechanism malfunctions and the throttle opens automatically, applying the brakes will close it.

Electronic throttle control is merely one of the electronic components located beneath the hood. Read the links on the next page to learn about others.

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