The ETCS system allows the ECM to precisely control the opening and closing of the throttle valve based on drivers input and is also interrelated with chassis control ECUs such as Traction Control and Vehicle Stability Control (Skid Control ECU).
The Accelerator Pedal Position Sensor (APPS) detects the accelerator pedal position (driver input) and sends a signal to the ECM. Based on the input from the APPS and other ECUs (ABS, TRAC and VSC), the engine ECM directs the Throttle Control Motor to change throttle valve position. The Throttle Position Sensor (TPS) detects throttle valve angle and confirms to the ECM that the desired throttle valve position has been achieved. Both the APPS and the TPS have two sensing elements. ➢ Electronic Throttle Control System-intelligence provides several advantages over a mechanical linked throttle valve system as the ECM can position the throttle valve for optimum performance under a variety of conditions. ➢ The ETCS-i system gives the ECM precise control over the opening and closing of the throttle valve, based upon the driver’s input (accelerator pedal). ➢ And in conjunction with input from chassis control ECUs, such as those for Traction Control and Vehicle Stability Control (Skid Control ECU). ➢ This system not only enhances drive line control, but also assists in reducing tailpipe emissions and improving fuel economy.
ETCS Control modes
• The ECM drives the throttle valve to a specified angle as determined by operating conditions. • Different throttle valve angles in relation to the accelerator pedal position are used to achieve different engine output characteristics. • The following describes the different modes that affect throttle valve angles. ➢ Non-linear Control - Non-linear control means the ECM can control the throttle valve opening rate and position based on such factors as accelerator pedal effort and engine rpm to achieve better performance and comfort. In slippery conditions, the throttle valve can be controlled to aid in vehicle stability. ➢ Shift Shock Reduction Control - The throttle control is synchronized to the Electronically Controlled Transmission control during the shifting of the transmission to reduce the shift shock. ➢ Idle Speed Control - The ECM adjusts the throttle opening to maintain the target idle speed. ➢ TRAC Throttle Control - As part of the TRAC system, the throttle valve is closed by a demand signal from the ABS, TRAC, and VSC ECU if an excessive amount of slippage is occurring at the driven wheel. ➢ VSC Coordination Control - VSC performance is enhanced when the throttle valve opening angle is modified by the ABS, TRAC, and VSC ECUs. ➢ Cruise Control - ETCS-i eliminates the need for a separate cruise control system. Cruise control strategies and functions are incorporated into the ECM.
Types of ETCS
❖ Link type system (1st Generation)
❖ Linkless type system (2nd Generation)
COMPONENTS OF ETCS
➢ Acceleration Pedal Position Sensor (APPS)
➢ Throttle Position Sensor
➢ Throttle Control Motor
➢ Magnetic Clutch
➢ Acceleration Pedal Position Sensor (APPS) - The APPS, which is mounted on the throttle body, is integrated with the throttle lever. The throttle lever is connected by cable to the accelerator pedal. As the driver moves the accelerator pedal the APPS signal voltage changes indicating pedal position. There are two voltage output signals from the APPS. The ECM uses these two signals to calculate the desired throttle valve angle. Also, by using two signals the ECM is able to compare and detect if there is anything wrong with the APPS's performance. Constructions
The non-contact type accelerator pedal position sensor uses a Hall IC. The magnetic yoke that is mounted on the...