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T.4.2.1 The APPS must be actuated by a foot pedal.
a. Pedal travel is defined as percent of travel from a fully released position to a fully applied position where 0% is fully released and 100% is fully applied.
b. The foot pedal must return to its original position when not actuated.
c. The foot pedal must have a positive stop preventing the mounted sensors from being damaged or overstressed.
d. Two springs must be used to return the foot pedal to the off position
e. Each spring must be capable of returning the pedal to the fully released position with the other disconnected. The springs in the APPS are not acceptable pedal return springs.
T.4.2.2 Two or more electrically separate sensors must be used as APPSs. A single OEM type APPS with two completely separate sensors in a single housing is acceptable.
T.4.2.3 The APPS sensors must have different transfer functions which meet one of:
Each sensor has a positive slope sense with different gradients and/or offsets to the other(s).
An OEM pedal sensor with opposite slopes. Non OEM opposite slope sensor configurations require prior approval.
The intent is that in a short circuit the APPSs will only agree at 0% pedal position.
T.4.2.5 If an implausibility occurs between the values of the APPSs and persists for more than 100 msec, the power to the (IC) electronic throttle / (EV) motor(s) must be immediately shut down completely.
(EV only) It is not necessary to completely deactivate the Tractive System, the motor controller(s) shutting down the power to the motor(s) is sufficient.
T.4.2.6 If three sensors are used, then in the case of an APPS failure, any two sensors that agree within 10% pedal travel may be used to define the (IC) throttle position / (EV) torque target and the 3rd APPS may be ignored.
T.4.2.7 Each APPS must be able to be checked during Technical Inspection by having one of:
A separate detachable connector that enables a check of functions by unplugging it
An inline switchable breakout box available that allows disconnection of each APPS signal.
T.4.2.8 The APPS signals must be sent directly to a controller using an analogue signal or via a digital data transmission bus such as CAN or FlexRay.
T.4.2.9 Any failure of the APPS or APPS wiring must be detectable by the controller and must be treated like an implausibility, see T.4.2.4 above
T.4.2.10 When an analogue signal is used, the APPS will be considered to have failed when they achieve an open circuit or short circuit condition which generates a signal outside of the normal operating range, for example <0.5 V or >4.5 V.
The circuitry used to evaluate the sensor must use pull down or pull up resistors to ensure that open circuit signals result in a failure being detected.
T.4.2.11 When any kind of digital data transmission is used to transmit the APPS signal,
a. The FMEA study must contain a detailed description of all the potential failure modes that can occur, the strategy that is used to detect these failures and the tests that have been conducted to prove that the detection strategy works.
b. The failures to be considered must include but are not limited to the failure of the APPS, APPS signals being out of range, corruption of the message and loss of messages and the associated time outs.
T.4.2.12 The current rules are written to only apply to the APPS (pedal), but the integrity of the torque command signal is important in all stages.