Torque Of Generator-AC (TGAC) Signal
The TCM calculates an AC generator torque from an AC current measured by the current sensor which is located inside the transaxle. The TGAC is a 50% duty cycle signal which the TCM sends to the PCM over the TGAC circuit. The TCM also broadcasts a redundant generator torque message to the PCM over the communication link. The typical TGAC signal ranges from 200 Hz to 400 Hz, where 300 Hz is equal to 0 Nm (0 lb ft) of torque, 200 Hz is equal to 250 Nm (185 lb ft) of negative torque, and 400 Hz is equal to 250 Nm (185 lb ft) of positive torque. The PCM uses the generator torque value as an input to the energy management control strategy, the torque monitor strategy, and the regenerative brake torque limits strategy. In the event of TGAC circuit failure the PCM initiates limited operating strategy (LOS) shutdown mode which disables the vehicle. The PCM also stores an appropriate DTC.
Torque Of Motor-AC (TMAC) Signal
The TCM calculates an AC traction motor torque from an AC current measured by the current sensor which is located inside the transaxle. The TMAC is a 50% duty cycle signal which the TCM sends to the PCM using the TMAC circuit. TCM also broadcasts a redundant traction motor torque message to the PCM over the communication link. The typical TMAC signal ranges from 200 Hz to 400 Hz, where 300 Hz is equal to 0 Nm (0 lb ft) of torque, 200 Hz is equal to 250 Nm (185 lb ft) of negative torque, and 400 Hz is equal to 250 Nm (185 lb ft) of positive torque. Positive torque is perceived as vehicle acceleration and negative torque is perceived as braking. The PCM uses the traction motor torque value as an input to the energy management control strategy, the torque monitor strategy, and the regenerative brake torque limits strategy. In the event of TMAC circuit failure the PCM initiates limited operating strategy (LOS) shutdown mode which disables the vehicle. The PCM also stores an appropriate DTC.
Torque Monitor
The torque monitor resides within the PCM as both software and as a redundant safety processor. The torque monitor detects certain computer concern of the PCM. The torque monitor also detects if the overall powertrain torque delivered to the output shafts of the vehicle is excessive to what the driver is requesting. The torque monitor detects 3 gross errors that are present for some calibrated amount of time
- unintended vehicle motion - the powertrain accelerates the vehicle when it should not (such as in NEUTRAL) or provides torque in the wrong direction.
- excess acceleration - vehicle accelerates at greater rate than the driver or the speed control requests.
- excess powertrain deceleration - vehicle powertrain braking exceeds driver demand.
When any of the gross errors are detected, the torque monitor communicates it to the PCM, which initiates appropriate action such as LOS mode. The torque monitor requested LOS mode can be cleared when the concern is no longer present, and the key is cycled to the OFF position for about 10 seconds.
Torque Determination and Energy Management
The PCM is responsible for torque determination and energy management functions. The PCM monitors gear selector position (PRNDL), brake pedal position (BPP) and accelerator pedal position (APPS). The PCM then makes a torque command determination. Positive torque is perceived as vehicle acceleration and negative torque is perceived as braking. Based on the amount of torque requested by the driver, the PCM decides which power source has to deliver the torque to meet the driver demand while the powertrain system is running most efficiently.
Scheme 109
Misfire Monitor Specifications
Misfire monitor operation, DTCs P0300 to P0304 (general and specific cylinder misfire), P0315 (unable to learn profile), P0316 (misfire during first 1,000 revolutions after start-up). The monitor execution is continuous. The misfire rate is calculated every 200 or 1,000 revolutions. The monitor does not have a specific sequence. The CKP and CMP sensors must operate correctly to run the monitor. The monitoring duration is the entire driving cycle (see disablement conditions below).
Typical misfire monitor entry conditions include entry condition minimum/maximum time since engine startup is 0 seconds, ECT is -7°C to 121°C (20°F to 250°F), RPM range is (full range misfire certified, with two revolutions delay) two revolutions after exceeding 150 RPM below drive idle RPM to red-line on tach or fuel cutoff. Profile correction factors learned in KAM are Yes, and the fuel tank level is greater than 15%.
Typical misfire temporary disablement conditions include closed throttle deceleration, fuel shut-off due to vehicle speed limiting or engine RPM limiting mode, and a high rate of change of torque (heavy throttle tip-in or tip-out).
The profile learning operation includes DTC P0315, unable to learn profile in three 97 to 64 km/h (60 to 40 mph) decelerations. Monitor execution is once per KAM reset, monitor sequence: profile must be learned before misfire monitor is active. Entry conditions include CKP, CMP, no AICE communication errors, CKP/CMP in synch. The monitoring duration; 10 cumulative seconds in conditions, a maximum of three 97 to 64 km/h (60 to 40 mph) defueled decelerations.
Typical profile learning entry conditions are engine in deceleration fuel cutout mode for four engine cycles, the brakes are not applied, the engine RPM is between 800 and 1,750 RPM, the change is less than 600 RPM, the vehicle speed is between 0 and 48 km/h (0 and 30 mph), and the learning tolerance is 1%.