Waldo Report post Posted February 7 11 hours ago, MeeLee said: My fusion charges the battery only if the battery level is low. If it is high, it actually drains the battery, as shown by the indicators, and lower mpg on trips. Have you never noticed this? As explained by an engineer, the battery sends power to both generator and power motor, and both of them will start working against one another, generating a massive amount of braking torque. "Massive" being rather small on a 4 ton car using only a 40hp motor. The generator and "power motor" are the same thing. What you're describing would essentially be throwing the vehicle in reverse and having the motor try to spin the wheels backwards. This would be incredibly unsmooth, and waste energy, never mind potentially dangerous. The Fusion does not do this, it only uses the generator to charge the battery and slow the car. When the battery is too full, it uses the friction brakes instead. This is clearly documented in the Ford Workshop manual. Brake Modes Because much of the brake torque required to stop the vehicle can be achieved through regenerative braking, it is not always necessary for the conventional friction brakes to be applied. The brake pedal uses a pedal feel simulator that acts against a curved bracket to give the driver a simulated pedal resistance as the brake pedal is applied. The ABS module uses the driver input on the brake pedal, wheel speed sensor input and the lateral deceleration messages from the RCM to determine the amount of deceleration the driver is requesting and which brake mode is necessary. Friction Braking Mode Under some circumstances, the brake torque generated by the electric motor is insufficient to bring the vehicle to a safe, controlled stop and requires the assistance of the conventional friction brakes. Additionally, the state-of-charge in the High Voltage Traction Battery (HVTB) may not allow for regenerative braking to take place or the vehicle may be experiencing an ABS or stability control event. In these instances, the ABS module activates a mechanical relay which supplies power to the brake vacuum pump. At the same time, the ABS module sends a PWM voltage to a solenoid mounted on the brake booster. The solenoid allows vacuum from the vacuum pump to enter the brake booster which moves the booster push rod and applies the conventional friction brakes. During certain braking events, the friction brakes can be applied directly by the driver. The brake booster push rod is equipped with an adjustable stop, once the brake pedal travels far enough to engage the stop, the brake booster push rod is forced into the master cylinder and the conventional friction brakes are applied. Regenerative Braking Mode The ABS module determines the amount of braking torque necessary and sends that info to the PCM along with the current threshold for ABS intervention. The PCM determines how much braking torque the electric motor can provide based on the High Voltage Traction Battery (HVTB) state-of-charge and sends this information back to the ABS module. At the same time, the electric motor is switched to a generator which supplies the determined amount of braking torque. Based on the amount of braking torque the PCM can deliver, the ABS module determines whether it is necessary to apply the friction brakes or if the brake torque from the electric motor is sufficient to safely stop the vehicl Quote Share this post Link to post Share on other sites
