Vehicle Sound Amplification: Description and Operation

SYSTEM

System Description


SYSTEM DIAGRAM







SYSTEM DESCRIPTION

- The approaching vehicle sound for pedestrians (VSP) system activates the VSP speaker during motor driving (engine is stopped), notifying pedestrians that the vehicle is approaching.
- Other than during motor driving (engine is running), VSP system is inactive.
- The VSP control unit is connected to the parts listed below, and it controls VSP system according to the input signals.
- Combination meter (VSP OFF indicator)
- Stop lamp switch
- VSP speaker
- The combination meter sends the following signals to the VSP control unit via communication line.
- Engine status signal
- Vehicle speed signal
- Ignition signal
- Shift position signal
- Reverse warning buzzer signal
- The VSP control unit sends the VSP OFF indicator signal to the combination meter via communication line.
- The VSP system consists of the following 3 types.
- Driving start sound
- Driving sound
- Reverse sound
- The VSP OFF indicator turns ON when a malfunction occurs in the VSP system.
- The VSP control unit has a diagnostic function. Diagnosis can be performed using CONSULT.

DRIVING START SOUND

- The driving start sound operates during motor driving (engine is stopped) when the selector lever is in the
"D" position and the brake pedal is released.
- The system switches to the driving sound after the driving start sound time (500 ms) ends.
- Other than during motor driving (engine is running), the driving start sound is inactive.
Operation Description
- The combination meter sends the following signals to the VSP control unit via the communication line.
- Ignition signal
- Shift position signal
- Engine status signal
- Vehicle speed signal
- Reverse warning buzzer signal
- The VSP control unit judges the driving start sound based on the signals input from the combination meter and on the stop lamp switch signal input from the stop lamp switch.
- When the VSP control unit judges that the driving start sound is necessary, it outputs the VSP speaker signal to the VSP speaker.
Operation Condition
The driving start sound operates when all of the following conditions are met.





Cancel Condition
The driving start sound operation stops when the following conditions is met.





NOTE:
The system switches to the driving sound after the driving start sound time (500 ms) ends.
Signal Path
- The VSP control unit judges operation of the driving start sound function based on the signal shown below, and it operates the driving start sound.





- When the VSP control unit judges that the driving start sound is necessary, it outputs the signal shown below.





Timing Chart











DRIVING SOUND

- The driving sound operates according to the vehicle speed during motor driving (engine is stopped) when the vehicle speed is 1 km/h (0.6 MPH) or more.
- The driving sound tone frequency changes in accordance with the vehicle speed.
- When accelerating, the driving sound operates until the speed reaches 30 km/h (19 MPH). When decelerating, the driving sound begins operating at 25 km/h (16 MPH).
- Operation stops when the vehicle is stopped or the vehicle speed reaches 0 km/h (0 MPH).
- Other than during motor driving (engine is running), the driving sound is inactive.
Operation Description
- The combination meter sends the following signals to the VSP control unit via the communication line.
- Engine status signal
- Vehicle speed signal
- Shift position signal
- The VSP control unit judges the driving sound based on the signals input from the combination meter.
- When the VSP control unit judges that the driving sound is necessary, it outputs the VSP speaker signal to the VSP speaker.
Operation Condition
The driving sound operates when the following conditions are met.






Cancel Condition
The driving sound operation stops when the following conditions are met.





NOTE:
When vehicle speed is less than 1 km/h (0.6 MPH).
Signal Path
- The VSP control unit judges operation of the driving sound function based on the signals shown below, and it operates the driving sound.





- When the VSP control unit judges that the driving sound is necessary, it outputs the signal shown below.





Timing Chart











REVERSE SOUND

- The reverse sound activates during motor driving (engine is stopped) when the selector lever is in the "R"
position.
- Other than during motor driving (engine is running), the reverse sound is inactive.
Operation Description
- The combination meter sends the following signals to the VSP control unit via the communication line.
- Shift position signal
- Reverse warning buzzer signal
- The VSP control unit judges the reverse sound based on the signals input from the combination meter.
- When the VSP control unit judges that the reverse sound is necessary, it outputs the VSP speaker signal to the VSP speaker.
Operation Condition
The reverse sound operates when the following conditions are met.





Cancel Condition
The reverse sound operation stops when the following conditions are met.





Signal Path
- The VSP control unit judges operation of the reverse sound based on the signals shown below, and operates the driving sound.





- When the VSP control unit judges that the reverse sound is necessary, it outputs the signal shown below.





Timing Chart











VSP SYSTEM MALFUNCTION DETECTION FUNCTION

When a malfunction in the VSP system is detected, the VSP OFF indicator turns ON.
Signal Path
- When the VSP control unit detects a VSP system malfunction, it sends the VSP OFF indicator signal to the combination meter via the communication line.
- The combination meter turns the VSP OFF indicator ON/OFF when the signal shown below is input.