Trip Computer: Description and Operation
Description
Trip computer receives all the information related to the trip and displays various data including the average speed from the ignition ON till the ignition OFF, average fuel consumption, current fuel consumption, driving time, outside temperature, time (including month and date) and distance to empty with the remaining fuel displaying them on the LCD of radio of audio system, tape and CD.
Switches and functions
Multi function key has switches such as "TRIP", "RESET", "O ", "\/", "SET" and "DATE".
1. TRIP switch
Mode is changed as shown whenever the switch is pressed once.
Distance to empty -> Driving distance -> Average speed -> Average fuel consumption -> Current fuel consumption -> Driving time -> Outside temperature
When the TRIP switch is pressed for more than a second, monitor turns off, and the monitor turns on if pressed again.
2. RESET switch
The system is initialized if the reset button is pressed for more than a second in the mode except distance to empty, outside temperature and current fuel consumption.
If the switch is pressed in outside temperature mode, it converts from Fahrenheit to Centigrade and vice versa.
If the reset button is pressed when the monitor is off, then monitor turns on.
3. UP switch
It operates while the "DATE" button is pressed.
Number increases one by one in every switch press in "MONTH", "DATE", "HOUR" and "MINUTE" reset mode. It increases quickly with the interval of 200 msec if the switch is pressed for more than 2 seconds.
4. DOWN switch
It operates while the "DATE" button is pressed.
Number decreases one by one in every switch press in "MONTH", "DATE", "HOUR" and "MINUTE" reset mode. It decreases quickly with the interval of 200 msec if the switch is pressed for more than 2 seconds.
5. SET switch
It operates while the "DATE" button is pressed.
Release the button if it is "DATE or HOUR' reset mode. Then, it starts from the 0 second again.
6. DATA switch
"DATE or HOUR" is changed if the "DATE" switch is pressed. Mode changes as follow whenever the switch is pressed once. Corresponding icon blinks.
HOUR -> MINUTE -> MONTH -> DATE -> SETTING completed
If the setting is complete, press the "MODE" switch again when the "MINUTE" blinks.
NOTE:
If "TRIP" + "RESET" switches are pressed simultaneously for more than 5 seconds, all settings are initialized.
Input/output characteristics
Input/output diagram
Input specification
1. BAT (+)
It is connected to the vehicle battery (DC 13.5V).
2. Speed sensor
Vehicle condition that keeps the speed of 60km/h at 637 RPM
637x 4 pulse/60sec=60km/h
3. Engine ECU (Fuel injection amount)
80mcc of fuel is injected per pulse.
4. ILL(+): Tail lamp switch
It is inputted from the switch to turn on the headlamp and tail lamp at night.
When the LCD is on, the brightness of LCD is reduced to the 80% of the daytime level.
5. Fuel sender
Input signal from fuel sender is the voltage detected in the fuel sender is almost proportional to the fuel level.
6. Fuel cap opening switch
This switch inputs B+ voltage for a while to judge the fuel filling status.
7. Outside temperature sensor
Voltage depending on the ambient temperature is inputted when the ignition is on.
Output specification
1. Watch and date
A. Display range :
Watch : 24 hour mode (00:00 - 23:59)
Month : 01 - 12
Date :01 - 31
B. Tolerance : ±2sec/day
C. It is displayed all the time after ACC
D. Mode is changed in the following sequence when the "DATE" button is pressed.
HOUR-> MINUTE -> MONTH ->DATE
E. Current reset mode is release when the "SET" button is pressed. Then, the second display starts with 0 again.
F. If "O" and "▼" button is not pressed within 10 seconds after "SET" button pressing, then the mode will be released.
G. Letter ":" between hour and minute blinks all the time.
H. Watch is set by the "DATE", "O", "▼" and "SET" button operation.
2. Distance to empty (DTE)
A. Display range: 50 km ~, 31 MILES ~
B. Tolerance : ± 30km, ± 20 miles
C. It displays the driving distance with the remaining fuel by applying the variable fuel consumption.
D. Since the display is not operative before the ignition on, only "---" is displayed.
E. If DTE is less than 50km, 31 miles, LCD displays "---" mark on and off with the time interval of 0.5 sec. (Audio installed vehicle)
F. DTE reduction in idle state (stopping at the traffic signal or temporary stopping) is based on the official fuel economy.
3. Driving distance (DD)
A. Display range: 0 - 999.9 km, 0 - 621.3 miles
B. Resolution : 0.1 km, 0.1 mile
C. Tolerance : ± 1km/100km, ± 2 miles / 130 miles
D. Since the vehicle speed is not provided before the ignition on, only "---" is displayed.
E. When the reset switch is turned on, accumulated driving distance is reset to 0
F. Accumulated driving distance is on display until engine cut off and ACC off. And it displays the accumulated driving distance after engine start, and keeps accumulating thereafter.
Accumulated driving distance remains even after ACC off.
G. Driving distance = Accumulated No. of pulses of vehicle speed
4. Average vehicle speed (AVS)
A. Display range: 0 - 250 km/h, 0 - 120 MPH
B. Tolerance : ± 3km/h, ± 2 miles / 130 miles
C. It starts calculating after 4-speed pulse from the ignition on.
D. Upon ACC on, the last average speed is reset to zero.
E. Upon restart, the previous average speed is reset to zero.
F. Upon reset switch on, current accumulated value will be reset to zero.
G. It displays average speed by calculating the accumulated speed from ignition on to ignition off.
H. Speed display is updated every second.
I. Average speed = Driving distance (accumulated) / driving time (accumulated)
5. Driving time (DT)
A. Display range: 00:00 - 99.59 hour
B. Tolerance : 2 min/ 99 hour
C. It starts calculating after 4-speed pulse from the ignition on.
D. Upon reset switch on, current accumulated value will be reset to zero.
E. It displays "---" before the ignition on because there is speed input.
F. It displays driving time by calculating the accumulated distance from ignition on to ignition off. Driving time remains unchanged even after the ACC off. And it revives the existing value and keeps accumulating.
6. Ambient temperature (AT)
A. Display range: -40.0 - 80.0 °C, 0 - 176°F
B. Resolution : 0.5°C, 0.5°F
C. Tolerance : ± 3°C, ± 5°F
D. Reset switch converts Fahrenheit to centigrade vice versa. It displays the average temperature for 1 second using the ambient temperature sensor installed on the vehicle. Temperature display increases at 0.5 °C per 90 seconds and decreases at 0.5 °C per 2 seconds
E. Temperature display does not increase if the vehicle speed is below 10 km/h. (Though, temperature display decreases regardless of vehicle speed)
F. It displays -40 °C if the temperature is below -40 °C, and displays 80 °C if the temperature is above 80 °C.
G. It displays "---" before the ignition on because sensor is not operating.
7. Average fuel consumption (AFC)
A. Display range: 0 - 20l/100km, 0 - 9 MPG
B. Tolerance : ±1l/100km, ± 0.5MPG
C. It starts calculating after 4-speed pulse from the ignition on.
D. It starts displaying AFC information after driving 500m.
E. It displays the information by calculating the cumulative driving distance and fuel injection from ignition on to ignition off. And it keeps the previous average fuel economy information even after the ACC off.
F. Accumulated data is reset to zero if the RESET button is pressed.
G. It displays "---" before the ignition on because sensor is not operating.
H. Average fuel consumption = injector injection amount / driving distance
8. Momentary fuel consumption (MFC)
A. Display range: 0 - 50l/100km, 0 - 23 MPG
B. Tolerance : ±1l/100km, ± 0.5MPG
C. It starts calculating after 4-speed pulse from the ignition on.
D. It displays the information by calculating the cumulative driving distance and fuel injection for every 0.5 second.
E. It displays "---" before the ignition on because sensor is not operating.
F. When the speed = 0 km/h and ENG = ON, it displays "---". Besides, it displays "---" (in MPG), if there is no fuel consumption while driving.
G. Momentary fuel consumption = injector injection amount / driving distance
