SsangYong Rodius (2013 year). Manual - part 73

10-4

1. OVERVIEW

The pre-heating system for D20DTR engine has the glow plug to the cylinder head (combustion 

chamber), and improves the cold start performance and reduces the emission level.

The pre-heating resistor (air heater) is used to heat the intake air.

This enables the diesel fuel to be ignited in low temperature condition.

The ECU receives the information such as, engine rpm, coolant temperature, engine torque, etc., 

through CAN communication during pre-heating process; and the pre-heating control unit controls the 

pre-heating, heating during cranking and post-heating by the PWM control.

Glow plug

Engine ECU (D20DTR)

Glow indicator

Glow plug control unit 

(GCU)

10-5

1413-00

2. SYSTEM OPERATION

1) Input/Output Diagram of Glow Plug Control Unit

2) System Diagram

10-6

3) Circuit Diagram

10-7

1413-00

4) Operation

Glow plug is installed in the cylinder head. It enhances the cold starting performance and reduces the 

exhaust gas during cold starting.

ECU receives the data (engine rpm, coolant temperature, vehicle speed) through CAN lines. Based on 

the data, GCU controls the pre-glow, cranking and post-glow. It also checks the glow plugs, and sends 

the result to ECU.

(1) Temperature/Current Properties of GCU

GCU increases the temperature of glow plug very rapidly (approx. 2 seconds up to 
1000°C)

FETs (similar to transistor) for each cylinder are integrated in GCU. During the pre-glow 

period, battery voltage is supplied to the glow plugs directly to heat them rapidly.

After getting the desired temperature by pre-glowing, the temperature is controlled by duty 

ratio.

Step 1:

Step 2 & 3: 

Step 4:

This shows the supplying voltage and time by GCU in each step. The step 4 is the period to keep 

the temperature.  

-

Step 1: I1

Step 2: I2

Step 3: I3

Step 4: I4