A heavy-duty truck's engine control module (ECM) is programmed for advanced injection timing at higher engine loads to optimize fuel efficiency. If the ECM uses an injection advance curve that increases timing by 0.5 degrees for every 100 Nm of torque increase, and the base timing at no load is 6 degrees BTDC, what is the injection timing at an engine output of 1200 Nm of torque?

Question: A heavy-duty truck's engine control module (ECM) is programmed for advanced injection timing at higher engine loads to optimize fuel efficiency. If the ECM uses an injection advance curve that increases timing by 0.5 degrees for every 100 Nm of torque increase, and the base timing at no load is 6 degrees BTDC, what is the injection timing at an engine output of 1200 Nm of torque?

Answer options:

• 10 degrees BTDC ✅ 12 degrees BTDC
• 15 degrees BTDC
• 18 degrees BTDC

Correct answer: 12 degrees BTDC

Explanation: The torque increase is 1200 Nm. The timing advance is 0.5 degrees per 100 Nm, so (1200 Nm / 100 Nm) * 0.5 degrees = 12 * 0.5 degrees = 6 degrees advance. The total injection timing is base timing + advance = 6 degrees BTDC + 6 degrees = 12 degrees BTDC.