Factors Influencing Engine Torque: A Comprehensive Playbook

Factors influencing engine torque can be broadly categorized into three groups: actuator factors, environmental status factors, and engine operating status factors. These factors play a crucial role in determining the overall performance and efficiency of an engine.

Actuator Factors

  1. Accelerator Pedal Percentage: The accelerator pedal percentage directly affects the amount of fuel injected into the engine, which in turn influences the engine’s torque output. A higher accelerator pedal percentage typically results in increased torque, while a lower percentage leads to a reduction in torque.

  2. Fuel Injection Timing and Quantity: The timing and quantity of fuel injection are critical factors that impact engine torque. Precise control of these parameters can optimize the combustion process, leading to increased torque and improved fuel efficiency.

  3. Fuel Injection Timing: The optimal timing of fuel injection can vary depending on engine speed, load, and other operating conditions. Retarding the injection timing can increase torque at low engine speeds, while advancing the timing can improve torque at higher speeds.

  4. Fuel Injection Quantity: The amount of fuel injected directly affects the air-fuel ratio, which in turn influences the engine’s torque output. Increasing the fuel injection quantity can boost torque, but excessive fuel can lead to incomplete combustion and reduced efficiency.

Environmental Status Factors

factors influencing engine torque

  1. Ambient Temperature: The ambient temperature can have a significant impact on engine torque. As the temperature increases, the air density decreases, which can lead to a reduction in the mass of air entering the engine. This can result in a decrease in the engine’s torque output.

  2. Studies have shown that a 10°C increase in ambient temperature can lead to a 2-3% decrease in engine torque [1].

  3. The impact of ambient temperature on engine torque is more pronounced at higher engine speeds and loads.

  4. Battery Voltage: The battery voltage can also influence engine torque, as it affects the performance of the engine’s electrical systems, such as the fuel injection and ignition systems. A low battery voltage can result in reduced torque output due to suboptimal fuel delivery and ignition timing.

  5. Typically, a battery voltage below 12V can lead to a noticeable decrease in engine torque [2].

  6. Maintaining a healthy battery voltage is crucial for ensuring consistent and reliable engine performance.

Engine Operating Status Factors

  1. Engine Temperature: The engine’s operating temperature can have a significant impact on torque output. As the engine warms up, the viscosity of the lubricating oil decreases, reducing mechanical losses and allowing the engine to produce more torque.

  2. Studies have shown that a 10°C increase in engine temperature can result in a 1-2% increase in engine torque [3].

  3. Ensuring the engine operates within its optimal temperature range is essential for maximizing torque output.

  4. Exhaust Pollutants: The presence of exhaust pollutants, such as nitrogen oxides (NOx), can also influence engine torque. Increased levels of these pollutants can indicate issues with the engine’s combustion process, which can lead to a reduction in torque output.

  5. Correlation analysis has shown that engine torque and NOx raw emissions are closely related, with a correlation coefficient of up to 0.9 [4].

  6. Monitoring and controlling exhaust pollutants can help maintain optimal engine torque and performance.

By understanding these factors and their impact on engine torque, engineers and technicians can optimize engine performance, improve fuel efficiency, and ensure reliable operation. Accurate measurement and monitoring of engine torque, using tools like dynamometers or torque telemetry systems, are essential for making informed decisions and implementing effective maintenance strategies.


  1. Li, Y., Duan, X., Fu, J., Liu, J., Wang, S., Dong, H., & Xie, Y. (2019). Development of a method for on-board measurement of instant engine torque and fuel consumption rate based on direct signal. Procedia Computer Science, 170, 671-676.
  2. Yuan, Z., Shi, X., Jiang, D., Liang, Y., Mi, J., & Fan, H. (2022). Data-Based Engine Torque and NOx Raw Emission Prediction. Energies, 15(12), 4346.
  3. Quantitative study on influence factors of power performance of variable valve timing (VVT) engines and correction of its governing equation. (2017). ResearchGate. DOI: 10.13140/RG.2.2.35394.63097
  4. Horsepower vs Torque: How Both Provide Insight into Engine Performance. (2022). Binsfeld Engineering. https://binsfeld.com/horsepower-torque/