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🧊thermodynamics ii review

key term - Bore-to-stroke ratio

Citation:

Definition

The bore-to-stroke ratio is a key engine design parameter that compares the diameter of the cylinder bore (the width) to the length of the piston stroke (the distance the piston travels). This ratio affects engine performance characteristics such as power output, torque, and efficiency. A higher bore-to-stroke ratio typically indicates a more performance-oriented engine, whereas a lower ratio may suggest a focus on low-end torque and efficiency.

5 Must Know Facts For Your Next Test

  1. A bore-to-stroke ratio greater than 1.0 indicates that the bore is larger than the stroke, which is common in high-revving engines designed for maximum power output.
  2. Engines with a lower bore-to-stroke ratio often produce more torque at lower RPMs, making them suitable for heavy-duty applications.
  3. The choice of bore-to-stroke ratio can influence fuel efficiency; a well-balanced ratio can enhance both power and efficiency.
  4. Engine manufacturers often optimize the bore-to-stroke ratio based on the intended use of the vehicle, such as racing or everyday driving.
  5. Changes in bore or stroke during engine design can have significant impacts on overall engine dimensions and weight, affecting vehicle handling and performance.

Review Questions

  • How does altering the bore-to-stroke ratio affect engine performance characteristics?
    • Altering the bore-to-stroke ratio directly impacts an engine's performance by influencing its power delivery and torque curve. A higher bore-to-stroke ratio typically allows for increased power at higher RPMs, making it suitable for performance applications. Conversely, a lower ratio may enhance torque at lower RPMs, benefiting applications that require strong pulling power or towing capacity.
  • Discuss how different industries might prefer varying bore-to-stroke ratios in their engines and why.
    • Different industries prioritize specific performance traits based on their operational needs. For example, racing engines benefit from higher bore-to-stroke ratios for better high-end power, while commercial vehicles might opt for lower ratios to achieve greater torque at low speeds. This divergence reflects how each industry balances factors like speed, load capacity, and fuel efficiency based on their unique demands.
  • Evaluate the implications of selecting a specific bore-to-stroke ratio when designing an engine for electric vehicles versus traditional internal combustion engines.
    • When designing engines for electric vehicles compared to traditional internal combustion engines, selecting a specific bore-to-stroke ratio can significantly influence performance metrics. Electric vehicles prioritize efficiency and may favor designs that maximize power delivery across a broad RPM range, potentially leading to different optimization strategies for bore and stroke. In contrast, traditional combustion engines might focus on maximizing torque or high-end horsepower depending on their application. The decision ultimately reflects broader trends in energy utilization and performance expectations in modern automotive engineering.