Determinants of firing order in multi-cylinder I.C. engines On what design factors does the firing order primarily depend when laying out a multi-cylinder internal combustion engine?

Introduction / Context:
The firing order determines vibration characteristics, crankshaft loading, exhaust pulse timing, and acoustics. Selecting an order is a multidisciplinary compromise among mechanical balance, torsional dynamics, and gas-exchange tuning.

Given Data / Assumptions:

• Multi-cylinder engine design problem.
• Crankshaft geometry fixed by cylinder arrangement and bank angle.
• Goal: smooth torque delivery, acceptable NVH, and good breathing.

Concept / Approach:
Because each firing event imposes forces and produces exhaust pulses, the spatial cylinder arrangement, crankpin phasing, and total cylinder count jointly constrain feasible firing sequences. Designers test candidate orders via torsional vibration analysis and gas-dynamic simulations to achieve even firing intervals and desirable pulse pairing.

Step-by-Step Solution:

Verification / Alternative check:
Common orders (e.g., 1-3-4-2 for inline-4) arise from these constraints and are validated by NVH testing and durability calculations.

Why Other Options Are Wrong:

Any single factor alone cannot fully dictate firing order; it is a combined optimization. Drivetrain layout is not a primary determinant.

Common Pitfalls:
Assuming firing order is chosen arbitrarily or solely for sound; it fundamentally affects mechanical stresses and smoothness.

Final Answer:

all of these