Cylinder blocks with multi-cylinder sleeves — principal merit Considering engine design trade-offs, what is the main merit of using a multi-cylinder type cylinder sleeve arrangement?

Introduction / Context:
Engine designers may use multi-cylinder sleeve or siamesed/cluster liner arrangements to package multiple cylinders tightly. The choice impacts block size, cooling passages, rigidity, serviceability, and manufacturing cost.

Given Data / Assumptions:

• Packaging priority (compact engine bay, reduced mass).
• Multi-cylinder sleeve concept aims to integrate or closely package liners across adjacent cylinders.
• Typical light-vehicle design constraints.

Concept / Approach:
By bringing cylinder bores closer together and simplifying liner interfaces, designers can reduce overall engine length/width and mass. This yields smaller external dimensions for a given displacement or allows more cylinders in a compact space, improving platform flexibility.

Step-by-Step Solution:
Assess trade-offs: space vs cooling and rigidity.Siamesed or multi-sleeve blocks reduce coolant gap between cylinders.Net effect: tighter packaging → smaller engine external dimensions.

Verification / Alternative check:
Many compact engines use siamesed bores (e.g., high-output small blocks) to fit within small engine bays; CAD packaging studies confirm dimension reductions relative to widely spaced bores.

Why Other Options Are Wrong:

• Better cooling efficiency: close bore spacing often challenges cooling, not improves it.
• High rigidity: can improve locally but not necessarily the primary merit versus packaging.
• None of these: a clear merit exists in packaging compactness.

Common Pitfalls:
Assuming any multi-sleeve design automatically improves cooling; engineers must carefully design coolant jackets to avoid hotspots.

Final Answer:
smaller engine dimensions