Engine classifications — alternate names for Diesel engines Diesel engines are also commonly referred to as which of the following?

Introduction / Context:
Internal combustion engines are commonly categorized by their ignition method. Accurately naming Diesel engines is foundational to understanding fuel systems, combustion characteristics, and emission control strategies.

Given Data / Assumptions:

• Standard reciprocating internal combustion engines.
• No exotic mixed-mode systems are considered.
• Terminology uses the conventional S.I. and C.I. abbreviations.

Concept / Approach:
Diesel engines compress only air to a high pressure and temperature. Near top dead center, fuel is injected and ignites due to the heat of compression. Therefore, the correct descriptor is compression ignition. Spark plugs are not used to initiate combustion, distinguishing them from spark ignition petrol engines.

Step-by-Step Solution:
Identify ignition source: self-ignition from compressed air temperature.Map to terminology: compression ignition (C.I.).Exclude other categories: spark ignition and external combustion (steam) are not applicable.

Verification / Alternative check:
Technical literature universally refers to Diesel engines as C.I. engines. Emissions regulations and fuel injection texts use this term consistently.

Why Other Options Are Wrong:
S.I. engines use a spark plug to ignite a premixed charge. Steam engines are external combustion systems where fuel burns outside the working cylinder to create steam.

Common Pitfalls:
Assuming glow plugs are ignition sources; they only aid cold starting by warming the air. The combustion event remains compression-initiated.

Final Answer:
compression ignition (C.I.) engines