AssetTrader Buying Guide to Diesel Engines

Introduction

There are two types of diesel engine, two strok and four stroke.

With two stroke engines there is a power stroke every second movement of the piston, with the four stroke this happens every fourth (Intake, Compression, Injection (power) and Exhaust).

When it comes to efficiency, Diesel Engines are superior to Petrol engines of similar output power. A good rule of thumb is that the diesel engine is 40% more efficient in terms of miles per gallon.

Across the industry, diesel engines are often categorised into three rough classes:
Low Speed Engine: These are the largest diesel engines (up to 15m tall) and are used typically to power ships. They are two stroke and have power outputs of up to 80MW operating at between 60 to 120 rpm. Running on low-grade (and therefore low viscosity) fuel, these diesel engines need the fuel to be heated prior to injection.
Medium Speed Engine: These engines are often used to power electic generators and are normally four stroke units. They run at between 300 and 1200 rpm, with the speed set depending on the generation frequency required (50 or 60 Hz).
High Speed Engine: High speed engines are designed to power trucks, buses, tractors etc. and run at approximately 1200rpm or more

Diesel engines are highly flexible and can run on a number of different fuel types. Diesel fuel from crude oil is the most common, however good quality diesel fuel can be obtained from alcohol and vegetable oil. Biodiesel as it is known, is growing in popularity, however it is still not widely available.