Overview

Winter can be very cold in Nordic countries; it is fairly normal to have temperatures below -20°C. Not everyone has a warm garage for their vehicles, so many people use an engine preheater, like the one shown in Figure 1.

The engine preheater is mounted into the vehicle (Figure 2) and typically heats the water inside the engine.

Starting a vehicle in a cold environment will put an engine under heavy stress. Starting an engine at -30°C puts the same wear on the engine as driving 600km (373 miles). Gasoline consumption during a cold start is much higher than the start of a preheated engine. Preheating the engine results in energy and cost savings, and creates less pollution.

There are two types of preheaters: one uses gasoline as energy and the other uses electricity. This article describes how to design a temperature-based heating system for an electrical engine preheater. Regardless of whether one uses an engine block heater, hose heater, oil heater, or contact heater—this temperature-based heating system described in this article will function correctly.