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Start-up of a diesel engine in low ambient temperatures is difficult or even impossible without additional devices which assist in this task. The problem of engine start-up is magnified at subzero ambient temperatures. This paper presents selected results of theoretical and experimental investigations of various heating systems which allow successful start-up of a Diesel engine in such low temperatures. The presented results provide a guidance for selecting a suitable heating system.

The behaviour of hydraulic control and power systems in subzero temperatures is important to designers and operators of hydraulically driven and controlled mobile machinery which have to operate in a cold climate environment. The paper presents typical results of tests on hydraulic fluids and on components of a hydraulic system in temperature down to -50°C. The low-temperature behaviour of the hydraulic systems was characterised by non-Newtonian characteristics of the hydraulic fluid, increased pressure losses, lower system efficiency. The effect of low temperatures on rheological properties of hydraulic fluids and characteristics of basic hydraulic components used in mobile machinery are discussed.

The operational behaviour of hydraulic and mechanical systems in subzero temperatures is of considerable interest to manufacturers and operators of mobile and earthmoving machines which work in extremely cold climatic conditions. The majority of such machines are designed for operation in moderate climatic conditions and will have to be specially adapted for working in very low temperatures. The adaptation of such machines to operation in subzero temperatures and verification of their operational limits may be very expensive as it usually requires field testing. To carry out such tests the machines and test equipment must be transported to a low temperature zone. The conduct of tests is weather dependent and only limited modifications to machines are possible under field conditions.