D4AF is an inline 4-cylinder engine with water-cooled and direct injection of diesel fuel with a displacement of 3.6 liters, which was installed on the Hyundai HD 65, HD 72, HD 78 trucks, designed for the transport of medium-tonnage loads (3.5 – 5 t ). The engine develops power up to 100 horsepower at 3400 rpm.
The combustion chamber of the engine consists of a cylinder head and an annular piston, while pinless fuel injectors are mounted in the cylinder head. With direct injection of fuel into the combustion chamber, the fuel-air mixture is ignited, which ensures the working stroke of the piston. The piston on this engine is cast, from an aluminum alloy with an insert inside, which provides the necessary clearance between the piston and the cylinder liner.
|Configuration||4-stroke, water-cooled and direct injection|
|Number of cylinders||4|
|Piston stroke, mm||105|
|Cylinder bore, mm||104|
|Power output, hp||100|
|Torque output, Nm / rpm||235|
The Hyundai D4AF engine belongs to the overhead valve type:
- Both inlet and outlet valves are made of surface-treated heat-resistant steel. The seat cone angle for both valves is 45 degrees. The valve stem is fitted with an oil scraper cap that regulates the amount of lubricant on the sliding surfaces between the valve and the guide sleeve.
- There are two unequally adjusted valve springs – an external and an internal one, the turns of which are opposite to each other.
- The rocker shaft is a hollow rounded rod with sealing caps at both ends for sealing. An oil channel runs inside. A steel ball tip is attached to the lower end of the pusher rod, and a spherical or concave tip is attached to the upper end. Both tips are made of case hardened high carbon steel.
The engine block of the D4AF engine is made of cast iron and is a rigid structure with a minimum concentration of stress and deformation. Three camshaft bushings are mounted in the camshaft bearings in the cylinder block.
Explanation of D4AF marking
|D||Motor fuel – diesel|
|4||Number of cylinders – 4|
|A||Engine Development Order|