TRUCK EXPERTS” EGR system

The range includes elements and components that can be repaired without harming the engine or combustion process. Particularly noteworthy are the repair kits for EGR system coolers. Such a kit includes the radiator core and all sealing and mounting elements. Instead of the EGR cooler repair kit, a remanufactured radiator can be chosen.

Another convenience for EGR system repairs is the range of remanufactured exhaust gas coolers with new or remanufactured EGR valves. During professional remanufacturing, the EGR cooler receives a new core, and the valve component is fully restored, e.g., by replacing the housing or moving valve element. The availability of parts for EGR system repairs in the Highway Automotive range significantly reduces repair costs and speeds up maintenance work. Currently, it is also particularly relevant that such repairs have a positive impact on reducing CO₂ emissions, as already manufactured parts are reused, saving the energy required for producing new ones.

EGR Valves

The EGR valve consists of two parts: a mechanical valve and a control unit. The mechanical part is usually a mushroom-shaped valve that closes the exhaust manifold outlet and directs exhaust gases into a special intake manifold connection. Often, especially in commercial vehicle engines, the exhaust gases directed into the intake manifold are cooled in the EGR cooler. Radiators can be of the exhaust gas-to-air or exhaust gas-to-coolant type. The choice depends on engine size, parameters, and purpose. Exhaust gases pass into the intake manifold through the valve under their own pressure.

The second part of the valve is the control unit, which moves the mechanical parts. The valve control unit is operated by the engine computer. Two EGR valve control systems are used: a vacuum actuator and a stepper motor system. The vacuum actuator is connected to the engine intake system – it uses vacuum from the intake manifold to operate the valve. An electric valve controlled by the engine computer is installed at the actuator’s inlet. When the valve is open, the vacuum pulls the membrane, which opens the EGR valve. The valve opening time determines the amount of exhaust gas in the recirculation process. The other control method uses a stepper motor. The motor, connected via a gear to the valve, allows stepless opening and closing. The engine computer regulates the stepper motor, which sets the EGR valve position. EGR valve failures usually occur due to soot accumulation on moving or sealing parts. Soot forms due to poor-quality fuel or engine wear when engine oil enters the intake system. Moving valve elements can also seize due to high temperatures caused by, for example, improper air-fuel mixture, damage to the EGR cooler, or loss of performance.

The mechanical part must withstand high exhaust gas temperatures, and the valve materials must be selected to prevent seizing and dimensional changes under heat. In small gasoline engines, EGR valves are non-serviceable; if they fail, the entire valve must be replaced. In commercial vehicle engines, such as in tractor trucks, construction machinery, and other vehicles, EGR valves can be serviced with repair kits. This range allows users to save on spare parts and create certain “stock” parts, which significantly reduces future repair times.