In the world of industrial engines, the Cummins QSB 4.5 holds a unique position.
It is the smaller brother of the popular QSB 6.7, which has always stood out with its compact design, modular construction, and high operational culture. In today's post, we will take a look at one of its first modifications – the version equipped with a Common Rail system, lacking the advanced exhaust cleaning systems that appeared in later generations.
Construction and fuel system
The Cummins QSB 4.5 is a 4.5-liter unit, with a cast iron monoblock and a cast iron cylinder head. A key element of this version is the Common Rail rail and the high-pressure pump supplying the injectors. Unlike the older 4BT 3.9, the new model uses fully electronic fuel dosage control. This system ensures precise injections and better performance characteristics across the entire RPM range. On the intake side, we find a turbocharger with a Wastegate valve. In later versions, it was replaced by more advanced variable geometry designs, controlled by a stepper motor and monitored by the ECU.
Performance and operational characteristics
Depending on the version and the equipment used, the QSB 4.5 could achieve up to 170 HP and 700 Nm of torque. The presented unit develops around 110 HP and 600 Nm – all parameters are available in the lower RPM range, making it ideal for work in machines requiring high force at low rotational speeds.
The maximum torque is available around 1500 RPM, while peak power is achieved at 2000 RPM. This is a characteristic that works perfectly in construction, agricultural, and mining machines.
Applications and design variants
The Cummins QSB 4.5 engine is used in many industries – from agricultural machines, through mining equipment, to construction and drilling machines.
Depending on the application, the oil filter mounting system was modified, among other things. In this version, a filter base integrated with an oil cooler was used, while in other configurations, the filter was moved to a convenient location in the machine. The timing system is located at the rear of the engine, on the flywheel side, which allows for better integration with equipment in machines with limited mounting space.
Modern control and sensors
In the discussed modification, the engine uses a full electronic control system (Full Authority), which supervises every element of the unit – from the turbocharger, through the EGR, to the injection system.
An extensive set of sensors monitors the position of the crankshaft and camshafts, oil pressure and temperature, as well as the operating parameters of the fuel system. An interesting solution is the integrated wiring harness for the injectors in the cylinder head gasket, which significantly simplifies the construction and servicing.
Quieter than its predecessor
Compared to older models, the Cummins QSB 4.5 generates a lower noise level – a few decibels less under identical working conditions and loads. This is the result of changes in construction and better fitting of mechanical elements.
The Cummins QSB 4.5 is a successful combination of compact design, high torque at low RPM, and the simplicity of the first modifications devoid of complicated emission systems. As a result, this engine is valued by both machine operators and service centers, which appreciate its durability and availability of parts.
The entire video can be seen here.
