Cummins QST30-G4 V12 Diesel Generator Engine

Overview

The Cummins QST30-G4 is a 30 litre V12 G-Drive diesel engine from the Cummins Quantum series, used in generator sets of roughly 800 to 1100 kVA at 50 Hz. Cummins states that the QST30 series delivers more power and torque in a smaller package than any other diesel engine on the market, using sophisticated electronics and premium engineering. The variant covered here is the fuel optimised two-pump, two-loop (2P2L) version, supplied with an integrated Coolpac and air cleaner kit.

Seven Star LLC supplies the Cummins QST30-G4 and its spares to generator assemblers, contractors, utilities and owners of large facilities in Oman and the GCC. Customers needing Cummins engine spare parts in Oman for QST30 generators can also rely on our team for filters and wear parts, from our office in Muscat.

Operating Principle

The Cummins QST30-G4 is a four-cycle, turbocharged and aftercooled diesel engine. Holset HX82 turbochargers use exhaust energy efficiently for improved emissions and fuel consumption. Charge air is cooled by a low temperature aftercooling circuit in a two-pump, two-loop arrangement: one pump and radiator loop cools the engine jacket, while a separate pump and loop keeps the aftercooler water colder, which lowers intake air temperature further than a single loop can.

The Quantum electronic fuel system and controls provide performance, efficiency and diagnostics, with electronic fuel pumps delivering up to 1100 bar injection pressure and eliminating mechanical linkage adjustments. In general engineering terms, keeping the intake air cool through a dedicated aftercooler loop is one of the most effective ways for a large engine to hold its rating in hot weather, because cooler air carries more oxygen and limits exhaust temperature.

Engineering Design of the Cummins QST30-G4

The Cummins QST30-G4 has twelve cylinders in vee configuration with a 140 mm bore and 165 mm stroke, giving 30.5 litres of displacement. Its 154 litre oil system is protected by a full-flow spin-on filter, fuel is cleaned by spin-on filters that include water separation, and the flywheel housing is SAE 0. The starting system is 24 V with a 35 A battery charging alternator.

The 2P2L Coolpac holds 141 litres of coolant mixed at 50 percent ethylene glycol and 50 percent water. Cummins lists a limiting ambient temperature of 50 degrees C at 50 Hz and 52.3 degrees C at 60 Hz, fan power of 36.2 kWm (50 Hz) and air flow of 12.6 cubic metres per second (50 Hz) at 13 mm water restriction. The package measures 3237 mm long, 2000 mm wide and 2041 mm high and weighs 3950 kg dry. A normal duty dry replaceable air cleaner element with restriction indicator is supplied.

Key Features

The Cummins QST30-G4 provides these advantages in large generator projects.

• A compact 30.5 litre V12 design gives high power and torque for its size, according to Cummins.
• Two-pump, two-loop low temperature aftercooling keeps charge air cool for strong hot-weather performance.
• The Quantum electronic fuel system injects at up to 1100 bar with no mechanical linkage adjustments.
• Holset HX82 turbocharging improves emissions and fuel consumption.
• An integrated Coolpac and air cleaner kit arrive as a complete, tested power package.
• Standby, prime and continuous ratings cover typical outputs from 774 kVA to 1103 kVA at 50 Hz.
• The same engine is rated up to 1273 kVA standby at 60 Hz for markets that need it.
• Electronic controls support diagnostics for faster service.

Industrial Applications

The Cummins QST30-G4 is a common choice for standby generators in hospitals, airports, data centres, large hotels, shopping malls and government complexes, and for prime power on mining, oil and gas and infrastructure projects. Multiple Cummins QST30-G4 sets can be synchronised to form a local power plant. In Oman and the wider GCC, the 50 degree C limiting ambient of the 2P2L Coolpac is an important specification for outdoor or containerised installations.

Seven Star LLC supplies the Cummins QST30-G4 for new generator assembly and engine replacement to customers in Muscat, Sohar, Duqm, Salalah and across the GCC, and provides model selection support from Muscat for consumables and spares. Related products include the Cummins C1000D5B 1000 kVA generator set, the Cummins QSK60-G4 V16 generator engine and the Cummins PowerCommand display-control assembly.

Technical Specifications

The data below for the Cummins QST30-G4 is taken from the Cummins specification sheet for the 2P2L fuel optimized version.

Ratings Definitions

Four rating classes appear on the Cummins sheet, all tied to ISO 8528. Standby (ESP) is for backing up a reliable grid during outages; prime (PRP) is for variable loads without an hour limit and includes a ten percent overload margin; limited-time running (LTP) applies to steady loads for a restricted number of hours; and continuous (COP) is for steady loads with no time limit. For a Cummins QST30-G4 installation, the rating should be chosen from the real load profile rather than the nameplate alone.

As general guidance for large sets, foundations, exhaust back pressure, fuel day tank sizing and room ventilation deserve as much attention as the engine selection itself. A V12 of this size moves a large volume of cooling air, and poor air flow is a common cause of high temperature shutdowns in hot climates.

How to Order

For a QST30 based power plant, an engine replacement or Cummins engine spare parts in Oman, contact Seven Star LLC with the load profile, frequency, number of sets and site details, or with the parts list and engine serial number. Our engineers in Muscat will review the request and issue a formal offer, the Cummins QST30-G4 specification sheet is downloadable below the product image, and we back every supply from our office in Muscat for Oman and the GCC.