EVO-MT® System Technology
The EVO-MT® System has been developed as a fully integrated solution and includes all required hardware for conversion to LNG operation. The EVO-MT® System is comprised of various components and assemblies that are retrofitted into the haul truck’s engine bay, chassis and operator cabin. The installation of the EVO-MT® System is performed onsite and without significant modification to the vehicle or engine utilizing conventional shop facilities and general technical labor. Installation typically requires 3 to 4 days using a 4 man crew working a single shift operation. After the EVO-MT® System has been installed, the truck can be operated on either 100% diesel fuel or on a combination of diesel fuel and LNG. The operating fuel mode can be manually selected if desired, however the system has been designed to automatically utilize LNG whenever it is available. In the event that the on-board LNG supply is exhausted, the System automatically reverts the engine to 100% diesel operation irrespective of operating mode or load condition. The switch from LNG/diesel (NG+D®) mode to 100% diesel mode is seamless and requires no action by the operator. After the LNG supply is replenished, the EVO-MT® System automatically reverts the engine to LNG+D mode. When operating NG+D® mode, the converted haul truck meets or exceeds OEM standards for performance, efficiency and reliability.
Engine Conversion
The EVO-MT® System allows for the in-frame conversion of the haul truck engine to NG+D® operation. The conversion process utilizes components that are installed externally of the engine and no changes or modifications to the cylinders, pistons, fuel injectors or cylinder heads are required. The EVO-MT® System retains the OEM diesel fuel system in its entirety and the engine maintains the capability to operate solely on diesel fuel when required. The EVO-MT® System interfaces with the engine cooling circuit in order to supply high temperature coolant to a heat exchanger / vaporizer for efficient conversion of the LNG from a liquid to a vapor state. Once the LNG is converted to a vapor phase, it is supplied to the engine’s air-intake system at a point upstream of the turbo-compressor inlets using low restriction air-gas mixing technology.
Protection and Control
The EVO-MT® System includes a powerful Electronic Control Unit (ECU) that monitors critical engine, chassis and System data and uses this information to dynamically control the operating fuel mode of the engine. The EVO-MT® System ECU also provides sophisticated engine protection and monitoring functionality with pre-alarm, alarm and shut-down logic that allows the engine to be switched from NG+D® mode to diesel-only operation seamlessly and automatically. These protective systems and control algorithms ensure continued engine reliability and uptime when operating on LNG. The ECU monitors critical engine parameters including exhaust gas temperature, manifold air temperature, vibration, engine coolant temperature, engine speed, compressor inlet pressure and manifold air pressure. Each ECU data channel is sampled 50 times per second (50 Hz) ensuring rapid detection and correction of anomalies.
Graphical User Interface
The EVO-MT® System allows for quick and simple access to both real time and logged System data using a proprietary graphical user interface (GUI) program. The GUI program is PC compatible and technical personnel can access System data using a convenient USB interface located in the operator cab. In addition to accessing System data, the GUI program is utilized during setup and commissioning of the haul truck for creation or loading of fuel mapping algorithms as well as for programming various System control, pre-alarm and alarm set points.
On-Board LNG Storage
LNG is safely and securely stored onboard the mine haul truck using a fully integrated Fuel Storage Module (FSM). The Fuel Storage Modules are fully engineered using computer aided design (CAD) and finite element analysis (FEA) to ensure that the module itself as well as its mounting structure can endure the harsh mining environment. The FSM's are pre-fabricated assemblies that significantly minimize the required installation downtime of the truck. FSM's are shipped to the mine site completely assembled and tested and can be installed using overhead shop cranes or mobile lifting systems. The FSM's are designed for specific haul truck configurations and/or duty cycles and normally include sufficient LNG storage capacity for a 12 hour refueling cycle.
Mechanical Drive Truck FSM's
Currently, GFS offers solutions for the Caterpillar 777 and 793. The FSM design for both of these mechanical drive trucks places the FSM on the truck's upper deck. A supporting structure extends down to the truck frame. The rear of the FSM mounts to a pivot point on the truck's horse collar allowing the entire FSM to tilt rearward for full access to the engine bay. Quick disconnects allow for the complete removal of the FSM in a little over an hour to accommodate major engine work or engine swaps. The fuel storage module includes multiple, double walled, vacuum insulated cryogenic tanks, LNG vaporizer, cryogenic safety controls, high and low pressure gas regulators and sensors.
Electrical Drive Truck FSM's
GFS offers EVO-MT® Systems for Komatsu 830DC, 830AC and 930E trucks. The standard FSM for these electrical drive trucks is a Hydraulic/LNG combo tank that mounts in the same location as the OEM hydraulic tank, requiring only a slight modification of the lower mount. The modified mount retains the ability to reinstall the OEM tank at any time. The FSM includes a single, double walled, vacuum insulated cryogenic tank, LNG vaporizer and cryogenic safety controls. Approximately 300 gallons of usable LNG along with 246 gallons of hydraulic fluid are carried in this FSM. For duty cycles that require additional LNG capacity, GFS offers an optional Diesel/LNG combo tank. This FSM is a direct replacement for the OEM diesel tank and provides for an additional 300 gallons of LNG and 650 usable gallons of diesel.
LNG Refueling
LNG refueling is performed using a pressurized, quick-disconnect coupling that allows for the safe and rapid refueling of the FSM. Electric drive truck solutions that incorporate GFS Corp's patented combo tanks included an integrated fueling compartment built into the front of the Hydraulic/LNG FSM. A remote fast fill diesel port is located there along with the LNG filling port to allow for fueling of both fuels in parallel. On mechanical drive trucks, where the FSM is located on the truck's upper deck, a remote LNG refueling receptacle is located according to customer requirements, often on the side of the OEM diesel tank. LNG fueling can be done using either permanent, semi-permanent or mobile cryogenic fuel transfer systems.