Series 2000 and Series 4000 engines above 750 bhp will meet Tier 4 Final standards with no aftertreatment or DPF required at any bhp. This will be achieved through a combination of two-stage turbocharging, EGR cooling, a new combustion system design and high-pressure common rail injection. Both series are based on proven MTU engine technology, and are designed to provide optimal transient behavior with rapid response to changes in engine load.
JCB Includes Recalibration Option
In mid-2012, JCB formally launched its technology solution to meet Tier 4 Interim/Stage IIIB requirements. The JCB Ecomax engine achieves emissions levels through the use of patented in-cylinder technologies, without the need for external exhaust aftertreatment or a DPF.
Using a patent-pending combustion process design, the company combines injection pressures of 29,000 psi in the common rail system with a variable geometry turbocharger for rapid response at low rpm to create a cleaner, more efficient burn. Cooled EGR is used to further reduce emissions, passing a small amount of the exhaust gas back through the engine to cool the combustion process and reduce NOx within the cylinder.
Upgraded fuel and air filters will ensure cleanliness of the fuel going into the engines, plus a 5-micron water separator and fuel filter for the fuel supply line will supplement the 2-micron engine filter. A crankcase ventilation filter is also required. However, the engines will be able to run on standard engine oils, helping to reduce owning and operating cost.
The Tier 4 Interim engines will have the same 500-hour service intervals as the previous models. It’s estimated that there will be an increase of $.05/hour over a typical 6,000-hour ownership period for a backhoe-loader, an amount the company says is offset by fuel economy and productivity benefits.
According to JCB, its Tier 4 Interim technology also enables the company or its dealers to sell a low-cost kit to recalibrate the electronic control unit, allowing Ecomax-equipped machines to be resold and operated in countries where poor quality (higher sulfur) fuels are used.
“By recalibrating the JCB Ecomax engine, turning off the EGR and reducing fuel injection pressures, it is possible for the engine to be run on higher sulphur content fuels,” says Alan Tolley, director of engine programs.
Truck Strategy Moves Off-road
Scania’s range of 9-, 13- and 16-liter industrial engines — covering outputs from 271 to 691 hp — will be fitted with nearly the same unique SCR system as its Euro 6 engines for trucks. Using the XPI (extra high-pressure injection) common-rail fuel injection system, an in-house technology, the required levels of NOx and particulates will be achieved without the need for any kind of particulate filter. XPI offers up to 34,800-psi injection pressure and allows freedom of injection timing and pressure.
The new engine platform for five-, six- and eight-cylinder configurations will also combine the XPI system and SCR. XPI fuel injection, engine management, EGR and SCR systems will be used in different combinations for different applications. The engine management system controls fuel injection, exhaust aftertreatment, charge-air and engine operating temperature. To improve the efficiency in the SCR catalyst, Scania will include a DOC.
Differences in fuel consumption will be lower in some cases or only slightly higher in others, depending on how the EGR is used in combination with the variable vane geometry turbocharger and SCR system.
Perkins Optimizes Engine Design
Perkins unveiled its new range of four-cylinder Tier 4 Final-compliant engines at Intermat 2012. The new models all incorporate the company’s specially optimized SCR technology.
The 1204F 4.4-liter, four-cylinder aftercooled engine is offered in a choice of two versions. The single turbo aftercooled 1204F-E44TA produces 147 hp, delivering improved fuel economy while offering greater power and torque. The twin turbo, aftercooled 1204F-E44TTA has power ratings up to 175 hp and employs twin turbochargers mounted in series for extra power density, low-speed torque and faster transient response.
Both 1204F models use aftertreatment comprising DOC/SCR modules. This compact solution not only achieves the significant reduction of NOx required, it also removes the need for any regeneration strategy for soot, since the formulation of particulate emissions is prevented in the combustion process. The small size of the DOC/SCR module means it can be mounted in a variety of remote locations, freeing up valuable space in the engine bay.