Volvo's answer to Stage IIIB and Tier 4 Interim legislation targets include the adoption of a combination of in-cylinder and external combustion solutions. It says its new generation of V-ACT engines (Volvo-Advanced Combustion Technology) offers achievements in combustion efficiency, emissions reduction, and engine performance.
The new engines will feature advanced ultrahigh-pressure variable fuel-injection systems, "super efficient" cooled exhaust gas recirculation (EGR), precise control of the turbochargers, powerful new engine management systems (EMS), and an integrated exhaust aftertreatment system that features a particulate filter and thermal regenerator.
Volvo said at this year's Bauma that its new generation of electronically controlled diesel engines offers lower emissions, enhanced engine monitoring and control, and higher torque—as well as improved performance. The units' switchable internal EGR function lowers the amount of oxygen in the combustion chamber, reducing combustion peak temperature and thus lowering the formation of NOx.
Because T4I engines require low-sulphur fuel, a new cooled EGR system was designed to allow more exhaust recirculation than the previous uncooled generation, thereby lowering NOx further.
To address the reduction of particulate matter (PM), the new Volvo system uses an advanced exhaust aftertreatment system that reduces PM by 90% compared to the previous machine series. The filter traps the particulates and temporarily holds them until there is a sufficient build up to merit regeneration, which effectively involves incinerating the particulates at temperatures above 600°C using a thermal regenerator. Volvo says it chose a regeneration system that would maximize the uptime of the machine.
The V-ACT's electronic control unit (ECU) plays a fundamental role in the next-generation technology. The new EMS version boasts a more powerful processor with the capability to support more functions than its predecessor at higher speeds and with more control. The ECU controls the entire EGR process, managing the mix of recirculated exhaust gas and fresh air that is so crucial to reducing NOx and PM emissions, while maintaining performance and economy.
Volvo is one of a select number of manufacturers that makes both engines and equipment, tailoring the engine/equipment system for optimal efficiency. The company also benefits from the research and technical solutions developed within the Volvo Group for sister companies Volvo Trucks and Volvo Penta for the on-highway equipment sector. Volvo says that experience—not to mention the millions of hours of real-world testing—has proven invaluable in producing off-highway engine systems that are compliant with the environmental emissions standards required of the new legislation.
Besides its work on state-of-the-art engine systems, Volvo stresses its other work involving systems, operators, and hybrids to result in a four-pronged approach to increasing fuel efficiency solutions across its entire product range.
In terms of systems, Volvo is launching a fuel-saving feature called OptiShift, which is being introduced for the L150F-L220F range of wheel loaders. OptiShift equipment will feature new torque converters with lock-up and free wheel stator and Volvo-patented Reverse By Braking technology, which reduces fuel consumption by up to 15%.
Volvo’s Eco Operator program is focused on training operators to develop an environmentally friendly style of driving through less accelerating and braking and by using the most economical engine speed range. This not only reduces emissions but also cuts fuel consumption by up to 5 to 25% without affecting productivity.
The last leg of its four-pronged approach to fuel efficiency is its continuing commitment to developing advanced hybrid technology suitable for off-highway duty cycles.