ENGINE TECHNOLOGY Bobcat Engine_B4459500_01-2015_EN_reworked.indd 1 1/30/2015 10:07:51 AM
A COMPANY THAT S GROWING WITH SOCIETY Bobcat prides itself on innovations that shape the future. For decades, we have led the way by implementing strategies to build cleaner production systems, reduce greenhouse gas emissions, design more eco-friendly products and continually upgrade our environmental management. The environmental protection requirements focus primarily on Particulate Matter (PM) and Nitrogen Oxides (NOx), as these are most relevant for diesel engines. WHAT DID BOBCAT DO TO MOVE FROM STAGE I TO STAGE IV? Stage I: we reduced Nitrogen Oxide (NOx) emissions from diesel engines Stage II: we focused on reducing NOx, Hydrocarbons (HC) and Particulate Matter (PM) Stage III: we achieved a major reduction of PM and a further reduction of NOx Stage IV: we have reduced NOx levels dramatically and have further reduced PM again Nitrogen Oxides (NOx) contribute to ground-level ozone, commonly known as smog. Particulate Matter (PM) consists of soot or unused fuel found in exhaust (which gives dirty engine exhaust its black colour). The introduction of Stage IV standards in 2014 offered us another opportunity to provide our customers with highperforming, reliable and cost-effective machines that meet their daily demands while operating with minimal impact on human health and the environment. WHAT IS STAGE IV? In 1999, a serie of emissions standards was imposed as part of European Directive 97/68/EC. Since then, the European Commission has refined and amended the directive through various Stages. Each Stage applies more stringent measures to address certain pollutants. Stage IV has come into effect in 2014 and requires that NOx be almost eliminated. As the emission values and the demands for compliance vary according to engine horsepower, the extent and type of change to our machines have varied considerably. However, a number of core improvements have been applied to all our equipment, including: turbo-charging, optimisation of the engine combustion system, and use of High Pressure Common Rail (HPCR) fuel injection systems. EMISSION EVOLUTION FOR OFF-ROAD EQUIPMENT Stage I (1999) Stage II (2002) Stage IIIA (2006) Stage IIIB (2011) Stage IV (2014) 0.54 ENGINE OUTPUT P 56 P 130 kw CO HC NOx PM in g/kwh Stage I (1999) 5.0 1.3 9.2 0.70 Stage IV (2014) 5.0 0.19 0.4 0.025 Emission reduction (in %) from Stage I to Stage IV 0% -85% -96% -96% The above table shows the magnitude of the reduction of emission levels from Stage I to the current Stage IV: STAGE IIIB & STAGE IV TECHNOLOGIES Several different technologies have been developed to meet the latest emission requirements: High Pressure Common Rail (HPCR) fuel system, Exhaust Gas Recirculation (EGR), Diesel Oxidation Catalyst (DOC), Diesel Particulate Emission Reduction 0.2 Filter (DPF) and Selective Catalytic Reduction (SCR). Bobcat uses a combination of these technologies, depending on Stage I (1999) - Stage IV (2014) the type of machine and the engine best suited for the machine. Particulate Matter (PM) - 0.02 Nitrogen Oxides (NOx) 6.6 4 2 0.4 9.2 2 3 Bobcat Engine_B4459500_01-2015_EN_reworked.indd 2-3 1/30/2015 10:07:58 AM
HIGH PRESSURE COMMON RAIL (HPCR) FUEL SYSTEM EXHAUST GAS RECIRCULATION (EGR) A highly efficient fuel injection system is essential for the clean operation of a diesel HPCR was added to some Bobcat machines in Stage IIIA. Its ECU is critical for future Stage IIIB and Stage IV technologies. Also known as CEGR (Cooled Exhaust Gas Recirculation), this system reduces NOx engine. HPCR is an advanced fuel injection by recirculating exhaust gases back into the design that does a better job regulating fuel pressure and injection timing. HPCR is being used on Bobcat s high-output engines, and its technology is instrumental in meeting Stage IIIB and Stage IV requirements. Common Rail engine. This dilutes the amount of oxygen in the combustion chamber and lowers the peak combustion temperature. As a result, NOx formation is reduced, but PM is increased. Therefore, Bobcat uses EGR in combination with after-treatment systems (DOC and / or Recirculated Gas Cooled, Recirculated Exhaust DPF), which are highly effective in reducing PM, as shown below. Exhaust Air Intake EGR characteristics No change to basic engine technology No special service or maintenance procedures No special operation instructions High Pressure Pump HOW DOES HPCR WORK? Fuel Pressure The high pressure pump applies high pressure to the fuel (1600 2400 bar) The Common Rail stores pressurised fuel The injectors deliver fuel to the engine DIESEL OXIDATION CATALYST (DOC) A DOC is a special catalyst that reacts with engine exhaust gas upon contact. The reaction transforms PM emissions in the exhaust into harmless substances such as water and carbon dioxide. Hydrocarbon Particulate Matter (PM) Injection Timing The ECU controls the injectors precisely to allow multiple fuel injections during each combustion cycle. Carbon Monoxide The benefits of better combustion High pressure transforms the fuel into an extremely fine mist as it leaves the injectors. The fuel combusts more thoroughly in this form, leading to: Lower fuel costs: as the fuel burns more completely, the engine needs less of it. Cleaner exhaust: less unburned fuel is emitted in the exhaust. Better performance: multiple injections during each combustion cycle make combustion last longer, creating more energy and more output from the engine. Increased comfort: longer-lasting combustion lowers peak engine cylinder pressure, which reduces engine noise levels, making operation more comfortable. HPCR also enables the application of additional technologies such as Diesel Oxidation Catalyst (DOC), Selective Catalytic Reduction (SCR) and Diesel Particulate Filter (DPF) systems. Nitrogen Oxide DOC characteristics No change to basic engine technology No special service or maintenance procedures No special operation instructions Water Carbon Dioxide 4 5 Bobcat Engine_B4459500_01-2015_EN_reworked.indd 4-5 1/30/2015 10:08:02 AM
DIESEL PARTICULATE FILTER (DPF) SELECTIVE CATALYTIC REDUCTION (SCR) A ceramic wall flow filtration system that separates PM from the exhaust removes PM from the engine s exhaust gas. Engines designed for SCR systems use higher fuel injection pressure and optimise combustion for better fuel economy and response. As a result, PM formation is reduced, but the amount of NOx in the exhaust increases. So, a urea solution (, also called DEF = Diesel Exhaust Fluid) is injected into the exhaust flow turning the NOx in DPF characteristics the exhaust gas into nitrogen and water, which do not harm the environment. Reduced NOx by engine design Better fuel efficiency Compact, easy-to-install technology DPF Regeneration Wall Flow Filter Dirty exhaust (brown arrows) passes through filter walls. PM is left behind and cleaner exhaust (blue arrows) exits. Supply Module Filter Tank To keep the DPF clean and working efficiently, the high temperature of the exhaust itself is used to burn accumulated PM off the filter. This semi-automatic cleaning process is called Regeneration. Barriers force exhaust to pass through filter walls. Diesel Engine Dosing Module with Injector Actuators s Level Engine Exhaust Gas with NOx Particles N 2 H 2 O Diesel Fuel Return SCR Catalyst Diesel Fuel Inlet Fuel Filter Fuel Pump SCR characteristics Reduced PM by engine design Better fuel efficiency Metering Unit (MU) Fuel Tank Compact, easy-to-install technology product is well-known and widely available No regeneration required Diesel Engine Actuators s Engine Exhaust Gas with PM Particles Injection Unit (IU) Differential Pressure DOC DPF 6 7 Bobcat Engine_B4459500_01-2015_EN_reworked.indd 6-7 1/30/2015 10:08:14 AM
EGR, DOC, DPF AND SCR: MATCHING TECHNOLOGY TO ENGINE NEEDS Bobcat uses different technologies to deliver the best performance and the lowest operating cost for each engine. The best option a combination of EGR and DOC; or EGR, DOC and SCR; or EGR, DOC and DPF is selected based on engineering characteristics and application requirements. ENGINE MAKER ENGINE TYPE FUEL SYSTEM TURBOCHARGER EMISSION CONTROL EMISSION CLASS HPCR WGT VGT EGR DOC DPF SCR KUBOTA Various Stage IIIA BOBCAT D18 Stage IIIB BOBCAT D24 Stage IIIB BOBCAT D34 Stage IV YANMAR 4TNV98 Stage IIIA YANMAR 4TNV94L Stage IIIA YANMAR 4TNV98C Stage IIIB PERKINS 1104D-E44TA Stage IIIA DEUTZ TCD3.6 L4 Stage IIIB Specifications and design are subject to change without notice. Pictures of Bobcat products may show other than standard equipment. www.bobcat.eu 2015 BOBCAT B4459500-EN (03-15) DI CE - Drève Richelle 167 - B-1410 Waterloo, Belgium Bobcat Engine_B4459500_01-2015_EN_reworked.indd 8 1/30/2015 10:08:39 AM