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The Volvo Bus Gas experience. New G9A gas engine Peter Danielsson Volvo Bus Corp. Sweden. Global production of Heavy Duty Diesel Engines 2004*. Volvo Powertrain. 161.000. DC Powersystems. Weichai Power. Caterpillar. Cummins. Scania. MAN. Yaroslavl.
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The Volvo Bus Gas experience New G9A gas engine Peter Danielsson Volvo Bus Corp. Sweden
Global production of Heavy Duty Diesel Engines 2004* Volvo Powertrain 161.000 DC Powersystems Weichai Power Caterpillar Cummins Scania MAN Yaroslavl * Engine Production 2004, 9 - 18 litre (excluding licensees / JV’s)
The Volvo CNG experience • First CNG deliveries in 1992 • More than 1.000 CNG buses delivered in Europe to nine countries • Third largest manufacturer of CNG buses in Europe • Fulfil R110 (ECE) legal requirements on safety • Current GH10C 290hp/ 1200 Nm closed loop CNG engine • Complete CNG bus offer, 7700 and 7500 models
G9A- Fourth generation CNG engine • Volvo have the experience of development of CNG engines and components • Integration of engine, gearbox, rear axel, electronic system and diagnostics tools for optimum performance and economy • The first manufacturer to obtain the ECE 110 certificate on safety • High quality • High durability • Long service life • Stochiometric combustion for low emissions • Dedicated 3-way CNG catalyst • Lambda sensor • Cooled EGR for durability
G9A gas engine G9A concept: stoechiometric + EGR + Three-way catalyst + Lambda sensor
A common platform for all Volvo Engines The MG9 engine use 90 % of Diesel parts • Common cylinder head • Common cylinder block • 4 valves per cylinder • Equal oil and water • system • Common valves system • Engine control unit • equivalent
G9A Combustion Technology Combustion technology: • Stoechiometric combustion (=1) • 3-way catalyst for reduction of NOx, HC and CO • Single point gas injection • Use of EGR (Exhaust gas recirculation) in order to reduce combustion temperatures Advantages: • Durable concept and possibility to reach EURO 6 • Engine able to adapt with different gas qualities • No derating up to 1500 m altitude EGR cooler and gas injection system EGR cooler, Waste Gate turbocharger and 3-waycatalyst
Combustion Control System Control technology: • Engine Control Unit with closed loop system based on air/ fuel (Lambda) sensor • Ignition coils with encapsulated electrical parts directly onto spark plug • Two knock sensors • Two Exhaust temperature sensors • Automatic adaptability to different gas qualities (closed loop control system) Advantages: • Ultra-low exhaust emission capability • Insensitive to varying gas quality • High reliability • Long service intervals Engine management system (EMS) and ignition system
G9A concept • Three-way catalyst: one component to reduce all emissions in the same time: • Reduction of the NOx: 2NO2 N2 + 2O2 2NO N2 + O2 • Oxidation of CO and HC: CO + ½ O2 CO2 2HC + 5/2 O2 2CO2 + H20 Three-way catalyst
Lambda 1 control Three-way catalyst Exhaust channel Exhaust gas recirculation EGR) MG9 Engine Turbo compressed Air Inlet channel Gas admission at 10 bars G9A concept
Main features for G9A • 300 hp/1400Nm and 260 Hp/1200 Nm rating • Good drivability, high torque at low rpm • High reliability • Long service intervals • Low service cost • Good fuel performance • Automatic adaptability to different gas qualities • Meets EURO 5/EEV emissions • Potential for ultra low exhaust emissions (EURO 6) • Low noise level • Most components common with the D9B diesel engine
Gas Base Engine • Gas engine cylinder head and power cylinder • Specially developed cylinder head with optimized swirl and spark plug tubes press fitted into the cylinder head. • Rotating valves with 3 grooves. • Bottle shape valve guides with a nitrided layer. • Special inlet valve seat with swirl-plate. • Special piston and rings. • Advantages • High reliability and durability. • Long service intervals. Cylinder head for gas engine
Legislative Demands -Exhaust Emission Standards 1996 Euro 2 (1996) Euro 3 (2001) PM (Particulate Matter) [g/kWh] Future level G9 technology Euro 6 (2012?) Euro 5 (2009) Euro 4 (2006) G9 level NOx [g/kWh] 2012
Fuel cylinders for gas for Volvo 7700 • 230 bars gas pressure • Polymer lining and carbon fibre reinforcement baked in epoxy resin • 214 litres volume • 5-8 cylinders depending on driving range • Slow and fast fill capabilities • Integrated safety- and temperature valves • Fulfils the safety regulation ECE R110 • Low weight (~500 kg)
“Well to Wheel” emissions of green house gases from Heavy Duty buses