The Volvo Bus Gas experience

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The Volvo Bus Gas experience

• New G9A gas engine
• Peter Danielsson
• Volvo Bus Corp. Sweden

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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 / JVs)
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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

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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

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G9A gas engine
G9A concept stoechiometric EGR Three-way
catalyst Lambda sensor
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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

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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
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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
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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
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G9A concept
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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

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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
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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 4 (2006)
Euro 5 (2009)
G9 level
NOx g/kWh
2012
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G9A emissions
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G9A performance
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Service intervals
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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)

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Well to wheel efficiency in Heavy Duty buses
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Well to Wheel emissions of green house gases
from Heavy Duty buses