BUS POWER
B4.5 AND B6.7 EURO VI ENGINES
SETTING THE
INDUSTRY
STANDARD
The four-cylinder B4.5 and six-cylinder B6.7 have
earned an unrivalled position as the world’s leading
engine platform for city bus applications, ranging all
the way from midi-bus to double-deck and intercity
buses, as well as coaches and hybrids. Indeed,
no other engines power more buses, in more cities,
and in more countries worldwide than the
Cummins B Series.
And that’s because no other engine can offer
such high levels of performance and in-service
reliability whilst operating under the most
challenging duty-cycles. The ability to keep
delivering under long service hours, very
high annual mileages and challenging route
terrain comes as standard with the Cummins
4.5-litre and 6.7-litre B Series.
PERFORMANCE
ENHANCED
The latest Euro VI B4.5 and B6.7 come
packed with performance enhancing
technology to realise the full potential of the
high strength, proven base engine platform.
Cummins Variable Geometry Turbocharger
(VGT TM) enables high torque from lower
engine speeds to improve driveability while
accelerating. A state-of-the-art fuel system
continually adjusts injection pressures to
minimise fuel consumption, particularly during
slow speed with high passenger loadings.
SMART EFFICIENCY
Due to a more compact envelope with the highest
power density in their class, the B4.5 and B6.7
bring a significant installation advantage, together
with an engine management system that seamlessly
integrates into the vehicle controls. Smarter
electronics also means that engine diagnostics and
trip data can be quickly accessed with Cummins
digital service tools, and instantly converted into
easy-to-read analytics to enable proactive
maintenance when its needed.
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STOP-START
TECHNOLOGY
The B4.5 and B6.7 Euro VI bus engines can incorporate
Cummins’ unique Stop/Start technology, with the capability to
eliminate almost all engine idling at bus stops, traffic lights and
pedestrian crossings. The engine-off mode can automatically
operate for up to 30 stops per hour, dependent on the route.
The engine position sensor ensures instant readiness for a soft
restart in just 0.5 seconds following the engine-off mode.
The Stop/Start function can achieve up to 8 percent fuel
savings on city bus duty cycles, potentially saving over 2,000
litres of fuel annually, with a corresponding greenhouse gas
saving of around 5 metric tons of CO2 per year. Stop/Start
technology is helping to enhance bus sociability around cities
for both passengers and pedestrians.
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B4.5
ROBUST DESIGN
While the B Series achieves the
longest life to overhaul of any
comparable engines, Cummins
goes even further by designing-in
ease of overhaul.
As a result, operators can maximise their
investment in keeping buses on the road
for longer with engine overhaul programs.
Scheduled engine service requirements are
few and far between, meaning that a bus
fleet goal of over 95 percent uptime availability
is fully achievable with the B Series.
And, you can be sure, wherever there is a Cummins-
powered bus, there is a Cummins service team ready to
provide expert technical support. From inspecting engine systems
on new buses before they enter service, training-up depot staff or
working with operators to minimise fuel consumption, this is all part B6.7
of Cummins’ commitment to support our customers.
HYBRID-ADAPTED
Cummins has achieved a Euro VI technology Cummins hybrid engines are fully optimised to
milestone by reaching a total of over 2,000 be used within all hybrid drivelines, including
hybrid-adapted engine installations in buses those supplied by Siemens, BAE Systems,
operating across Europe, making a major Eaton and Allison. They are compatible with
contribution to improving air quality and both series or parallel hybrid systems, as
reducing the carbon footprint. Cummins hybrid engine parameters are adjusted to lower or
versions of the B4.5 and B6.7 are specially higher average speed duty cycles. The hybrid
configured to integrate with the hybrid driveline engine is streamlined by eliminating power-
and provide a seamless engine on/engine off take-off accessories used to drive steering
function for the vehicle. pumps, fan drives, air compressors and air-
conditioning as they can be run directly from
Cummins’ hybrid engine expertise has played the electrical supply from the battery. The
a key role in helping many bus manufacturers starter motor can also be removed, although
on the road to electrification and has achieved this is retained in some buses as a back-up.
remarkable results in terms of fuel savings,
emissions reduction and vehicle sociability. With Cummins engines specifically developed
On-road testing with Cummins engines on city to enhance hybrid system performance, this
bus duty cycles has indicated that nitrogen capability provides operators with the energy
oxide (NOx) emissions are capable of being choice they need alongside conventional
reduced to 50 percent below the Euro VI clean diesel drivelines, the option of renewable
standard. In terms of fleet decarbonisation, natural gas power, full-electric and fuel cell
we typically see hybrid drive buses reducing solutions from Cummins.
fuel consumption and related CO2 emissions
by around 33 percent, with the engine
contributing an important part of that reduction.
COACH POWER
The same attributes that have established the B6.7 Fuel and CO2 reductions are even more impressive
as the leading mid-range engine for city buses have with a new generation of coaches of up to 13
proved equally applicable to the growing market for metre length utilising Cummins B6.7 hybrid engine.
midi-sized coaches, with less than 11 metre length This design meets the need for shorter distance
and with up to 40 seats capacity. The exceptional commuter, suburban or school transport operating
power density of the 6.7-litre makes it the engine of through low emission zones.
choice for this highly versatile class of coach, used
for roles including day touring, intercity services, For smaller coaches sized below 8.5m length and
luxury shuttle duties or premium long distance touring. with around 30 seat capacity, the compact B4.5
is an ideal power source with up to 210 hp output.
When powered by the B6.7 there is no compromise While the B4.5 brings the operational cost saving
on performance. Specific coach engine ratings of a high efficiency 4-cylinder engine, out on the
release the full potential of the B6.7 up to 320 hp road it provides the smooth acceleration and
to provide rapid acceleration and high cruising relaxed cruising speed associated with the
speeds. But what really sets the Cummins-powered larger B6.7.
midi-coach apart from full size coaches is the
remarkably lower fuel consumption – enabling a
major cost saving for operators.
B6.7
STEP AHEAD
B4.5
TO PHASE-E
The Euro VI Phase-E regulatory step is particularly relevant
for bus operations, as it is focused on tighter control limits
for NOx emissions during lower speed city operations and
under cold start conditions. Certification is dependent
on test results taken during real-world drive cycles,
verifying results first taken under engine emissions test
cell conditions.
On-road testing with Cummins Phase-E engines during
typical city bus duty cycles have indicated a further
25 percent reduction in Nitrogen Oxides (NOx) compared
to the initial Phase-A engines when Euro VI was first
introduced in 2015.
This nearer-to-zero reduction has been verified with the
use of high precision Portable Emissions Measurement
Systems (PEMS) installed on the Cummins-powered
test vehicles.
LOWERING THE
BIODIESEL
CARBON FOOTPRINT
Beyond the substantial fuel saving benefits offered by the latest B4.5
and B6.7 engines, an even lower carbon footprint can be achieved
when running on B20 biodiesel or HVO renewable fuel. Compared with
conventional fossil-based fuel, HVO (Hydrotreated Vegetable Oil) offers the
potential to reduce greenhouse gas (GHG) emissions by 40 to 90 percent,
HVO depending on the feedstock of the fuel.
ENGINE RANGE specifications
BUS RATINGS
150 hp @ 2300 rpm (112 kW) 650 Nm @ 1000 rpm
B4.5 180 hp @ 2300 rpm (134 kW) 700 Nm @ 1000 rpm
210 hp @ 2300 rpm (157 kW) 850 Nm @ 1200 rpm
250 hp @ 2100 rpm (187 kW) 1000 Nm @ 1000 rpm
B6.7 280 hp @ 2100 rpm (209 kW) 1100 Nm @ 1000 rpm
300 hp @ 2100 rpm (224 kW) 1200 Nm @ 1100 rpm
HYBRID RATINGS
B4.5-H 210 hp @ 2300 rpm (157 kW) 850 Nm @ 1200 rpm
280 hp @ 2100 rpm (209 kW) 1100 Nm @ 1000 rpm
B6.7-H
300 hp @ 2100 rpm (224 kW) 1200 Nm @ 1100 rpm
COACH RATINGS
180 hp @ 2300 rpm (134 kW) 750 Nm @ 1100 rpm
B4.5
210 hp @ 2300 rpm (157 kW) 850 Nm @ 1200 rpm
290 hp @ 2300 rpm (217 kW) 1100 Nm @ 1000 rpm
B6.7
320 hp @ 2300 rpm (239 kW) 1200 Nm @ 1100 rpm
b4.5 b6.7
Displacement 4.5-litre 6.7-litre
Architecture 4-cyl. with EGR / VGT 6-cyl. with EGR / VGT
Ratings Range 112-157 kW / 150-210 hp 164-239 kW / 220-320 hp
Peak Torque 850 Nm @ 1200 rpm 1200 Nm @ 1100 rpm
Dry Weight 372 kg 522 kg
Size L x W x H 809 x 738 x 875 mm 1097 x 788 x 921 mm
Oil drain interval Up to 2000 hours
Up to 50,000 km (city bus) or 80,000 km (intercity/coach)
Note: oil drain intervals are dependent on application / duty cycle, based on using CK-4 API (CES 20086 approved)
oil specification.
The Diesel Particulate Filter and Selective Catalytic
Exhaust aftertreatment
Reduction (DPF-SCR) exhaust aftertreatment was
Architecture DPF-SCR switchback unit purpose-designed by Cummins to work with the
engine as an integrated emissions control system.
Weight 84 kg
The DPF-SCR combines with in-cylinder combustion
Size L x W x H 847 x 610 x 464 mm and the exhaust gas recirculation system to lower
PM and NOx, certified to the Phase-E requirement
of the Euro VI regulations.
B4.5 PEAK TORQUE
1000
900
850 Nm 210 hp rating
800
Torque (Nm)
700 Nm 180 hp rating
700
650 Nm 150 hp rating
600
500
400
700 900 1100 1300 1500
Speed (rpm)
B6.7 PEAK TORQUE
1400
1200 300/320 hp rating
1200 Nm
280 hp rating
1100 Nm
Torque (Nm)
1000 250 hp rating
1000 Nm
220 hp rating
900 Nm
800
600
700 900 1100 1300 1500
Speed (rpm)
The B4.5 and B6.7 rapidly deliver high levels
of torque from low engine speed to enhance 114 168 210 230 501 611 910
vehicle driveability. TAURON ARENA KRAKÓW WIECZYYSTA
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DIGITAL
DIAGNOSTICS
Cummins INSITE TM performs engine
diagnostics and displays electronic engine
information on your PC. With step-by-step
diagnostics, built-in engine drawings and
schematic diagrams, working with INSITE
is easy. Using this software speeds up
troubleshooting procedures, helping to
minimise down time and ensures your bus
can quickly be back on the road again.
Features:
Quick access to trip information
Adjust parameters and review/clear
fault information quickly and easily
Easy-to-follow troubleshooting assistance
Wiring and sensor location diagrams
Store engine and trip information for future
use, or as a programming template
B4.5
Using telematics, you can wirelessly connect
your engine for continuous monitoring and
diagnosis of system fault alerts using a
convenient Cummins mobile app, email or
web portal. Products such as Connected
Diagnostics and Connected Advisor
can play a major role in maximising the
uptime availability of your fleet by setting
up a diagnostic health report, delivered
automatically. This enables preventative
maintenance to be scheduled, knowing what
needs immediate action and what can wait
until the next service inspection.
Connected
Solutions ™
Public Transport
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DELHI TRANSIT
Cummins B series platform is used by bus manufacturers
5 Av &
worldwide to meet all Euro equivalentE 79
standards
St and in
North America is by far the highest volume bus engine of
its class meeting EPA regulations.
B Series global credentials are further enhanced with
manufacturing facilities located in six countries.
Cummins Inc.
Box 3005
Columbus, IN 47202-3005
U.S.A.
cummins.com
Bulletin 5600346 Produced in U.K. Rev. 9/23
©2023 Cummins Inc.
