Suzuki K12N Specifications
| Engine Model: Suzuki K12N |
| Engine Type: 4-cycle inline 4-cylinder DOHC 16-valve VVT liquid-cooled gasoline |
| Total Displacement: 74 cu.in (1.19 L) |
| Rated Engine Power: 89 hp (66 kW) at 6000 rpm |
| Fuel System Type: Dual Injection (DualJet) |
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The Suzuki K12N, marketed under the DualJet
designation, represents the zenith of Suzuki’s K-series engine development for
small-displacement, high-efficiency petrol powertrains. Introduced as a direct
successor to the K12B, the K12N was engineered to meet increasingly stringent
global emission standards - specifically BS6 and Euro 6 - while delivering a
measurable improvement in fuel economy without sacrificing drivability.
The engine’s defining innovation is its dual injection system, which employs two
fuel injectors per cylinder, totaling eight injectors for the inline-4
configuration. This architecture enables highly stratified fuel delivery,
optimizing combustion stability, reducing wall-wetting losses, and enabling a
high compression ratio of 12.0:1. The K12N also incorporates Dual Variable Valve
Timing (Dual VVT) on both intake and exhaust camshafts, an integrated
starter-generator (ISG) for seamless idle stop-start operation, and a
friction-reduction strategy that includes ultra-low-viscosity engine oil
(0W-16).
With a displacement of 1,197 cc derived from a bore and stroke of 73.0 mm x 71.5
mm, the engine is an undersquare design favoring low- to mid-range efficiency.
It has become the flagship petrol engine for Maruti Suzuki’s premium hatchback
and sedan range, as well as a replacement for the G12B in commercial
applications, underscoring its versatility across passenger and light commercial
segments.
Engine Code: K12N.
Engine Family: Suzuki K-series (DualJet).
Configuration: Inline 4-cylinder.
Valvetrain: Double Overhead Camshaft (DOHC), 16 valves (4 per cylinder).
Displacement: 1197 cc (73.0 cu.in).
Bore: 73.0 mm (2.87 in).
Stroke: 71.5 mm (2.81 in).
Compression Ratio: 12.0:1.
Firing Order: 1-3-4-2.
Fuel System: Dual Injection (DualJet) - 2 injectors per cylinder, 8 injectors
total.
Variable Valve Timing: Dual VVT.
Valvetrain Drive: Silent timing chain.
Maximum Power: 90 PS (66 kW; 89 hp) at 6000 rpm.
Maximum Torque: 113 Nm (83 lb-ft) at 4400 rpm.
Idle Speed: 700 ± 50 rpm.
Maximum Engine Speed: 6500 rpm (fuel cut-off).
Emission Standard: BS6 / Euro 6.
The cylinder block is constructed from aluminum alloy,
continuing the K-series tradition of lightweight, high-thermal-efficiency
construction. The block features an open-deck design with cast-in iron liners, a
departure from the linerless aluminum bore technology used in some earlier
K-series variants. This iron liner construction provides enhanced wear
resistance and improved piston ring sealing, particularly important given the
engine’s high compression ratio and the friction-reduction strategies employed.
The block incorporates a bedplate-style lower crankcase - a structural aluminum
member that bolts to the main bearing caps - which significantly increases
bottom-end rigidity and reduces crankshaft flex. The crankshaft is a forged
steel unit supported by five main bearings. Connecting rods are manufactured
from powdered metal (sintered) with fracture-split caps, ensuring precise
bearing bore geometry.
The pistons are constructed from high-silicon aluminum alloy with an optimized
skirt profile and a low-friction coating to reduce mechanical losses. Piston
cooling jets are integrated into the cylinder block, directing oil to the
underside of each piston crown to manage thermal loads under sustained
high-speed operation.
The cylinder head is manufactured from aluminum alloy
and houses a Double Overhead Camshaft (DOHC) arrangement with 16 valves. The
combustion chamber adopts a pent-roof configuration with a centrally located
spark plug, optimized for the high compression ratio and the dual-injection fuel
delivery pattern. The camshafts are hollow to reduce rotational mass and
incorporate continuously variable valve timing mechanisms on both the intake and
exhaust sides.
Dual VVT allows independent adjustment of valve opening and closing events
across the engine operating range, enabling internal exhaust gas recirculation,
reduced pumping losses, and optimized volumetric efficiency. The valvetrain
employs roller rocker arms with integrated hydraulic lash adjusters, eliminating
the need for periodic valve clearance adjustments.
The roller follower design reduces friction at the cam-to-follower interface by
converting sliding contact to rolling contact. The intake and exhaust valves are
manufactured from heat-resistant steel, with the exhaust valves featuring a
hollow stem filled with sodium in certain applications to enhance heat transfer
away from the valve head.
The fuel system is the defining technological feature
of the K12N. It employs a DualJet architecture, utilizing two fuel injectors per
cylinder positioned in the intake port. This configuration allows for up to two
injection events per intake stroke per injector, enabling precise control over
fuel atomization, mixture formation, and combustion stability. The
eight-injector arrangement reduces the distance between the injector tip and the
intake valve, minimizing fuel adhesion to the port walls - a phenomenon known as
wall-wetting - and improving cold-start emissions.
The system operates at a nominal fuel pressure of 4.0 bar (58 psi). The Engine
Control Module (ECM) calibrates injection timing and duration based on engine
load, speed, and temperature, with the ability to stage multiple injection
pulses to create a stratified charge under low-load conditions. This fuel
delivery strategy, combined with the 12.0:1 compression ratio and Dual VVT,
achieves a significant reduction in fuel consumption in urban driving cycles.
The system includes an electric fuel pump mounted within the fuel tank and a
returnless fuel rail design to reduce fuel heating and evaporative emissions.
The lubrication system is a pressurized, full-flow
wet-sump design utilizing a rotor-type oil pump with a variable displacement
mechanism in certain applications. The oil pump is mounted to the front of the
crankshaft and draws fluid from an aluminum oil pan with a capacity of 3.3
liters (3.5 qt) including the filter. A spin-on, full-flow oil filter is mounted
to the cylinder block. The K12N is engineered for ultra-low-viscosity oils to
minimize internal friction and improve fuel economy. The recommended oil
viscosity is 0W-16, with 0W-20 also approved for service in markets where 0W-16
is unavailable.
The oil specification meets ILSAC GF-6 or equivalent standards, formulations
designed to provide wear protection while maintaining flow characteristics at
low temperatures. An oil pressure switch monitors system pressure, and the
integrated starter-generator (ISG) system is interlocked with oil pressure to
ensure adequate lubrication before restarting the engine during stop-start
operation.
The cooling system is a sealed, pressurized arrangement
with an electrically controlled water pump in some variants, though the
mainstream K12N employs a belt-driven centrifugal pump. The water pump is
mounted to the cylinder block and driven by the serpentine accessory belt.
Coolant circulates through the aluminum cylinder block and cylinder head, with a
wax-element thermostat having an opening temperature of 82°C (180°F). The
cooling system incorporates a dual-pass radiator configuration to maximize heat
rejection in a compact frontal area.
A coolant bypass circuit allows circulation during warm-up to ensure rapid
engine temperature rise, reducing friction losses and enabling the engine to
reach optimal operating temperature quickly. The total cooling system capacity
is 4.5 liters (4.8 qt). A 1.1-bar (16.0 psi) radiator cap maintains system
pressure. In vehicles equipped with the integrated starter-generator, the
cooling system may include an auxiliary electric water pump to maintain cabin
heating and thermal management during idle stop events.
Ignition System: The ignition system is a coil-on-plug
design, with a dedicated ignition coil mounted directly over each spark plug.
The ECM controls ignition timing based on inputs from the crankshaft position
sensor, camshaft position sensors (dual, for Dual VVT), knock sensor, and engine
load parameters. The spark plugs are iridium-tipped for extended service life
and consistent ignition performance under the high compression ratio.
Intake and Exhaust Systems: The intake system utilizes a composite plastic
intake manifold with integrated acoustic tuning to enhance low-end torque. The
throttle body is electronically controlled (drive-by-wire), allowing precise
airflow management for idle control, traction control integration, and
stop-start operation. The exhaust manifold is integrated into the cylinder head
in certain configurations - a design that reduces weight, accelerates catalyst
light-off during cold starts, and allows the engine to reach operating
temperature more rapidly.
Engine Management and Stop-Start System: The engine is managed by a 32-bit
Engine Control Module (ECM) that integrates fuel injection, ignition timing,
Dual VVT control, idle speed control, and stop-start logic. The integrated
starter-generator (ISG) replaces the conventional alternator and starter motor
with a single unit mounted directly to the engine. During deceleration, the ISG
recovers kinetic energy to charge the battery. When the vehicle comes to a stop,
the ECM shuts down the engine; upon brake release or clutch engagement, the ISG
restarts the engine in less than 0.3 seconds. A dedicated auxiliary battery and
DC-DC converter support the increased electrical demands of the stop-start
system.
Emission Control: The emission control system includes a close-coupled three-way
catalytic converter, a heated oxygen sensor upstream and a downstream oxygen
sensor for catalyst monitoring, a positive crankcase ventilation (PCV) system,
and an evaporative emission control system with a charcoal canister and purge
solenoid. The DualJet system’s precise fuel metering contributes to lower
cold-start hydrocarbon emissions, reducing the need for catalyst enrichment
during warm-up.
Overall Length: 580 mm (22.8 in)
Overall Width: 590 mm (23.2 in)
Overall Height: 650 mm (25.6 in)
Dry Weight (without ancillaries): 86 kg (190 lb)
Dry Weight (fully dressed with manifolds, ISG, and flywheel): 102 kg (225 lb)
Engine Oil Capacity (with filter change): 3.3 liters
(3.5 qt).
Engine Oil Capacity (without filter change): 3.1 liters (3.3 qt).
Engine Oil Specification: 0W-16 (ILSAC GF-6); 0W-20 as approved alternative.
Oil Change Interval: 10,000 km (6,250 miles) or 12 months.
Coolant Capacity: 4.5 liters (4.8 qt).
Coolant Specification: Ethylene glycol-based, silicate-free long-life coolant.
Coolant Change Interval: 40,000 km (25,000 miles) or 24 months.
Timing Chain: Inspect chain tensioner and guides at major engine service.
Valve Clearance: Hydraulic lash adjusters - no adjustment required.
Spark Plug Type: Iridium-tipped (NGK IFR6J-11 or equivalent).
Spark Plug Gap: 1.0 mm (0.039 in).
Spark Plug Replacement Interval: 60,000 km (37,500 miles).
Drive Belt (serpentine) Tension: Inspect belt every 20,000 km (12,500 miles).
Fuel Filter: Integrated with fuel pump assembly - no scheduled replacement.
Air Filter Replacement Interval: 30,000 km (18,750 miles) or as indicated by
restriction indicator.
Idle Speed: Non-adjustable - controlled by ECM.
Cylinder Head Bolts: 30 Nm (22 lb-ft)
Main Bearing Cap Bolts (bedplate to block, M8): 23 Nm (17 lb-ft)
Main Bearing Cap Bolts (bedplate to block, M10): 45 Nm (33 lb-ft)
Connecting Rod Cap Bolts: 25 Nm (18 lb-ft)
Camshaft Cap Bolts: 12 Nm (9 lb-ft)
Camshaft Sprocket Bolts (intake): 55 Nm (41 lb-ft)
Camshaft Sprocket Bolts (exhaust): 55 Nm (41 lb-ft)
Crankshaft Pulley Bolt: 150 Nm (111 lb-ft)
Flywheel Bolts: 70 Nm (52 lb-ft)
Intake Manifold Bolts: 23 Nm (17 lb-ft)
Exhaust Manifold Nuts: 23 Nm (17 lb-ft)
Spark Plugs: 25 Nm (18 lb-ft)
Oil Pan Bolts: 11 Nm (8 lb-ft)
Water Pump Bolts: 11 Nm (8 lb-ft)
Oil Filter (spin-on): 15 Nm (11 lb-ft)
Engine Mount Brackets: 45 Nm (33 lb-ft)
Maruti Suzuki Swift (facelift 2021-present): The K12N
was introduced in the Swift facelift as the replacement for the K12M, delivering
improved fuel economy and compliance with BS6 Phase 2 emission standards. The
engine is paired with either a 5-speed manual transmission or a 5-speed
automated manual transmission (AMT), with the integrated starter-generator
system enabling idle stop-start functionality across both transmission types.
Maruti Suzuki Dzire (2020-present): The K12N powers the compact sedan variant of
the Swift, calibrated for a balance of fuel efficiency and low-end torque
suitable for urban and highway driving. The engine in this application
emphasizes refinement and noise reduction, with additional acoustic covers and
optimized engine mounts.
Maruti Suzuki Baleno (2022-present): The premium hatchback received the K12N as
part of its mid-cycle update, marketed under the DualJet branding. This
application highlights the engine’s responsiveness and reduced vibration
characteristics, with the Dual VVT system calibrated for a broader torque
plateau.
Maruti Suzuki Wagon R (1.2L variants): Select higher-specification variants of
the Wagon R utilize the K12N, offering a performance-oriented alternative to the
standard 1.0-liter K10B engine. This application leverages the engine’s compact
dimensions and lightweight construction to maintain the Wagon R’s agile urban
handling characteristics.
Maruti Suzuki Eeco (late 2022-present): The K12N replaced the G12B engine in the
Eeco van, marking a significant modernization for this commercial vehicle
platform. In this application, the engine is calibrated for durability and
consistent torque delivery under load, with the DualJet system and Dual VVT
contributing to improved fuel economy in stop-start urban delivery cycles. This
application may omit the idle stop-start system in certain commercial variants
to suit operator requirements.
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