Honda K24W1 Specifications
| Engine Model: Honda K24W1 |
| Engine Type: 4-cycle inline 4-cylinder DOHC 16-valve i-VTEC liquid-cooled gasoline |
| Total Displacement: 144 cu.in (2.35 L) |
| Rated Engine Power: 185-189 Hp (138-141 kW) at 6400 rpm |
| Fuel System Type: Gasoline direct injection |
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The Honda K24W1 is a 2.4-liter naturally aspirated
inline-four engine developed under the Earth Dreams Technology banner. It
represents a fundamental evolution within the K-series engine family,
distinguished by the introduction of direct fuel injection and a reversed
cylinder head orientation. The engineering focus prioritized thermal efficiency,
reduced internal friction, and an optimized power band for mid-range torque.
Constructed entirely from aluminum alloy, the K24W1 employs a 16-valve DOHC
valvetrain with a two-stage i-VTEC system operating on the intake camshaft. This
configuration was specifically calibrated to deliver linear power delivery
suitable for mid-size sedan applications.
Engine Layout: Transverse inline-4.
Valvetrain: DOHC, 16-valve with i-VTEC (intake side only).
Displacement: 2,356 cc (2.4 L).
Bore x Stroke: 87.0 mm x 99.1 mm (3.43 in x 3.90 in).
Compression Ratio: 11.1:1.
Fuel System: Direct injection (DI).
Ignition System: Electronic, coil-on-plug.
Maximum Power: 185 hp (138 kW) @ 6,400 rpm.
Maximum Power: 189 hp (141 kW) @ 6,400 rpm for sport trims equipped with dual
exhaust.
Maximum Torque: 181 lb-ft (245 Nm) @ 3,900 rpm.
Engine Redline: 6,800 rpm.
VTEC Engagement: 4,800 rpm.
The cylinder block is constructed from high-pressure
die-cast aluminum with cast-in-place iron cylinder liners. Open-deck design
reduces overall mass while maintaining adequate structural rigidity for a
naturally aspirated application. The block incorporates offset cylinder
placement relative to the crankshaft centerline; this offset reduces piston
thrust load against the cylinder wall during the power stroke, contributing to a
reduction in mechanical friction.
A lightweight, four-main-bearing crankshaft is forged from steel, featuring
counterweights optimized for reduced rotational inertia. Connecting rods are
fracture-split powder metal, and the pistons are aluminum-alloy with a
low-friction skirt coating. The oil pan is a stamped steel construction with an
integrated baffle to maintain oil pickup under cornering loads.
The cylinder head employs a reverse-flow configuration
where the intake manifold mounts to the rear (firewall side) and the exhaust
manifold integrates into the front. This arrangement shortens the exhaust path
to the catalytic converter, enabling faster catalyst light-off during cold
starts and improving emissions performance. The head is cast from aluminum alloy
with a pent-roof combustion chamber design optimized for direct injection. Valve
seats and guides are sintered metal for durability under high thermal load.
Intake valves measure 35 mm (1.38 in) in diameter, while exhaust valves measure
30 mm (1.18 in). The two-stage i-VTEC system on the intake side utilizes three
rocker arms per cylinder: a primary low-lobe follower, a secondary low-lobe
follower, and a high-lobe follower.
A hydraulically actuated locking pin connects the followers when engine speed
reaches 4,800 rpm, switching from the low-lift to the high-lift cam profile.
Exhaust valve actuation is fixed, utilizing conventional roller rockers. Valve
clearance adjustment is performed manually via threaded adjusters and lock nuts
on the rocker arms.
The fuel system operates as a direct injection
configuration with a high-pressure mechanical pump driven by a four-lobe cam on
the exhaust camshaft. Fuel pressure is regulated between 2.0 and 20.0 MPa (290
and 2,900 psi) depending on engine load and operating conditions. The pump
supplies fuel to a rail-mounted injector for each cylinder, with injectors
positioned centrally within the combustion chamber between the intake valves.
This placement allows precise fuel delivery stratification and enhanced charge
cooling, which enables the 11.1:1 compression ratio to operate on 87-octane fuel
without knock. The low-pressure fuel system within the fuel tank uses an
electric pump to supply the mechanical high-pressure pump. Fuel lines are
constructed from stainless steel braided hose in the high-pressure circuit.
0A gear-type oil pump mounted to the crankshaft nose
provides lubrication. The pump is integrated into the front timing cover
assembly and features a relief valve calibrated to maintain system pressure. Oil
flow is directed through a full-flow spin-on filter located on the cylinder
block. Main and connecting rod bearings are tri-metal construction with
lead-indium overlay for conformability under high load.
Piston cooling jets are not present on this naturally aspirated application. Oil
capacity including filter is 4.2 L (4.4 qt). Recommended oil viscosity is SAE
0W-20 meeting Honda specifications for low-friction performance. A crankcase
ventilation system incorporates a positive crankcase ventilation (PCV) valve
located on the intake side of the cylinder head.
The cooling system uses a cross-flow radiator with an
electric cooling fan controlled by the engine control unit. A wax-type
thermostat with a bypass valve maintains operating temperature, with an opening
temperature of 82°C (180°F). The water pump is a centrifugal design driven by
the timing chain tensioner arm via a sprocket.
Coolant flow follows a reverse-flow path entering the cylinder head first to
maximize thermal management around the combustion chambers before circulating
through the cylinder block. Coolant capacity is 6.1 L (6.4 qt) for the complete
system. The cooling system utilizes a pressurized reservoir tank with a 1.1 bar
(16 psi) pressure cap.
| Intake and Exhaust Systems |
The intake system features a tuned plastic manifold
with integrated resonance chamber to optimize volumetric efficiency in the
mid-range. An electronically controlled throttle body manages air intake with no
mechanical cable connection to the accelerator pedal.
The exhaust system incorporates a four-into-one manifold cast integrally with
the cylinder head. A single catalytic converter is mounted directly below the
exhaust port exit. Oxygen sensors positioned before and after the catalyst
provide feedback for closed-loop fuel control.
Ignition is managed by individual coil-on-plug units
mounted directly over each spark plug. The engine control unit determines
ignition timing based on knock sensor feedback, camshaft position, crankshaft
position, and load parameters. A knock sensor is mounted on the cylinder block
below the intake manifold to detect detonation and adjust timing accordingly.
The timing drive consists of a silent-type chain with friction-reducing coating.
A hydraulic tensioner automatically maintains chain tension, and fixed guides
direct the chain path around the crankshaft sprocket, camshaft sprockets, and
water pump drive sprocket.
Overall engine dimensions measured from accessory drive
pulley to flywheel mounting face are 620 mm (24.4 in) in length, 670 mm (26.4
in) in width, and 710 mm (28.0 in) in height. Complete engine weight with all
accessories and fluids is 138 kg (304 lb). The cylinder block alone contributes
32 kg (71 lb) to the total assembly.
Oil change interval is 8,000 km (5,000 mi) under severe
service conditions; standard interval is 12,000 km (7,500 mi). Valve clearance
inspection interval is 160,000 km (100,000 mi). Cold valve clearance
specifications are 0.21 mm to 0.25 mm (0.008 in to 0.010 in) for intake valves
and 0.25 mm to 0.29 mm (0.010 in to 0.011 in) for exhaust valves. Spark plug
replacement interval is 160,000 km (100,000 mi) using iridium-tipped plugs with
a gap of 1.0 mm to 1.1 mm (0.039 in to 0.043 in).
Engine coolant replacement interval is 160,000 km (100,000 mi) or ten years,
followed by 80,000 km (50,000 mi) intervals thereafter. Drive belt inspection is
recommended every 24,000 km (15,000 mi). Timing chain inspection is not required
under normal operating conditions; no replacement interval is specified.
Cylinder head bolts: initial torque 29 Nm (21 lb-ft) in
sequence, then 90-degree angle, then 90-degree angle again. Connecting rod cap
bolts: 20 Nm (15 lb-ft) plus 45-degree angle. Main bearing cap bolts: 49 Nm (36
lb-ft) plus 45-degree angle. Camshaft bearing cap bolts: 12 Nm (9 lb-ft) in
sequence. Camshaft sprocket bolt: 93 Nm (69 lb-ft).
Crankshaft pulley bolt: 181 Nm (134 lb-ft). Intake manifold bolts: 23 Nm (17
lb-ft). Exhaust manifold nuts: 25 Nm (18 lb-ft). Spark plugs: 18 Nm (13 lb-ft).
Oil filter: 12 Nm (9 lb-ft). Valve clearance adjuster lock nuts: 20 Nm (15
lb-ft). Timing chain tensioner bolts: 12 Nm (9 lb-ft). Water pump bolts: 12 Nm
(9 lb-ft). Thermostat housing bolts: 12 Nm (9 lb-ft). Oil pan bolts: 12 Nm (9
lb-ft) in sequence. Flywheel/flexplate bolts: 98 Nm (72 lb-ft).
The K24W1 served as the primary four-cylinder engine
for the North American ninth-generation Honda Accord across multiple trim
levels.
Specific applications include:
2013-2017 Honda Accord LX.
2013-2017 Honda Accord Sport.
2013-2017 Honda Accord EX.
2013-2017 Honda Accord EX-L.
Sport trim variants received a dual exhaust system from the factory, resulting
in the increased power output of 189 hp (141 kW) due to reduced exhaust
backpressure. All applications utilized the engine in transverse orientation
with either a continuously variable transmission (CVT) or a six-speed manual
transmission depending on trim level and market availability. The engine was not
offered in all-wheel drive configurations.
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