Audi CNHA Specifications
| Engine Model: Audi CNHA |
| Engine Type: 4-cycle 4-cylinder DOHC 16-valve turbocharged liquid-cooled diesel |
| Total Displacement: 120.1 cu.in (1.96 L) |
| Rated Engine Power: 188 Hp (140 kW) at 4200 rpm |
| Fuel System Type: Common rail direct injection |
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The Audi CNHA is a 2.0-liter, 4-cylinder common rail
diesel engine belonging to the Volkswagen Group’s EA288 modular engine family.
Introduced starting in 2013 as a successor to the EA189 series, this engine
represented a fundamental redesign focused on reducing internal friction,
improving thermal management, and meeting stringent Euro 6 emissions standards.
The CNHA variant is designated as the high-output version, delivering a balance
of refined power delivery and fuel efficiency through advanced technologies such
as a variable geometry turbocharger (VTG) and a high-pressure fuel system. Its
architecture is defined by a compact, rigid construction designed for transverse
or longitudinal mounting in Audi’s mid-size and executive vehicle lines.
Engine Code: CNHA
Displacement: 1968 cc (120.1 cu.in)
Configuration: Inline 4-cylinder, four-stroke, diesel
Bore: 81.0 mm (3.19 in)
Stroke: 95.5 mm (3.76 in)
Compression Ratio: 15.8:1
Valvetrain: Double overhead camshaft (DOHC) driven by a toothed belt, operating
4 valves per cylinder for a total of 16 valves.
Induction System: Single turbocharger with variable turbine geometry (VTG) for
optimized boost across the engine speed range.
Fuel System: Common Rail direct injection with solenoid injectors; maximum
injection pressure of 2000 bar (29,007 psi).
Emissions Control: Selective catalytic reduction (SCR) with AdBlue injection,
diesel particulate filter (DPF), and exhaust gas recirculation (EGR).
Power and Torque
Max Power Output: 140 kW (190 PS; 188 hp) at 3800-4200 rpm.
Max Torque: 400 Nm (295 lb-ft) at 1750-3000 rpm.
Emission Standard: Euro 6.
The cylinder block is constructed from gray cast iron
(GGG 40) to provide a rigid foundation capable of withstanding the high
mechanical and thermal loads of diesel combustion. A significant departure from
its predecessor is the use of a “closed-deck” design, where the cylinder bores
are fully integrated into the upper crankcase.
This configuration increases structural rigidity, reduces distortion under high
cylinder pressures, and improves bore cooling. The block houses the main bearing
caps, which are bolted in place with a four-bolt fastening system for enhanced
strength. The cylinder bores are subjected to a honing process that creates a
micro-finished surface to optimize oil retention and reduce friction against the
pistons.
The cylinder head is manufactured from aluminum alloy
(AlSi8Cu3Fe) and features a cross-flow design. It is a two-part construction
consisting of the main cylinder head and an integrated exhaust manifold housing,
a design that promotes rapid heat-up of the exhaust gases and the aftertreatment
system during cold starts. The valvetrain utilizes roller finger followers with
hydraulic lash adjusters, eliminating the need for manual valve clearance
adjustments.
Intake valves have a diameter of 29.5 mm (1.16 in), while exhaust valves measure
25.9 mm (1.02 in). The exhaust valves are sodium-filled to dissipate heat more
effectively, ensuring durability under high exhaust gas temperatures. The double
overhead camshafts are chain-driven from the rear of the head in the EA288
architecture, a change from the belt-driven cams of earlier engines, improving
timing stability.
The CNHA engine is equipped with a common rail direct
injection system developed by Bosch. A high-pressure fuel pump (pump-injector
unit) draws diesel from the fuel tank and delivers it to the central rail, or
accumulator, where it is stored at pressures up to 2000 bar. The system uses
solenoid-actuated injectors, which enable precise control over injection timing,
duration, and the number of injection events per combustion cycle.
Multiple injection strategies - including pilot, pre, main, and post injections
- are employed to refine combustion for reduced noise, lower emissions, and
improved fuel economy. The post-injection phase is critical for generating the
heat required to initiate regeneration of the diesel particulate filter.
The lubrication system is a pressurized wet-sump design
with an oil capacity of 4.7 L (5.0 qt). An oil pump with a variable displacement
mechanism is driven directly by the crankshaft. This pump adjusts its output
based on engine load and speed, reducing parasitic losses and improving overall
efficiency. The system is equipped with an oil cooler integrated into the oil
filter module to maintain optimal operating temperatures.
The engine mandates the use of a low-ash, low-SAPS (sulfated ash, phosphorus,
sulfur) engine oil meeting Volkswagen specification VW 507 00, with a viscosity
grade of 5W-30 or 0W-30 being mandatory. This specific oil is required to
prevent premature clogging of the diesel particulate filter and to ensure the
longevity of the emissions control systems.
The cooling system features a cross-flow configuration
with a total capacity of 9.0 L (9.5 qt) using a G13 coolant, a silicate-based
fluid with extended service life. A key innovation in the EA288 family is the
use of a dual-circuit cooling system. One circuit manages the engine block and
cylinder head, while a second, separate circuit is dedicated to the exhaust gas
recirculation (EGR) cooler and the turbocharger.
This architecture allows for more precise thermal management, enabling the
engine to reach operating temperature faster while effectively cooling critical
high-temperature components under load. An electric water pump is used for the
EGR cooler circuit, allowing coolant circulation even after the engine is
switched off to prevent localized overheating.
The variable turbine geometry (VTG) turbocharger is
mounted directly to the integrated exhaust manifold. It uses adjustable vanes
around the turbine wheel to control exhaust gas flow, effectively varying the
aspect ratio of the turbine. This allows for rapid spooling at low engine speeds
for responsive torque delivery while preventing over-boost at high engine
speeds, eliminating the need for a traditional wastegate.
Exhaust Aftertreatment: The emissions control system is
extensive. Exhaust gas first passes through the diesel oxidation catalyst (DOC)
to convert hydrocarbons and carbon monoxide. It then moves through the diesel
particulate filter (DPF) which traps soot particles. Periodic regeneration of
the DPF occurs through post-injection of fuel to raise exhaust temperatures and
burn off accumulated soot.
Downstream of the DPF is the SCR (selective catalytic reduction) catalyst. An
AdBlue (diesel exhaust fluid) injector introduces a urea-water solution into the
exhaust stream upstream of the SCR catalyst. This fluid decomposes to ammonia,
which reacts with nitrogen oxides (NOx) to convert them into harmless nitrogen
and water. An additional ammonia slip catalyst (ASC) is integrated to prevent
any excess ammonia from being released into the atmosphere.
Engine Management: Engine control is governed by a Bosch EDC17 (Electronic
Diesel Control) engine control unit (ECU). This unit processes data from
numerous sensors - including manifold absolute pressure, intake air temperature,
crankshaft position, and exhaust gas sensors - to manage fuel injection, boost
pressure, EGR flow, and the regeneration cycles of the aftertreatment system.
Length: 650 mm (25.6 in)
Width: 650 mm (25.6 in)
Height: 700 mm (27.6 in)
Weight: 150 kg (331 lbs).
Engine Oil (with filter change): 4.7 L (5.0 qt).
Specification: VW 507 00. Viscosity: 5W-30 or 0W-30.
Cooling System: 9.0 L (9.5 qt). Coolant type: G13 (or G12).
Timing Belt Replacement Interval: The manufacturer specifies an interval of
210,000 km (130,000 mi). However, due to environmental and operational factors,
a replacement interval of 5 years or 120,000 km (75,000 mi) is widely practiced
to ensure reliability.
AdBlue Consumption: Average consumption is approximately 1.5% of diesel fuel
consumption. Tank capacity is vehicle-dependent, ranging from 12 to 20 L (3.2 to
5.3 gal).
Oil Drain Plug: 30 Nm (22 lb-ft).
Oil Filter Housing (canister): 25 Nm (18 lb-ft).
Timing Belt Tensioner Nut: 20 Nm (15 lb-ft) + 45-deg rotation.
Crankshaft Pulley / Vibration Damper: 10 Nm (7 lb-ft) + 90-deg rotation.
Cylinder Head Bolts: Stage 1: 40 Nm (30 lb-ft).
Cylinder Head Bolts: Stage 1: Stage 2: 60 Nm (44 lb-ft) + 180-deg rotation.
Main Bearing Cap Bolts: 50 Nm (37 lb-ft) + 90-deg rotation.
Connecting Rod Bolts: 30 Nm (22 lb-ft) + 90-deg rotation.
High-Pressure Fuel Pump Mounting Bolts: 20 Nm (15 lb-ft) + 90-deg rotation.
The CNHA engine was utilized as the high-output diesel
option in several Audi models featuring the MLP (Modular Longitudinal Platform)
architecture.
Audi A4 (B8.5, Facelift, 8K): 2013-2015. Application in the Audi A4 2.0 TDI
quattro with 140 kW output.
Audi A5 (8T, Facelift): 2013-2016. Installed in
the Audi A5 2.0 TDI quattro.
Audi A6 (C7, Facelift, 4G): 2014-2018. Used in
the Audi A6 2.0 TDI ultra and standard versions with 140 kW.
Audi Q5 (8R, Facelift): 2013-2017. Found in the
Audi Q5 2.0 TDI quattro.
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