Acura Automobiles: 2016 Acura ILX

Acura’s gateway sport sedan brings a new level of powertrain performance and sophistication to its segment as the 2016 ILX gains a completely new direct-injection (DI) engine, backed by an equally new and advanced dual-clutch automatic transmission—both playing a key role in challenging the notion of what “gateway” can mean. The new powertrain powers all iterations of the 2016 ILX.

Replacing both the standard 2.0 and 2.4-liter engines in the 2015 ILX, the ILX’s new Direct-Injection 2.4-liter DOHC i-VTEC 4-cylinder engine combines power with exceptional efficiency. It produces peaks of 201 horsepower and 180 lb.-ft. of torque—51 more horsepower and 40 lb.-ft. more torque than the outgoing 2.0-liter automatic transmission-equipped model. Compared to the 2.4-liter manual transmission model, the new ILX engine’s maximum horsepower is the same but it arrives 200 rpm earlier at 6,800. Peak torque is up 10 lb.-ft., arriving at 3,600 rpm versus 4,400 rpm for the outgoing 2.0-liter with improvement across a broad speed range. The 2016 ILX also boasts fuel-economy ratings superior to both of the outgoing powertrains, with an EPA rating of 25/36/291 mpg city/hwy/combined.

To make the most of its powerful, refined and efficient new engine, the ILX features a highly advanced new 8-Speed Dual-Clutch Transmission (DCT) featuring Sequential SportShift. The DCT, with its closely-spaced ratios, ultra-quick shifts and automatic downshift rev-matching, gives the new ILX an aggressively sporting, yet refined feel. The torque converter provides exceptionally smooth operation in stop-and-go situations, plus it offers off-the-line torque multiplication for substantially improved initial acceleration that a DCT alone cannot equal.

Powertrain at a Glance:

Engine

  • 2.4-liter, DOHC, inline-four engine produces peak output of 201 horsepower at 6,800 rpm and peak torque of 180 lb.-ft. at 3,600 rpm 
  • i-VTEC® (intelligent Variable Valve Timing Control and Lift Electronic Control) for intake valves
  • Computer-controlled Direct Injection (DI) with multi-hole fuel injectors
  • 11.6:1 compression ratio
  • High-strength steel crankshaft
  • Drive-by-Wire™ throttle system
  • Direct ignition system
  • Detonation/knock control system
  • Maintenance Minder™ system optimizes service intervals
  • 100,000 +/- miles tune-up interval3
  • High-flow, close-coupled next-generation precious metal catalytic converter plus under floor catalytic converter
  • LEV III/ ULEV125 Emissions compliant 
  • 25/36/291 (city/highway/combined) mpg EPA fuel-economy ratings

Transmission

  • Sequential SportShift 8-Speed Dual-Clutch Transmission (DCT) with Torque Converter and Paddle Shifters
  • Straight-gate style console-mounted shifter
  • Sequential SportShift allows semi-manual operation
  • Steering wheel-mounted, racing-inspired paddle shifters
  • Cooperative control between Drive-by-Wire throttle system and transmission makes for quicker, smoother shifts
  • Advanced shift-hold control limits up shifts during spirited driving
  • Grade Logic Control System reduces gear “hunting” on steep hills 

Direct-Injected 2.4-liter In-line 4-cylinder Engine
The ILX’s new Direct Injection (DI) 2.4-liter DOHC i-VTEC 4-cylinder engine brings a host of intelligent technology to its segment. The engine’s i-VTEC system combines VTC (Variable Timing Control), which continuously adjusts the intake camshaft phase, with Variable Valve Timing and Lift Electronic Control (VTEC), which changes valve lift, timing and duration of the intake valves. Increased engine displacement, a new Direct Injection (DI) system, dual-stage intake manifold and other technologies combine to produce up to 40 lb.-ft. more torque with greater power available over the entire operating range, especially in the crucial mid-rpm area.

Fuel economy ratings are exceptional, due in part to efficient Direct Injection, a new combustion-chamber design, offset cylinder bores and a range of friction-reducing technologies. The ILX has an EPA fuel-economy rating of 25/36/291 mpg city/hwy/combined. That’s a significant increase over both the outgoing 2.0-liter and 2.4-liter engines, which were rated at 24/35/281 and 22/31/25, respectively. The new 4-cylinder engine also meets LEV III/ULEV125 emissions standards in select states, and Federal Tier 2, Bin 5 standards.

Engine Block, Crankshaft and Pistons
The ILX’s engine has a lightweight die-cast aluminum block with a single main-bearing cradle design that creates a rigid assembly to help minimize noise and vibration. Cast-in iron cylinder liners provide long-lasting durability. Each journal on the forged-steel crankshaft is micropolished to reduce internal friction. To improve smoothness throughout the rpm range and help lower noise levels, the engine is fitted with an internal balancer unit. Consisting of a pair of chain-driven counter-rotating shafts located in the lower block and integrated into the oil pan, the balancing system helps quell the inherent second-order harmonic vibrations that normally impact inline 4-cylinder engines.

To reduce piston-sliding friction, the cylinder bores are offset by 8.0 mm from the crankshaft. This gives the connecting rods a more favorable angle during each power stroke, which reduces side loading on the pistons and in turn, improves efficiency. The engine features a forged crankshaft for high rigidity and low friction. Lightweight pistons have a carefully optimized skirt design to minimize reciprocating weight, and reduced weight minimizes vibration and increases operating efficiency. The piston crowns are dished, to help maintain stable combustion and to optimize distribution of the stratified fuel charge from the direct injector in each cylinder. This close control over the combustion process boosts overall operating efficiency.

Dual-Stage Intake Manifold
To maximize power output, the engine has a dual-stage intake manifold with two different intake runner lengths that are selected based on the operating conditions. An actuator and a set of four butterfly valves control the intake-runner switching process. At low engine speeds, the long runners are used to improve low-end torque. At higher engine speeds the system switches to the short intake runners for greater high-rpm power. The result is intake tuning that is optimized for the engine’s entire operating range.
  
Cylinder Head and Valvetrain
The lightweight cylinder head is made of pressure-cast aluminum alloy, with exhaust passages cast directly into the cylinder head. This eliminates the need for a traditional separate exhaust manifold and allows the close-coupled catalytic converter to be mounted directly to the cylinder head. 

A silent chain drives the dual overhead cams and features a double-arm tensioner design that reduces operating friction. The cam drive is designed to be maintenance free throughout the life of the engine.

To help boost fuel efficiency and power, the combustion chamber shape and valve angles have been optimized. The included valve angle is a narrow 35 degrees, which decreases the surface-to-volume ratio and helps create a flatter, more compact combustion chamber that reduces unburned hydrocarbon emissions. With this combustion chamber shape and the precise control of direct injection, the compression ratio set at 11.6:1.

The cylinder head features a new “tumble port” intake design. In combination with the new combustion chamber and piston crown shape, the design’s high level of airflow tumble helps create a homogenous fuel mixture for low fuel consumption and high airflow for high power output.

iVTEC Valve Control System
The ILX’s DOHC 16-valve i-VTEC engine uses an advanced valve-control system to combine high power output with high fuel efficiency and low emissions. The system combines VTC (Variable Timing Control), which continuously adjusts the intake camshaft phase, with Variable Valve Timing and Lift Electronic Control (VTEC), which changes valve lift, timing and duration of the intake valves.

At low rpm, the VTEC intake valve timing and lift are optimized for high torque and low fuel consumption. As engine rpm builds past 4,900 rpm, the VTEC system transitions to a high-lift, long-duration intake cam profile for superior high-rpm engine power.

The “intelligent” portion of the system is its ability to continuously vary the timing of the intake cam relative to that of the exhaust camshaft. This helps boost power and also provides a smoother idle (allowing idle speed to be reduced). The intake cam timing is varied based on input from sensors that monitor rpm, timing, throttle opening, cam position and exhaust air-fuel ratio. The result is increased fuel efficiency and lower NOx emissions.

Cold-Air Induction System
To maximize power output, the ILX has a cold-air intake system that picks up engine induction air from the grille area at the front of the vehicle. Cooler intake air has greater density, which allows the direct-injection system to add proportionately more fuel for enhanced power output. 

Direct-Injection System
The ILX direct-injection system features a compact, high-pressure, injection pump that allows both high fuel flow and pulsation suppression, while variable pressure control optimizes injector operation. A multi-hole injector delivers fuel directly into each cylinder (not to the intake port, as in conventional port fuel-injection designs), allowing for more efficient combustion and greater power output.

The multi-hole injectors help create the ideal stoichiometric fuel/air mixture in the cylinders for good emissions control. Theoretically, a stoichiometric mixture has just enough air to completely burn the available fuel. Based on the operating conditions, the direct-injection system alters its function for best performance. Upon cold engine startup, fuel is injected into the cylinders on the compression stroke. This creates a weak stratified charge effect that improves engine start-up and reduces exhaust emissions before a normal operating temperature is reached. For maximum power and fuel efficiency, fuel is injected during the intake stroke once the engine is fully warmed up. This helps create a more homogeneous fuel/air mix in the cylinder. This improves volumetric efficiency, and the cooling effect of the incoming fuel improves anti-knock performance.

Drive-by-Wire™ Throttle System
The ILX Drive-by-Wire™ throttle system replaces a conventional throttle cable with smart electronics that “connect” the accelerator pedal to a throttle valve inside the throttle body. The result is less under-hood clutter and lower weight, as well as quicker and more accurate throttle actuation. Plus, a specially programmed “gain” rate between the throttle pedal and engine offers improved drivability and optimized engine response to suit specific driving conditions.

Acura’s Drive-by-Wire throttle system establishes the current driving conditions by monitoring throttle pedal position, throttle valve position, engine speed (rpm) and road speed. This information is used to define the throttle control sensitivity that gives the ILX’s throttle pedal a predictable and responsive feel that meets driver expectations.

Direct Ignition and Detonation/Knock Control
The ILX’s Electronic Control Unit (ECU) monitors engine functions to determine the best ignition spark timing. Engine block-mounted acoustic detonation/knock sensors “listen” to the engine, and based on this input, the ECU can retard the ignition timing to prevent potentially damaging detonation. An ignition coil unit for each cylinder is positioned above each spark plug’s access bore. 

Close-Coupled Catalysts
The exhaust manifold is cast directly into the ILX’s aluminum cylinder head to reduce weight, decrease parts count, and create more under-hood space. The result of this casting design is that the primary catalytic converters are positioned much closer to the combustion chambers, enabling extremely rapid converter “light-off” after engine start. A significant weight savings is realized by eliminating traditional exhaust manifolds.

Emissions Control
The 2016 ILX meets the tough EPA Tier 2/Bin 5 and CARB LEV III/ ULEV125 emissions standards, and is certified to this level of emissions performance for 120,000 miles. A number of advanced technologies are factors in the emissions performance. The unique cylinder head-mounted close-coupled catalytic converters light off more quickly after engine start up, and a 32-bit RISC microprocessor within the Electronic Control Unit (ECU) boosts computing power to improve the precision of spark and fuel delivery. 

The engine also features Programmed Fuel Injection (PGM-FI) that continually adjusts the fuel delivery to yield the best combination of power, low fuel consumption and low emissions. Multiple sensors constantly monitor critical engine operating parameters such as intake air temperature, ambient air pressure, throttle position, intake airflow volume, intake manifold pressure, coolant temperature, exhaust-to-air ratios, as well as the position of the crankshaft and the camshafts.

Friction-Reducing Technologies
The ILX engine makes use of friction-reducing technologies designed to improve engine efficiency. The outer skirts of lightweight aluminum pistons feature a special coating that reduces overall friction as the pistons move within the cylinder bores. Plateau honing further lowers the friction level between the pistons and the cylinders by creating an ultra-smooth surface. Plateau honing is a 2-stage machining process that uses two grinding processes instead of the more conventional single honing process. This also enhances the long-term wear characteristics of the engine.

One-Touch Start System
To ensure consistent starting, the ILX has a one-touch start system that maintains starter engagement until the engine starts. Should the driver release the Start button before the engine starts, the system will continue cranking to start the engine. Simply push the Start button (with a foot on the brake pedal and the fob in the vehicle)—the engine is designed to automatically start up. 

100,000+/- Mile Tune-up Intervals
The ILX’s engine does not require scheduled maintenance for 100,000+/- miles or more, other than periodic inspections and normal fluid and filter replacements. The first tune-up includes water pump inspection, valve adjustment and installation of new spark plugs.

Maintenance Minder™ System
To eliminate unnecessary service stops while ensuring that the vehicle is properly maintained, the ILX has a Maintenance Minder™ system that continually monitors the vehicle’s operating condition. When maintenance is required, the driver is alerted via a message on the Multi-Information Display (MID).

The Maintenance Minder™ system monitors operating conditions such as oil and coolant temperature along with engine speed to determine the proper service intervals. Depending on operating conditions, oil-change intervals can be extended to a maximum of 10,000 miles, potentially sparing the owner considerable expense and inconvenience over the life of the vehicle. The owner-resettable system monitors all normal service parts and systems, including oil and filter, tire rotation, air cleaner, automatic transmission fluid, spark plugs, timing belt, coolant, brake pads and more. To mitigate the potential for driver distraction, maintenance alerts are presented on the MID only when the ignition is first turned on, not while driving.

Sequential SportShift 8-Speed Dual-Clutch Transmission (DCT) with Torque Converter
To maximize performance and fuel efficiency, the 2016 ILX has a standard 8-Speed Dual-Clutch Transmission (DCT), in which one clutch controls the odd gears while the other clutch controls the even gears. This arrangement allows automatic or manual gear changes with a much smaller interruption in power to the wheels, resulting in millisecond-quick shifts. In addition, the DCT’s efficient power transmission and wider overall ratio range contribute to the ILX’s substantial gain in fuel efficiency. Compared to a conventional manual transmission, the operation of the clutches and shifting mechanisms are electronically controlled, eliminating the need for a clutch pedal or manual shift lever. The DCT with its closely spaced ratios, ultra-quick shifts and automatic downshift rev-matching, gives the ILX an exhilarating and sporty feel. The DCT transmission in the ILX also features a steering wheel-mounted paddle-shifter system that lets the driver take manual control of transmission gear selection, further heightening the driving experience.

The ultra-thin torque converter complements the efficient operation of the DCT by providing exceptionally smooth operation in stop-and-go situations, plus it offers off-the-line torque multiplication for improved initial acceleration that a DCT alone can’t equal. In an aggressive standing-start launch, the torque converter substantially improves initial acceleration.

Cooperative Transmission Control
Both shift performance and smoothness are improved by cooperative control between the Drive-by-Wire throttle system and the transmission. The engine is throttled by the engine management system during upshifts and downshifts, thus the function of the engine and transmission can be closely choreographed for faster, smoother shifting. As a result, the peak g-forces (or “shift shock”) are reduced significantly during upshifts and downshifts. 

Automatic Modes
The ILX transmission can be operated in two different, fully automatic modes that are controlled by the shift lever. In Drive (D) mode, the transmission combines fuel efficiency with smooth operation and responsive power when needed. When Sport (S) mode is selected, the transmission switches to more aggressive mapping that puts the emphasis on performance-oriented driving, with higher engine rpm for greater acceleration and response.

Smart Transmission Logic
The ILX transmission incorporates an advanced Grade Logic Control System, Shift Hold Control and Cornering G Shift Control — all of which reduce unwanted shifting and gear hunting. The result is smart transmission operation that optimizes fuel efficiency and keeps the transmission in the appropriate gear for driving conditions, generating excellent performance and smooth operation.

While ascending or descending hills, Grade Logic Control alters the transmission’s shift schedule to reduce shift frequency and improve speed control. The transmission ECU continually measures throttle position, vehicle speed and acceleration/deceleration to determine when the vehicle is on a hill. The shift schedule is then adjusted — during ascents to hold the transmission in lower gears to boost climbing power, and during descents to provide greater engine braking.

Shift Hold Control keeps the transmission in its current (lower) gear ratio during aggressive driving, as in the case of decelerating at a corner entry. Shift Hold Control leaves the chassis undisturbed by eliminating excess shifting and ensures that power will be immediately available (without a downshift) at the corner exit. Cornering G Shift Control monitors the vehicle lateral acceleration to determine when the ILX is turning. When the system detects sufficient cornering speed, it will suppress any unwanted upshifts. This prevents the transmission from upshifting during a corner, which could upset the chassis balance thus requiring downshifting again at the corner exit when the throttle is applied.

Paddle Shifter Operation in Drive Modes
While in Drive mode, special transmission logic programming allows the use of the steering-wheel-mounted paddle shifters. When the driver operates the paddle shifters, the transmission responds to the driver’s shift command and then returns to its normal fully automatic mode if further paddle shift inputs are not made within a given time. This special logic makes it easy for the driver to command a quick downshift without leaving the convenience of Drive mode.

Paddle Shifter Operation in Sport Mode
When Sport is selected with the shifter, a pull on the racing-inspired paddle shifters (mounted on the steering wheel) places the transmission in fully manual mode until another mode of operation is selected. A digital display in the instrument cluster indicates which gear the transmission is in.

A double-kick-down feature lets the driver command a sport-minded double downshift — such as from Fifth to Third gear. By pulling on the left downshift paddle twice in rapid succession, the transmission will drop directly to the chosen lower gear ratio. The Drive-by-Wire throttle system also creates a “blip” of the throttle to help match gear speeds while downshifting.

To prevent harm to the powertrain when the transmission is paddle shifted by the driver (including during double-kick-down shifts), the system will inhibit potentially damaging shifts. As an added safety measure, the Electronic Control Unit (ECU) can also cut off fuel to the engine to prevent over-revving. On downshifts, the transmission will not execute a driver command that will over-rev the engine.

1 Based on 2016 EPA mileage ratings. Use for comparison purposes only. Your mileage will vary depending on driving conditions, how you drive and maintain your vehicle and other factors.

2 Customers who choose to use Regular gasoline should expect reductions in power, performance and fuel economy.

3 Does not apply to fluid and filter changes or periodic inspections. Please refer to the maintenance section of your owner’s manual to determine all appropriate maintenance intervals.