|The Cruze Diesel is identified by a discreet badge on the trunk. Click to enlarge.|
US buyers hunting for a non-premium diesel passenger car (i.e., not a truck or SUV, and not a vehicle from BMW, Audi, Porsche or Mercedes-Benz) have until recently only had Volkswagen-brand cars as an option: Beetle, Golf, Jetta, Passat. Accordingly, Volkswagen of America (VoA) diesel sales to date in 2014 represent slightly north of 23% of all Volkswagen of America sales. In August, Jetta posted 3,988 diesels sales (26% of Jetta sales, while Passat TDI sales were 2,767 units, representing 30.1% of sales of the vehicle.
However, Chevrolet is trying to challenge that passenger car diesel hegemony with the compact Cruze Diesel, introduced for MY 2014, and now with a facelift for MY 2015. (Earlier post.) Chevrolet is positioning the Cruze, which features a US-modified 2.0L diesel from GM’s European lineup (the engine is manufactured in Kaiserslautern, Germany) to challenge Jetta on the basis of highway fuel economy and power, as well as content. Based on a week with the car (MY2014), the claimed fuel economy superiority may be tough to realize in real-world driving (especially in the face of the new, more fuel-efficient diesel in the 2015 Jetta, earlier post) but overall, the Cruze Diesel is a worthy challenger, and a very good and thrifty drive, especially on the highway.
Fuel economy background. GM introduced the 2014 Cruze Diesel in early summer 2013 in the US with an EPA-estimated fuel economy of 27 mpg city, 46 mpg highway and 33 mpg combined (8.7, 5.1 and 7.1 l/100 km). At that time, the MY2014 Cruze Diesel was going up against the MY2014 Jetta with fuel economy of 30 mpg city, 42 mpg highway, 34 mpg combined (7.8, 5.6 and 6.9 l/100 km, respectively).
In short, while the Cruze’s highway fuel economy edged out that of the 2014 Jetta, its city and combined estimates fell short of that of the Volkswagen. Our week of driving the Cruze Diesel bore that out; realized city fuel consumption, especially on a daily low-speed route of queuing at intersections, stop signs, stop lights, and chugging up hills (all with air-conditioning on), fell well short of the EPA estimate for the Cruze diesel. On the other hand, the highway fuel economy (when not facing with a choked Interstate crawling with traffic) was at or above the EPA estimate (with the air-conditioning on).
For 2015, the Cruze Diesel received a facelift that refreshes its appearance and increases the connectivity and content options for the vehicle; the powertrain remains the same.
|The 2014 Cruze Diesel. Click to enlarge.||The 2015 Cruze Diesel receives updated front fascia design and technologies including 4G LTE and Text message alerts in addition to MyLink’s 7-inch screen and Siri Eyes Free compatibility. Click to enlarge.|
However, for 2015, the Jetta TDI is newly equipped with the strategic EA 288 diesel, which offers more power and better fuel economy: 31 mpg city and 45/46 mpg highway (automatic/manual). Again, to summarize, Volkswagen closed the highway fuel economy rating gap with the Cruze, and expanded its lead in city driving fuel economy.
|2014 Ecotec 2.0L I-4 Turbo Diesel (LUZ). Click to enlarge.|
Diesel engine. SAE-certified at 151 horsepower (113 kW) and 264 lb-ft of torque (358 N·m), the 2.0L turbo-diesel enables 0-60 mph acceleration of about 8.6 seconds in the Cruze. It also produces at least 250 lb-ft of torque (339 N·m) between 1,750 and 3,000 rpm and has an overboost feature capable of increasing torque to an estimated 280 lb-ft (380 N·m), for short bursts of stronger acceleration.
The Cruze Diesel’s 2.0L turbo-diesel engine is based on a proven design already used in markets around the globe; the Cruze engine is assembled at GM’s plant in Kaiserslautern, Germany (home of the 2.0L diesels for the Opel Insignia and Astra). It is the cleanest diesel engine produced by General Motors and meets North American diesel emission standards, generating 90% less NOx and particulate emissions compared to previous-generation diesels.
The cylinder block is made of strong gray cast iron, with five main bearings. To minimize weight, it features an aluminum cylinder block, which helps the 2.0L turbo-diesel weigh in at only 408 pounds (185 kg).
|Torque and power chart for the Cruze Diesel. Click to enlarge.|
The cylinder head incorporates dual overhead camshafts with four valves per cylinder and maintenance-free hydraulic lifters with low-friction roller-finger followers. The engine features quiet belt-driven cams/valvetrain with high-strength belt material and tensioner rated for 100,000 miles.
A forged steel crankshaft anchors the engine’s rotating assembly, for durability over a long engine life. It is used with steel connecting rods, floating piston pin bearings, and high-strength aluminum pistons. The pistons also feature a reinforced top ring and integral combustion bowl design that’s an integral component of the combustion system.
Piston oil jets help reduce friction and optimize piston temperature for greater performance and efficiency. The jets, mounted at the bottom of each cylinder, are part of the engine’s oiling circuit and spray engine oil at the bottom of the pistons.
The 2.0L turbo-diesel uses a central direct fuel injection system, with the injectors positioned in the middle of each cylinder and the bowl in the pistons serving as the combustion chambers. This enables a high 16.5:1 compression ratio that enhances power and combustion efficiency.
The common-rail fuel system with Piezo injectors creates multiple injections per combustion for greater performance, efficiency and quietness. Ceramic glow plugs are employed with the combustion system. They provide greater cold-start performance over conventional metal glow plugs (an engine oil heater is offered for cold climates).
|The days of “diesel clatter” permeating the passenger cabin are long gone. The Cruze Diesel, like its Jetta competitor, is pleasingly quiet, with the distinctive diesel sound almost undetectable in the cabin. From the outside, however, it’s clearly a diesel.|
Top left to right: decibel readings in cabin at idle, no air conditioning, etc. (47.9 dB); outside at idle, proximate to the driver’s side front fender (70 dB); under the hood at idle (81.5 dB). Bottom: sound recordings at each condition. (The initial “click” in the in-cabin recording is the key in the ignition.) (Reminder: the decibel is a logarithmic unit.)
(As a note, the in-cabin at-idle noise for the 2015 Jetta TDI is about 46 dB, according to this measurement application; in-cabin at-idle for a gasoline-engined Jetta is 41 dB.)
In cabin, at intermediate speed (40 mph / 64 km/h), with no air conditioning or radio, the noise level increased to ~ 65-70 dB.
(dB measurements made with SPLnFFT on iPhone 5s. Open access paper from the Acoustical Society of America on smartphone sound measurement applications available here.)
A variable-nozzle turbocharger broadens the 2.0L turbo-diesel’s overall torque curve. It is mounted close to the exhaust outlet of the engine for quicker spool up of the turbine and faster light off of the exhaust catalyst. The turbocharger bearings are oil-lubricated and cooled via an oil cooler. An intercooling system produces a cooler, denser air charge for greater torque and power.
A variable-swirl intake manifold design optimizes air charge mixture motion in the cylinders for a more-efficient combustion that enhances performance and reduces emissions.
The exhaust gas recirculation (EGR) control system features a high-capacity cooler and bypass feature that enable the engine to meet United States and Canada diesel emissions regulations. The exhaust after-treatment system includes a diesel particulate filter and diesel emission fluid (DEF) injection for the Selective Catalytic Reduction (SCR) system.
An approximately 4.5-gallon (17-liter) tank holds enough diesel emissions fluid (DEF, or urea) for an estimated 8,000 miles (13,000 km) of driving between refills. The system is also designed for servicing to coincide with oil changes, for greater convenience.
The 2.0L turbo-diesel is capable of running on B20 biodiesel.
Transmission. In the Cruze, the 2.0L diesel is paired with the Aisin-Warner AF40-6 six-speed automatic transaxle—a compact, lightweight, electronically controlled system for front-wheel-drive and all-wheel-drive applications. A unique combination of a conventional five-pinion planetary gear set and a compound Ravignaux gear set—known as a Le Pelletier arrangement—makes the AF40-6 very lightweight and compact.
Shifts are managed by a transmission control module (TCM) that oversees clutch-to-clutch actuation, while gear changes are accomplished by one clutch engaging the instant the clutch from the previous gear disengages.
The AF40-6 uses a six-element, dual-stage torque converter with a lock-up clutch that helps optimize fuel economy.
The transmission was really the only element of the Cruze with which we had any major issue. Under “normal” use-case conditions, the six-speed auto performs perfectly acceptably, with rapid shifts smoothly moving up to minimize engine speed.
However, under a condition of kickdown from stop or from very slow speed (for example, a driver is pulling into an intersection to make a right turn at red and spots a rapidly approaching vehicle, then floors it to get ahead rather than braking), the transmission hesitates for a very perceptible 1-2 seconds before responding. Based on our driving experience, the transmission in manual mode had no such hesitation.
In other words, under the same condition, the transmission in manual select mode stepped rapidly and very responsively up through the gears; after hitting third, we’d move back to full automatic.
(On a recent short test drive of the new 2015 Jetta TDI, featuring the new EA 288 diesel and the 6-speed DSG transmission, we did not experience comparable hesitation on low-speed kickdown.)
Connectivity. GM continues to improve its connectivity options and in-vehicle content. The enhanced connectivity and convenience features for the 2015 Cruze include a new Text Message Alerts feature for smartphone users with Bluetooth profile (MAP), which reads incoming texts through the vehicle’s speakers, and Siri Eyes Free for iPhone iOS 6 and iOS 7 users to enhance connectivity and convenience. Each enables voice-controlled connectivity, to help keep phones in pockets and hands on the wheel.
Additional standard and available features include:
Seven-inch-diagonal color touch screen and additional USB ports (Volkswagen has yet to equip the Jetta with even a single USB port)
Chevrolet connected by OnStar 4G LTE with built-in Wi-Fi hotspot
Next-generation OnStar and MyLink enhancements with natural language voice recognition
OnStar 4G LTE with available Wi-Fi hotspot provides a mobile hub for drivers and passengers with easy access to apps and services that require a high-speed data connection. If the vehicle is on, the connection is on, allowing passengers to connect personal devices such as smartphones, laptops and tablets, to high-speed wireless Internet. Each vehicle can accommodate seven devices at one time.
Sales. Cruze is the cornerstone of Chevrolet’s North American small-car lineup, which is attracting a greater share of the market and more young, first-time customers to Chevy showrooms. Cruze is also Chevrolet’s best-selling car around the world, with more than 2.5 million sold globally since its launch in mid-2010.
In the US in 2014, the entire Cruze line has sold 189,699 units through August, up 3.6% from 2013. August sales of the Cruze line were down 2.0% from the year before, to 23,345.
Of that, the combined August retail and fleet sales for Cruze diesel was 732 units—up about 23% from last month—while year-to-date sales through August are 4,252 units. This represents a 3.1% share of Cruze sales for August and 2.2% of Cruze sales for the year. In other words, the Cruze Diesel is beginning to pick up momentum within the brand sales, and with understated advertising and branding.
The model we reviewed carried a base price of $24,985, and was equipped with audio with navigation, enhanced safety package, premium Pioneer audio and convenience options bringing the total price to $27,395, before the destination charge of $825.