The Chrysler World Engines: 1.8, 2.0, 2.4 ... and Tiger Shark
Tiger Shark to the rescue
The “World Gas Engine” spawned a new generation, dubbed “Tigershark,” in 2.0 and 2.4 liter versions. Wiped clean of the Daimler errors, the Tiger Shark is more balanced than the horsepower-biased first generation; expected production is 600,000 per year, and it is to completely replace the current World Gas Engine starting in 2012. There are both standard Dual-VVT (2.0) and MultiAir (2.4) versions.
The VVT system on the 2.0 and 2.4 was reworked for a broader power band, sacrificing some peak horsepower but increasing gas mileage and performance; swapping the intakes; and updating the valvetrain to roller cam followers, doing away with the buckets on the valve springs.
| Engine | Horsepower (2008) |
Horsepower (TigerShark) |
MPG (Caliber) |
Torque (Lb-Ft) |
Torque (TigerShark) |
|---|---|---|---|---|---|
| 1.8 liter | 148 @ 6,400 rpm | 220 (turbo) | 28/35 | 125 @ 4,400 rpm 124 @ 5,500 rpm |
|
| 2.0 liter | 158 @ 6,400 rpm | 160 @ 6,400 | 28/34 | 141 @ 5,200 rpm 135 @ 5,200 rpm |
145 @ 4,800 |
| 2.4 liter (Caliber) | 172 @ 6,000 rpm | 184 hp @ 6,250 |
25/31 | 165 @5,200 rpm | 171 @ 4,800 |
| 2.4 turbocharged | 285 | 255 - 300 | 22/28 | 260 |
Thanks, Kerryman, for the gas mileage numbers! MPG is from FWD Caliber for 1.8, 2.0; AWD Caliber for 2.4.
The “world engines” replaced the “Neon” 2.0 and 2.4 liter four cylinder engines starting in 2006. They boasted advanced technologies including dual variable valve timing and a flow-control valve intake manifold. The basic engines were designed jointly by Chrysler, Mitsubishi, and Hyundai, and are made and used by all three - in different configurations. Reviewers generally praised the Hyundai version more than the Mitsu, and the Chrysler version, being tuned for peak paper power, comes in last - except when turbocharged. The World Engine is criticized for being rough and noisy, and making poor power at lower engine speeds, but it was reportedly cheaper to build than the old 2.0 / 2.4 liter engines.
The engines made by Chrysler are in three displacements, all familiar to Chrysler owners (because all three are similar to the current Neon/Stratus engine): 1.8, 2.0, and 2.4 liters. The 2.4 was rated at 172 horsepower and 165 lb-ft of torque, reaching ULEV II emissions standards and increase gas mileage by 5% over the current line. Some of the gain is due to variable valve timing, with continuously variable phasing of both the intake and exhaust valves ("dual VVT"); wedge-shaped heads were used. Though Chrysler was late to the variable valve party, it was the first company to offer dual VVT in the United States on entry-level vehicles.
The engines were designed to be turbocharged and supercharged, partly through use of large water jackets and metal areas around each siamesed cylinder.
Noise, vibration, and harshness were addressed through an isolated valve cover and damped oil pan, a variety of select-fit parts, and the flow control valve ("variable") intake manifold. The bell housing is designed for a tighter than usual connection to the transmission, hopefully eliminating the oil leaks that often come to high-mileage engines.
The engine was built in a new joint-venture plant in Dundee, Michigan; blocks were made by J.L. French of Wisconsin. The older 2.4 liter engines made in Mexico continued for a Russian venture making vehicles closely based on the Sebring/Stratus (using the tooling that was retired in May 2006). The photos with blue backgrounds (or no backgrounds) are courtesy of Chrysler.
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Who is actually designing the engines?
Reportedly, the basic block was designed by Hyundai, and Chrysler and Mitsubishi then made a large number of modifications to make it more efficient and adapt it to their uses and technologies. Most of the packaging/dressing components, such as intake manifolds and valve timing equipment, were developed by each partner independently. For example, the variable valve timing was developed by Mercedes. J.L. French makes the blocks for American engines, with Nemak providing head castings from Mexico. GEMA was a separate company which paid royalties to external and internal partners and patent holders.
The plastic intake manifold has equal-length runners with electrical flow control valves that, when closed, increase air tumble by blocking over half the intake port. Over 3,200 rpm, the valves are opened to allow full airflow. The valve cover is also composite (plastic) and has a variety of vibration-reducing seals.
The electro-hydraulic dual valve timing system uses oil under pressure to adjust timing (both intake and exhaust) using cam phasing so that timing is continuously variable. There is little overlap at idle and more overlap at speed, to permit built-in exhaust gas reburning without a pump. The exhaust cam can move through 35 degrees; the intake through 40 degrees. The cams ride on tappets that come in four dozen very similar thicknesses; the tappets are automatically matched to the individual heads during assembly, eliminating the need to adjust valve lash.
While all the engines use essentially the same block, displacement is changed by shortening the stroke or using thicker piston liners. The pistons themselves have short skirts and friction-reducing graphite patches. The crankshaft is forged steel, is located above the balance shaft/oil pump, and draws oil from the oil pan; it includes an integrated pump. The blocks are all automatically measured at the factory and key components such as pistons and bearings are matched to individual engines to reduce machining and noise, while increasing engine efficiency.
Why are they designing and building engines with two competitors?
According to GEMA, Chrysler took the lead in development of the Mercedes dual variable valve timing system.
Regarding the factory: "Flexible machining centers in a hospital-clean manufacturing environment are the basis to the GEMA business model," said GEMA President Coventry. "Compared to the traditional transfer line process, this model incorporates part recognition and automatic changeover features to allow different products to flow down the line seamlessly; even allowing for a batch size of one. An even greater benefit that machining centers give us over transfer lines is uninterrupted flow, even if there is machine downtime. In the end, we're creating a final product with higher precision, better performance and durability that greatly exceeds each partner company's previous standards."
GEMA invested more than $700 million in the 1 million square-foot dual Dundee plant. Each of the two Dundee plants will have capacity of 420,000 units per year.
Chrysler World Engine specifications: 2.4 liter (in 2009 Chrysler Sebring trim)
| As used in 2009 Sebring | TigerShark as used in Dart |
| |
Displacement |
144 cu. in. (2360 cu. cm) | 144 cu. in. (2360 cu. cm) | |
Bore x Stroke |
3.46 x 3.82 (88 x 97) | 3.46 x 3.82 (88 x 97) | |
Valve System |
Chain-driven DOHC, 16 valves, electronically controlled dual Variable Valve Timing, direct-acting shimless mechanical bucket tappets | Chain-driven DOHC, 16 valves, MultiAir, roller tappets | |
Fuel Injection |
Sequential, multi-port, electronic, returnless | ||
Construction |
High-pressure die-cast aluminum block with dry iron liners, Cast-aluminum cylinder heads, cast-aluminum ladder frame, forged steel crankshaft | ||
Compression |
10.5:1 | Not yet provided | |
Power (SAE net) |
172 bhp (129 kW) @ 6,000 rpm | 184 bhp (138 kW) @ 6,250 rpm | |
Torque (SAE net) |
165 lb.-ft. @ 4,400 rpm | 171 lb.-ft. (200 N•m) @ 4,800 rpm | |
Max. Engine Speed |
6,500 rpm (electronically limited) | Not provided | |
Fuel Requirement |
Unleaded regular, 87 octane (R+M)/2 | Unleaded regular | |
Oil Capacity |
5.0 qt. (4.7L) SAE 5W-20 | Not provided | |
Coolant Capacity |
7.2 qt. (6.8L) | Assumed to be 7.2 qt. (6.8L) | |
Emission Controls |
Single catalytic converter, Dual heated oxygen sensors and engine features | Not provided, assumed to be the same | |
Fuel Economy |
23/31 Estimated EPA MPG (City/Hwy) | Not provided | |
