Hyundai KIA Tau G8B V8 petrol engine

Hyundai KIA
dew
Manufacturer:	Hyundai Kia Automotive Group
Production period:	2008-present
Style:	90 ° V
Engines:	4.6 L (4627 cc), 5.0 L (5038 cc)
Cylinder firing order:	1-2-7-8-4-5-6-3

The Tau range is an eight-cylinder , four-overhead-camshaft ( QOHC ) gasoline engine with four valves per cylinder. The engines are built in Ulsan ( South Korea ). The engine block and cylinder head are made of aluminum . The 4.6-liter output opens the series with a 92 mm bore and a 87 mm stroke. The 5.0 L version has been extended to 96 mm.  Weights have not been published so far. The idling speed is 550 revolutions per minute, in the 4.6 L engine, it increases in park and idle position of the automatic to 700th The Tau series is the only not offered in Europe, all others were at least partially installed for Europe. All engines of the Tau series are controlled by an electronic accelerator pedal .The power transmission from the crankshaft to the cylinder head by means of maintenance-free timing chain , the ancillariesare driven by a toothed belt. For this every 30,000 km an inspection is provided, an exchange only when needed.

The valves are operated by roller rocker arms, which act like a rocker. At the vertex of the cam is on. During its rotation, it presses one side and thus the valve downwards, while on the other hand, the hydraulic tappet, which extends by means of a built-in spring, always lies flush. This form of valve clearance compensation is maintenance-free, even an inspection is not provided in the maintenance plan. Wear would be signaled by a ticking sound. This occurs even in wintry cold start for about a minute until the oil inside the lash adjuster reaches the necessary viscosity to equalize the game. On versions with 344 and 375 hp, a fault can also be a cause of noise.

Tau

The first eight-cylinder engine exclusively Korean development was introduced in 2008 with the 4.6 L Tau. In the same year followed by a 5.0 L version for the long version of the luxury sedan Hyundai Equus . Both received an increase in performance in 2010, the details of which are described below. The five-year development of the series cost $ 260 million and ended just before the onset of the economic crisis . Given the concurrent trend towards smaller displacement and the manufacturer's target of achieving the lowest average consumption on the US market by 2025, the series's potential for larger displacement has been eliminated. Over five liters of displacement, the power increase no longer ran linearly to increase consumption. General Motorsand Ford announced in the dew premiere of her departure from V8 series. 2009 and 2010, the Tau V8 was added to the " Ward's 10 Best Engines " list. Ward's AutoWorld is an industry journal published since 1924 for the car trade.

In the late 1990s, there was already with the Omega V8 developed by Mitsubishi V8 gray cast iron engine in Hyundai Equus . He had gasoline direct injection (GDI), which required due to their system typical high compression but super gasoline . At that time, this was rare in South Korea. The resulting drop in performance made the clientele complain. Hyundai responded in 2002 with the changeover to intake manifold injection, while Mitsubishi itself had to stop using the engine due to the crisis, after only 15 months. Despite these initial difficulties Hyundai made him in collaboration with Mitsubishi until 2008 for his top model Equus. 

Tau engines have a dual CVVT named camshaft adjustment for the intake and exhaust side. This has an influence on the timing of the valve opening on both sides, but not on the valve lift and thus the opening duration . It is therefore comparable to the BMW double-VANOS technology . In addition to a better torque in the lower speed range, it reduces above all the nitrogen oxide values, by the exhaust gas recirculation effect of a large overlap is used - this already sucked exhaust gas is sucked back into the combustion chamber.The opening of the valves is friction-reduced via roller rocker arms with a hydraulic valve clearance compensation. This keeps the valve clearance permanently to zero and avoids ticking noises. However, in contrast to mechanical bucket tappets, attention must increasingly be paid to oil quality and level. If the hydraulic tappet is partially filled with air, for example due to the oil level being too low, it does not fulfill its play- compensating effect and there is a ticking sound. The combination of hydraulic tappets with roller drag levers is the most frictionless and cost-intensive form of valve actuation in production. It was published in the 2008 also Kappa seriesand is the only one for which Hyundai / KIA no longer provides for inspections and thus underlines their freedom from maintenance .

The series has a variable intake system (Variable Intake System). This takes into account the pulsation of the air in the intake manifold, which is caused by the opening and closing of the valves. If these negative and positive pressure pulses find a rhythmically adapted path into the engine compartment, a slight resonance charging effect is created, similar to a turbocharger . To achieve it opens at low and high speeds suitable for this purpose, short air. At medium speeds, the longer air duct is used by means of a flap, resulting in a consistently high torque.The 90 ° V orientation of the two four-cylinder benches has the advantage of complete compensation of first and second order inertial forces, as there is always a cylinder on the opposite bank moving in the opposite direction to the one just igniting. The result is a particularly quiet engine running and the saving of an unnecessary balance shaft .For this, however , the crankshaft must have a cross-plane design. In this, the diagonally opposite connecting rods move simultaneously.  However, this has the undesirable side effect of alternate not between left and right bank ignition sequence. This irregularity is then reflected in the air turbulence in the intake, which must therefore be given special attention in its design. Hyundai / KIA therefore mentions the "dozens" of hand-molded prototypes during intake manifold development.  Thus, the otherwise unequal cylinder filling could be compensated recognizable remains the cross-plane shape at the acoustically distinctive exhaust noise. The lighter, cheaper, alternately igniting flat-plane construction would in turn generate greater vibration by free second-order inertial forces. Here, the directly opposite connecting rods move in opposite directions, but in an inner and outer pair at the same time, instead of in four individual graduations .

The pistons were friction-reduced with a MoS² coating, as it were, the chromium-nitride coating acts on the piston rings.  The cylinder block's T5 die casting processresults in smoother expansion, which minimizes friction.Mid-2010 was a performance-enhancing revision. Here, the valves have been enlarged, which allows the air to flow faster - especially at higher speeds, a performance-enhancing effect. In addition, the air flow in the variable intake system has also been optimized. Consumption is classified in the North American EPA rating with 13.8 to 15.7 l in the city and 9.4 to 12 l / 100 km on the highway, rising from limousine to four-wheel drive SUV. 

Problems

When cold and cold, the oil pump does not always apply enough pressure to open the timing chain tensioner valve . Then the chain has slipped and adjusted the ignition behavior of the engine. This can lead to gasoline residues in the cylinder. On the next launch, these cause very non-round running with some black smoke on the exhaust. Hyundai updated the engine's engine control software in November 2010, but the behavior was repeated on some engines. The control unit stores the error codes P0300 (general ignition fault) or P0301 to P0308 (ignition fault in cylinders 1 to 8).Drivers recommend a "warm-up phase" of 30 seconds before and after re-parking at sub-zero temperatures until the increased idle speed drops.  It affects 4.6 L engines prior to model year 2011 ( Hyundai Genesis with 375 hp and KIA Borrego with 344 hp, Hyundai Equus were exported only from the model year 2011). After a case-by-case examination, the manufacturer swapped the timing chain tensioner and, if damage had occurred, the entire engine. All repairs are covered by the five to ten year drive warranty in the supplied markets. 

Tau GDI 

In early 2011, the 5.0 L engine was equipped with a GDI named direct injection . At the same time, all vehicles with a Tau engine received Hyundai's own 8-speed automatic transmission instead of the 6-speed version from ZF Sachs . Their increased efficiency is rather low, such as the Genesis with a pint reduced Highway consumption by EPA shows norm. Their advantage lies in technical independence, faster acceleration and nominal unlocking to the competition. For 2014 Hyundai plans therefore a 10-stage variant.  The new GDI engine in 2011 as its predecessor in 2009 and '10 in the " Ward's 10 Best Engines"List added. Ward's AutoWorld is an industry journal published since 1924 for the car trade. One reason for the decision was the highest horsepower per liter displacement uncharged V8  . Development over 40 months cost 10.5 million euros.

In conventional injection for gasoline engines, the injection valve is located in the intake manifold upstream of the intake valve. With increasing speeds, however, the opening time of the valve is always shorter, and thus the time window for introducing the fuel. In the direct injection is therefore injected directly into the cylinder. Hyundai used as most GDI competitors for homogeneous stoichiometric mixture formation and dispensed with an inhomogeneous stratified charge (stratified fuel charge). The latter is associated with systemic disadvantages, such as significantly increased fine dust levels. It starts with a pilot injection and ignition to set the piston in motion. During its downward movement follows the thrusting, actual fuel injection and ignition. This more precise, cooling, fuel-in-cylinder fueling system increased the cylinder's compression ratio from 10.4 to 11.5. This leads to a fuel saving of around five percent ( see ) and also causes a higher exhaust gas temperature. This benefits the faster heating catalyst. The higher injection pressure of 150 bar (without GDI about 5 bar) also causes a more homogeneous fuel atomization and thus a cleaner combustion. This goes along with a system typical Tick noise. Consumption is rated at 14.7 in the city and 9.4 l / 100 km on the highway in the practical North American EPA rating. It is therefore barely above the 4.6 L model without GDI.

Technical Data 

Used in

Hyundai Equus

• Equus VI
  • G8BA: 2008-2011
  • G8BB: 2009-2011 (as government vehicle in South Korea)
  • G8BE: 2011-today

Hyundai Genesis

• Genesis Bra
  • G8BA: 2008-today
  • G8BE: 2011-today

KIA Borrego

• Borrego HM
  • G8BA: 2008-2011 (V8 option only in Canada and US, vehicle was not accepted by the US market and sales discontinued in 2009)