Hyundai KIA Nu
| Hyundai / KIA | |
|---|---|
|
|
| Nu, Nu Hybrid, Nu GDI, Nu CVVL | |
| Manufacturer: | Hyundai / KIA |
| Production period: | 2010-present |
| Design: | Inline four-cylinder |
| Engines: | 1.8 L (1797 cm³), 2.0 L (1999 cm³) |
| Cylinder firing order: | 1-2-4-3 |
| Previous model: | Hyundai KIA Theta |
| Successor: | none |
| Similar models: | none |
The Nu series is a four-cylinder gasoline engine with a double overhead camshaft ( DOHC ) and four valves per cylinder. The engines are manufactured in South Korea , for China and North America in Shandong ( China ).
general characteristics
The engine block and cylinder head are made of aluminum . The 1.8 liter engine weighs 112 kg. Weights and cylinder dimensions of the other engines are currently unknown, the same applies to the idling speed of the series.
All engines in the Nu range are controlled by an electronic accelerator pedal .
The power transmission from the crankshaft to the cylinder head takes place by means of a maintenance-free timing chain , the auxiliary units are driven by a serpentine belt. An inspection is planned for this from 100,000 km every 25,000 km, an exchange only if necessary.
In the engines without CVVL , the valves are operated via roller rocker arms, which act like a rocker. While one side pushes the valve downwards, the hydraulic valve lifter, which is stretched by means of a built-in spring, is flush with the other (see valve closed ( Memento from July 16, 2014 in the Internet Archive ), valve open ( Memento from February 21, 2014 in Internet Archive )). With CVVL technology , the cam rests on a roller wheel, which presses a lever with low friction to open the valve. This lever is adjustable and is used to vary the opening duration and valve lift. Both forms of valve clearance compensation are maintenance-free, even an inspection is not included in the maintenance plan. Wear would be communicated by a ticking sound.
Nu
The Nu series sums up all the technologies that the manufacturer developed for its gasoline engines up to 2010, apart from direct injection and turbochargers. However, none of them made their debut with this series, which is why its highest level of expansion was chosen for the presentation .
Adopted from its predecessor series , a D (ual) -CVVT named camshaft adjustment varies the inlet and outlet side. It has an influence on the time at which the valve is opened on both sides, but not on the valve stroke and thus the opening time. It is therefore comparable to the BMW double VANOS technology . In addition to better torque in the lower speed range, it primarily reduces nitrogen oxide levels by using the exhaust gas recirculating effect of a large overlap - exhaust gas that has already been emitted is sucked back into the combustion chamber. The D-CVVT is not always listed due to its serial nature.
The variable intake system (Variable Induction System) is also dedicated to the air supply . This takes into account the pulsation of the air in the intake manifold, which occurs when the valves are opened and closed. If these negative and positive pressure impulses find their way into the engine compartment that is adapted to their rhythm, a slight resonance charging effect occurs, similar to a turbocharger . To achieve this, a suitable, short air path opens at low and high speeds. At medium speeds (3000 to 5500), the longer air duct is used by means of a flap, which results in consistently high torque and five percent more power.
While the technologies listed above appeared with the Theta II series , the offset crankshaft dates back to the 2006 Gamma series . The pistons are constantly pressed against a cylinder wall by the rotary movement of the crankshaft. An offset of their position by one centimeter allows the pistons to slide downwards with less friction in the ignition phase. This reduction in friction not only reduces consumption but also vibrations. Toyota , for example, uses the same procedure in the Prius .
The use of friction-reducing coatings on pistons and valve actuation is not known, but these are used in other engine series and are therefore likely to remain unmentioned here.
To reduce costs, this expansion stage has not been adapted to the automatic stop-start system ( ISG) , which was developed together with Bosch .
Real consumption ranges from less than 5 to over 9 liters, with the American EPA standard value of 7.1 l / 100 km in between.
Nu hybrid
For South Korea, the engine in the manufacturer's first full hybrid drive was swapped for a 2.0L engine from the Nu series . All other properties were retained. The network now makes 191 instead of the previous 209 hp. In terms of consumption, the result cannot be determined for the time being, as the South Korean consumption calculation differs significantly from the American one, with which the 209 hp variant was previously only measured. According to the figures, consumption fell from 6.4 to 4.8 liters per 100 km, which clearly exceeds the effect of swapping two similar engines.
Nu GDI
Half a year after the Nu series, this was equipped with direct injection (GDI) and used for the market launch of the Hyundai i40 in summer 2011 for the first time. Together with the variable valve lift CVVL is the G asoline D irect I njection a prerequisite for the next homogeneous engines .
With conventional injection for gasoline engines, the injection valve is located in the intake manifold in front of the inlet valve. With increasing engine speeds, however, the opening time of the valve becomes shorter and shorter, and thus the time window for introducing the fuel. With direct injection , injection is therefore carried out 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 system-related disadvantages, such as significantly increased fine dust values.
It starts with a pilot injection and ignition to set the piston in motion. During its downward movement, the actual fuel injection and ignition takes place. With this more precise fuel supply, which takes place directly in the cylinder, the compression rate in the cylinder could be increased. This leads to fuel savings ( cf. ) and also causes a higher exhaust gas temperature. The catalytic converter, which heats up faster, benefits from this and can thus reduce emissions during the cold start phase. The higher injection pressure of 150 bar (without GDI approx. 5 bar) also results in more homogeneous fuel atomization and thus cleaner combustion. It is accompanied by a system-typical ticking noise.
To reduce consumption, the Nu GDI is available with the automatic stop-start system ISG , the effect of which in other vehicles is about 0.2 l / 100 km in standard consumption, but due to its standard feature in vehicles with Nu GDI engines, it can only be checked by manual deactivation is.
Nu CVVL
With the presentation of this variant, the 44-month development period for the Nu series ended in April 2010, the cost of which of 153 million euros is likely to relate specifically to CVVL technology. It replaces dual CVVT technology, but only varies the valves on the inlet side. All other properties are identical to the Nu series .
In the CVVL system, the cam rests on a roller wheel, which presses a lever with low friction, which then opens the valve. This lever lies on an eccentric shaft so that its pivot point can be adjusted. A servomotor takes over this task and thus changes the rotation deflection. This changes the valve lift, the opening duration and the opening time. These three effects are interrelated. Because a long stroke means a long opening time, since the stroke paths have to be covered with accelerations that are not too fast, in a manner that is gentle on the material. A longer opening time also means that the process starts earlier and ends later. This also changed the timing. An independent variation of the parameters is only possible with a camshaftless opening of the valves (see Multiair system). The structure of the CVVL system, however, is similar to the BMW Valvetronic , but its elements are arranged differently. The CVVL was developed in the European Group Powertrain Center in Rüsselsheim, but its exact structure has not yet been announced.
The CVVL eliminates the need for a throttle valve , which reduces the associated throttle losses . These occur on all elements that divert the air flow, including the valves themselves. However, the main cause is the throttle valve, which controls the amount of air being drawn in. Without it, more air would flow into the cylinder at part load, which would cause the combustion temperature and thus the amount of nitrogen oxide to rise above the Euro limit values due to its more oxygen . The variable valve lift can now take over the air control itself. This saves five and a half percent fuel compared to a Nu engine without valve variation, which does not exist. The effect on the actual base level of the series should be between three and four percent.
Hyundai's vice head of development explains the Nu series as the link between theta and gamma engines . The former in particular is architecturally unsuitable for a 1.8 liter displacement. Regardless of this, the manufacturer had such a version in the Theta series for years. The statement should therefore focus on the future viability, especially the suitability for homogeneous mixtures (HCCI) . These require very precise valve control and injection. With CVVL and GDI, the Nu series fulfills both requirements, albeit in separate engines so far. Hyundai / KIA is planning its first homogeneous engine for 2012.
Outlook (Nu HCCI)
The efficiency expectations for homogeneous engines are based primarily on their higher compression and the low-emission combustion. An increase in compression from today's standard 11: 1 to 15: 1 results in an efficiency increase of around 20% ( see ). However, this high compression creates uncontrolled combustion of the gasoline after ignition. With this “ knocking ” the mixture burns too quickly, ie before the piston has finished its way up. This creates high pressures and temperatures that can damage the engine. Therefore, engine controls with knock sensors avoid too early ignition.
In order to increase compression, the mixture must be prepared in such a way that it ignites at the right time and at several points at the same time. The latter, in order to achieve residue-free combustion - because unburned fuel increases harmful emissions. A similar, partially homogeneous combustion has already been achieved by engines with gasoline direct injection and stratified injection ("Stratified Injection"). However, they emit large amounts of nitrogen oxides and also produce soot, especially when there are load changes. They therefore require expensive nitrogen oxide filtering of the exhaust gas, and European standards since 2009 have also limited soot emissions for gasoline engines. Homogeneous engines work with variable valve lift. They suck a large amount of exhaust gas back into the cylinder and thus regulate compression ignition. The lack of oxygen in the exhaust gas prevents ignition too early, while its warmth enables self-ignition in the first place. This needs about 1000 ° K. The combustion creates a temperature around 2000 ° K; Due to the low calorific value of the mixture, around 600 ° cooler than in conventional gasoline engines. The nitrogen oxide levels are thus reduced to a minimum. However, compression ignition has a disadvantage. The problem is the pressure during ignition, which increases from 24 to 36 bar in the partial load range, especially its rapid increase and decrease due to the homogeneous, i.e. simultaneous combustion of the entire fuel, which gives it its name. This is why homogeneous engines only work with compression ignition in partial load operation, while under full load they rely on less compression and a spark plug. The same applies at high speeds, at which the injection nozzles can no longer keep up with the production of a homogeneous mixture. For this reason, it makes sense to choose a series of motors with larger cubic capacities for HCCI development, as only they provide enough power to drive as often as possible in partial load operation (see Diesotto motor ). Full load operation would push the materials to their limit, not to mention turbo-charging.
CVVL is therefore necessary in order to adjust the valves precisely for compression and exhaust gas recirculation rate, especially during load changes. Then, in order to protect the material, there is also a change from compression ignition to spark ignition using a spark plug at low compression. GDI in turn enables pilot injections. This is the only way to add the gasoline to the inflowing air one after the other and distribute it precisely in the combustion chamber, which is a prerequisite for auto-ignition.
Hyundai / KIA has not yet stated what effect homogeneous operation will one day have. To classify HCCI engines, however, it is worth knowing that the European consumption calculation can be carried out almost exclusively in partial load operation. The first engines with an HCCI-equivalent compression of 14: 1 are the Skyactiv-G drives from Mazda. However, these dispense with auto-ignition, which means they can probably maintain the high compression even under full load. Such an engine will be used for the first time in summer 2011 in the Mazda 3 facelift.
Data
| series | Engine code | Displacement (cm³) | Stroke × bore (mm) | Power at (1 / min) | Torque at (1 / min) | cylinder | compression | Charging | injection |
|---|---|---|---|---|---|---|---|---|---|
| Nu 1 | G4NB | 1797 | 87.2 x 81.0 | 148 at 6500 | 178 at 4700 | 4th | 10.3 |
VIS (2 way) |
MFI |
| Nu | G4NA | 1999 | 97 x 81.0 | 164 at 6500 | 201 at 4800 | 4th | 10.3 | VIS (2 way) |
MFI |
| Nu hybrid | G4NE | 1999 | 97 x 81.0 | 150 at 6500 + 40 electric |
179 at 5000 + 205 electrical at 0 - 1400 |
4th | 12.5 | - | MFI |
| Nu GDI | G4NC | 1999 | 97 x 81.0 | 177 at 6500 | 213 at 4700 | 4th | 11.5 | VIS (2 way) |
GDI |
| Nu CVVL | G4ND | 1999 | 97 x 81.0 | 170 at 6200 | 196 at 4300 | 4th | -? - | VIS (2 way) |
MFI |
commitment
The Nu engines installed worldwide are listed for each model; not all configurations are offered in every country.
Hyundai
Hyundai Elantra
- Elantra UD / MD
- G4NB (148 hp): 2010-present
Hyundai i40
- i40
- G4NC (177 hp): 2011-present
Hyundai Sonata
- Sonata YF
- G4NE (190 hp): 2011-present (South Korea only)
KIA
- Optima TF
- G4NA 2.0 CVVL (170 PS): from 2012
KIA Soul
- Soul AM
- G4NA (164 hp): 2011-present (North America and Canada)
Individual evidence
- ↑ Production in Shandong, China
- ↑ Weight comparison Beta II CVVT and Nu 1.8 (32 kilograms lighter)
- ↑ a b c d e f Nu Details ( Memento from February 26, 2012 in the Internet Archive )
- ↑ Inspection interval of the toothed belt Hyundai Elantra manual Chapter 7, p. 10
- ↑ Inspection interval of the toothed belt Hyundai Elantra manual, Chapter 7, pp. 7-16
- ↑ Ticking or clicking noise due to loose valve adjustment plate: Sporadic clicking of an XM TCT. In: YouTube . March 12, 2010, accessed April 30, 2019 .
- ↑ Presentation of the Nu range at the Seoul Motor Show 2010
- ↑ Video for the Nu series
- ↑ Explanation of the Hyundai CVVT technology including images
- ↑ Gas exchange # four-stroke reciprocating engine
- ↑ a b animation of the Hyundai CVVL
- ↑ Nu offset crankshaft reduces consumption by one percent ( Memento from February 26, 2012 in the Internet Archive )
- ↑ a b Justification of the Nu series without ISG, GDI and CVVL
- ↑ Real highway consumption 4.8 liters Elantra Nu D-CVVT
- ↑ Real winter consumption 9.4 liters Elantra Nu D-CVVT ( Memento of the original from April 2, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ EPA standard consumption of the Nu D-CVVT
- ^ Hyundai Sonata Hybrid with Nu D-CVVT
- ↑ Nu GDI performance data ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ Use of the Nu GDI in the Hyundai i40
- ↑ Hyundai GDI uses a homogeneous mixing ratio
- ↑ a b Fine dust values for gasoline engines ...
- ↑ a b ... increased by direct injection
- ↑ 2011 Hyundai Sonata, Detailed Walk Around. In: YouTube . May 1, 2010, accessed on April 30, 2019 (English, noise from approx. 4:00 minutes).
- ↑ Development costs of the Nu engines: 240 billion South Korean won = 153 million euros
- ^ Description of the CVVL
- ↑ Animation of the BMW Valvetronic
- ↑ a b Report on the development of the Hyundai CVVL ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ Savings through the CVVL compared to the basic engine without CVVL and CVVT
- ^ Explanation of the necessity of the Nu series
- ↑ p. 4 - Requirements for HCCI operation (PDF; 1.4 MB)
- ↑ p. 37 Hyundai schedule for drive technologies ( Memento of the original from February 22, 2014 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 4.2 MB)
- ↑ Fuquan Zhao, Thomas W. Asmus, Dennis N. Assanis, John E. Dec, James A. Eng, Paul M. Najt: Homogeneous Charge Compression Ignition (HCCI) Engines: Key Research and Development Issues . Society of Automotive Engineers , Warrendale, PA, USA 2003, ISBN 076801123X , pp. 11-12.
- ↑ a b p. 17 and 18: Temperature and pressure changes in the homogeneous engine (PDF; 1.4 MB)
- ↑ Jürgen Warnatz, Ulrich Maas, Robert W. Dibble: Combustion: Physical and Chemical Fundamentals, Modeling and Simulation, Experiments, Pollutant Formation , 4th Edition. Edition, Springer , Berlin, Germany 2006, ISBN 3-540-25992-9 , pp. 175-176.
- ↑ Production of the homogeneous mixture by pilot injection
- ↑ page 5 Coverage of the NEDC by HCCI operation (PDF; 1.4 MB)
- ↑ Details of the Mazda SKYACTIV drives ( Memento of the original from January 21, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Consumption data for SKYACTIV drives ( memento of the original from October 24, 2010 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
