V-TEC

Technology V ariable valve T iming and top spin E lectronic C ontrol (progressive electronic control of temporization and opening of the valves) of Honda to improve the effectiveness of combustion. He was invented by the originator Kenichi Nagahiro.

Description

DOHC VTEC

System VTEC gets much power with high mode while preserving the power and the couple at low mode. On engine VTEC 1.6 (B16A2) developing 160 ch and 150 Nm of couple, 90% of this couple (are 135 Nm) are available as of 2100 tr/min and this up to 8000 tr/min. That makes it possible to have a very pleasant daily control. System VTEC varies the distribution and the lifting of the 4 valves (by cylinder) using camshafts presenting of the different profiles. Engine DOHC VTEC includes/understands 3 cams per couple of valves (2 admission and 2 exhaust).

SOHC VTEC

Appeared in 1992 on engine 1.6 of Civic Esi, it offers a power of 125 ch to 6500 tr/min and a couple of 142 Nm with 5200 tr/min. Like DOHC VTEC, it delivers 90% of its couple (that is to say 127 Nm) between 2000 and 6600 tr/min. On this engine, it raised and the variable distribution are carried out only with the admission. The camshaft is provided with 5 cams per cylinder. 2 tumblers and 3 rocking-levers transmit the requests to the two inlet valves.

VTEC-E

This system makes it possible the Moteur to function with 2 Soupape S with bottom and average mode in order to provide better a />Lorsque Couple moteur.

Others

There still exists of other versions, of which:

  • the i-VTEC which also uses technology VTC;
  • the Hyper-VTEC adding the possibility of using only two, three or four of the cylinders of the engine according to the mode and the load by closing their valves and while cutting the injection; a saving in gasoline 30% compared to the standard engine being advanced.

Technique

The two valves " VTEC" have a tail of valve in two parts, connected between them by a room filled with oil. A piston makes it possible to increase or decrease the pressure in this room.

  • If the pressure is low, the impulse given by the camshaft is not transmitted to the valve: The valve remains closed permanently.
    Ce operation can be progressive (variable opening).
  • If the pressure is strong, the valve behaves like a valve " normale" , in only one part: The valve opens like the others.

DOHC VTEC

With bottom and average mode, the engine functions on the external cams whereas with high mode it functions on the intermediate cam (medium). This one is known as more " pointue" because the time of opening and the lifting are more important. The lifting of the cams is done via rocking-levers. The interlocking of the VTEC depends on 4 factors:

  1. the mode and the engine load
  2. the speed of the vehicle
  3. the temperature of the liquid of cooling.
A slide of stop in two parts is in the rocking-levers. A spring and a thrust maintain the slide at rest. In this position, the 3 rocking-levers are free. In lower part of 5300 tr/min, the valves function only with their respective cams whereas the third follows the movement. Between 5300 and 6000 tr/min (according to the load), and if the factors agree, an electrical signal orders the electromagnetic sluice gate, which makes it possible the oil pressure to actuate the slide. The oil pressure is higher than the effort of the spring. The slide solidarizes the 3 rocking-levers and it is the intermediate cam which comes into play. If a failure came to this producing on the level of the one of the components of system VTEC, the calculator would pass automatically in program of help. This program uses only the external cams.

SOHC VTEC

The factors ordering the interlocking of the VTEC are the same ones as for engine DOHC VTEC:

  1. the mode and engine load
  2. the speed of the vehicle
  3. temperature of the liquid of cooling.
As on DOHC VTEC, with low mode the engine functions on the external cams. That supports inter alia the saving in fuel. With high mode, the three tumblers are solidarized and the inlet valves function on the intermediate cam.

Appearance

System VTEC was introduced by Honda into its range of motor bikes in 1999 on the CB 400 Super Furnace. It was used before on certain models of cars of which the CRX and the Integra . Starting from 2002, the series of motor bikes VFR VTEC also has this system.

First engine VTEC of series is the C30A (3.0l; 280cv) which equipped the NSX since 1989 First engine VTEC " populaire" is the B16A1 (1.6l; 150cv), assembled in CIVIC VT-I (EE9) and CRX VT-I (EE8) in 91… which will be then followed B16A2 equipping the 2 following generations with Civic (EG6, EG9 and EK4) and CRX (EG2), of 1991 to 2000, and which will be the 1st engine of series to have an output (power/liter of cubic capacity) of 100cv/l with 1.6l and 160cv!!!

See too

Internal bonds

External bonds

  • vtec.net

  • honda4all.com
  • CTR TEAM - site devoted to the Civic Type R
  • EJ Squad France - Site dedicated to the Civic Half-compartment

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