Who was the first to invent variable valve timing? does anyone know? I know honda first popularized it, i'm not sure whether honda invented it though.

 

i think mercedes back in the 30's had something along the lines of variable valve timing.
notice i said "i think" so dont take it for concrete

 

nissan had a better system than vtec at the release of the nsx and it was critisized for being ignorant in comparison to the 300zx... many other cars had it before nissan too. honda just made it common to economy cars

though vvt is inportant it was variable ignition timing that was the real kicker

With the advent of electronic ignitions and microcomputers in the 1970s and
80s, a greater range of options in the control of ignition timing became
available. However, the programmed look up table in each cars computer
memory was still a compromise averaging the optimum firing angles of all of
the cylinders in all of the engines being manufactured. With electronic
control engineers dreamed that if suitable sensors
could be invented, an optimum closed loop control system with feedback could
be designed that might some day optimally control each cylinder
individually.

that day came... now we have cars that can adjust timing of the spark and the vavle train to optimum performance levels but what REALLY matters is that the system is OUTDATED and vtec will be gone soon as they are currently working on CVVT (constant variable valve trains) which would self modify to maximize all power levels and fuel economy through out the powerband. in conjunction with a cvt transmission and a proper lsd setup this combination will make a 150 hp economy car ruin a contemperary spots car due to it's powerband being solid and kept high by the gearing, ignition timing and valves running at optimal power at all times in a pull and also putting that power to the ground effectivly.

 

The first experimentation with variable valve timing and lift was performed by General Motors. GM was actually interested in throttling the intake valves in order to reduce emissions. This was done by minimizing the amount of lift at low load to keep the intake velocity higher, thereby atomizing the intake charge. GM encountered problems running at very low lift, and abandoned the project.

The first functional variable valve timing system, including variable lift, was developed at Fiat. Developed by Giovanni Torazza in the 1970s, the system used hydraulic pressure to vary the fulcrum of the cam followers. The hydraulic pressure changed according to engine speed and intake pressure. The typical opening variation was 37%.

The next big step was taken by Honda in the late 1980s and 90s, where Honda began by experimenting with variable valve lift. Pleased with the results, engineers took the knowledge and applied it to the B16A engine, fitted to the 1989 EF9 Honda Civic. From there it has been used in a variety of applications, from sport to utility, by many different auto makers.

In the year 1992, BMW introduced VANOS, their version of a variable valve timing system, on the BMW M50 engine used in the 3 Series. VANOS significantly enhances emission management, increases output and torque, and offers better idling quality and fuel economy. The latest version of VANOS is double-VANOS, used in the new M3. Double-VANOS adds an adjustment of the intake and outlet camshafts.

Variable valve timing was the sole domain of overhead cam engines until the 2005, when General Motors began offering the LZE and LZ4, pushrod V6 engines with VVT. For the 2006 model year, General Motors will introduce the Vortec 6200, the first mass-produced pushrod engine with variable valve timing.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2k.civic.si &raquo;</TD></TR><TR><TD CLASS="quote">The first experimentation with variable valve timing and lift was performed by General Motors. GM was actually interested in throttling the intake valves in order to reduce emissions. This was done by minimizing the amount of lift at low load to keep the intake velocity higher, thereby atomizing the intake charge. GM encountered problems running at very low lift, and abandoned the project.

The first functional variable valve timing system, including variable lift, was developed at Fiat. Developed by Giovanni Torazza in the 1970s, the system used hydraulic pressure to vary the fulcrum of the cam followers. The hydraulic pressure changed according to engine speed and intake pressure. The typical opening variation was 37%.

The next big step was taken by Honda in the late 1980s and 90s, where Honda began by experimenting with variable valve lift. Pleased with the results, engineers took the knowledge and applied it to the B16A engine, fitted to the 1989 EF9 Honda Civic. From there it has been used in a variety of applications, from sport to utility, by many different auto makers.

In the year 1992, BMW introduced VANOS, their version of a variable valve timing system, on the BMW M50 engine used in the 3 Series. VANOS significantly enhances emission management, increases output and torque, and offers better idling quality and fuel economy. The latest version of VANOS is double-VANOS, used in the new M3. Double-VANOS adds an adjustment of the intake and outlet camshafts.

Variable valve timing was the sole domain of overhead cam engines until the 2005, when General Motors began offering the LZE and LZ4, pushrod V6 engines with VVT. For the 2006 model year, General Motors will introduce the Vortec 6200, the first mass-produced pushrod engine with variable valve timing.

</TD></TR></TABLE>

good info.