variable valve engine comparo

[ferdine]

Mitsu have MIVEC, Mazda has SVT, etc.

The world doesn't revolve around Toyota and Honda. :lol:

Here is wikipedias entry of Mazda'z SVT:

S-VT
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S-VT, or Sequential Valve Timing, is an automobile variable valve timing technology developed by Mazda. S-VT varies the timing of the intake valves by using hydraulic pressure to rotate the camshaft. S-VT was introduced in 1998 on the ZL-DE engine and is used in the B-, Z-, and J-families of engines.



And here is MIVEC's:

MIVEC
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Mitsubishi Innovative Valve-timing-and-lift Electronic Control system (MIVEC) is an automobile variable valve timing technology developed by Mitsubishi Motors. MIVEC varies the lift of valves by using two different camshaft profiles. It is similar to Honda's VTEC system, but differs from it in the fact that the MIVEC system activates at a lower RPM and has a slightly more conservative cam grind, allowing the transition to appear more subtle at the cost of higher RPM performance. A more limited MIVEC system in the Lancer Evolution controls only valve timing, not lift.

MIVEC technology has been incorporated into the "World Engine", an engine co-developed by Mitsubishi, DaimlerChrysler and Hyundai as the Global Engine Manufacturing Alliance.

And here is a snapshot of VTEC's:

DOHC VTEC

Honda's VTEC system is a simple method of endowing the engine with multiple camshaft profiles optimized for low and high RPM operations. Instead of one cam lobe actuating each valve, there are two - one optimized for low RPM stability & fuel efficiency, with the other designed to maximize high RPM power output. Switching between the two cam lobes is determined by engine oil pressure, engine temperature, vehicle speed, and engine speed. As engine RPM increases, a locking pin is pushed by oil pressure to bind the high RPM cam follower for operation. From this point on, the valve opens and closes according to the high-speed profile, which opens the valve further and for a longer time. The DOHC VTEC system has high and low RPM cam lobe profiles on both the intake and exhaust valve camshafts.

The VTEC system was originally introduced as a DOHC system in the 1989 Honda Integra sold in Japan, which used a 160 hp (119 kW) variant of the B16A engine. The US market saw the first VTEC system with the introduction of the 1990 Acura NSX, which used a DOHC VTEC V6. DOHC VTEC motors soon appeared in other vehicles, such as the 1992 Acura Integra GS-R.


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So that means VTEC's timeline in "mass market" started as early as 1989 and Mazda followed nine years earlier. No mention of MIVEC's entering the mass market so I have no idea. So who really got the headstart in technology offered to the public then? I don't belittle Mazda's RX 8 but we are talking about reciprocating motors here not rotary.

[mazdamazda]

So that means VTEC's timeline in "mass market" started as early as 1989 and Mazda followed nine years earlier. No mention of MIVEC's entering the mass market so I have no idea.

Still relying solely of wikipedia? :lol:

FYI. MIVEC was launched in the early 90s.

And oh, GM pioneered VVT technoloy and Nissan was first one to sell VVT engines (1987 AFAIK).

So who really got the headstart in technology offered to the public then? I don't belittle Mazda's RX 8 but we are talking about reciprocating motors here not rotary.

Technology? Then?

The Mazda GTX sold in the late 80s had a 220hp engine. Honda Integra had 160hp? W-O-W! :charing:

Heck... the Fairlady had 150hp engine already in the 1970s.

:lol:

[orly_andico]

*m2, you can't dissuade the honda fanboys.

although i think the Mazda GTX is not an NA engine.

according to our "canonical" source Wikipedia, the first VVT technology came out in 1975, courtesy of GM. And the Nissan VG30 in 1986.

[mazdamazda]

Orly... yup... turbo yung GTX. just pointing out that "technology" per se is not just the realm of Honda.

[alwayz_yummy]

while sa research ko, napansin ko hindi talaga honda ang piooner sa variable valve tech. either renault/nissan nga...

and sheet comparison, b16a is only rated at 160ps, 4age 20v 170ps, while yung sr16ve 175ps...dont know yung MIVEC 6a10 and 11..MIVEC4g92 ata is 1800...

for me,ha, ang boy racers will always say b16 is da best...

[orly_andico]

ang alam ko nga the first mass-market engine to break 100hp/L was the eagle talon tsi (it's actually some mitsubishi) with a 4g63 engine. don't know kung turbo yun.

it could be argued that Mazda is actually the most innovative engine manufacturer, with their Wankel rotaries and the Miller-cycle KJ-ZEM in the Millennia.

i'm sure most honda fanboys don't even know what a Miller-cycle engine is.

[alwayz_yummy]

yup, agreee ako sa wankel-rotary engine. diba twin turbo yun? nasolve na ata ng mazda ang consuption probs dun sa rx7s nila.....im not a honda fan, pero di familliar ang miller-cycle may much common name po ba to?

[orly_andico]

miller cycle (as opposed to the usual otto cycle gasoline engine) is a modification where the intake valves are held open during the compression stroke. this reduces pumping losses and increases engine efficiency, at the expense of reduced displacement (due to some intake air getting pushed out again).

the KJ-ZEM is based on a 3.0L V6 but only displaces 2.3L due to the loss of displacement. however it produces the power of the 3.0L V6 with the fuel consumption of a 2.3L.

the cycle is called "Miller cycle" if there is a roots-type supercharger on the intake to make up for the lost air. if there is no supercharger it's called an Atkinson-cycle. the Prius has an Atkinson-cycle gasoline engine.

the main use is really to make the system more fuel-efficient.

[alwayz_yummy]

di lang pala ko familliar sa name, pero discussed na name yan sa ICE(internal combustion engine) subject namin...so miller's difference is may supercharger, otherwise atkinson pala un..

[ferdine]

Still relying solely of wikipedia? :lol:

FYI. MIVEC was launched in the early 90s.

:

Here to be exact:
1992

Pajeros finish first, second and third in the overall category of the Paris-Cape town rally.
The "Galant", "Eterna" and "Emeraude" are launched.
The first generation of the "Lancer Evolution" is launched.
The "Debonair" is launched.
INVECS 4-wheel multi-link suspension
4G92 MIVEC engine
Distance Warning System, Passenger airbag
Football Club, Mitsubishi Motors Corporation is established

And oh, GM pioneered VVT technoloy and Nissan was first one to sell VVT engines (1987 AFAIK).
:

Nissan did of course but on a bigger displacement engine:

In 1986 Nissan developed their own form of VVT with the VG30DE{TT) engine for their Mid-4 Concept. Nissan chose to focus their NVCS(Or Nissan Valve-Timing Control System) mainly at low and medium speed torque production because the vast majority of the time, engine RPMs will not be at extremely high speeds. The NVCS system can produce both a smooth idle, and high amounts of low and medium speed torque. Although it can help a little at the top-end also, the main focus of the system is low and medium range torque production. The VG30DE engine was first used in the 300ZX (Z31) 300ZR model in 1987, being the first production car to use VVT technology.

VG30DETT
The 3.0 L (2960 cc) VG30DETT produces 280 hp and 283 ft.lbf when mated with a 4 speed automatic transmission. When used with a 5spd manual transmission, it was rated at 300hp and 283tq. It featured twin T25 turbochargers, twin intercoolers and variable valve timing.

It is used in the following vehicles:

1990–1996 Nissan 300ZX Twin Turbo
1990–1999 Nissan Fairlady Z Twin Turbo

So comparing a VG30DETT to the first integra sold commercially is like comparing an orange to a kalamansi.

Technology? Then?

The Mazda GTX sold in the late 80s had a 220hp engine. Honda Integra had 160hp? W-O-W! :charing:
:

And from answers.com about the Mazda GTX:

The JDM GTX model featured all wheel drive and a turbocharged 1.8 L BP engine. In the U.S. it came with a 1.6L turbo, with the AWD. In 1992, the rare GT-R version was added (ALSO JDM), featuring a number of performance enhancements over the GTX model. These included a stronger gearbox, sodium filled valve stems, an aggressive front bumper and bonnet vents, an up-graded turbo. It is difficult to find a Familia GTR that has not been thrashed to death by a low budget rally team.

This could be the reason why

Heck... the Fairlady had 150hp engine already in the 1970s.
:lol:

Never heard about fairlady. Hindi pa ako isinilang non.

At least masasabi ko lang na Honda popolarized it in mass market and it becomes a like a tradition. Just like my friend asking another friend, "Pare ano ba yong MIVEC? Sagot naman ng isa kong kaibigan,, ano yan. VTEC ng Mitsu.
Para ba gang, Ale, pabili ng Colgate, pero Close-Up naman ang binigay.