8th Generation Honda Civic Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
3,049 Posts
Discussion Starter #1
What is this about some cars not having throttles? I've heard the R18, some BMWs, and diesels? I'm just interested in how this works. Could someone who knows how explain?
 

·
Tuna Fiddle
Joined
·
19,256 Posts
It doesn't have a throttle cable that connects the accelerator pedal to the throttle body like a conventional system. There is instead a sensor on the pedal and one of the the throttle body that communicate with eachother and determine how far the throttle body opens.
 

·
Registered
Joined
·
3,049 Posts
Discussion Starter #4
I didn't mean the DBW throttle (although I can understand why it would sound like thats what I was talking about), I was told that apparently some cars have no butterfly valve throttle body anymore.
 

·
Registered
Joined
·
803 Posts
you know I can see why car companies would go that rout. if you have fuel injection then you could take the butterfly valve out and that way there would be less resistance. I mean the butterfly valve just regulates the amount of air and fuel that goes in the engine, and the engine can only draw in so much air so.
 

·
Registered
Joined
·
1,198 Posts
I didn't mean the DBW throttle (although I can understand why it would sound like thats what I was talking about), I was told that apparently some cars have no butterfly valve throttle body anymore.
r18 has a butterfly valve saw it on mine when I was cleaning the intake tubes out.
 

·
Registered
Joined
·
4,243 Posts
I believe diesels don't have throttle bodies, they work by varying the ammount of fuel injected into the engine.

The R18 has a throttle body, it's just that it's controlled by a wire and not a cable.

There is a new technology I heard about years ago and I think BMW was teh one pioneering it, where the gasoline engine would have no throttle body, but each valve would be computer controlled and the ammount of air taken into the engine would be set by how far the computer opens each valve. For idle the intake valves would just open a hair, and under WOT they would open all the way and the computer would continuously vary valve timing and all that crap to get the most power. The engine did not use a camshaft, each valve was electronic.
 

·
Registered
Joined
·
3,049 Posts
Discussion Starter #8
There is a new technology I heard about years ago and I think BMW was teh one pioneering it, where the gasoline engine would have no throttle body, but each valve would be computer controlled and the ammount of air taken into the engine would be set by how far the computer opens each valve. For idle the intake valves would just open a hair, and under WOT they would open all the way and the computer would continuously vary valve timing and all that crap to get the most power. The engine did not use a camshaft, each valve was electronic.
thats the one I was thinking of, I guess that never went anywheres?
 

·
Registered
Joined
·
1,567 Posts
it takes ecu commands via the throttle position sensor. the cool one to think about are the multi throttle body <1 per cylinds> that most liter bikes are pushing, and the new m3
 

·
Registered
Joined
·
10,957 Posts
I believe diesels don't have throttle bodies, they work by varying the ammount of fuel injected into the engine.

The R18 has a throttle body, it's just that it's controlled by a wire and not a cable.

There is a new technology I heard about years ago and I think BMW was teh one pioneering it, where the gasoline engine would have no throttle body, but each valve would be computer controlled and the ammount of air taken into the engine would be set by how far the computer opens each valve. For idle the intake valves would just open a hair, and under WOT they would open all the way and the computer would continuously vary valve timing and all that crap to get the most power. The engine did not use a camshaft, each valve was electronic.
true diesel don't need a throttle body at all. Which is why they get great MPG. Diesels are also able to operate at a huge range of A/F ratios unlike the gasoline engine. In some cases the diesel engine is sucking in 10X more air than needed.

Throttle bodies are a control/restriction point. They restrict/control air flow which is why the intake manifold has a vacum when running.

The r18 does have a throttle body but it is able to keep it open and uses the -vtec to control air intake amounts. The new g35's also use valve timing. It will become standard in order to get the most MPG out of an engine.

you know I can see why car companies would go that route. if you have fuel injection then you could take the butterfly valve out and that way there would be less resistance. I mean the butterfly valve just regulates the amount of air and fuel that goes in the engine, and the engine can only draw in so much air so.
Without a butterfly valve or proper valve control timing the engine would run wide open. The throttle aka gas pedal doesn't really control gas amount it controls the amount of air. (diesels work the opposite)
 

·
Banned
Joined
·
6,166 Posts
you know I can see why car companies would go that rout. if you have fuel injection then you could take the butterfly valve out and that way there would be less resistance. I mean the butterfly valve just regulates the amount of air and fuel that goes in the engine, and the engine can only draw in so much air so.
No you would still need something to regulate the amount of air coming into the intake valve regardless of fuel injection.
What is this about some cars not having throttles? I've heard the R18, some BMWs, and diesels? I'm just interested in how this works. Could someone who knows how explain?
I haven't heard about it and I don't see how it could work.
true diesel don't need a throttle body at all. Which is why they get great MPG. Diesels are also able to operate at a huge range of A/F ratios unlike the gasoline engine. In some cases the diesel engine is sucking in 10X more air than needed.

Throttle bodies are a control/restriction point. They restrict/control air flow which is why the intake manifold has a vacum when running.

The r18 does have a throttle body but it is able to keep it open and uses the -vtec to control air intake amounts. The new g35's also use valve timing. It will become standard in order to get the most MPG out of an engine.



Without a butterfly valve or proper valve control timing the engine would run wide open. The throttle aka gas pedal doesn't really control gas amount it controls the amount of air. (diesels work the opposite)
True. Diesels don't need spark plugs as well you can't really compare diesels to gasoline engines, it doesn't work the same. Without the throttle body it would require using GDI (Gasoline Direct Injection) and other modifications to work, IF IT WORKED. Diesels have been using GDI systems for years (where the injector is in the cylinder wall and injects it directly into the cylinder not behind the intake valve). But again that could only regulate the A/F ratio so much you would still need to have something regulate the amount of air flow. A combustion ratio is 20:1 lean to about I think 5:1 rich and outside those limits combustion will not occur. A car normally runs about 16:1 to 12:1 because it tries to stay as close to 14.7:1 which is the perfect A/F ratio. Outside of 16-12 limits the car runs like **** but will still run.

Again if it could work, which it might, it would definately have to be a true ram air system with GDI. Little air generated at low speeds and a lot of air at high way speeds which would really be the opposite.

I don't know I am confused, while accelerating you need more air flow and at cruising speed you would need less air flow therefore a ram air system wouldn't be idle unless you were at high speeds accelerating... I don't see this working.
 

·
Registered
Joined
·
1,567 Posts
I think ducatti or buell bikes use a seystem called desmodronic or something like that with no cam.
ive never heard of such a thing, its interesting. the biggest thing in liter bike engines now are independent throttle bodies. could u imagine cam less engines!
 
1 - 13 of 13 Posts
Top