On Horse Power

[JEBar]

I think that kinda sonded like a poletician

not really, I understood your post .... can't say the same for the conflicting political info airing right now ..

Jim

ON EDIT: I was trying to ask about the dual cam feature where it changes with the need for power .... I saw it explained somewhere on the forum .... like I said, I'm no expert in this area

 

[goofyone]

please keep in mind that this question is being asked by a person with very limited knowledge in this area ===> would the dual valve system used in the Elio engine be capable of generating more torque for helping maintain speed going up mountain roads

Jim

Good question!

I believe you are referring to the two stage intake valve lift and timing system that allows the engine to have two modes of operation one for more power and another for more efficiency. The operation of this system would be controlled by the ECU engine control computer and these systems are indeed generally sensitive to engine load. So if the engine is under increased load, such as when climbing a hill, the ECU should detect this and switch the engine to the higher power mode of operation.

 

[RKing]

Good grief, I need to spell check
Any way I think with the weight to power ratio being better than a late model ( ) MGB and almost a "rental car like" Malibu we should be fine. Also have to trust that there are "car people" involved that will not let this be a "miserable little thing". Also Powertrain is designed for the application, no compromize.

 

[JEBar]

Good question!

I believe you are referring to the two stage intake valve lift and timing system that allows the engine to have two modes of operation one for more power and another for more efficiency. The operation of this system would be controlled by the ECU engine control computer and these systems are indeed generally sensitive to engine load. So if the engine is under increased load, such as when climbing a hill, the ECU should detect this and switch the engine to the higher power mode of operation.

yep, that is what I was trying to address .... would it be correct to say the higher power mode would generate higher torque .... naturally, the higher power would come at a reduction in mpg's

Jim

 

[RKing]

Goofyone ,any more info on two stage valve lift? I saw the animation and can see the double lobe, but another recent thread implies threaded valve adjustment so I have come to wonder if we should take too much from the animation. We had a "new engine" rollout for he plant and they had an engine on display. Went to look closer afterward and it was the same engine we already make, hardly anyone noticed, kinda scary actually!
Ahyway ,does IAV state that the production engine has VVL , I think I saw that Elio stated no VVT? I do see what I assume is a cam timing ring pocket in the rear of the cam cover, so that could easily be a cam phaser instead.

 

[goofyone]

yep, that is what I was trying to address .... would it be correct to say the higher power mode would generate higher torque .... naturally, the higher power would come at a reduction in mpg's

Jim

You got it. More torque and also higher fuel consumption.

 

[goofyone]

Goofyone ,any more info on two stage valve lift? I saw the animation and can see the double lobe, but another recent thread implies threaded valve adjustment so I have come to wonder if we should take too much from the animation. We had a "new engine" rollout for he plant and they had an engine on display. Went to look closer afterward and it was the same engine we already make, hardly anyone noticed, kinda scary actually!
Ahyway ,does IAV state that the production engine has VVL , I think I saw that Elio stated no VVT? I do see what I assume is a cam timing ring pocket in the rear of the cam cover, so that could easily be a cam phaser instead.

I really do not know what to make about the recent valve adjustment news as I have actually heard this from others on previous occasions however what I have heard from more than one source who should know is that the bucket tappets are hydraulic. We will just have to wait and see what plays out.

EM and IAV have all along stated simple two step VVL, as seen in the animation with the dual cam lobes, and more recently they have clarified that VVL is still on board however they do not have plans for VVT at this time.

There is indeed a pocket which can accommodate a cam phaser however what I have actually been able to confirm, independently from two sources, is that this is simply a provision in the design which is not planned to be used at this time unless the engine somehow falls short of expectations. IAV has apparently gone ahead and designed in a number of upgrade paths into the current design.

The Elio will be using a dual lift or shifting hydraulic bucket on the intake. This allows for high and low lift based on engine RPM and load demands. There are three lobes per intake. Effectively the same system as Porsche uses as it's Variocam Plus System. As pointed out earlier in this post the bucket tappets are hydraulic. The integral cam cover with integral cam bores, would require a lot of tooling to allow the use of a shim style mechanical adjustment.

To clear up any doubt, the cams run in the parent aluminum of the camcover and cylinder head. This is a proven method in engine design for 35 plus years. It does require tighter design and manufacturing tolerances with today's lower viscosity oils.

I had to go back and re-read the Tech Talks a few days ago and discovered that Elio Motors has actually all along stated that this engine would feature variable valve lift and not variable valve timing. In the very first Tech Talk IAV/Elio states that this engine will use 'two-step variable lift technology' and in Tech Talk v24 EM confirms that VVT will not be used in this engine. This information is further corroborated by the IAV/Elio demo engine spec sheet stating that 'switchable tappets' will be used as switchable tappets are specifically used to change lift. Switchable tappets are commonly used as one component of a VVT package however there is nothing to say they can not be used on their own. You can also see the arrangement of the intake cam lobes in the Elio engine animation video.

Tech Talk V1: http://us6.campaign-archive2.com/?u=24b371802c83d81776b06aa68&id=545e7f615f
Tech Talk V24: http://us6.campaign-archive1.com/?u=24b371802c83d81776b06aa68&id=4801365dc7

 

[RKing]

thanks Goofyone , I had not seen most of that info. Very confused about the adjustment references, hope o clear that up in Rome. Also saw in Elio print that it's a 5 speed. Wonder if they are going to have to pay anything for borrowing Tech??

 

[skygazer6033]

To say the tappets are hydraulic seems to be causing some confusion. Switchable tappets engage three cam lobes, two lobes contact the tappets near the outside diameter while the third lobe contacts the tappets center. The center of the tappet is extended to contact the third lobe to provide increased lift. This is done hydraulically by engine oil pressure. So in this respect the switchable tappets are hydraulic. However that doesn't necessarily mean they are "hydraulic lifters" in respect to clearance control. Does seem like a waste of machinery to increase lift without also increasing duration as well.

 

[goofyone]

To say the tappets are hydraulic seems to be causing some confusion. Switchable tappets engage three cam lobes, two lobes contact the tappets near the outside diameter while the third lobe contacts the tappets center. The center of the tappet is extended to contact the third lobe to provide increased lift. This is done hydraulically by engine oil pressure. So in this respect the switchable tappets are hydraulic. However that doesn't necessarily mean they are "hydraulic lifters" in respect to clearance control. Does seem like a waste of machinery to increase lift without also increasing duration as well.

I had thought about the fact that the center lobe could be shaped slightly differently to allow increased duration as well as lift.

No matter what news I get I always just keep going back to the fact that we just do not have enough hard data on the valvetrain yet so we will just have to wait and see what EM/IAV have for us when we hear more about this engine testing.