the 305 GM motor is what I had in mind haha

1/25/2012 9:06:39 PM

The Hyundai 1.8 Nu engine (Nu as in the greek letter) found in the current generation Elantra uses a two piece cylinder head. The cam cap bolts secure the cam carrier (upper cylinder head piece) to the rest of the cylinder head. This gives flexibility to use a different cam carrier for a different application of the engine.

1/28/2012 8:18:19 PM

Subaru's done this for years, though the cam isn't really interchangeable. It's mostly just an extra step preventing me from dumping a cylinder head right in the solvent tank. Stupid.

It amazes me that so many carmakers fail to use replaceable cam bearings any more, they just let it grind right into the aluminum. Disposable cars.



[Edited on January 28, 2012 at 10:29 PM. Reason : .]

1/28/2012 10:27:53 PM

The Lexus IS 250C has a retractable hardtop designed and supplied by Aisin, who also designed the system for the SC430.



The hardtop is divided into three roof panels:



A number of metal links and moveable interior panels ("trays") provide support for the roof panels while being parts of the roof opening process.





A series of electric motors with integrated position sensors are used to open and close the roof in a nominal 20 seconds (E93 BMW 3 series is around 23 seconds). The coordination and overall control sequence takes place in several stages and is pretty complicated. This is to ensure that the panel opens smoothly on each side without major noise, while the control module constantly checks for faults in the system:

1/29/2012 4:59:47 PM

Quote :

"It amazes me that so many carmakers fail to use replaceable cam bearings any more, they just let it grind right into the aluminum. Disposable cars."

I have never seen replaceable cam bearings in any head i have disassembled.

1/29/2012 6:05:02 PM

Exactly. My bike has roller bearings on the cam. Built to last, even with no oil pressure.

I'm sure they don't bother because they don't want to deal with the thermal expansion issues of a steel bearing in an aluminum hole, but it can be done. They'd rather you just buy a new head anyway...$5 bearings don't keep the dealerships in business.

You'd think subaru of all people would avoid introducing new joints that leak oil since they have such a hard time keeping their fluids in anyway. Or at least use single simple rubber gasket valve covers that any grease monkey can slap on rather than an extra part that has to be squeaky clean using exactly the right sealer so it won't leak and still clamp the cam properly.

Don't get me started on that VW $500 plastic clusterfuck of a waterpump on the previous page.

^^LOL at the "golf bag" trunk, but hey, it's a leisure car. Those roofs are pretty clever. I wonder if anyone has ever attempted a telescoping roof that slides back into the trunk, rather than folding. Actually, I'm surprised that convertibles are still legal.

[Edited on January 29, 2012 at 6:48 PM. Reason : .]

1/29/2012 6:28:32 PM

Quote :

"I'm sure they don't bother because they don't want to deal with the thermal expansion issues of a steel bearing in an aluminum hole, but it can be done. They'd rather you just buy a new head anyway...$5 bearings don't keep the dealerships in business."

It may save manufacturing costs, or it may reduce friction to do it that way. It's probably both. Reducing friction helps with fuel economy and emissions regulations.

Quote :

"Don't get me started on that VW $500 plastic clusterfuck of a waterpump on the previous page."

You could blame emissions and fuel economy regulations for that one, but the Germans do tend to overengineer in response. I can just see that engine throwing a gazillion codes when the electric motor fails and one of those valves stays open. Of course, you could say that about electronic throttles and they seem to be pretty reliable on most cars.

Quote :

"LOL at the "golf bag" trunk, but hey, it's a leisure chick car. "

1/29/2012 7:37:24 PM

Great thread, btw. Several of these topics were completely new to me. When gas prices explode later this year there will be a mad rush to squeeze efficiency out of existing technology. Very exciting.

1/29/2012 9:24:37 PM

Thanks. I am trying to have some variety. There have been very rapid developments in powertrain stuff over the past few years so that deserves a lot of attention. Some of this stuff is stupid complex and I can't easily explain it in a length that won't put people to sleep or make their brain hurt. Understanding one thing needs knowledge of something else, so it becomes a layered thing. I was starting to put together something on the 8 speed automatic transmission in the Lexus IS-F but understanding the main features (clutch-to-clutch shifting) requires many nested explanations... it's still a slushbox but it's very different from a GM TH350 or other basic A/T, which are still stupid complicated.

I've been looking through stuff on why an OBD II catalyst monitor system works the way it does, and it's pretty damn complicated when you really dig into stuff like catalytic converter oxygen storage capacity. So I'll just keep posting short things that are kind of neat and maybe intersperse with heavier technical topics.

Somebody had asked on the last page if in-cylinder modeling is verified experimentally. Here's a picture of the single cylinder transparent/optical engine used in Ford's Ecoboost E85 prototypes:



Here is some of what an optical engine can produce: a series of images that can then be combined to produce a statistical visualization of fuel distribution in the cylinder.

1/29/2012 10:00:33 PM

Here's color video inside the cylinder as well:
http://www.youtube.com/watch?v=cy_yaAOKjA8

And while I'm posting video, here's a valvetrain at 14,000rpm.
http://www.youtube.com/watch?v=nsa6kq-qqIE
Flat tappet buckets rotate like that as well. Ever try to drill through a tappet? I had to slide hammer one out its' bore once. Man that is some tough metal they use for the plating.

Bouncy, bouncy:
http://www.youtube.com/watch?v=i_NpzU4pGjc
This video would seem like a good case for desmodromic valves, but really with modern progressive valve springs it's only an issue on sportsbikes. I would think that hybrid engines would stay in a narrow rev range anyway, making valve float a moot point.

1/30/2012 7:04:10 AM

Desmo valves wear to sometimes be less accurate then that.

Keep in mind that that is a .7" lift cam with up to a 2:1 rocker ratio in nascar so that spring is moving 1.4" in next to no time at all.



[Edited on January 30, 2012 at 8:31 AM. Reason : .]

1/30/2012 8:08:45 AM

The original 1967 Camaro was a combination of body-on-frame and unibody construction while using a solid rear axle and leaf springs:



During development of the body shape, Chevrolet built a 1/4 scale clay model and placed it in a 60s wind tunnel where they used all sorts of antiquated methods involving ink and such to study airflow effects





Chevrolet did utilize some computer calculations during suspension development to held achieve targets for understeer behavior.

1/30/2012 8:39:33 PM

"I know what will reduce this drag coefficient! Let's put big flat plastic covers over the headlights!" haha.

I'd never thought about the old camaros being a unibody design, I've just never dealt with them much. More an a-body guy, myself. Hmm, you may have just helped me out on something.

[Edited on January 30, 2012 at 10:57 PM. Reason : .]

1/30/2012 10:45:15 PM

and this is why you hear about so many "back halved" cars for drag racing...

mustangs are similar but with more of a frame ish structure on them.

1/31/2012 8:09:27 AM

In 2009 Honda developed a Kinetic Energy Recovery System (KERS) to be used in Formula 1 racing (the team for that year was scrapped due to the economic crisis). This is essentially a mild hybrid system, where an electric motor and gear reduction system stores braking energy in batteries:





That year rules stipulated that in one lap a maximum of 400kJ energy could be expended with a total output of 60 kW. Honda figured this would be good for about 6 seconds of assist max orh about two car lengths of advanced position.



[Edited on January 31, 2012 at 7:55 PM. Reason : .]

1/31/2012 7:52:05 PM

I'm sure they agonized over the decision to put another heavy battery in a race car. I can't wait to see this technology make its way to NASCAR in about 40 years.

Have you heard anything about hydraulic hybrids other than in UPS trucks?

1/31/2012 9:05:24 PM

I haven't really dug into hydraulic hybrids much but I do know that Chrysler is working on one for a minivan type of application. Who knows if it will see the light of day.

1/31/2012 9:18:30 PM

where is corner entry speed for a non kers car (assuming its higher due to the lower weight of the car)

2/1/2012 12:43:41 PM

^ Is that a question about the graph above or just a general question about F1 racing? I really don't know that much about F1, but I know a little bit about Honda's program because they have had some periods of major success. They were very very successful in the days of the small displacement turbo engines (80s). I've got some specs on their old turbo motors here I can put together.

2/1/2012 6:30:59 PM

I was just thinking that the cornering speed is said to be the same but I don't think they would be.

2/1/2012 9:17:08 PM

Recently a woman won a lawsuit against Honda having to do with the fuel economy claims for a Civic hybrid in California. There is a lot of confusion about the way fuel economy is calculated. The current method is the 5 cycle approach but that changes. There are a bunch of calculations done with certain coefficients that have all been boiled down into a spreadsheet:

http://www.epa.gov/oms/cert/dearmfr/cisd0709_enclosure2_calculator.xls

So the manufacturers run an FTP75 warm (75F) cycle, FTP75 cold (20F) cycle, a USO6, an SC03, and the highway test. I have mentioned these tests before:



1. The FTP75 is the "city" drive cycle that's been around for a long time, and may also be called LA-4.

2. The US06 is the high speed drive cycle, not to be confused with the highway test. This was first introduced about 10 years ago.

3. The HFET is the old "highway" test cycle that's been around for a long time.

4. The SC03 has the vehicle drive with the air conditioning on in a dyno room with very expensive heat lamps meant to simulate the effect of the sun.



the bag part refers to the sampling bags that are taken after segments of a particular test. The exhaust air is captured inside a bag using very expensive equipment. It takes millions and millions of dollars to do these tests. The EPA can change the weight of the drive cycles if they want to; it comes down to them in the end, although they consult with the industry when making a change.

[Edited on February 4, 2012 at 9:01 AM. Reason : .]

2/4/2012 9:00:23 AM

Below is a chart showing engine rpm and gear versus vehicle speed on the Ford GT:



This chart shows heat rejection into the coolant and oil vs engine rpm:

2/5/2012 10:44:18 PM

Two trends in exhaust systems are the move toward the use of integrated catalysts as well as stainless, double-wall designs:



Benteler isn't a household name but they are a major supplier of exhaust-related components. This is a CAD model of exhaust manifolds for a certain twin turbo V6:





These types of manifolds are more expensive but they have packaging advantages and can improve catalyst warm-up during emissions certification tests. From a reliability/consumer standpoint well the ones with integrated catalysts are going to be $Texas to replace. However they will be warrantied with the rest of the emissions system so it will depend on the level of certification to know how long the warranty lasts.

[Edited on February 10, 2012 at 9:34 PM. Reason : .]

2/10/2012 9:33:30 PM

Honda recently introduced a new hybrid NSX concept car. They had originally planned a 5 liter 500hp V10 engine with some interesting technology choices. There's a lot to say about this engine but in the interest of brevity I will probably break this into two parts and focus mostly on charts and diagrams rather than written explanation. This engine was in a few s2000 mules before Honda killed the project.

The engine was targeted as a fuel efficient and high performing V10 engine that can be daily-driven and run hard on a track. So right now I'll cover some performance technology introduced in Honda's literature on the subject, and in the future I will cover some of the fuel efficiency and emissions technology.



The engine is a short-stroke V10 designed to be high revving:



A series of reliability studies determined the frequency under which the engine must perform in US daily driving conditions, Autobahn high-speed conditions, and track conditions:



Key to this performance are optimized intake and exhaust systems as well as bottom-end enhancements. The intake system uses independent intake and exhaust systems for each bank:



The intake system is two-stage on each bank. For lesser intake airflow, a single butterfly controls airflow for a given bank. For high performance driving individual throttlebodies downstream of the plenum chamber are used:





This design allows more even mixtures under low loads for emissions purposes, because the individual throttlebodies could degrade over time due to wear or carbon deposits. For the exhaust system, each bank uses a 5-1 header with a merge collector:



For low weight and high strength, titanium connecting rods were adopted. A Diamond-Like Carbon coating reduces wear on the the thrust surface. The crank had special stress-relieving grooves adopted from Honda's F1 program. See the diagram below:



I will cover the fuel efficiency technology such as the special knock & misfire control system later.

2/12/2012 10:21:53 PM

The venerable 5.9 Cummins diesel engine found in many Ram trucks originally started life 30 years ago as part of the Cummins B series line for mostly industrial and heavy-duty use. This engine was available in 3,4, and 6 cylinder configurations with naturally aspirated and turbocharged options available for many applications. One thing I find interesting here is the 3.9 liter 4 cylinder B series engine, which Wikipedia tells me was used in bread trucks among other things. This engine originally had 4 basic exhaust configurations:





Here are some performance curves for the n/a and turbo versions:



The top charts show the naturally aspirated engine. BMEP, or Brake Mean Effective Pressure, is a sort of displacement-independent measure of engine performance. Compare the brake specific fuel consumption between the n/a and turbo models. BSFC measures how much fuel is used to obtain power output (lower number is better). Looking at this curve may not make much sense without a little context. Indulge in this apples vs oranges comparison for a moment. Here are some BSFC maps for the two engines that have been offered in the Toyota Prius:



The 1NX-FXE is the 1.5 offered in the 1st and 2nd generation Prius, while the 2ZR-FXE is the 1.8 currently offered in the Prius. You can see that 30 year old large 4 cylinder diesel engines are by this one metric equal or more fuel efficient than a highly optimized modern 4 cylinder gas engine. The key difference is that 1) obviously those Prius engines are intended for a completely different application 2) Prius engines, for all intents and purposes, don't pollute.

2/18/2012 9:22:15 AM

Who fucking cares about some old ass tractor engine??

How about you explain something worthwhile we all take for granted like why there are two squirters for windshield washing or the interior trunk release or something?

2/18/2012 3:57:38 PM

^ Troll user is trolling.

However the topic of the trunk release is actually kind of interesting because it relates to a trend in the newest vehicles, which is a smart keyless fob. A conventional keyless entry system has a fob with an unlock button. Smart key systems will unlock (or give permission to unlock) the doors, steering wheel, and the trunk based on proximity while also being used for push-button start. Consider this diagram showing components in the smart key system of the Hyundai Genesis coupe:



boxed in red is the smart key control module which uses serial communication to send and receive commands from other control modules. Through the serial network it can work with the immobilizer system to maintain security.



when the key fob is within range, it will communicate wirelessly with the smart key control module. The Smart key module can then issue commands that give permission for a button on the door to allow vehicle entry, or it can allow activation of trunk/hatch release. It will also release the steering wheel lock. In this particular vehicle, the body control module will activate the trunk release relay according to this block diagram:



RKECMD = Remote Keyless Entry command [conventional Keyless system]
SMKCMD = Smart Key system command
ATWS = Anti-Theft Warning System [related to immobilizer/security]

For this vehicle the smart key itself communicates with two different frequencies



[Edited on February 18, 2012 at 6:14 PM. Reason : .]

2/18/2012 6:11:42 PM

On the last page I discussed Honda's cylinder deactivation and displayed an image showing a very basic Pressure-Volume indicator diagram.



I want to discuss these further, as they are very important for understanding many different types of engines. A pump or engine of some sort that does work is going to convert a larger volume of air into a smaller volume of air at higher pressure, and then expand it out. We can understand this by looking at a Pressure-Volume trace, which should be looked at as a cycle. Pressure-Volume diagrams can be traced back to steam engines:



This 18th century apparatus would move a writing instrument upward in response to an increase in pressure, and slide it to the side as volume changed. By understanding the area under the curve we can get an idea of how much basic work is being done, and then ultimately figure out other stuff if we have enough information. Let's fast-forward to the early 90s, to the development of the Navistar T444E diesel engine, more popularly known as the Ford Powerstroke 7.4. Here is a Pressure-Volume indicator diagram of the engine at heavy load and high rpm [for a diesel]:



X axis is crank position and Y axis is combustion chamber pressure. The area under the upwardly sloping area of the curve shows the IMEP (red text), or Indicated Mean Effective Pressure. The more compression and expansion performed on the gases, the greater the IMEP. Higher IMEP is directly related to greater usable engine output. The lower portion of the curve shows the Pumping Mean Effective Pressure or PMEP. This shows energy expended moving air in and out of the cylinder. I'm not as familiar with all the ins and outs of how this can look on a diesel engine, but the shape of this curve can vary according to a lot of factors. Valve timing, scavenging effects, and manifold design play a big role. On a gas engine throttle position will affect PMEP, with a wide open throttle reducing pumping losses.

qualitatively speaking, IMEP - PMEP = NIMEP is the basic relationship, where NIMEP = Net Indicated Mean Effective Pressure . Note that in the diagram, EVO = Exhaust Valve Open and IVC = Intake Valve Closing

In the past I have made references to something called Brake Mean Effective Pressure. This is a way of measuring engine performance and load independent of characteristics like displacement. Brake Mean Effective Pressure takes the NIMEP and subtracts frictional losses. I imagine NIMEP and IMEP are often used interchangeably. I think the best way to make sense out of IMEP/BMEP is to compare numbers from a lot of engines. Generally speaking, newer engines have much higher specific output and will achieve higher BMEP numbers when run at full load (either through more forced induction or just better naturally aspirated performance).

Here is a pressure and temperature (heat release) trace for the above P-V Powerstroke engine diagram:



The shape and timing of the pressure ("P") and temperature ("T") curves can give a good idea of how the combustion is doing--whether combustion is delayed/inefficient, or whether it is spiking too high (indicative of knock on a gas engine).

For reference, here is a Pressure-Volume indicator diagram for the same Powerstroke engine at lower rpm (~1800 vs ~3000). You can see there is a lot less pumping loss even though the engine is running at similar loads. I'm not 100% sure of all the effects at work but I imagine that at lower rpm there are fewer pulsation and backpressure effects to work against.



[Edited on February 20, 2012 at 9:50 PM. Reason : .]

2/20/2012 9:28:09 PM

Cool, no one ever listened when I said the best compressors make the best engines.

The easiest way for me to picture an engine just as an air pump is simply the centrifugal jet engine. Nothing but compressor(s) combustion chamber and turbine(s).

The old ass compressors/diesels with opposed pistons and a central um? combustion chamber that some company is acting like is going to save the world, I'd like to know more about why they think a 30 year old design is relevant again?
New valve design ?

2/20/2012 10:40:40 PM

link?

2/20/2012 10:43:48 PM

http://www.ecomotors.com/ecomotors-internationals-opposed-piston-opposed-cylinder-engine-promises-revolutionize-commercial-ve

2/20/2012 10:50:47 PM

And it's 105 year old design, originally a 2 stroke diesel.

2/20/2012 10:52:59 PM

haha this is funny as crap... watch the video and it's some German dude who invented it talking (their headquarters are 20 minutes from me). The main page you linked to reads like the old ads for the Wankel engine in the early 1960s (during the research stage) and the ad claims a lot of the same benefits that Wankel was promoting back then. The emphasis on power density and lack of camshafts/valvetrain sounds VERY familiar.

For the sake of everyone I hope that ithis is in fact a great leap forward (if you'll excuse the Maoist allusion) for propulsion in general. But history is littered with ambitious engine designs and propulsion concepts that simply cannot overcome the inertia of the current system. Internal combustion engines have evolved very slowly in some ways. Things are the way they are for a reason, even if they aren't necessarily "good" reasons.

So many institutions have been built up around the current systems of gas and diesel engines; the supplier network, test equipment, tooling for manufacturing, knowledge of design and testing proceedures, and then everything on the sales/consumer side. The actual real world benefits will have to be very very cost-effective while having immediate customer acceptance for this to go anywhere.

2/21/2012 5:55:56 PM

I was wondering of you saw something I didn't, I mean it is still a 2 stroke so emissions will suck. I was just wondering if something like direct injection could "fix" the 2 stroke but I really don't think that's the problem, the inherent nature to burn oil is what I thought the issue was.

2/22/2012 6:47:29 AM

There are a bunch of direct injected 2 strokes in various stages of R&D, but I'm not sure there's much market penetration

2/22/2012 9:21:45 PM

It's well known that the GM LS1 engine (Gen III smallblock) has superior top end horsepower to its predecessor, the LT1/LT4:



however the LS1 also has superior refinement and noise suppression due to a revised firing order, a different block design, etc:





brake-specific fuel consumption is also improved due to reduced friction among other things

2/25/2012 6:52:58 PM

I have briefly mentioned the BMW N20 engine in earlier posts. The N20 is the turbo 4 cylinder replacing the naturally aspirated N52 3.0 inline-6 engine. Having driven an N52-powered E90, it's got the classic BMW I6 feeling. On paper the new N20 has a similar characteristic to many other downsized turbo engines that have been introduced recently.



You can see the lower revving nature with a flatter torque curve. It's in many ways an N55 (the I6 twin turbo engine) with 2 less cylinders. According to BMW's internal specs, there is about a 20% decrease in average fuel consumption for the new 3 series:

3/1/2012 7:25:03 PM

I posted this in the 335 thread as well:

It looks like the N20 has a different style high pressure fuel pump than the N55/N54. It looks like BMW has two styles of HPFP: the 3-plunger style, used in the N54/N55 6 cylinder engines, and the single plunger style used in the N20 (4 cylinder), N63 (8 cylinder), and N74 (12 cylinder). Here is the N54/N55 style:



and here is the N63/N74/N20 style:



Both styles are demand-control pumps which is now a standard characteristic. A demand-control pump has a valve controlling how much fuel enters the pump, as opposed to having some kind of pressure relief system after the pump outlet like you would find on early direct injected engines, such as the early VW 1.4 GDI engines. For reference, here is the HPFP of a 3.5 Ford Ecoboost engine:



Here is the early VW pump:



Note that this is a radial pump design (camshaft lies in the middle) with no demand control valve.

3/1/2012 10:59:38 PM

The new BMW F30 3 series uses electric power steering with an available variable ratio system:



The system labeled "1" is the basic non-variable electric power steering. The system labeled "2" has the variable ratio rack to make parking maneuvers easier. You can see that the teeth in the center of the rack are shaped differently.

3/3/2012 1:19:28 PM

DO NOT LIKE VARIABLE RATIO..

MAKES STEERING FEEL NUMB!

3/3/2012 1:58:08 PM

more useless BS



Hey why don't you cut/paste some rambling info on shit people might find they take for granted, like the starter bendix or the star wheel adjuster.

3/6/2012 4:35:41 PM

right back to your old grumpy ass self ehh?

3/6/2012 4:50:41 PM

Eh?

3/6/2012 9:21:17 PM

Eh?

3/6/2012 9:23:19 PM

So the 996 Porsche 911 turbo two-step adjustment of intake valve timing and lift/duration. This system uses direct-actuated valves where the cam pushes on a tappet which in turn pushes open the valve. The valve has an inner and outer tappet. Under low lift condition, only the inner tappet moves to open the valve. For high lift, the inner tappet locks into the outer tappet. The cam is ground precisely such that the lobes will actuate the valve at low and high lift while have a certain clearance.

Intake valve timing can be advanced a fixed number of degrees by applying oil pressure to push the adjuster in the axial direction. This is sort of like the double VANOS continously variable valve actuation system used in BMW's recent S85 V10 engine. Here are the four possible intake valve timing/lift settings:



[Edited on March 6, 2012 at 9:39 PM. Reason : eh?]

3/6/2012 9:28:03 PM

Below is a diagram I have labeled of the supercharger for GM's 4.4 Northstar supercharged engine:



This engine was found in the STS-V sedan and XLR-V coupe. The supercharger assembly combined with an air-to-water intercooler for fast response and high torque. You can see that air entered axially through the middle, flowing through the belt-driven rotors and then through runners towards the intake ports. A bypass valve can bleed off boost. The bypass valve used vacuum from before the rotors to open the valve via a diaphragm actuator. The engine control module can also activate a duty-controlled solenoid to operate on the other side of the diaphragm in order to bleed off boost under certain situations.

3/11/2012 1:17:58 PM

i wonder why not screw?

3/11/2012 1:40:31 PM

above all it was noise apparently, at least compared to modifying an existing Roots system (which is what they did). This is a luxury application.

3/11/2012 1:44:59 PM

The diagram below clearly illustrates the advantages of an intercooler on a turbocharged engine:



The Ford fuel injected single overhead cam 2.3L 4 cylinder engine came on several vehicles in the mid 80s, including the Thunderbird and Mustang SVO. Only the Mustang SVO came with an intercooler (the "phase III" engine). Looking at the diagram, the charge air temperatures peak around 140F for the intercooled engine. Charge air temps rise much higher on the non-intercooled engine. As a result, the non-intercooled engine requires more retarded ignition timing to prevent knock.

3/12/2012 7:26:57 PM

noone gives a fuck

3/12/2012 8:33:53 PM