Tech Talk - Engines (Basics and Architecture)

As a child growing up in a war zone watching F14s and Iraqi Migs dog fight at VERY low altitude sparked a huge interest in mechanical engineering. While in panic and scared I remember distinct conversations with my little neighbor buddy about after burners, what it was, how engines work and get those HUGE jets off the ground and able to maneuver the way they did.

Fast forward many years of self learning, engineering undergrad and grad school, a few restored junk yard cars (1982 Toyota Supra - MY ALL time fav car to this day) and realization I'll never be a fighter pilot, I now do the next best affordable thing: collect blue collar affordable well engineered sporty cars =)

After all, controlled combustion a few feet in front of you thousands of cycles per minute is a testament to ingenuity and engineering know how.

So, we all know what an engine is, but took me a while to understand the basics and all the little nuances (and these come into play when you car shop or have it serviced).

I'm doing the tech talk series here specifically because of a heated conversation I had with service managers and "master techs" at a dealership working on my faulty Scion FR-S engine.

Here it goes, as usual let's start with some terminology: 

• ICE: Internal Combustion Engine (to us mere mortals ... Engine =) 
• Inline Motor: this is common for 3 , 4, 5 and even 6 cylinder smaller displacement motors where all cylinders and inline with each other 
• V motors: think V6 and V8 (V10 & V12 for those with fancy taste and a big valet ;) , where you have an exact number of cylinders per bank (ex: V6 is 3 in each bank) and typically the most common V configuration is the 90 degree V (90 degrees being the angle between the banks) 
• W motors: A configuration used mainly by the VW auto group which is a variation of the V architecture putting two of them side by side if you will to increase number of cylinders and displacement in a much smaller packaging (VW for example has used W8s in several versions of their global models: Passat W8 of a few generations ago) 
• Boxer Engines (Boxer-4 or Boxer-6): horizontally apposing pistons (Porsche and Subaru are the only ones using this configuration today)
• Flat Engines (Flat-4 or Flat-6): same as above, Boxer and Flat are the same 
• Rotary engines: Only Mazda uses these now, we'll have a segment on this all it's own 
• NA: Naturally aspirated (there is NO Force induction involved - there will be a tech talk section just for that) 
• FI (Force Induced) or FF (Force Fed) or Boosted motors: When we use a mechanical (and some times combined with logical ECU mappings) to force feed more air/fuel into the motor (more of those = more power) 
• Boost: The amount of force fed into the engine: 
• For every 14-15PSi (which is about 1 atmosphere you roughly can simulate doubling the displacement)
• For example a 2.00 Liter motor with 14-15 lbs of boost is almost like having a 4.0 liter motor!!! (more powahhhhhhhhhhhhhhhhhhhhhhh but at a cost of more heat / complexity of course) 
• Turbo Charged engines: Force Induced architecture using Turbos driving off of the exhaust cycle 
• Supercharged Engines: Force Induced architecture using a pully and belt driven mechanism off the normal engine revolution cycles 
• Twin Charged Engines: simultaneously both Turbo and Supercharged (a whole section on this soon) 
• Displacement (Simply think of this as the size of the engine measured in CC, liters, cubic inches etc), great doc here
• Electric motors: What you have now in mild, full or EV cars (this is a simple electric motor just like the ones you see in a small remote control car but MUCH MUCH bigger =) 
• Gasoline motors: they run on gas (all variations, pure, ethanol, E85 or other mixes) 
• Diesel motors: they run on diesel or bio diesel 
• RPM: Revolutions Per Minute, this is one of your gauges in the cluster (omitted on certain models of cars) and it shows you the revolutions the engine is making per minute 

There are large amounts of details, pros and cons for all the terms mentioned above, so I'll break them up into individual engine topics over the next few weeks and just focus on basics of ICEs for now. 

How an engine really works:

• To understand this we need to look at the actual internal combustion cycle
• Most cars these days use what is called a four-stroke combustion cycle to convert gasoline into kinetic motion. 
• This four-stroke approach is known as the the Otto cycle (in honor of Nikolaus Otto who invented it in 1867) 
• Really good reference here for the rest of you geeks that want even more info
• Intake stroke: air and fuel are taken into the cylinder as the piston moves downwards.
• Compression stroke: where the air and fuel are compressed by the upstroke of the cylinder.
• Combustion stroke: compressed mixture is ignited and the expansion forces the cylinder downwards.
• Exhaust stroke: waste gases are forced out of the cylinder.
• The intake and outlet ports open and close to allow air to be drawn into the cylinder and exhaust gases to be expelled.
• The engine is effectively a device which sucks in air, compresses it, ignites it and then blows the air out again to create power to the road wheels. In terms of the performance gains possible, there are a vast multitude of different techniques and technologies. 
• Really good video clip here:

Did you know: 

• For the ICE to work properly we need MANY auxiliary systems 
• Cooling, fuel injection, lubrication, ECU to name a few 
• This is why routine maintenance of these auxiliary systems are critical 
• For example, replacing fluids at the critical milestones are VERY important 
• Some fluids will need to be replaced at 3-10K miles (your engine oil) 
• Some fluids will need to be replaced in 30-60K miles (your coolant and other fluids) 
• Aside from replacements, at certain mile markers some of these aux systems need to be flushed (which is not only drain and replace but flush and clean the entire system) 
• Engine oil is a of the KEY fluids some interesting facts below: 
• up to %80 of oil's duty is cooling (not lubrication, I know I was surprised too when I learned this) 
• It works hand in hand with the coolant running through the coolant jackets around the engine block to dissipate heat 
• The grade & type of oil recommended is based on the designed tolerances on the engine (we'll do a tech talk segment just on engine oil) 
• The better your engine breathes IN (your intake, air filter mainly) and OUT (exhaust cycle with headers, cats and mufflers) the more power you get and the more responsive the throttle response will be 

Good habits:

• Restoring a junk yard car for myself and helping countless buddies do the same we learned valuable lessons 
• Temp regulation and proper lubrication are the biggest and easiest two things you'd want to focus on (easy items and will cover the basics of your engine health) 
• For one, I try to ALWAYS get the models that have an RPM gauge 
• This is my #1 ally in watching the engine behavior over time and in daily driving 
• Idle patterns, RPM gauge behavior (dips and jumps) and seeing WHERE you or the car actually  changes gears is key 
• As a rule of thumb, I never jump in ANY car and drive off (regardless of season) 
• I usually leave 5-10 minutes early if at all possible and use this simple trick: 
• turn the car on
• Let one or two songs play while the car warms up 
• During the songs do a walk around the vehicle and listen, smell and look around (even on brand new cars - this is how I found the breather valve leak on the rear dif on my BRAND new 2010 STi in first week of purchase) 
• I do the same after being done before shutting it off (one song is sufficient) 
• Then for every trip, even the shortest I make sure I make it last a minimum of 10+ minutes
• If you can't do this, just drive the car and keep RPMs at 2000 or less 
• Most cars if you have an RPM gauge and want to try this will start off near 2000 RPMs after a cold crank and then in 5 minutes or so reaching operational temps drop down to around 750 RPMs (that's the industry avg for operational temp idle for almost EVERY car I've owned) 
• If I don't have time I do this approach of short shift at 2000 and wait for temp gauge to read normal operation temp before exceeding it
• While driving always check your gauges: Water temp, Oil Pressure, Oil temp (if you have it) 
• These will fluctuate but where it settles normally tells you a lot about health of the engine and each system 
• Check your fluid levels and quality once a month (coolant level and color, engine oil level and color (the color is a bit tricky for most) 
• Check for leaks, fluid marking under, on and around the car 
• Why are these good habits: 
• consider this:
• On a cold crank in the morning, your car has been sitting all night and gravity has done a fabulous job of pulling everything down into the oil pan 
• Unless you own a HIGH end performance car with a dry sump oil system (which I don't and couldn't afford anyways ;) 
• That means nothing is yet fully coated with lubricants 
• Simply giving your car a few minutes to cycles all vital fluids around each and every system and getting to operating temps will ensure a better operational and longer life span 
• This is extremely important with force fed engines 
• Same goes for shut down, allow a few minutes for the car to cycle lubricants around and gradually cool off key systems before an ignition off 
• The 10min driving route habit is also key for preserving your battery life (each cold crank needs about 10 minutes of driving to counter it and fully recharge the battery back) 
• Also, NOT ALL engines technologies are created equal, for example Rotary engines are DESIGNED to burn some oil because the engine oil is used to lubricate the ceramic APEX seals and you need at least a good 10 minute for every crank to let those seals lubricate properly (most Mazda dealers that know the product will walk you through a conversation around that and even advise you to leave your Rotary engine Mazda on for example the whole time if you wash it at home so it can safely lubricate and run its paces while you get done with the wash in 10-15 minutes)