Engine

The engine is the center of the internal combustion powertrain system. All other components of the greater system exist to service the engine in different ways. This means the engine is sensitive to design changes made across the entire powertrain.As of 2019, the FSAE rules require an internal combustion engine with a displacement of 710cc or less. Available OEM motors within this displacement limit are largely sourced from motorcycles and snowmobiles. The purpose of an internal combustion engine is to convert the chemical energy in gasoline or ethanol into mechanical energy used to propel the car. The engine is one of the most complicated single parts of any vehicle. The engine is often the heaviest single part of an internal combustion vehicle.

Please take a look at the outline in the discussion section before making changes to this page

Theory

Main page: Otto Cycle

Structure

I think wikipedia does a very detailed explanation on general engine layout, i think we should probably focus on bike engines w.r.t. fsae competitions.

Engine configuration is a case where the 80/20 rule really applies: the last bit of effort really doesn't get you too much. The bike engines are supersport engines and already configured to perform at a high level (albeit with a bike transmission and unrestricted intake). Removing first gear and some of the higher gears and using a dedicated racing clutch are probably the lowest hanging fruits with regards to the actual engine itself. A custom oil pan is likely essential for many engines due to packaging but a custom wet sump will lack any moving parts.

The structure and operation of motorcycle engines differs from typical car engines in a few key places: size, layout, redline bb. Engines used in these competitions are all under 150 lbs with 600cc 4 cyl coming in at about 125-140, depending on brand or custom parts. Single cylinder engines typically weigh in the neighborhood of 70-90 pounds. These engines are almost exclusively overhead cam layout.

structure: cams, ports, valves, cylinder, piston, conrods/crank, oil and wp, case and covers. crossflow cylinder discussion? Yamaha yzf that have intake in front and exhaust in the rear - contrast to every other engine

I dont know anything about snowmobile engines so someone else is gonna have to do that.

Engine Control

Main page: Engine control

Most modern engines are controlled by an engine control module (ECM) that determines when to inject the fuel and when to ignite the charge using various sensors and an engine tune.

Goals

Reliability

If the engine finishes endurance, it was reliable. (to some teams, to others, maybe they need one engine to last many years due to budget constraints or the fact that they're running an aprillia and there's only two in the US)

Michael Royce in Learn & Compete states that “[reliability] must be the number one technical objective of the team”.

Engine to engine comparisons are difficult, and the literature is sparse at best. Most available engine specific reliability reports are anecdotal. However, brand comparisons are both easier and more widely available. Consumer Reports performed such a comprehensive study on motorcycle reliability. The reliability study is focused on how often the bikes would need to have repairs within the first four years of purchase. The three big Japanese motorcycle companies, Yamaha, Suzuki, and Honda, are the only three with under 15% of the bikes with repairs needed. Yamaha leads the brands with 11% compared to the 12% for Honda and Suzuki each. It is important to consider that this study included the bike as a whole, and that for all of the studied motorcycles“mechanical engine problems were relatively rare, with only 3 percent having trouble with the cylinder head or valvetrain, or with the crankcase, crankshaft, or pistons. Similarly, only 3 percent needed transmission repairs, although 7 percent had clutch problems.” LA Times [citation needed] researching this study reported an interview stating "European bikes are engineered for character and sex appeal, and Japanese bikes are engineered for reliability,". This sentiment can be found echoed in the FSAE online forums.

Another aspect of reliability is parts and tools availability. If something breaks, how easy is it to get hold of spare parts quickly in order to fix the engine? Do you need special tools to service the engine, and can you buy, borrow or manufacture these?

Power/Torque

An obvious goal of an engine is to produce enough power to accomplish your designed team goals. How much is enough? What RPM should we make peak power? Torque? To all of these questions, it depends heavily upon your team's design philosophy. All could be relatively determined from a rudimentary laptime simulation, but will need to be confirmed via testing.
Also worth noting theory on how to determine ideal peak power position (histogram of engine speeds, peak torque at roughly that speed. Can also loosely perform an "integral" by multiplying engine speed occurrences with the power output at that point as when the integral is maximized, the most power was put down to the track)

I imagine there is a lot more to expand upon here - Novotny

Examples of teams design philosophy:

• we have a novice driver - we want our torque curve to be wide and flat
• we run a CVT and the engine will hold at a specific RPM during all events and we only want torque at that spot at the expense of all else
• we are a first year team and we dont know what we are doing so we are just going for peak torque everywhere
• we have the torque curve in the shape we want so we are just tuning for peak torque everywhere
• we are running with huge boost and need to run with an AFR of 9 or else we'll be building a bomb
• we can't get our engine to idle, so we're spending the whole year tuning at 1.5K RPM and didn't get around to anything else
• our driver is a 4th year masters student who has 8 years of FS driving and can put the engine wherever he wants, we are giving him peak torque at 9650 RPM because thats what gives him the fasted lap times during testing

Torque and power are determined by testing the engine on a dynomometer (need page for dynos).

Power Limiting Factors

Piston Speed Limit

"a. Automotive / Motorcycle engines 914.4 m/min (3,000 ft/min)
b. Industrial Engines 731.5 m/min (2,400 ft/min)
The calculated speed will be rounded to the nearest 500 rpm."
test speeds - http://fsaeonline.com/content/Noise%20Test%20Speeds%202015.pdf
[100% VE v choked flow graph for cbr example?]
Back of envelope calc for CBR at 11K
599cc four cyl
4 stroke means 2 cyl per rev
299.5 cc per rev
3294.5 L per min at 11K rpm
using air at 25C, 0psig (no boost, 100% VE)
1.2 kg air per m3 [1]
0.0012 kg_air/L
3.9534 kg/min at 11K rpm
0.06589 kg/s at 11K rpm
assuming an afr of 13.1 [citation needed]
0.00503 kg_gasoline/sec at 11K rpm
Q_LHV of gasoline is 46e3 kJ/kg fuel
231 kJ/s or kW at 11K rpm
somehow "proves" 100% VE for honda CBR600RR shouldn't even be restricted by the restrictor - this becomes a bruh moment.

Efficiency

high speed low drag babey

Simulation

otto cycle matlab sims for freshmen

1D engine sims

Ricardo WAVE or GT-Power are commonly used. I (and the guy who I edited over) have had good success with Ricardo. From my experience, WAVE is good for understanding trends, but not necessarily getting a precise power number. The 1D model is especially suspect for the highly 3D behavior you see with the restrictor and plenum. The strength really lies in getting an engineering understanding of how to design an intake and exhaust for a given torque curve e.g. how long should I make my runners, do I run a 4-2-1 or a 4-1 exhaust, and how large should my plenum be.

Oil System

Main page: Oil

Mounting System

Vibration Reduction

Best Practices

How to care for an engine.

How/when to service.

How to diagnose issues.

Why combustion is more romantic than electric.

Common Engines

I think bc the cbr, r6, and a few of the 450s are so common, we can use this to list what we have done to optimize for FSAE use.

Example: gear removal, EWP, custom valving, suggested idles, mounting tips, weights/mass, stock water pump flow rates, oil recomendations, intake mounting recs. exhaust mounting recs, heat generation, wiring, injectors

Honda CBR 600RR

• remove first gear, breaks traction with any reasonable FDR
• max heat dissipation of ~10kW needed from cooling system (utoronto 2007 - https://manualzz.com/doc/35576578/design-and-optimzation-of-a-formula-sae-cooling)
• remove the thermostat control to keep temps down

Yamaha R6

Yamaha WR/YZ450

• WPI runs WiSECO high compression piston

see all engines here