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16 results for “automotive”

Formulae (16)

Power from Torque & RPM

P = \frac{\tau \times N}{9549}

Engine power in kW from torque and rotational speed.

Automotive & EnginesBasic

Horsepower from Torque (Imperial)

HP = \frac{\tau \times N}{5252}

Horsepower from torque (lb-ft) and engine rpm.

Automotive & EnginesIntermediate

Compression Ratio

CR = \frac{V_d + V_c}{V_c}

Ratio of cylinder volume at bottom vs top of the stroke.

Automotive & EnginesBasic

Engine Displacement

V = \frac{\pi}{4} b^2 s\, n

Total swept volume of all cylinders.

Automotive & EnginesBasic

Gear Ratio

GR = \frac{N_{out}}{N_{in}}

Ratio of driven to driving gear teeth.

Automotive & EnginesIntermediate

Vehicle Speed from RPM

v = \frac{\pi d N}{GR \cdot G_f}

Road speed from engine rpm, gearing and tyre diameter.

Automotive & EnginesBasic

Fuel Economy (L/100km)

E = \frac{100\, F}{d}

Litres of fuel used per 100 km travelled.

Automotive & EnginesBasic

Miles Per Gallon

MPG = \frac{d}{F}

Distance in miles per gallon of fuel.

Automotive & EnginesIntermediate

Braking Distance

d = \frac{v^2}{2 \mu g}

Distance to stop from speed v with friction μ.

Automotive & EnginesIntermediate

Power-to-Weight Ratio

PWR = \frac{P}{m}

Engine power divided by vehicle mass — the key to acceleration.

Automotive & EnginesAdvanced

Aerodynamic Drag

F_d = \tfrac{1}{2}\rho v^2 C_d A

Air resistance a car must overcome, rising with speed squared.

Automotive & EnginesBasic

Kinetic Energy of Vehicle

KE = \tfrac{1}{2} m v^2

Energy that brakes must dissipate to stop a moving car.

Automotive & EnginesBasic

Torque from Force

\tau = F \times r

Turning effect of a force applied at radius r.

Automotive & EnginesIntermediate

EV Range

R = \frac{E}{c}

Electric-vehicle range from battery capacity and consumption.

Automotive & EnginesBasic

EV Charging Time

t = \frac{E}{P}

Hours to charge a battery at a given power.

Automotive & EnginesBasic

Tyre Rolling Circumference

C = \pi d

Distance covered in one wheel revolution.