Department of Engine

Power Boosting Technology

Variable-valve timing (VVT)

Basic Principles

VVT's benefit to fuel consumption and emission

Different systems:

1. Cam-changing VVT - e.g. Honda 3-stage VTEC, Nissan VVL

2. Cam-phasing VVT - e.g. BMW Vanos / Double Vanos, Toyota VVT-i

3. Cam-changing + Cam-phasing VVT -  e.g. Toyota VVTL-i, Porsche Variocam Plus, Honda i-VTEC, Audi Valvelift, Mercedes Camtronic, GM iVLC

4. Rover's unique VVC

5. Continuous variable valve lift (CVVL) - e.g. BMW Valvetronic, Nissan VVEL, Toyota Valvematic

6. Electrohydraulic valve control - e.g. Fiat Multiair

Intake and exhaust

Tuned intake manifold

Variable intake manifold

Variable length intake manifold

3-stage variable length intake manifold

Continuous variable length intake manifold - e.g. BMW DIVA

Resonance intake manifold - e.g. Porsche VarioRam

Tuned exhaust & variable back-pressure exhaust

Multi-valve engines


Advantages and Disadvantages

Solutions - e.g. Toyota T-VIS

Number of Valves - 3, 4, 5 or more

Forced induction

Ram Air Intake


Roots type supercharger

Eaton TVS supercharger

Lysholm (screw type) supercharger

Centrifugal supercharger



Light pressure turbo

Variable turbine geometry (VTG)

Variable-volume turbine by Koenigsegg


Parallel Twin-turbo

Sequential Twin-turbo

2-Stage Variable Twin-turbo

Twin-scroll turbo

Cross-bank turbocharging - BMW twin-turbo V8 as example

Turbo + Supercharger - e.g. Volkswagen Twincharger


Twin-spark plug

Compression ratio

Variable Compression - Saab SVC

High Compression engines - Mazda Skyactiv-G

Green Technology


Lean burn engine

Direct injection by stratified charge - Mitsubishi GDI

Direct injection by EGR - Renault IDE

Mercedes 3-valve approach to cut cold start emission

Honda ULEV and ZLEV engines

Mazda Miller Cycle engine

Throttleless engines - BMW Valvetronic

Exhaust Gas Recirculation (including EGR by means of VVT)


Modern diesel engines

Common-rail direct injection diesel engines

PSA Particle Filter

Alternative fuel

Electric cars

Hybrid cars

Toyota Prius

Honda Insight

Fuel Cell cars - Mercedes NECAR 4

Engine Packaging

Volkswagen VR6 and W-engines

First generation VR6

Second generation, 24-valve VR6

W12 engine

W16 engine

W8 engine

W18 engine

Advanced materials

Aluminum head and block

Plastic or magnesium intake manifolds

Aluminum pistons and cylinder liners (including Nikasil and FRM)

Titanium connecting rods

Forged components

Engine Smoothness

Introduction and basic theory

Inline 2-cylinder engines

Inline 3-cylinder engines

Inline 4-cylinder engines (versus boxer-4)

Inline 5-cylinder engines

Inline 6-cylinder engines

V6 engines

V8 engines - flat-plane and cross-plane crank

V10 engines

V12 engines

All horizontally opposed (boxer) engines

Volkswagen VR6, W12 and W16

Volkswagen W8

Copyright© 1997-2015 by Mark Wan @ AutoZine