Design of Variable Valve Timing and Electronic Control for Honda R18A

Abstract

This paper explores the Variable Valve Timing and Lift Electronic Control (VTEC) system developed by Honda, focusing on its mechanisms, design methodology, and impact on engine performance. VTEC optimizes engine efficiency and power by switching between cam profiles suited for low-RPM stability and high-RPM power output, controlled by the engine\'s computer based on operational conditions. We examine the intricate workings of the VTEC system, detailing its hydraulic actuation and the resulting enhancements in torque and horsepower. Our study centers on the Honda R18A engine, targeting increased maximum RPM and power output. Using theoretical analysis validated through Ricardo Wave software and MATLAB simulations, we determine optimal valve lift and timing to achieve the desired performance. Additionally, the research addresses the geometric parameters influencing airflow through the valves, providing a comprehensive understanding of the VTEC system\'s contribution to engine efficiency and driving experience. This investigation not only underscores the technological advancements in variable valve timing but also presents practical insights for automotive engineering applications.

Introduction

I. INTRODUCTION

VTEC is a type of variable valve-timing system developed and used by Honda. It stands for Variable Valve Timing & Lift Electronic Control. Like most other variable-valve timing systems, VTEC varies oil pressure to shift between different cam profiles. At higher engine speeds, the cam profile allows greater valve lift, which allows more air into the cylinder. This helps generate more horsepower. Since its introduction in the late 1980s, VTEC has been used in many of Honda's best performance cars including the NSX, Integra Type R, S2000, and Civic Type R.

II. HOW IT WORKS

The original VTEC system replaced a single cam lobe and rocker with a locking multi-part rocker arm and two cam profiles: one optimized for low-RPM stability and fuel efficiency and the other designed to maximize higher-RPM power output. The VTEC system essentially combines low-RPM fuel efficiency and stability with high-RPM performance. And the transition occurs seamlessly, allowing for smooth performance across the entire powerband. The switching operation between the two cam lobes is controlled by the engine computer. Based on speed, load, and engine RPM, the computer switches between the efficient cam and the high-performance cam. A solenoid is actuated that engages the rocker arms on the high-performance cam. At that point the valves open and close according to the high-lift profile, opening the valves further and for a longer time. This allows more air and fuel to enter and burn, creating stronger torque and horsepower. Honda cars equipped with VTEC technology tend to be more efficient across a wider rpm range than many comparable vehicles, and they’re a lot of fun to drive in the right conditions, but most motorists won’t notice their VTEC kicking in. It’s active when the engine is operating relatively high in the rev range, and you rarely get there in normal driving conditions, especially if your car has an automatic transmission. But, if you’re the shift-your-own-gears type and you like twisty roads, VTEC makes a noticeable difference. [1][2]

References

[1] Akima, Kazuhiro, Kazuyuki Seko, Wataru Taga, Kenji Torii, and Satoshi Nakamura. Development of new low fuel consumption 1.8 L i-VTEC gasoline engine with delayed intake valve closing. No. 2006-01-0192. SAE Technical Paper, 2006. [2] Seko, K., W. Taga, K. Torii, S. Nakamura, K. Akima, and N. Sekiya. \"Development of 1.8 L i-VTEC Gasoline Engine for 2006 Model year Honda CIVIC.\" HONDA R AND D TECHNICAL REVIEW 18, no. 1 (2006): 8.. [3] Ic engine by v ganesan. [4] Heywood, John B. \"Internal combustion engine fundamentals.\" (No Title) (1988). [5] Kolchin, Al?bert Ivanovich, and Veniamin Pavlovich Demidov. Design of automotive engines. MIR publishers, 1984. [6] Matsuki, Masato, Kenji Nakano, Tohru Amemiya, Yuichiro Tanabe, Daisuke Shimizu, and Ichirou Ohmura. \"Development of a lean burn engine with a variable valve timing mechanism.\" SAE transactions (1996): 653-663.

Copyright

Copyright © 2024 Aaditya Bandgar, Pratik Barge, Abhishek Bhamare, Somesh Bhamre, Giridhar Bhande, Ganesh Korwar. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.