The VTEC Engine / 1989

Achieving A Naturally Aspirated 100 Horsepower: The Leap to a Dream

The VTEC Engine / 1989

Variable Valve Timing for Power and Fuel Economy

In order to develop its next generation of engines for the mainstream market, Honda's NCE (New Concept Engine) program was launched in March 1984. Specific targets identified through the program included high torque in both the low- and high-rpm ranges and dramatic increases in horsepower per liter. The program was a success, resulting in a series that included the DOHC engine found in the 1985 Civic and Integra, and the SOHC center-plug engine in the 1987 City.

Variable Valve Timing for Power and Fuel Economy

The structure of Honda's VTEC engine, the ultimate expression of an original concept

Ikuo Kajitani, who was employed in the First Design Dept at Honda's Tochigi R&D Center, was involved in the development of these four-valve engines. Through his experience in engine design, Kajitani had become convinced that Honda's next engine should offer a mechanism that could alter the timing of the valves.

"Characteristically," Kajitani said, "four-valve engines are known as high-revving, high-output machines. And for that reason we knew it would be quite difficult to achieve low-end performance if the engine's displacement were too small."

Problems certainly arose during the process of development. A reduction in the valve's interior angle, attempted in order to increase low-end torque, resulted in a broken timing belt and valve spring as the unit reached the upper range of revolutions. To address the problem, the development staff put in uncounted hours studying how to balance these two critical areas of engine performance. They knew they had already succeeded with their DOHC and SOHC powerplants, but to develop a new unit that would outperform its predecessors they would have to bridge the gap between the low end and the upper limit.

One group already had examined the idea of switchable valve timing. In January 1983, a year before the NCE program began, a research team was formed to study the mechanism as a means of enhancing fuel economy. Even though by the end of 1982 Honda engines were already capable of a world-beating 50 miles per gallon (mpg), there would be an effort to improve.

A possibility was thus identified through the study of a new valve mechanism. Specifically, it was believed that the installation of a new set of cam followers and rocker arms for high-speed operation on the intake and exhaust sides would help, along with the switching of cam hills according to engine speed. This was to be their solution to higher engine efficiency.

This was the so-called "valve stopping + variable valve timing" mechanism employed in the NCE program. As a core technology for Honda's proposed new line of engines, the mechanism then underwent a program of study and refinement under the careful supervision of Honda's research staff. Eventually the mechanism evolved into Honda's VTEC (Variable Valve Timing & Lift Electronic Control System) engine. Launched via the 1989 Integra, this innovative technology surprised the world with a new level of performance from a compact, fuel-efficient engine.

The Challenging Spirit of Honda

1990 - 1999
  1. The Birth of Twin Ring Motegi / 1997The Birth of Twin Ring Motegi / 1997
  2. Entry to Champ Car Racing / 1994Entry to Champ Car Racing / 1994
  3. Odyssey / 1994Odyssey / 1994
  4. Establishment of Honda Taiyo, Kibo-no-Sato Honda and Honda R&D Taiyo / 1992Establishment of Honda Taiyo, Kibo-no-Sato Honda and Honda R&D Taiyo / 1992
  5. Hosting Hosting "Orei-no-kai" / 1991
  6. The NSX / 1990The NSX / 1990
1980 - 1989
  1. The VTEC Engine / 1989The VTEC Engine / 1989
  2. Honda EV Plus: The Dream of an Electric Vehicle / 1988Honda EV Plus: The Dream of an Electric Vehicle / 1988
  3. An Automated Line for Painting and Coating / 1988An Automated Line for Painting and Coating / 1988
  4. Four-Wheel Steering System (4WS) / 1987Four-Wheel Steering System (4WS) / 1987
  5. The Airbag System / 1987The Airbag System / 1987
  6. The ZE Engine (GX110 / 140 / 240 / 270 / 340 Series) / 1983The ZE Engine (GX110 / 140 / 240 / 270 / 340 Series) / 1983
  7. Formula One Entry / 1983Formula One Entry / 1983
  8. Development of Honda's Franz System Car / 1982Development of Honda's Franz System Car / 1982
  9. The World's Smallest Welding Line / 1982The World's Smallest Welding Line / 1982
  10. Transfer Lines for Modular Components / 1981Transfer Lines for Modular Components / 1981
  11. The Car Navigation System / 1981The Car Navigation System / 1981
  12. City / 1981City / 1981
  13. The F200 The F200 "Komame" Mini-Tiller / 1980
  14. Establishing Honda of America Manufacturing / 1980Establishing Honda of America Manufacturing / 1980
1970 - 1979
  1. The Oval Piston Engine / 1979The Oval Piston Engine / 1979
  2. Returning to the World Motorcycle Grand Prix / 1979Returning to the World Motorcycle Grand Prix / 1979
  3. The HR21 Lawn Mower / 1978The HR21 Lawn Mower / 1978
  4. Creating Hometown Forests / 1977Creating Hometown Forests / 1977
  5. The ME Engine (G100 / 150 / 200 / 300 / 400 Series) / 1977The ME Engine (G100 / 150 / 200 / 300 / 400 Series) / 1977
  6. Introducing the Accord / 1976Introducing the Accord / 1976
  7. CG125 / 1975CG125 / 1975
  8. Establishment of Honda Engineering / 1974Establishment of Honda Engineering / 1974
  9. Company Leaders Honda and Fujisawa Retire; Kawashima Assumes Presidency / 1973Company Leaders Honda and Fujisawa Retire; Kawashima Assumes Presidency / 1973
  10. Announcing the Civic / 1972Announcing the Civic / 1972
  11. Introducing the CVCC / 1972Introducing the CVCC / 1972
  12. Holding All Honda Idea Contests / 1970Holding All Honda Idea Contests / 1970
  13. Launching the Office of Safe Driving Promotional Operations / 1970Launching the Office of Safe Driving Promotional Operations / 1970
1960 - 1969
  1. The Dream CB750 FOUR / 1969The Dream CB750 FOUR / 1969
  2. Launching the Honda 1300 / 1968Launching the Honda 1300 / 1968
  3. The Hondamatic Transmission / 1968The Hondamatic Transmission / 1968
  4. Entering the Auto Market at Last / 1966Entering the Auto Market at Last / 1966
  5. The E300 Portable Generator / 1965The E300 Portable Generator / 1965
  6. Formula One Entry / 1964Formula One Entry / 1964
  7. Kyoto: Celebrating the Company's 15th Anniversary / 1963Kyoto: Celebrating the Company's 15th Anniversary / 1963
  8. Establishing Belgium Honda / 1963Establishing Belgium Honda / 1963
  9. Launching the S360 and T360 / 1962Launching the S360 and T360 / 1962
  10. Employing the Employing the "My Record" Project and Expert Certification / 1960
  11. The R&D Center Goes Independent / 1960The R&D Center Goes Independent / 1960
1950 - 1959
  1. Establishing American Honda Motor Co. / 1959Establishing American Honda Motor Co. / 1959

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