Designing a Dream: A Hundred Horses per Liter

The DOHC/VTEC mechanism with a set of three cam followers and rocker arms on both the intake side and exhaust side. A wide torque band is achieved through the speed-sensitive switching of cam hills.

<< 1. Variable Valve Timing... for Power and Fuel Economy
<< 2. Designing a Dream: A Hundred Horses per Liter
<< 3. An Open Invitation to Participate
<< 4. Discerning Genuine Technologies
<< 5. Pursuing Excellence Through Trial and Error
<< 6. Applying the Technology to All Honda Models
<< 7. The Confidence Needed to Innovate

"Find a new technology to lead the next generation of Honda engines." This was the directive issued by the top management at Honda R&D, and in response a project was proposed to expand the variable valve-timing approach. Since it had originally been created to improve fuel economy, the engineering staff's new assignment would be to combine outstanding mileage with impressive output across the entire powerband.

This proposal was approved as a D-development project, and was instituted in November 1986. The objective was to develop a new engine for the 1989 Integra.

Kajitani, serving as LPL of the engine development project, was excited about the new opportunity. He knew that working on VTEC technology would not merely solve many problems he had experienced in development of the DOHC and SOHC engines, but would play a major role in the creation of future powerplant designs.

Kajitani believed the specification for Honda's new engine-90 horsepower per liter, or 140 in all from a 1.6-liter unit-was not really reflective of the 1990s approach. After all, the DOHC engine already produced 130 horsepower, but the new engine would only have ten more than that. He knew it just was not enough. Then, as if to read Kajitani's mind, Nobuhiko Kawamoto, then president of Honda R&D made a thoughtful suggestion:

"Why don't you raise your target to 100 horsepower per liter?" he asked.

It had always been thought that a normally aspirated engine could not be made to produce 100 horsepower per liter. But Kajitani could see in Kawamoto the passionate vision of an engineer, and he felt inspired by such a straightforward proposal. Of course, he knew it would mean 160 horsepower from only 1.6 liters, at a maximum of 8,000 rpm.

"I understand," Kajitani replied. "We'll make that our goal." Though he was by no means certain such a thing could be done, he certainly had the energy to try. Kajitani knew that in order to embark upon a challenging path, they must set their goals high.

"It felt like a dream," Kajitani recalled. "Conventional engines in those days could only produce 70 or 80 horsepower per liter. But here we were, being asked to increase it all the way to 100 horses. It wasn't going to be easy.

"An engine becomes subject to a higher load as you increase its rpm," said Kajitani. "So, we had to keep in mind the quality-assurance target of fifteen years, or 250,000 kilometers, for a mass-production engine. We all wondered how on earth we were going to reach that number while ensuring the required quality of mass production."

Kajitani, thus, set a goal for the new VTEC Integra engine: 160 horsepower and 8,000 rpm. Regardless of any obstacles they might encounter down the road, this was the goal they would reach.
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