The Official Name: CVCC

An EPA hearing was held at the Department of Agriculture building in Washington, D.C., on March 19, 1973. (Photo courtesy of Mr. Tasku Date)

When Soichiro Honda heard that research had determined there was a prospect of reducing toxic substances using the N600 engine, he declared that he would make a public announcement about the low emission engine.

Date, Yagi, and Nakagawa immediately convened in the reception room at Honda R&D Center, in order that they might come up with a name for Honda’s new engine. The official name they decided on just before the announcement was “CVCC,” an acronym for “Compound Vortex Controlled Combustion.”

“Even though we had determined the possibility, we were still in the middle of research,” Date recalled. “In fact, we were still processing our patent application. This meant that the name of the engine had to be contrived carefully, in order that the public announcement not reveal even a part of its structure. And we were as yet undecided about how to supply fuel. We got our heads together to come up with a name that was unique; something that had a bit of punch to it.”

C (“Compound”) represented the engine mechanism with two combustion chambers: main and auxiliary. V (“Vortex”) represented the vortex, or swirl, generated in the main chamber. Caused by a jet of flame from the prechamber injected via a nozzle, the vortex had the effect of increasing the speed of engine combustion. CC (“Controlled Combustion”) represented the engine’s ability to properly control the speed of combustion.

Answering the question as to why the engine was publicly announced while it was still being researched, Yagi simply said, “Mr. Honda told us, ‘If I asked you guys when it would be completed, you’d never tell me that you had it completed to a tee. The company would go bankrupt before you’d say that.’ So, he took a chance, announcing it publicly once it was clear that the prospect for such an engine existed.

“As we say at Honda, it was Mr. Honda’s habit to ‘leave you upstairs and take down the ladder.’ By making a public announcement on the CVCC, I believe he aimed to build up our morale. In the process, he could promote our work in research and development.”

Soichiro Honda held a news conference on February 12, 1971, at the Federation of Economic Organizations Hall in Tokyo’s Ote-machi. There he announced, “We now have the prospect of developing a reciprocating engine (CVCC) that meets emission regulation standards for 1975. We will launch the commercial production of this engine in 1973.” Indeed, the announcement inferred that there was a chance of satisfying the requirements of the U.S. Clean Air Act. Moreover, in the February 26 special issue of the Honda Company Newsletter Mr. Honda informed his employees that the prospects of doing so were quite good.

Many problems had yet to be resolved, though. First of all, the company had to prove that the technical concept of an engine with a prechamber was effective for use in actual automobiles. The new engine was to be installed in the Civic, a small passenger car then in the process of development. Though the engine displacement had been determined according to that product, it was concluded that it would be necessary to develop a 2000 cc CVCC engine, based on standing data and simulation results. This was because in order to clear the emission level stipulated by the Clean Air Act, the engine had to be operated with the air/fuel mixture of around twenty across entire engine load.

The engine was thus given the development number 993. A blueprint was drawn, and just two months later the first prototype engine was completed. An additional 100 units were manufactured with the help of workers at the Saitama Factory (now Wako Plant). The engines were installed in Nissan Sunny bodies following bench tests of their basic performance. Then the chassis dynamometer tests began.

As predicted, lean combustion through the prechamber method reduced CO, NOx, and HC, although the figure for HC was not quite up to the 1975 standards of the Clean Air Act. However, subsequent research on the manifold emissions system, combined with the right combination of main chamber, prechamber and fuel-supply method, produced the desired oxidation reaction in the exhaust pipe through the heat present in the exhaust gas. This resulted in the reduction of HC, consequently revealing the possibility that Honda’s new CVCC engine would satisfy the U.S. standards without the need for a catalytic converter.

The U.S. Environmental Protection Agency required that automobiles continue to meet the standards after 50,000 miles of driving. Thus, research was continued on a fuel-supply device that could supply the ideal air-fuel mixture under any conditions. Moreover, they began to look for a durable structure that was capable of generating more stable oxidation at the exhaust pipe.
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<< The 1970 U.S. Clean Air Act Photo >>
<< Launch of the AP Lab
<< Achieving Lean Combustion through Trial and Error
<< Developing an Engine with a Prechamber
<< The Official Name: CVCC
<< The CVCC Engine System: An Immediate Success
<< Civic/CVCC Fuel Economy Draws Praise in the U.S.
<< The CVCC: Expressing the Honda Philosophy

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