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A Honda Civic engine with CVCC
A Honda Civic engine with CVCC

CVCC, or Compound Vortex Controlled Combustion (複合渦流調整燃焼方式, Fukugō Uzuryū Chōsei Nenshō Hōshiki), is an internal combustion engine technology developed and trademarked by the Honda Motor Company.[1]


The technology's name refers to its features as such:

  • Compound for the use of two combustion chambers,
  • Vortex for a vortex generated in the main combustion chamber, increasing combustion speed, and
  • Controlled Combustion for the combustion occurring in a timely, controlled manner.[1]


Following the establishment of an "Air Pollution Research Group" by Honda in 1965, its collection of emissions data from American automakers, and subsequent research into emissions control and prechambers, the first mention of CVCC technology was by Soichiro Honda on February 12, 1971, at the Federation of Economic Organizations Hall in Otemachi, Chiyoda-ku, Tokyo.[1]

On the advice of University of Tokyo professor Tsuyoshi Asanuma, then-Honda R&D Director Tasuku Date, Engine-performance Research Block head Shizuo Yagi, and then-Engineering Design Chief Engineer Kazuo Nakagawa began research into lean combustion. After Date suggested the use of a prechamber, which some diesel engines utilized, the first engine to be installed with the CVCC approach for testing was a single-cylinder, 300 cc version of Honda's EA engine installed in a modified Honda N600 hatchback in January 1970.[1] This technology allowed Honda's cars to meet Japanese and American emissions standards in the 1970s without the need for a catalytic converter.

A type of stratified charge technology, it was publicized on October 11, 1972 and licensed to Toyota (as TTC-V), Ford, Chrysler, and Isuzu before making its production debut in the 1975 ED1 engine. As emission laws advanced and required more stringent admissible levels, CVCC was abandoned in favour of PGM-FI (Programmed Fuel Injection) on all Honda vehicles. Some Honda vehicles in Japan used electronically controlled "PGM-Carb" carburetors on transitional Honda D, E and ZC engines.

In 2007, the Honda CVCC technology was added to Japan's Mechanical Engineering Heritage list.


Honda CVCC engines have normal inlet and exhaust valves, plus a small auxiliary inlet valve which provides a relatively rich air–fuel mixture to a volume near the spark plug. The remaining air–fuel charge, drawn into the cylinder through the main inlet valve, is leaner than normal. The volume near the spark plug is contained by a small perforated metal plate. Upon ignition flame fronts emerge from the perforations and ignite the remainder of the air–fuel charge. The remaining engine cycle is as per a standard four-stroke engine.

This combination of a rich mixture near the spark plug, and a lean mixture in the cylinder allowed stable running, yet complete combustion of fuel, thus reducing CO (carbon monoxide) and hydrocarbon emissions. This method allowed the engine to burn less fuel more efficiently without the use of an exhaust gas recirculation valve or a catalytic converter, although those methods were installed later to further improve emission reduction.


The most significant advantage with CVCC was that it allowed for carbureted engines that did not rely on intake swirl. Previous stratified charge engines needed costly fuel injection systems. Additionally, previous engines tried to increase the velocity and swirl of the intake charge to keep rich and lean mixtures separated; Honda was able to maintain separation via the shape of the combustion chamber.[citation needed]

The design of CVCC also allowed it to be adapted to existing engines, since only the cylinder head needed to be modified.[1]

Early design flaw

Some early CVCC engines had problems with the auxiliary valves' retaining collars vibrating loose. Once unscrewed, oil would leak from the valvetrain into the prechamber, causing a sudden loss of power and large amounts of smoke to flow from the exhaust pipe. These symptoms usually indicated the failure of critical oil seals in the motor that would result in costly repairs. However, the solution was quite simple; Honda corrected the problem with metal retaining rings that slipped over the valves' retaining collars and prevented them from backing out of their threads.[citation needed]


The 1983 Honda Prelude (the first year of the second generation of Preludes) used CVCC in combination with a catalytic converter to reduce emissions, along with two separate sidedraft carburetors (instead of a single, progressive twin-choke carburetor). This new system was called CVCC-II. The following year, a standard cylinder head design was used, and the center carburetor (providing the rich mixture) was removed. The Honda City AA, introduced in November 1981, also used a CVCC-II engine called the ER.[2] Its use of CVCC was also known as COMBAX (COMpact Blazing-combustion AXiom).

CVCC-equipped engines

Series Displacement Valvetrain Aspiration Power Torque Applications
ED 1,487 cc (1.5 L; 90.7 cu in) SOHC 12-valve 3-barrel carburetor 52 hp (39 kW) @ 5,000 rpm 68 lb⋅ft (92 N⋅m) @ 3,000 rpm 1975- Honda Civic CVCC (ED1)

1975- Honda Civic Wagon (ED2)

1976-1979 Honda Civic CVCC (ED3)

1976-1979 Honda Civic Wagon (ED4)

EF 1,598 cc (1.6 L; 97.5 cu in) 68 hp (51 kW) @ 5,000 rpm 85 lb⋅ft (115 N⋅m) @ 3,000 rpm 1976-1978 USDM Honda Accord CVCC[3]
EJ 1,335 cc (1.3 L; 81.5 cu in) 68 hp (51 kW) @ 5,000 rpm 77 lb⋅ft (104 N⋅m) @ 3,000 rpm 1980- Honda Civic (EJ1)

1980- Honda Ballade (EJ1)

1980- Triumph Acclaim (EJ1)

1981-1983 Honda Civic CVCC (EJ1)

EK 1,751 cc (1.8 L; 106.9 cu in) 72 hp (54 kW) @ 4,500 rpm (six-port cylinder head, 1979-1980)

75 hp (56 kW) @ 4,500 rpm (eight-port cylinder head, 1980-1981)

94 lb⋅ft (127 N⋅m) @ 3,000 rpm (six-port cylinder head, 1979-1980)

96 lb⋅ft (130 N⋅m) @ 3,000 rpm (eight-port cylinder head, 1980-1981)

1979-1983 USDM Honda Accord CVCC

1979-1982 USDM Honda Prelude CVCC

1981-1985 JDM Honda Vigor[3]

EM 1,487 cc (1.5 L; 90.7 cu in) 52 hp (39 kW) @ 5,000 rpm (1980)

63 hp (47 kW) @ 5,000 rpm (1981-1983)

68 lb⋅ft (92 N⋅m) @ 3,000 rpm (1980)

77 lb⋅ft (104 N⋅m) @ 3,000 rpm (1981-1983)

1980-1983 Honda Civic (EM1)
EP 1,601 cc (1.6 L; 97.7 cu in) SOHC 8-valve 2-barrel carburetor 89 hp (66 kW) @ 5,500 rpm 95 lb⋅ft (129 N⋅m) @ 3,500 rpm 1980-1985 Honda Quint

1980-1981 Honda Accord

ER (CVCC-II) 1,231 cc (1.2 L; 75.1 cu in) SOHC 12-valve 1-barrel carburetor

2-barrel carburetor

44 hp (33 kW) @ 4,500 rpm (1-barrel carb, EU)

55 hp (41 kW) @ 5,000 rpm (1-barrel carb, EU, super fuel)

60 hp (45 kW) @ 5,000 rpm (2-barrel carb, JDM, Pro versions)

62 hp (46 kW) @ 5,000 rpm (2-barrel carb, JDM)

66 hp (49 kW) @ 5,000 rpm (2-barrel carb, JDM, manual R and Cabriolet)

60 lb⋅ft (82 N⋅m) @ 2,500 rpm (1-barrel carb, EU)

69 lb⋅ft (93 N⋅m) @ 3,500 rpm (1-barrel carb, EU, super fuel)

71 lb⋅ft (96 N⋅m) @ 3,000 rpm (2-barrel carb, JDM, Pro versions)

72 lb⋅ft (98 N⋅m) @ 3,000 rpm (2-barrel carb, JDM)

72 lb⋅ft (98 N⋅m) @ 3,000 rpm (2-barrel carb, JDM, manual R and Cabriolet)

1981-1986 Honda City[2][4]
ES (CVCC-II) 1,829 cc (1.8 L; 111.6 cu in) Dual sidedraft carburetors (ES1)

3-barrel carburetor (ES2)

100 hp (75 kW) @ 5,500 rpm (ES1)

86 hp (64 kW) @ 5,800 rpm (ES2)

104 lb⋅ft (141 N⋅m) @ 4,000 rpm (ES1)

99 lb⋅ft (134 N⋅m) @ 3,500 rpm (ES2)

1983-1984 Honda Prelude (ES1)

1984-1985 Honda Accord (ES2)

EV 1,342 cc (1.3 L; 81.9 cu in) 3-barrel carburetor 60 hp (45 kW) @ 5,500 rpm (USDM)

79 hp (59 kW) @ 6,000 rpm (JDM)

70 hp (52 kW) @ 6,000 rpm (Rover 213)

73 lb⋅ft (99 N⋅m) @ 3,500 rpm (USDM)

82 lb⋅ft (111 N⋅m) @ 3,500 rpm (JDM)

1983-1986 Honda Civic (EV1)[5]

1983-1986 Honda CR-X (EV1)

1984-1990 Rover 213 (EV2)

EW 1,488 cc (1.5 L; 90.8 cu in) 3-barrel carburetor 58–76 hp (43–57 kW) 80–84 lb⋅ft (108–114 N⋅m) 1984-1985 Honda Civic/CR-X DX (EW1)

1984-1986 Honda Civic (EW1)

1984-1986 Honda Shuttle (EW1)

EY 1,598 cc (1.6 L; 97.5 cu in) Carburetor 93 hp (69 kW) @ 5,800 rpm 98 lb⋅ft (133 N⋅m) @ 3,500 rpm 1983 Honda Accord 1600 E-AC


  1. ^ a b c d e "Honda Global | Introducing the CVCC / 1972". Retrieved 2020-12-15.
  2. ^ a b World Cars 1985. Pelham, NY: The Automobile Club of Italy/Herald Books. 1985. pp. 345–346. ISBN 0-910714-17-7.
  3. ^ a b How to Rebuild Your Honda Car Engine by Tom Wilson, copyright 1985, HP Books, ISBN 0-89586-256-5
  4. ^ Koichi Inouye (1985). World Class Cars Volume 2: Honda, from S600 to City. Tokyo: Hoikusha. pp. 120–125. ISBN 4-586-53302-1.
  5. ^ World Cars 1985, pp. 346–348
This page was last edited on 18 December 2020, at 09:21
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