CVCC is a trademark by the Honda Motor Company for an engine with reduced automotive emissions, which stood for "Compound Vortex Controlled Combustion". The first mention of Honda developed CVCC technology was done by Mr. Soichiro Honda February 12, 1971, at the Federation of Economic Organizations Hall in Otemachi, Chiyoda-ku, Tokyo. Honda's engineers at the time, Mr. Date conferred with Mr. Yagi and Mr. Nakagawa about the possibility of creating lean combustion via a prechamber, which some diesel engines utilized. The first engine to be installed with the CVCC approach for testing was the single-cylinder, 300 cc Honda EA engine used in the Honda N600 hatchback in January 1970. This technology allowed Honda's cars to meet United States emission standards in the 1970s without a catalytic converter. A type of stratified charge engine, it first appeared on the 1975 ED1 engine. As emission laws advanced and required more stringent admissible levels, Honda abandoned the CVCC method and introduced PGM-FI, or Programmed Fuel Injection on all Honda vehicles. Some vehicles in Japan had a combination of electronically controlled carburetors, called PGM-Carb on specific, transistitional Honda D, E and ZC engines.
In 2007, the Honda CVCC technology was added to the Mechanical Engineering Heritage of Japan.
Construction and operation 
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.
Advantages over previous stratified charge engines 
Honda's big advancement with CVCC was that they were able to use carburetors and they did not rely on intake swirl. Previous versions of stratified charge engines needed costly fuel injection systems. Additionally, previous engines tried to increase the velocity and swirl of the intake charge in keeping the rich and lean mixtures separated. Honda was able to keep the charges adequately separated by combustion chamber shape.
Early design flaw 
Some of the early CVCC engines had a problem with the auxiliary valves retaining collars vibrating loose. Once unscrewed, engine oil would leak from the valvetrain into the pre-combustion chamber, causing a sudden loss of power and massive amounts of smoke to emanate from the exhaust pipe. The condition simulated a blown engine, even though the needed repair was quite simple. Honda eventually came up with a fix involving metal retaining rings that slipped over the collars and prevented them from backing out of their threads.
The 1983 Honda Prelude (the first year of the second generation of Preludes) used a CVCC design and a catalytic converter to reduce emissions, called CVCC-II, along with 2 separate sidedraught carburettors (instead of a single progressive twin choke carburettor). The following year a standard cylinder head design was used and the centre carburettor (providing the rich mixture) was dropped. The Honda City AA, introduced in November 1981, also used a CVCC-II engine called the ER.
List of CVCC equipped engines 
The ED series introduced the CVCC technology. This group displaced 1,487 cc (1.487 L; 90.7 cu in) and used an SOHC 8-valve design. Output with a 3 barrel carburetor was 52 hp (39 kW) @ 5000 rpm and 68 lb·ft (92 N·m) @ 3000 rpm.
- 1975- Honda Civic CVCC
- 1975- Honda Civic Wagon
- 1976-1979 Honda Civic CVCC
- 1976-1979 Honda Civic Wagon
The EF was an SOHC 12-valve (CVCC) engine, displacing 1.6 L (1598 cc). Output was 68 hp (51 kW) @ 5000 rpm and 85 lb·ft (115 N·m) @ 3000 rpm.
- 74 mm bore x 93 mm stroke
- Cast iron block & aluminum cylinder head
- Six port cylinder head (4 intake port / 2 exhaust ports)
- Valve order (IEEIIEEI)
- Three barrel Keihin carburettor (1976 had manual choke, 1977 & 1978 were automatic choke)
- Point type ignition
The EJ displaced 1,335 cc (1.335 L; 81.5 cu in) and was an SOHC 12-valve CVCC engine with a 3 barrel carburetor. 4 intake valves, 4 exhaust valves, and 4 auxiliary valves. Output was 68 hp (51 kW) @ 5000 rpm and 77 lb·ft (104 N·m) @ 3000 rpm.
The EK was an SOHC 12-valve (CVCC) engine, displacing 1.8 L (1,751 cc). Output varied (see below) as the engine itself was refined.
- 77 mm bore x 94 mm stroke
- Cast iron block & aluminum cylinder head
- Three barrel Keihin carburettor (all were automatic choke)
- Electronic ignition
- Oil cooler (or provision for this in the block)
- Cylinder head iterations:
- Six port cylinder head (4 intake port / 2 exhaust ports) & IEEIIEEI valve order for 1979 & 1980 49 state
- Eight Port cylinder head (4 intake port / 4 exhaust ports) & IEEIIEEI valve order for 1980 (California only) and 1981 (50 states)
- Eight Port cylinder head (4 intake port / 4 exhaust ports) & EIEIIEIE valve order from 1982 to end of CVCC production (1985)
- Power: 6-port output was 72 hp (54 kW) at 4,500 rpm and 94 lb·ft (127 N·m) at 3,000 rpm, while the original 8-port head raised this to 75 hp (56 kW) at 4,500 rpm and 96 lb·ft (130 N·m) at 3,000 rpm. The revised 4-port (82 & later) had another slight horsepower increase.
1979-1983 Honda Accord CVCC (US market)
1979-1982 Honda Prelude CVCC (US market)
1981-1985 Honda Vigor (JDM)
EK9 is not related to the EK engine - EK9 is simply the chassis code for 1996-2000 Honda Civic Hatchbacks.
The EM displaced 1,487 cc (1.487 L; 90.7 cu in) and was an SOHC 12-valve CVCC engine. Early versions produced 52 hp (39 kW) @ 5000 rpm and 68 lb·ft (92 Nm) @ 3000 rpm, while later ones upped the output to 63 hp (47 kW) @ 5000 rpm and 77 lb·ft (104 N·m) @ 3000 rpm. All used a 3 barrel carburetor.
1980-1985 Honda Quintet / Quint (Japan)
1980-1981 Honda Accord
The long-stroke, 12-valve CVCC-II for Japan and 8-valve for Europe and Asia ER four-cylinder engine was only used in the AA/VF/FA series City/Jazz (1981–86). It was available as a normally aspirated carburated version or with Honda's own PGM-FI fuel injection as one of a very few turbocharged engines built by Honda. The Japanese market CVCC engine was also known as COMBAX, an acronym of COMpact Blazing-combustion AXiom. The E-series were tuned for economy, with higher gearing and later on with computer controlled variable lean burn. As of March 1985, the naturally aspirated ER engines gained composite conrods (a world first in a production car), lighter and stronger these helped further reduce fuel consumption.
The lower powered engines in the commercial "Pro" series had a lower compression, a mechanically timed ignition rather than the breakerless setup found in the passenger cars, and a manual choke. The ER had five crankshaft bearings and the overhead camshaft was driven by a cogged belt.
|Engine type||Inline four, SOHC CVCC-II 12-valve|
|Displacement||1,231 cc (75.1 cu in)|
|Bore x stroke||66.0 x 90.0 mm|
|Fuel type||Leaded (export) or unleaded (domestic)|
|33 kW (45 PS) DIN at 4500 rpm||82 N·m (60 ft·lb) at 2500 rpm||1 bbl carburetor||10,2:1 (normal)||European market|
|41 kW (56 PS) DIN at 5000 rpm||93 N·m (69 ft·lb) at 3500 rpm||1 bbl carburetor, manual choke||10,2:1 (super)||European market (ER1 & ER4 engine)|
|61 PS (45 kW) JIS at 5000 rpm||9.8 kg·m (96 N·m; 71 lb·ft) at 3000 rpm||2 bbl carburetor||9,0:1 (unleaded)||Pro T, Pro F|
|63 PS (46 kW) JIS at 5000 rpm||10.0 kg·m (98 N·m; 72 lb·ft) at 3000 rpm||2 bbl carburetor||10,0:1 (unleaded)||E-series, U, R (AT), Cabriolet (AT)|
|67 PS (49 kW) JIS at 5000 rpm||10.0 kg·m (98 N·m; 72 lb·ft) at 3500 rpm||2 bbl carburetor||10,0:1 (unleaded)||R and Cabriolet with MT|
|100 PS (74 kW) JIS at 5500 rpm||15.0 kg·m (147 N·m; 108 lb·ft) at 3000 rpm||FI, turbo||7,5:1 (unleaded)||City Turbo|
|110 PS (81 kW) JIS at 5500 rpm||16.3 kg·m (160 N·m; 118 lb·ft) at 3000 rpm||FI, turbo + intercooler||7,6:1 (unleaded)||Turbo II "Bulldog"|
Carburetor versions used either a single or 2bbl downdraft Keihin. The turbocharger in the Turbo and Turbo II was developed together with IHI, the Turbo II being equipped with an intercooler and a computer controlled wastegate.
ER1-4 Honda City
The ES displaced 1,829 cc (1.829 L; 111.6 cu in). All ES engines were SOHC 12-valve engines. The ES1 used dual sidedraft carburetors to produce 100 hp (75 kW) @ 5500 rpm and 104 lb·ft (141 N·m) @ 4000 rpm. The ES2 replaced this with a standard 3 barrel carburetor for 86 hp (64 kW) @ 5800 rpm and 99 lb·ft (134 N·m) @ 3500 rpm. Finally, the ES3 used PGM-FI for 101 hp (75 kW) @ 5800 rpm and 108 lb·ft (146 N·m) @ 2500 rpm.
- 1983-1984 Honda Prelude
- 1984-1985 Honda Accord
The EV displaced 1,342 cc (1.342 L; 81.9 cu in) and was an SOHC 12-valve design. 3 barrel carburetors produced 60 hp (45 kW) at 5,500 rpm and 73 lb·ft (99 N·m) at 3,500 rpm for the US market. The JDM version, featuring 12 valves and auxiliary CVCC valves, produced 80 PS (59 kW) at 6,000 rpm and 11.3 kg·m (111 N·m) at 3,500 rpm. It was available in all bodystyles of the third generation Honda Civic.
The final E-family engine was the EW, presented along with the all new third generation Honda Civic in September 1983. Displacing 1,488 cc (1.5 L; 90.8 cu in), the EWs were SOHC 12-valve engines. Early 3 barrel EW1s produced from 58 to 76 hp (43 to 57 kW) and 108 to 114 N·m (79.7 to 84.1 lb·ft). The fuel injected EW3 and EW4 produced 91 hp (68 kW) at 5,500 rpm and 126 N·m (92.9 lb·ft) at 4,500 rpm. The "EW" name was replaced by the Honda D15 series, with the EW (1, 2, 3, 4, and 5) renamed to D15A (1, 2, 3, 4, and 5) in 1987. It also received a new engine stamp placement on the front of the engine like the "modern D series" (1988+).
- 1983-1987 Honda Civic non-CVCC EFI (CDM)
- 1985- Honda Civic/CRX Si non-CVCC
- 1985-1986 Honda CRX Si non-CVCC
- 1986 Honda Civic Si non-CVCC
- similar to the EW1, Fuel injected CVCC 12Valve 4 Aux valves. A third throttle plate in the throttle body supplied intake air to a 5th injector which powered the CVCC ports, The rated power is different between the Civic and the CR-X: the Civic makes 100 PS (74 kW) at 5,800 rpm and 13.2 kg·m (95.5 lb·ft) torque at 4,000 rpm, the CR-X made 110 PS (108 hp) at 5,800 rpm and 13.8 kg·m (99.8 lb·ft) torque at 4,500 rpm. Differences in power are largely down to a more efficient exhaust system on the CR-X it used a factory cast iron 4-2-1 extractor went through a catalytic converter further down the exhaust system and had twin exit tail pipes. The Civic had a short 4-1 design into a catalytic converter and single pipe exit. There was a revised intake manifold for vehicles produced in 1986 and 1987. The EW5 was only available in Japan. It came in the following models: CR-X 1.5i, Civic 25i Hatchback, Ballade CRi Sedan.
EY (1,598cc:80.0X79.5) 94PS/5,800rpm 13.6 kg·m/3,500rpm
Engine manufacturer Honda Engine code EY Number of cylinders Straight 4 Capacity 1.6 litre 1598 cc (97.516 cu in) Bore × Stroke 80 × 79.5 mm 3.15 × 3.13 in Bore/stroke ratio 1.01 Valve gear SOHC 3 valves per cylinder 12 Total valves
Used in 1983 Honda Accord 1600 E-AC (all trim levels)
- Honda Worldwide
- World Cars 1985. Pelham, NY: The Automobile Club of Italy/Herald Books. 1985. pp. 345–346. ISBN 0-910714-17-7.
- How to Rebuild Your Honda Car Engine by Tom Wilson, copyright 1985, HP Books, ISBN 0-89586-256-5
- Koichi Inouye (1985). World Class Cars Volume 2: Honda, from S600 to City. Tokyo: Hoikusha. pp. 120–125. ISBN 4-586-53302-1.
- "Honda: Auto Lineup Archive". Honda Motor Co., Ltd. Archived from the original on 2010-07-08.
- Auto Katalog 1985. Stuttgart: Vereinigte Motor-Verlage GmbH & Co. KG. 1984. pp. 236–237.
- According to "Honda City Turbo II" page in the Honda Auto Archive and Auto Katalog 1985, p 232. World Class Cars #2: Honda (p 121) lists compression as 7,4:1.
- World Cars 1985, pp. 346–348
- Setright, L. J. K. (1975). Some Unusual Engines. London: Mechanical Engineering Publications Limited.
- An Evaluation of a 350 CID Compound Vortex Controlled Combustion (CVCC) Powered Chevrolet Impala