| Honda F engine | |
| Manufacturer: | Honda |
| Configuration: | Naturally aspirated Inline-4 |
| Valvetrain: | SOHC, DOHC 4 valves x cyl. with VTEC (on some versions) |
| Block: | Cast iron, Aluminum |
| Head: | Aluminum/magnesium |
| Fueltype: | Gasoline |
| Coolingsystem: | Water-cooled |
| Redline: | 9,200 |
| Compression: | 8.8:1-11.7:1 |
| Displacement: | NaNcc |
| Power: | NaN0NaN0 |
| Torque: | NaN0NaN0 |
The Honda F-Series engine was considered Honda's "big block" SOHC inline four, though lower production DOHC versions of the F-series were built. It features a solid iron or aluminum open deck cast iron sleeved block and aluminum/magnesium cylinder head.
This engine was also used in the Rover 618i, assembled in Swindon at the Honda facility.
This engine was used for the Honda Accord European (CG8,CH6) from 1998 to 2002 VTEC S. Japan use variant (F18B) in (CD3,CF3) 1.8 VTS/VTE, from 1993 to 2002
The F18B2 won the 1.8L category of the International Engine of the Year competition for 2000.
This engine series was used in the Accord, Ascot Innova and Prelude in Japan and Europe. The DOHC F20A was also derived from this engine (see below).
This engine also spawned many variants, according to market, but the specs remain largely similar.
The F20A3 is used in the early carbureted CB3.The F20A5 is used in the CB3 and CB4 Chassis.
Used in the Honda Accord Coupe (CD9) (1994-1997) and the Honda Accord Aerodeck (CE2) (Wagon) (1994-1997)Produced for the Netherlands, Belgium, France, Germany, Switzerland and Luxembourg
All the models that came with the F20B3 had a 5 speed manual gearbox.
This engine series is similar to the F20A above, used in the Honda Accord CC7 (1993-1996) and CE8 (1996-1998) in Europe. Also the Rover 620i (1993-1999)
This engine is the low compression brother of F20Z1. This engine was used in the same models as the F20Z1.
This engine series was used in the Honda Accord and Honda Prelude S. Aside from differences in tuning, these engines are substantially similar.
This engine was used in the 1994-1997 Honda Accord EX (1993 in JDM Accord models 2.2VTE, VTL & VTS) and the 1997 Acura CL. It was the first F-series engine to feature VTEC.
This engine was used in the European Accord known as the Honda Aerodeck.
The F22B2, F22B3, F22B6 and F22B8 are similar, though their exhaust headers vary between each.
This engine was used in the 1998-2002 Honda Accord LX, EX, and SE, LEV models, and in the Acura 2.3CL in North America.
Acceleration 0-60mph for the 4-cylinder models is improved (around the mid-9-second mark), with comparable fuel efficiency to its predecessor: 23mpgus/city and 30mpgus/hwy for LX and EX models with automatic transmissions. Emissions of Non-Methane Organic Gases (NMOG), also known as unburned hydrocarbons, produced during engine warm-up are considerably lower. The LX and EX engines produce less than 0.075 grams per mile, qualifying them for California LEV (Low-Emission Vehicle) status. In California, the Accord EX with the available automatic transmission will produce less than 0.03 grams per mile of NMOG, qualifying it as the first gasoline-powered vehicle to reach ULEV (Ultra-Low Emission Vehicle) status. The five-main bearing block is high-pressure die-cast from aluminum alloy. The walls of the block extend below the centerline of the crankshaft, which helps stiffen the bottom end. FEM (Finite Element Method) computer analysis was used to arrive at optimum thicknesses for the block ribs and walls in order to minimize engine vibration. Additional bottom-end rigidity comes from a larger, stronger bearing-cap beam that ties directly into the cylinder-block skirt. An aluminum-alloy stiffener has been added between the transmission case and the block, just behind the bearing carrier. The stiffener serves to tie the block and transmission together into a single, reinforced unit. FEM was also used to design this stiffener so that it would not only stiffen the area, but also help minimize high-frequency engine vibration. Finite-element analysis of the Accord's piston design by Honda engineers yielded a new ultra-short, lightweight skirt design, which is very rigid and resistant to vibration and piston slap. Like the V-6 engine the pistons are gravity-cast aluminum alloy and utilize full-floating wrist pins in order to minimize noise. The engine's drop-forged single-plane steel crankshaft and connecting rods have been designed to be stronger and operate with less friction, much like the V-6 components. The I-section, drop-forged steel connecting rods have a completely new design and are considerably lighter than their predecessors (475 g vs. 578 g), which helps to minimize vibration. Big end-bearing journal diameter has been reduced from 48mm45mm. Rod thickness is down from 24mm20mm and the bolt size is smaller. Like the V-6 rod bolts, those of the 4-cylinder engine are torqued to the plastic region of the bolt material in order to ensure a solid union between the bearing cap and the connecting rod. The engine block incorporates the Honda-designed second-order balance system that cancels the inertial forces common to large-displacement 4-cylinder engines. The system consists of a balance shaft on either side of and parallel to the crank-shaft, 812NaN2 above its centerline. Driven by a toothed belt, these balance shafts rotate in same directions at twice engine speed. Eccentric weights built into the shafts generate inertial forces that counteract the second-order forces created by the motion of the pistons and connecting rods. This Honda system minimizes vibration in the entire rpm range.
Cylinder Head
The 16-valve, single-overhead-camshaft cylinder head features four valves per cylinder and pentroof combustion chambers. Individual valves are smaller and lighter in 4-valve heads, which allows the engine to be revolved to a higher rpm, helping to extend the engine's power range. Valve actuation is via rocker arms and a hollow, belt-driven single overhead camshaft. The single-over-head-camshaft design requires less under-hood space than the more conventional dual overhead camshafts normally used with 16-valve, 4-cylinder engines. The adoption of a sophisticated knock control system optimizes ignition timing and allows for a higher compression ratio (9.3:1 from 8.8:1). Unleaded regular fuel is specified.
Revised Intake System
The intake system was simplified in shape to reduce induction resistance and noise. A larger twin-chambered air box designed to dampen resonant intake tract noise replaces the previous Accord's smaller, single-chamber damper. The new box is 10.7 liters in capacity, compared to the older unit's 8.2 liters. The larger box also eliminates the need for a second resonant-frequency damper and an additional side branch. The 2.3-liter Accord 4-cylinder engine intake manifold has been redesigned to add more power and lower emissions. The individual cast-aluminum runners have revised dimensions to better take advantage of the different air-flow characteristics of the 2.3-liter engine. A larger plenum chamber reduces induction noise and the incorporation of exhaust gas recirculation (EGR) ports into the plenum, upstream of the throttle plates, eliminates the need for a separate fitting and port in each intake runner.
Low vs. High Speed Operation
During low-rpm operation, only one intake valve (primary) opens, allowing air and fuel into the combustion chamber. The other intake valve (secondary) has only a slight amount of lift and its timing is staggered. As a result, the air-fuel charge drawn through the open intake valve undergoes a swirl effect. The swirl creates a stratified charge with a rich mixture near the spark plug for good light-off, and a progressively leaner mixture toward its periphery. This stratified charge, combined with improved EGR control, results in lower emissions especially during the critical warm-up period, and better fuel economy. Low-friction, roller-bearing rocker arms are used to help reduce friction and improve engine efficiency, except the secondary intake valve rocker arm does not have a roller-bearing. At high speed, as calculated by the ECU based on several inputs, a VTEC oil control valve is energized and oil pressure is routed to the small piston train in each 3 arm set of intake rocker arms. The pistons shift slightly which locks all three rocker arms together. Both intake valves then move together on the center rocker arm cam profile which changes intake valve timing and dwell and increases airflow into each cylinder. Springs in the piston train return the pistons back to their low rpm positions when the oil pressure is removed. Each center rocker arm is held against its cam lobe by an anti-free motion spring during low speed operation.
Emissions
NVH
Transmission
| Low Speed Operation | Low Speed Operation | High Speed Operation | All Conditions | ||
|---|---|---|---|---|---|
| Primary Intake Valve | Secondary Intake Valve | Both Intake Valve | Exhaust Valve | ||
| Valve Opens | 24° ATDC | 26° ATDC | 0° TDC | 30° BBDC | |
| Valve Closes | 23° ABDC | 76° BBDC | 36° ABDC | 15° BTDC | |
| Lift | 7mm | 1.8mm | 10mm | 9mm |
This engine was used in the 1998-2002 Honda Accord ULEV models. It is substantially similar to the F23A1, but features ULEV certification with a slight reduction of power: 1480NaN0 with a maximum torque of 2040NaN0. This engine has a different exhaust manifold, a more restrictive intake manifold, and a 32-bit ECU that uses an AFR (Air Fuel Ratio) oxygen sensor when compared to the F23A1.
This engine was used in the 1998-2002 Honda Accord DX, the 1998-2002 Honda Accord LXi in New Zealand and the 2002 Honda Accord LX VP (value package) in North America.
This engine was substantially similar to the F23A1. It was used in the 1998 Honda Odyssey, the 1998-1999 Isuzu Oasis, and EUDM Honda Shuttle.
Bore NaNmm. Compression ratio: 9.3:1
This engine was used in the Honda Accord sixth (CL3 - Europe) (2001-2003).
Bore NaNmm. Compression ratio: 9.3:1
This engine was used in the 1990–1993 CB3 and CB4 Honda Accord 2.0Si, Honda Prelude Si - SR JDM-EDM and Honda Ascot Innova.
This engine series was used in the 1997-2001 CF4, CF5, CF9, CL3 Honda Accord and Honda Torneo from Japan. It uses a DOHC VTEC cylinder head similar to the H22A found in the Prelude but was designed to comply with many countries' sub-2.0 liter tax. The automatic transmission versions received the lower hp version 1800NaN0, as it was tuned for more mid-range torque than its manual transmission counterpart. The F20B manual version also utilized bigger cams, intake and throttle body from the H22 type S.
See main article: Honda F20C engine. This engine was a radical departure from previous F engines, and only shared basic dimensions such as bore spacing. It was designed specifically for the Honda S2000 and shares some engineering with the Honda K engine. A long-stroke F22C1 variant was also produced.
This engine was a reworked version of the F20C with a new rod/stroke ratio and more displacement thanks to a longer stroke. Consequently, the redline was dropped to 8,000rpm. The camshafts were revised along with valve springs and retainers. The compression ratio also fell. All these changes resulted in improved low-end torque output but also raised the peak torque by 6%. Power output stayed the same.
This engine was used in the mk4 1992–1996 Honda Prelude Si in Japan. It is similar to the H23A.The mk5 1997 Honda Prelude also used this engine in first years of manufacture sold as Si only in Japan.