F23A1
Contenido
• - Honda Accord LX, EX, SE y LEV 1998-2002.
• - Acura 2.3CL (América)
- Cilindrada: 2254 cm³ (2,3 L; 137,5 plg³)
- Diámetro × carrera: 86 x 97 mm (3,39 x 3,82 pulgadas)
- Culata: SOHC 16 válvulas, VTEC
- Relación de compresión: 9.3:1
- Potencia: 150 HP (112 kW) @ 5700 rpm
- Par: 205 N·m (151 lb·pie) @ 4900 rpm.
La aceleración de 0 a 100 km/h (0 a 62 mph) para este modelo de motor mejora, colocándose alrededor de 9 segundos con la eficiencia de combustible comparable a su predecesor: 10,22 L/100 km (9,8 km/L; 23,0 mpgAm) en ciudad y 7,84 L/100 km (12,8 km/L; 30,0 mpgAm) en autopista para los modelos LX y EX con transmisión automática. Las emisiones de gases orgánicos no metanos (GONM), también conocidos como hidrocarburos no quemados y producidos durante el calentamiento del motor, son considerablemente más bajos. Los motores LX y EX producen menos de 0.0075 g/km, calificándolos en California como «LEV» (Low-Emission Vehicles, ‘vehículos de baja emisión’). En California, el Accord EX automático producía menos de 0.003 g/km de GONM, calificándolo como el primer vehículo con motor de gasolina en obtener el sello «ULEV» (Ultra-Low Emission Vehicle, ‘vehículo de emisión ultra-baja’).
Las paredes del bloque se extienden por debajo de la línea central del cigüeñal, lo que ayuda a ser más rígido el extremo inferior. Se utilizó análisis por computadora FEM (Finite Element Method, ‘método de elementos finitos’) para llegar a espesores óptimos para las costillas de bloque y las paredes con el fin de minimizar la vibración del motor. El FEM también se utilizó para el diseño de este refuerzo de manera que no solamente sería para aumentar la rigidez, sino también ayudar a minimizar las vibraciones del motor.
Butt
Designed with four valves per cylinder (16 in total) and with a SOHC camshaft and domed combustion chambers. The individual valves are smaller and lighter than previous engines with four valves per cylinder, which allow the engine to rev to higher revs, helping to increase its power range. The valves are actuated by rocker arms and a belt-driven hollow camshaft. The single overhead camshaft design requires less space under the hood than the conventional dual overhead camshafts typically used with 16 valves and 4 cylinders. The adoption of a sophisticated knock control system optimizes ignition timing and enables a higher compression ratio from 8.8:1 to 9.3:1. The use of regular unleaded fuel is specified.
Revised Admission System
The intake system was simplified in such a way as to reduce induction resistance and noise. A larger airbox designed to dampen resonant intake tract noise replaces the previous Accord's smaller single-chamber one. The new box is 10.7 liters (2.8 galAm) in capacity, compared to 8.2 liters (2.2 galAm) for the smaller unit. The larger box also eliminates the need for a second resonator to reduce noise, adding more power and fewer emissions. The individual cast aluminum ducts have received a dimensional revision to better take advantage of the different airflow characteristics of the 2.3 liter (0.6 galAm) engine. A larger plenum reduces induction noise and the incorporation of exhaust gas recirculation (EGR), eliminates the need for a separate fitting and port on each intake runner.
Low Speed Operation
During low rpm operation, only one intake valve per cylinder opens, allowing air and fuel to enter the combustion chamber. The other intake valve has only a slight amount of lift and its timing is stepped. As a result, the fuel-air charge drawn through the open intake valve is subjected to a swirl effect. The swirl creates a stratified charge with a rich mixture near the spark plug and a progressively richer air mixture. This stratified charging, combined with better EGR control, results in lower emissions, especially during the critical warm-up period, and improves fuel consumption. Low friction rocker arm roller bearings are used to help reduce friction and improve engine efficiency.
Emissions
The EX and LX models were qualified as “LEV” (Low-Emission Vehicles, ‘low emission vehicles’) in California. Automatic transmission EX models were qualified as “ULEV” (Ultra-Low Emission Vehicles, ‘ultra-low emission vehicles’) in California. The improvements of these engines to achieve these ranges are based on various systems such as a stratospheric VTEC charge and electronically controlled gas recirculation (EGR). The ULEV engines use a 32-bit ECU with individual airflow control per cylinder, lean air-fuel ratio during fast idle, high-efficiency catalyst, and a low thermal mass exhaust system.
Transmission
Automatic transmissions provide direct control over the driver as it is controlled by PCM (Powertrain Control Module) for smoother and faster shifting. It has a cruise control also controlled by the PCM and an ECU on the transmission. It was possible to reduce shifting noise compared to the predecessor transmission. Regarding the manual transmission, the inner diameter was reduced to achieve a smoother shift, with the same level of resistance and durability.