1988 Acura Legend Engine
Advanced design, first pioneered in Honda's Formula 1 engine program, was employed in the development of the Legend's lightweight aluminum alloy 2.7-liter 24-valve, SOHC fuel-injected V-6 engine. It utilizes a 90 degree cylinder bank design and innovative single-overhead camshaft, making the engine extremely compact -- which allows in part for the Legend's low, aerodynamic hoodline.
Among the numerous advanced engine systems are a pent-roof combustion chamber, which permits a symmetrical four-valve layout and central spark plug location, equal length crossflow exhaust and intake ports, variable intake control manifold and programmed fuel injection.
The Variable Intake Control System combines mechanical precision with electronic control. At low engine speeds, air passes through long (630mm) but relatively narrow (in cross section) rectangular ports. Their shape and dimensions create high intake air velocity and inertia, which increases volumetric efficiency and produces more torque for improved acceleration.
As engine speed increases, the engine's Electronic Control Unit (ECU) directs a solenoid actuator which opens six individual butterfly valves that allow air into short (420mm), oval, funnel-shaped ports - passing a greater volume of air into the combustion chambers. The transition from one set of ports to the other assures smooth power delivery throughout the full rpm range. Low to mid-range engine response is improved without sacrificing high end power. Torque is rated at 162 lbs-ft at 4500 rpm.
A sophisticated computer-controlled sequential fuel injection system helps develop the maximum engine power rating of 161 horsepower at 5900 rpm. An eight-bit microcomputer analyzes information from seven sensors (which monitor throttle angle, crankshaft angle, coolant temperature, manifold air pressure, atmospheric pressure and exhaust gas oxygen content) and uses the input to maintain the proportion of fuel and air within the ideal range. The ignition system is fully electronic.