Honda changes the game - On Cars

Automotive Design & Production, August, 2002 by Kermit Whitfield

Although Honda has been late to the game that's garnering sales for its competitors (particularly--egad!--Toyota) in the compact SUV category, with the Pilot, it is now solidly in the field. In fact, Honda's tardy entry is so cleverly put together that it may change the game in the compact SUV segment. The Pilot's development brief was to provide a safe, quiet environment for families while offering all-weather traction on roads and medium-duty off-road capability. It also sought to remedy some of the weaknesses of traditional SUVs: terrible dynamics, limited interior space and egregiously poor fuel economy. The pursuit of these goals explains practically every engineering measure taken on the vehicle.

Rigid Body. The Pilot is based on Honda's global light truck platform that underpins both the Odyssey minivan and the Acura MDX SUV. (About 65% of the parts are common between the Pilot and the MDX.) It features a unit body construction with an underlying structure that resembles a ladder-back truck frame. It achieves high torsional rigidity by employing two longitudinal rails that run the entire length of the body and are connected by eight box-section cross-members. Structural integrity is bolstered by four steel C-rings that connect the floor, body sides and roof.

To further enhance body integrity and reduce intrusion from side impacts, the doors of the vehicle are fitted with reinforced steel stiffeners that connect the A-, B- and C-pillars at the beltline and high-strength steel (HSS) tubular beams at wheel height. Honda has applied HSS extensively in the Pilot including in the A- and B-pillars, side sills, front and rear subframes and tailgate, and reckons that its use has cut 33.8 lb. out of the vehicle. Additionally, the doors utilize laser-tailored blanks that combine heavier and lighter gauge steel for strength where needed and weight reduction.

To project an air of cut-above refinement and quality, tight body gaps are maintained throughout the vehicle. One way this is done is through the use of one-piece side panel stampings that offer better fit and finish around the doors and windows. Another is through the addition of a skirt attached to the lower edge of the headlights that allows for better control of the gap between the headlight and the body.

To deter would-be thieves (and, no doubt, to try to keep their new SUV's name off of the annual "Most Stolen Vehicles" list that always features several Hondas), the Pilot's engineers have designed in several anti-theft measures: steel guards deflect sophisticated tools like bent coat hangers from the lock rod and latch mechanism, rear lock rods are located behind the center sashes and cannot be reached from outside, and key cylinders are eliminated from all but the driver's door, and that has been strengthened with a double thickness of steel.

Isolated Chassis. Honda has sought to reduce the NVH (noise, vibration and harshness) levels often associated with SUVs mainly through the extensive use of isolation components for the chassis and powertrain. Both the front subframe that attaches to the rails that support the engine and front suspension, and rear subframe which supports the rear suspension are fully isolated from the body by four tuned rubber mounts. (From the ease of assembly point of view, this means that the entire suspension is installed with only eight bolts in one quick operation.) Likewise, the rear axle drive unit is connected to the rear subframe by rubber isolators and is equipped with a dynamic damper that mitigates propeller-shaft and drive-shaft vibration. Frank Paluch, the Pilot's chief engineer, or "large project leader" in Hondaspeak, points out that though the isolation design is largely a carry over from the MDX, the components were completely re-tuned for greater ride comfort vs. driving performance.

Modified Powertrain. When it came to the engine, the Pilot team's job was to replace some of the premium elements of the MDX's excellent 3.5-I V6 and tune the power plant for fuel economy and smoothness as opposed to off-the-line performance. The three-rocker setup for the variable valve timing system was replaced with one based on two rockers per cylinder, and the dual stage intake system was jettisoned. In its place a new intake and exhaust system was developed by Honda R&D Americas (Raymond, OH) to optimize the power characteristics of the modified engine. (Though Honda has stated in the past that it has no intention of moving fundamental engine development outside of Japan, this project clearly shows that the powertrain staff in Ohio is increasing its capabilities.) According to Paluch, "The low- and mid-range rpm are completely different than the MDX, which has a flat, broad torque curve. The Pilot's torque curve is more gradual but it peaks out in the same area." Knock sensors were also adjusted so the new SUV could avoid the premium fuel diktat of its upscale predecessor. The result: the Pilot achieves fuel economy of 17 mpg in city driving and 22 mpg on the highway, peaks out at 240 hp and runs on regular fuel.