Genchi-Genbutsu and creating the Toyota 4Runner - On Cars

Automotive Design & Production, Oct, 2002 by Gary S. Vasilash

There is also a V8. This is a 4.7-liter 32-valve, dual overhead cam unit that provides 235 hp 4,800 rpm and 320 lb.-ft. of torque @ 3,400 rpm. It is quite similar to the engines used in the Sequoia, Land Cruiser and Tundra. Although it has aluminum heads, it has an iron block.

Both engines have the ETCS-i system--that's a linkless electronic throttle control system with intelligence. Which is a throttle-by-wire system: there's no cable between the pedal and throttle. This is a third generation system, one that has had several installations in Lexus cars, as well as in the Toyota Avalon and MR-2. Not only does this cut down on NVH through the dash panel (more about dash panel NVH momentarily), but it also helps assure better performance and fuel economy by figuring out what the real intent is of that foot on the pedal.

There are two transmissions available for the 4Runner, a four-speed automatic for the V6 models and Toyota's first fivespeed automatic transmission in a truck for the V8. There are new transfer cases for each type of engine, both of which are said to be the world's first application of a Torsen limited-slip center differential in a mid-size SUV.

Up or Down

One of the fundamentals of electronics, like ABS systems, is that processors are typically more responsive than people. Four-channel ABS is standard on all 4Runner models (something that is becoming atypical in the market.

Presumably, in the SUV market there are those who aren't ordinarily off-roaders but who, because they can, decide that they need to take their vehicles off the pavement. For those who are not familiar with hill climbing, one problem can be that as one's foot is lifted from the brake to start climbing the grade, there is a tendency for the vehicle to slip back or sideways, both of which can be troublesome. There is a standard Hill-start Assist Control (HAC), which controls the brakes so as to prevent the vehicle from rolling backwards for approximately five seconds. But then there is the matter of going down. So there is the DAC--Downhill Assist Control, which is standard on all 4WD models. In this case, one selects the feature on the console, puts the transfer case in L4, and takes all feet off of all pedals (which takes more than a small amount of faith, particularly on steep grades): just as in the case of a cruise control, once a pedal is depressed, the system kicks out. The system controls both the brakes and the throttle and maintains a speed of about 2 to 4mph. (Speaking of speed: the 4Runner is said to be the world's first use of active, or solid-state, wheel speed sensors; these sensors are capable of sensing both speed and direction of rotation: they make use of magnetic resistance elastography, which fundamentally means that there are bi-pole magnets in each wheel bearing that are read by two Hall-effect sensors so that there is extreme accuracy in measurement.) The noise mentioned in the previous section comes from the ABS braking system, as the valves are opening and closing in a controlled frenzy. This system, incidentally, is like that in the BMW X5 and the Range Rover, both of which are somewhat more dear in price than the 4Runner.