Interpretation ID: nht91-3.36

DATE: May 1, 1991

FROM: Cliff Chuang -- Chief Design Engineering, Prospects Corporation

TO: Legal Counsel -- NHTSA

TITLE: Re Require Confirmation For The Interpretation Of New FMVSS Standard number 118

ATTACHMT: Attached to letter dated 7-1-91 from Paul Jackson Rice to Cliff Chuang (A38; Std. 118)

TEXT:

We have received the new FMVSS #118 published on April 16, 1991. Our company is currently developing advanced power window and power sunroof control systems for the automotive industry. Several of our interpretations to the new standard #118 need to be confirmed in writing by your office.

First, the new FMVSS #118 section S5 (a) says: "Notwithstanding S4, power window, partition or roof panel systems which, while closing, reverse direction when they meet a resistive force of 22 pounds or more from a solid cylinder of 4 to 200 mm in diameter and open to at least 200 mm, may close: ... "

Our interpretation of "22 pounds or more" is that 22 pounds is set as the MINIMUM level of the resistive force for the control system to reverse the window moving direction from closing to opening. Most motors that are currently used in the vehicle power window systems have a maximum force of around 65 pounds. Assume the motor has to give X pounds of force to move the window upward in a normal closing, if an obstruction occurs, naturally the motor will provide more force in order to continue to move the window upward. The force level can change very rapidly when the obstruction occurs. When the total force reaches the minimum level of (X + 22) pounds, or exceeds the minimum level and reaches anywhere between (X + 22) pounds and the maximum force (i.e., 65 pounds), if the control system has the capability to immediately reverse the window moving direction from closing to opening to at least 200 mm, then this control system complies with FMVSS #118 S5.

Second, the new FMVSS #118 section S5 (b) says: "The 4 to '200 mm dimension cited in S5 (a) is measured from the window or panel's leading edge to the daylight opening."

Our interpretation is that this 4 mm daylight opening can-be seen from inside the passenger compartment. We attached diagram Fig.-l (for window), Fig.-2 and Fig.-3 (for sunroof) to explain our understanding.

Please examine our interpretations and confirm them in writing as soon as possible. Your confirmation will have significant impact on our system development. I am looking forward to hearing from you soon.

Fig.-1 -- Window Diagram (graphics omitted) Fig.-2 -- Sunroof Diagram (graphics omitted)

Fig.-3 -- Sunroof Diagram (graphics omitted)