UN R140 Supplement 6 (00 series) · UNECE Regulation No. 140 (ECE R140) — Uniform provisions concerning the approval of passenger cars with regard to Electronic Stability Control (ESC) Systems.
UN R140 — Supplement 6 to the 00 series of amendments
Supplement 5 → 6
- What changed
- If tyre saturation occurs before the calculated magnitude angle, its amplitude may be the final steering amplitude only if it is at least 6.5 A.
- Tyre saturation is considered to have occurred when all listed parameters have not increased between two successive increments of 0.5 A. These parameters are peak lateral acceleration, second peak yaw rate and lateral displacement 1.07 seconds after BOS.
- The peak values do not need to occur in the same test run.
- Why
- The amendment proposal to the Electronic Stability Control testing procedure is to take account of vehicles with low steering gear.
- Continuing to increase the steering wheel amplitude after front tyre saturation does not give more information.
- Vehicles with quick steering characteristics that might appear in the future may need too much torque for the 270 degrees sine amplitude at 0.7 Hz.
Q1What changed6 changes
Final steering amplitude at tyre saturation (para. 9.9.4.)
New text in paragraph 9.9.4. gives an option for the final steering amplitude. If tyre saturation occurs before the calculated magnitude angle, its amplitude may be the final steering amplitude only if it is at least 6.5 A.
Conditions for tyre saturation (para. 9.9.4.)
Tyre saturation is considered to have occurred when all listed parameters have reached their peak value. The parameters are peak lateral acceleration (paragraph 9.11.3.), second peak yaw rate (paragraph 9.11.8.) and lateral displacement 1.07 seconds after BOS (paragraph 9.11.9.). A parameter has reached its peak value when it has not increased between two successive increments of 0.5 A. The peak values do not need to occur in the same test run.
Q2Why it changed
- Proposed by
- Experts from the European Association of Automotive Suppliers and the International Organization of Motor Vehicle Manufacturers
- Working party
- GRVA, 17th session (September 2023)
Reasons
The amendment proposal to the Electronic Stability Control testing procedure is to take account of vehicles with low steering gear.
Source
“their latest amendment proposal (ECE/TRANS/WP.29/GRVA/2023/23) to the Electronic Stability Control testing procedure to take account for vehicles with low steering gear”
Reaching a fixed amplitude at the given 0.7 Hz sine frequency needs more torque with quick steering gear ratio systems than with slow ones. It also produces much more wheel steer.
Source
“Reaching fixed amplitude, i.e., fixed steering wheel angular speed due to given 0.7 Hz sine frequency, requires more torque with quick steering gear ratio systems than with slow steering gear ratio systems, and produces much more wheel steer.”
Above approximately 7 to 8 A, the vehicle behaviour is similar for all amplitudes, because the front tyres are saturated. Front tyre saturation occurs when there is no increase of yaw rate, lateral acceleration or deviation of the trajectory.
Sources (2)
“The vehicle behaviour (yaw rate, lateral acceleration and thus trajectory) is similar for all amplitudes above approximately 7 to 8 A (i.e., more than 7 times the steering wheel angle corresponding to 0.3 g), because front tyres are “saturated”.”
“Front tyres saturation occurs when there is no increase of yaw rate, lateral acceleration or deviation of the trajectory.”
Above front tyre saturation, more steer of the front wheels does not give more lateral force. Continuing to increase the steering wheel amplitude after front tyre saturation does not give more information.
Source
“Above front tyres saturation, more steer of the front wheels doesn’t provide more lateral force, so yaw rate and lateral acceleration don’t increase. Continuing to increase steering wheel amplitude after front tyre saturation doesn’t give more information.”
Vehicles with a significantly low steering gear ratio (quick steering characteristics) might appear in the future. These vehicles may need too much steering wheel torque to achieve the 270 degrees sine amplitude at 0.7 Hz, which conventional steering robots cannot reach. This would then jeopardize the easy approval of future beneficial steering equipment, for example steer-by-wire (SBW) systems.
Sources (2)
“There might appear in the future some vehicles which have significantly low steering gear ratio (i.e., quick steering characteristics) and may need too much steering wheel torque to achieve the 270 degrees sine amplitude at 0.7 Hz”
“not reachable by conventional steering robots), then jeopardizing the easy approval of future beneficial steering equipment e.g. steer-by-wire (SBW) systems.”
Document trail
- —Amended in sessionGRVA-16-23-Rev.1Amendments to ECE/TRANS/WP.29/GRVA/2023/9
- 2023-07RevisedECE/TRANS/WP.29/GRVA/2023/23Proposal based on ECE/TRANS/WP.29/GRVA/2023/9, as amended by GRVA-16-23/Rev.1
- —Working party adoptsECE/TRANS/WP.29/GRVA/17Session report, para. 94
- 2023-12Sent to WP.29ECE/TRANS/WP.29/2024/9Text that GRVA sent to WP.29 and AC.1
- 2024-03WP.29 adoptsECE/TRANS/WP.29/1177Adopted at the 192nd session (session report, para. 140)
- 2024-09-22In forceC.N.416.2024.TREATIES-XI.B.16.140UN depositary notification
Q3Who is affected
Vehicle manufacturer
- Do not use a tyre saturation amplitude below 6.5 A as the final steering amplitude.
- For the tyre saturation option, make sure all three parameters did not increase between two successive 0.5 A increments.
Component supplier
- No direct action for this role.
Technical service / Approval authority
- For the tyre saturation option, check that all three parameters did not increase between two successive 0.5 A increments.
- Do not require the peak values to occur in the same test run.
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ⓘ This report gives advice only. It is not legal or type-approval advice.