The shift recommendation shall be provided by means of a distinct visual indication, for example a clear indication to shift up or up/down or a symbol that identifies the gear into which the driver should shift. The visible indication may be complemented by other indications, including audible ones, provided that these do not compromise safety.

The GSI must not interfere with or mask the identification of any tell-tale, control or indicator, which is mandated or supports the safe operation of the vehicle. Notwithstanding point 1.3, the signal shall be designed so that it does not distract the driver’s attention and to avoid interfering with proper and safe vehicle operation.

The GSI shall be located in compliance with paragraph 5.1.2 of UNECE Regulation No 121. It shall be designed such that it can not be confused with any other tell-tale, control or indicator the vehicle is equipped with.

An information display device may be used to display GSI indications provided that they are sufficiently different from other indications so as to be clearly visible and identifiable by the driver.

Temporarily, the GSI indication may be automatically overridden or deactivated in exceptional situations. Such circumstances are those that may compromise the safe operation or integrity of the vehicle, including activation of traction or stability control systems, temporary displays from driver assistance systems or events relating to vehicle malfunctioning. The GSI shall resume normal operation after the exceptional situations ceased to exist, and within a delay of 10 seconds or longer, if justified by specific technical or behavioural reasons.

The GSI shall suggest changing the gear when the fuel consumption with the suggested gear is estimated to be lower than the current one giving consideration to the requirements laid down in points 2.2 and 2.3.

The GSI shall be designed to encourage an optimised fuel efficient driving style under reasonably foreseeable driving conditions. Its main purpose is to minimise the fuel consumption of the vehicle when the driver follows its indications. However, regulated tailpipe emissions shall not be disproportionately increased with respect to the initial state when following the indication of the GSI. In addition, following the GSI strategy should not have any negative effect on the timely functioning of pollution control devices, such as catalysts, after a cold start. For this purpose vehicle manufacturers should provide technical documentation to the type-approval authority, which describes the impact of the GSI strategy on the vehicle’s regulated tailpipe emissions, under at least steady vehicle speed.

Following the indication of the GSI must not compromise the safe operation of the vehicle, e.g. to prevent stalling of the engine, insufficient engine braking or insufficient engine torque in the case of high power demand.

The manufacturer shall provide an explanation of the purpose, use and functions of the GSI in a ‘GSI section’ of the user manual accompanying the vehicle.

This test is to be performed on a warmed up vehicle on a chassis dynamometer according to the speed profile described in Appendix 1 to this Annex. The advice of the GSI is followed for shifting up gears and the vehicle speeds, for which the GSI recommends shifting, are recorded. The test is repeated 3 times.

Vⁿ_GSI shall denote the average speed at which the GSI recommends shifting up from gear n (n = 1, 2, …, #g) into gear n + 1, determined from the 3 tests, where #g shall denote the vehicle’s number of forward gears. For this purpose only GSI shift instructions in the phase before the maximum speed is reached are taken into account and any GSI instruction during the deceleration is ignored.

For the purposes of the following calculations V⁰_GSI is set to 0 km/h and V^#g_GSI is set to 140 km/h or the maximum vehicle speed, whichever is smaller. Where the vehicle cannot attain 140 km/h, the vehicle shall be driven at its maximum speed until it rejoins the speed profile in Figure I.1.

Alternatively, the recommended GSI shift speeds may be analytically determined by the manufacturer based on the GSI algorithm contained in the extended documentation package provided according to point 3.1.

Vⁿ_std shall denote the speed at which a typical driver is assumed to shift up from gear n into gear n + 1 without GSI recommendation. Based on the gear shift points defined in the type 1 emission test4 the following standard gear shift speeds are defined:

V⁰_std

0 km/h;

V¹_std

15 km/h;

V²_std

35 km/h;

V³_std

50 km/h;

V⁴_std

70 km/h;

V⁵_std

90 km/h;

V⁶_std

110 km/h;

V⁷_std

130 km/h;

V⁸_std

V^#g_GSI;

Vⁿ_min shall denote the minimum vehicle speed the vehicle can be driven in the gear n without stalling of the engine and Vⁿ_max the maximum vehicle speed the vehicle can be driven in the gear n without creating damage to the engine.

If Vⁿ_std derived from this list is smaller than V^{n + 1}_min, then Vⁿ_std is set to be V^{n + 1}_min. If Vⁿ_std derived from this list is greater than Vⁿ_max, then Vⁿ_std is set to be Vⁿ_max (n = 1, 2, …, #g – 1).

If V^#g_std determined by this procedure is smaller than V^#g_GSI, it shall be set to V^#g_GSI.

The manufacturer shall supply the type-approval authority with the functional dependence of the vehicle’s fuel consumption on the steady vehicle speed when driving with gear n according to the following rules.

FCⁿ_i shall denote the fuel consumption in terms of kg/h (kilograms per hour) when the vehicle is driven with the constant vehicle speed v_i = i × 5 km/h – 2,5 km/h (where i is a positive integer number) in the gear n. These data shall be provided by the manufacturer for each gear n (n = 1, 2, …, #g) and vⁿ_min ≤ v_i ≤ vⁿ_max. These fuel consumption values shall be determined under identical ambient conditions corresponding to a realistic driving situation that may be defined by the vehicle manufacturer, either by a physical test or by an appropriate calculation model agreed between the approval authority and the manufacturer.

The following distribution should be used for the probability P_i that the vehicle drives with a speed v, where v_i – 2,5 km/h < v ≤ v_i + 2,5 km/h (i = 1, …, 28):

Where the maximum speed of the vehicle corresponds to step i and i < 28, the values of P_{i + 1} to P₂₈ shall be added to P_i.

FC_GSI shall denote the fuel consumption of the vehicle when the driver follows the advice of the GSI:

FC^GSI_i = FCⁿ_i, where V^{n – 1}_GSI ≤ v_i < Vⁿ_GSI (for n = 1, …, #g) and FC^GSI_i = 0 if v_i ≥ V^#g_GSI

FCGSI = Σ28i=1Pi × FCGSIi/100

FC_std shall denote the fuel consumption of the vehicle when standard gear shift points are used:

FC^std_i = FCⁿ_i, where V^{n – 1}_std ≤ v_i < Vⁿ_std (for n = 1, …, #g) and FC^std_i = 0 if v_i ≥ V^#g_GSI

FCstd = Σ28i=1Pi × FCstdi/100

The relative saving of fuel consumption by following the advice of the GSI of the model is calculated as:

FC_{rel. Save} = (1 – FC_GSI/FC_std) × 100 %

The following information shall be recorded:

• the values of Vⁿ_GSI as determined according to point 4.1,

• the values FCⁿ_i of the fuel consumption speed curve as communicated by the manufacturer according to point 4.3,

• the values FC_GSI, FC_std and FC_{rel. Save} as calculated according to point 4.5.