Daimler rolls out fourth-gen tech across smart range
Daimler’s smart has applied its fourth generation of electric drive tech across the range including the fortwo coupé and fortwo cabrio models, and for the first time, its four-seater forfour model as well. Smart will be the only car manufacturer worldwide to offer its full model range with both combustion engines and pure battery-electric drive options. The range is expected to come to market in early 2017.

A 60 kW (81 hp) electric motor at the rear of the smart electric drive transmits its power via a constant ratio to the wheels. Torque of 160 Nm (118 lb-ft) is immediately available from a standstill. The electric drive has a range of approximately 160 km (99 miles) in accordance with the New European Driving Cycle, making it suited for urban use. The maximum speed is electronically limited to 130 km/h (81 mph) to maximize the range. Electric energy consumption on the NEDC is 13.1 – 12.9 kWh/100 km.

Daimler’s smart has introduced the fourth generation of its electric drive technology, applied not only not only in the smart fortwo coupé and smart fortwo cabrio, but for the first time also in the four-seater smart forfour. smart will be the only car manufacturer worldwide to offer its full model range with both combustion engines and pure battery-electric drive options. Market launch will start in early 2017. In Germany prices for the smart fortwo electric drive will start at €21,940 (recommended retail price including 19% VAT).

The electric motor is a separately excited three-phase synchronous motor. With this construction there is an excitation winding on the rotor that is magnetized when current flows. The flow of energy from the high-voltage battery to the electric motor is controlled by the power electronics that are compactly interlocked with the drive unit. The drive is produced in Renault’s plant in Cléon, Northern France. (Earlier post.)

The smart electric drive has an energy-efficient air conditioning system. An electric heater booster (high-voltage PTC; Positive Temperature Coefficient) heats the interior while an electrically powered AC compressor cools it.

The smart is equipped with a lithium-ion battery from the Daimler subsidiary Deutsche ACCUMOTIVE. The company based in Kamenz, Saxony, has been building the electric heart of the smart electric drive since 2012 (see the corresponding section for details).

The battery has capacity of 17.6 kWh and is housed in the vehicle underbody between the two axles in a safe position that is favorable for the vehicle's centre of gravity. The battery consists of 96 flat cells and the cell chemistry has been improved compared with the predecessor battery.

To strengthen customers’ trust in the drive technology, smart is guaranteeing that the maximum energy content of the pack is not less than the specified battery capacity over eight years and/or to a mileage of 100,000 kilometers (62,137 miles).

Daimler is currently investing €500 million in the construction of a second battery factory in Germany and is therefore greatly expanding the production capacities for lithium-ion batteries from Deutsche ACCUMOTIVE.

From the autumn of 2017 a particularly powerful 22 kW fast charger will be available as an option in Europe. This enables the smart electric drive to be charged much more quickly—in less than 45 minutes if local conditions allow three-phase charging.

ECO mode. As well as the basic drive program, the smart electric drive driver can select the ECO mode. This is designed for a particularly efficient driving style. In addition, the maximum speed is limited, the accelerator pedal curve adjusted and the maximum recuperation level is pre-selected. Furthermore, the air conditioning control adjusts the outlet air temperature from the air vents to reduce the energy consumption.

The driver can deactivate the ECO program with the kickdown function if necessary, for example for an overtaking manoeuvre. Pushing the accelerator pedal right down activates a temporary boost. This enables maximum acceleration with defined maximum battery power if the current charge level and the temperature of the battery allow this function.

The level of energy recuperation in overrun mode or when braking depends on the battery condition (charge level and temperature). In Western Europe, the smart electric drive models have anticipatory radar-based recuperation that is active in the basic drive program. The traffic situation is monitored with a radar sensor and a recuperation level that suits the current situation is selected. The electronically controlled recuperation takes place in five levels as soon as the driver takes their foot off the accelerator pedal (overrun mode). If the road is clear coasting is activated.

In the ECO drive program the highest recuperation level is automatically set.

To save energy and further extend the range, the smart electric drive also features pre-entry climate control.

smart control app. With the “smart control"’ app (available in Western Europe) electric drive information can be called up via smartphone, tablet or PC and functions such as pre-entry climate control or intelligent charging can be conveniently controlled remotely. The new model has more operating options than the predecessor. For example, two programmable departure times mean that intelligent charging and pre-entry climate control do not always need to be reset for frequent journeys.

The “smart control” app enables simple operation of lots of functions of the smart electric drive. smart drivers can see the current battery state of charge and the range before they set off or activate the pre-entry climate control of the interior while the car is charging. The most important functions at a glance:

Vehicle information: battery charge level, range, average fuel consumption, mileage, eco score, next service, tire pressure.

The vehicle functions departure time and pre-entry climate control: compared with the previous series two programmable departure times mean that these functions do not always need to be reset for frequent journeys, for example the daily commute. The programmed departure time can be used both for intelligent charging (see below for details) and for the pre-entry climate control. If the departure time is set the previous evening, the vehicle has a perfect interior temperature the next morning. If the customer wants to spontaneously set the temperature before a trip for a vehicle that is not connected to a charging station this can also be done via the "smart control" app as long as the battery charge level is at least 30%.

Charging properties: during the charging process the charge level, remaining charging time, charging capacity, range, the current state of charge (SOC) and the charging profile (expected state of charge depending on the time) can be called up. In addition, the smart electric drive enables convenient charging with automatic authentication and cashless payment in accordance with the ISO-defined Plug & Charge profile. When a contract has been concluded with an energy provider the contract certificate needed can be transferred to the vehicle via a charging station. The "smart control" app assists the customer with the contract conclusion by displaying the Plug & Charge ID. The current contract status in the vehicle is always shown on the "smart control" app. Furthermore, "intelligent charging" can be activated for a charging process. With the help of information from the infrastructure or – if this is not available – a tariff table specified by the driver on the "smart control" app cost-optimized charging of the vehicle is possible. The tariff table can also be used to select solar power from the customer's own photovoltaic system as the preferred charging option, for example.

Equipment and features. The smart electric drive models surpass the standard equipment of their siblings with conventional drive as they additionally have a dashboard instrument with power meter and battery status display (standard) or the winter package with heated steering wheel for maximum climate comfort (optionally available). The electric drive design package (optionally available) gives the vehicle an expressive look with tridion safety cell and door mirror caps painted in exclusive electric green.

The electric drive versions come with extensive safety and comfort equipment. The standard equipment includes power steering, LED daytime driving lights, central locking with radio remote control, visual locking-verification signal and immobiliser, cruise control with limiter (variable speed limitation), exterior temperature indicator with frost warning (not in USA/Canada), instrument cluster with monochrome LCD display and trip computer, and electric windows. The Cool & Audio package with smart Audio-System with AUX/USB Bluetooth interface and automatic climate control is also on board as a standard feature.

In addition the smart electric drive models have several special features such as the dashboard instrument with power meter and state of charge, located next to the A-pillar trim on the dashboard.

The electric power recuperated is displayed on the left side of the power meter and the electric power currently called up is shown on the right side. LEDs between the segments show the available power and power that can be called up. The battery charge status is displayed in the lower part of the dashboard instrument.

The standard equipment also includes an instrument cluster with a monochrome display in LCD technology where the functions charge level and total eco score that are specific to the electric drive can be shown.

A color 8.9 cm display in TFT technology (Thin-Film Transistor) with a trip computer is available as special equipment. These are the additional functions:

Display of radar-based recuperation combined with the ECO button (in Western Europe only)

Extended display of the charging rate

Display of the battery charge level with animated battery icon

Detailed specific eco score for the electric vehicle

Histogram including recuperated energy

Energy flow display including auxiliary consumers with digital values

Setting and display of pre-entry climate control and smart charging in conjunction with entering a departure time

Electric drive customers who opt for the smart Media-System with a 7-inch color display and touchscreen operation can also look forward to several additional functions: