Volvo XC90 Excellence T8 Hybrid: Technical highlights

The Volvo XC90 T8 Hybrid is now on sale in India, and the feature-laden SUV has quite an interesting list of technological innovations that makes this Volvo stand out.

The XC90 is based on Volvo's Scaleable Product Architecture (SPA) platform. Volvo says that SPA was designed to accommodate hybrid technology right from the beginning and that made it easier to incorporate the hybrid system.

Internal combustion engine

The 2.0-litre, 4-cylinder petrol engine is both turbocharged as well as supercharged. While a turbocharger works on exhaust gas pressure, a supercharger is, essentially, an air-compressor that increases the density of air supplied to an engine. Thus there's more oxygen supplied to the engine at each intake cycle. The fruit of turbocharging and supercharging is evident in the engines power figure.

It produces 320PS which is quite a lot when you consider the small engine size. It is mated to an 8-speed Aisin gearbox. More gears means better drive ability and improved fuel economy.

The hybrid system

In the T8 Hybrid, Volvo has placed the Lithium-ion battery where you'd usually find the drive shaft. The electric motor is placed over the rear axle. The whole system thus lies in between the front and rear axles.

This enabled Volvo to continue to offer the same cabin space as a regular XC90. The central tunnel-mounted battery also gives the SUV a lower centre of gravity that enables easier handling.

The electric motor develops 60KW or 83PS and 240Nm.

Driving modes

Volvo has developed clever driving modes to make the most of this hybrid system. There are six modes, including Pure, Hybrid, Power and AWD.

In Pure mode, the XC90 uses the electric motor only. On a full charge, the XC90 can cover 42km. This is especially useful in a city drive cycle. The T8 Hybrid also features brake energy recuperation. Using brake by wire technology, the energy is generated during braking and used to charge the battery or store it for later use.

In the hybrid mode, the XC90 uses the petrol and electric motor. The engine powers the front axle while the real axles are powered by the electric motor. The AWD mode is switchable which helps in energy conservation.

The Power mode is designed to offer maximum performance by using the combined 400PS output of the engine and electric motor.

The electric motor provides instant torque that aids acceleration as the petrol engine builds speed.

The crankshaft-mounted starter generator CSIG is a powerful 34KW motor located between the engine and gearbox. It performs three functions.

First, it allows seamless transition from pure electric to combustion engine drive. Secondly, it acts as a powerful generator, and lastly, it acts as an electric engine booster. It works with the turbocharger and super charger to deliver 150Nm of torque when needed.

The battery cooling system is incredible. The unique cooling system is composed of two extra circuits. The first cools the CISG and the large electric motor on the rear axle, while the second cools the battery in one of two ways – passively (via the radiator) or actively (through integration with the car's climate system).

Radar-based safety systems

In the Volvo XC90 T8 Hybrid, there are also a host of radar-based safety features. Note that the radar systems are located all around the car - a 360-degree radar system. The system also relies on inputs from cameras.

1. Adaptive cruise control: The radar keeps track of the distance to the vehicle ahead when cruising at the predetermined speed. When the vehicle ahead slows down (say for a curve or speed hump), the system slows down the XC90 to a pace that maintains a safe gap to the vehicle ahead. As the vehicle ahead of XC90 accelerates, this system gradually increases the speed to the limit that's specified.

2. Lane departure warning: The radar system helps the driver stick to the lane and sends out a beep if the XC90 veers to another lane.

3. Collision warning with auto braking: This is an important component of the radar-based safety system and one that's required given our road conditions. It detects pedestrians, cyclists and large animals who seem to spring out of nowhere on busy city streets.

It's even more useful in the night where spotting them is more difficult. How often have you been caught surprised as a pedestrian or a cyclist crosses your path at night? This system then is pretty good, then. In fact, if the driver fails to react, the system automatically applies the brakes.

4. Blind spot detection: This is highly effective when driving around tight bends. It detects objects in the driver's blind spot, and alerts the driver of the same. The system also warns the driver of cross traffic at intersections.

5. Park pilot assist: The benefit of having a 360-degree radar system is also evident when parking in a tight spot. The radars on the sides, for instance, can detect an object, like a large stone or the edge of a sidewalk, that's undetected by a driver reversing into a parking spot.

Volvo says that the XC90 T8 Hybrid offers both performance and lower emissions than most hybrids.