Technical Developments Enhance The New Suzuki Vitara Hybrid

Several technical developments have been incorporated into the new Suzuki Vitara Turbo Hybrid to enhance efficiency and general driving pleasure.

Raising the power supply of the integrated starter generator (ISG) to 48 volts increases the electric motor output which in turn increases the amount of electric motor assist and regenerated energy. The additional power and torque make a real difference, according to Rodney Brown, Technical Service Manager for Suzuki New Zealand.

“The 48V Hybrid system has new torque-fill control and torque boost features that enhance driving feel by adding more torque from the electric motor to engine torque during acceleration,” said Brown.

In addition, an electric motor idling function in the manual transmission model reduces fuel consumption by using the ISG motor to idle the engine without injecting fuel.

“Under take-off or acceleration when a lot of fuel in required, the ISG assists the engine to reduce the load on it, and that’s how fuel efficiency is improved,” he said.

When the Vitara is cruising, the ISG minimises the electrical power generation or stops it altogether so that the engine can reduce mechanical load and fuel consumption. During deceleration the ISG generates electrical power intensively to charge the lithium-ion battery in the auxiliary power module and the Suzuki’s lead-acid battery.

With the introduction of a more powerful ISG and greater capacity lithium-ion battery, the 48V hybrid system incorporates four new power assist modes. When the Vitara Hybrid is running at a minimal engine speed with low torque, the ISG motor torque is added to boost total torque, improving fuel economy and drivability at lower speeds.

When greater acceleration is required the ISG supplements the engine torque and compensates for any delay in response. The Vitara Hybrid’s power assist mode improves thermal efficiency, regardless of the engine load. The ISG controls optimum thermal efficiency of the engine and is prevalent when the lithium-ion battery is in a high stage of charge.

“This power assist mode adds power to the engine even if the accelerator is only lightly pressured and is available until the lithium-ion battery discharges to a certain level,” said Brown.

“In the manual transmission Vitara Hybrid, a motor idling mode maintains an engine speed higher than the standard engine idling speed to create a ‘fuel cut’ condition, also enabling the vehicle to re-accelerate quickly.”

The Vitara Hybrid is the first Suzuki vehicle in New Zealand to feature a gasoline particulate filter (GPF) which cleans the exhaust emissions of particulate matter. This is now required to enable the Vitara to meet the higher emission regulations demanded in most world markets.

A more sophisticated exhaust gas recirculation system sees purified exhaust gas downstream of the particulate filter flowing into the EGR cooler, cooling the gas in the combustion chamber. As a result, engine performance improves and there is reduced piston knocking, pumping loss and improved fuel economy as well as a reduction of NO_x and CO₂.

Rodney Brown says an electronic heater shut off valve in now used to enable the engine coolant to warm up faster. “This is achieved by stopping the coolant flow through the heater core until needed,” he said. “The faster the coolant and engine reach operating temperature the more efficient the engine is.”

The piston cooling jets which blast oil onto the undersides of the pistons are now operated only when needed, reducing load on the engine’s oil pump and consequently improving efficiency. Adding to this, the oil pump itself is electronically controlled so that when high oil flow or pressure is not needed the pump can be adjusted to reduce engine load.

Other firsts for the Vitara Hybrid include the engine automatic start stop operation that makes use of the ISG to restart the engine and the tyre pressure monitoring system (TPMS).

“The TPMS control module receives signals from four tyre pressure sensors, identifies data according to the ID code of each sensor and uses the identified data to compare air pressure in each tyre with the tyre pressure value that is specified,” said Brown. When the tyre pressure is judged to be lower than the specified value, the TPMS control module turns on the low tyre pressure warning light in the combination meter.

“Unfortunately, some people forget to regularly check their tyre pressures, so this feature does it for them. There are, of course, safety and fuel economy benefits in having correct tyre pressures,” he said.