48 V High Power: Electric Drive for Excellent CO₂ Emissions and Electric Driving Features

Abstract

Future motor vehicles regulatory requirements for CO₂ emission reduction require a significant increase in hybrid vehicles in the fleet mix of manufacturers.

The use of the internal combustion engine is increasingly replaced by the electric drive in hybrid vehicles and the challenges for exhaust aftertreatment increase, as the thermal supply of the internal combustion engine for thermal management decreases. The electric machine must have sufficient performance to enable corresponding driving patterns not only in the test cycle but also in real-life operation.

Results from Vitesco Technologies 48 V Eco-Drive System have shown that for P2 compared to a P0 hybrid, the challenge for emissions is significantly exacerbated by an increase in pure electric driving capability, especially for plug-in hybrid vehicles. At the same time, technological advances allow 48 V drives to penetrate areas of application that were previously reserved for high-voltage solutions.

This paper presents a compact design 48 V 30 kW electric machine solution, suitable for a P2/P4 configuration intended for full hybrid applications or even a plug-in hybrid and characterized by compact design with a very high-power density. At the same time, the system approach of exhaust aftertreatment is illustrated. A 48 V 30 kW “electric” means not only less CO₂, but also increased electric driving and more total driving performance with significantly less effort and complexity due to 48 V as compared to a high-voltage solution.

With the help of simulations and vehicle measurements, CO₂ potentials as well as various emission-relevant driving conditions of a 48 V 30 kW high-performance hybrid are examined. At the same time challenging environmental conditions and the potential for improvement is determined by the advanced Emicat® exhaust aftertreatment system.

CO₂ performance is also the result of intelligent operating strategies. In the future, they will have to make their contribution robustly to the lowest CO₂ in every driving cycle. For this purpose, connectivity and optimization algorithms in real time are enablers [6].

Glossary

AER:

All Electric Range

BSG:

Belt Starter Generator

CH₄:

Methane

CO:

Carbon Monoxide

CO₂:

Carbon Dioxide

DCT:

Dual Clutch Transmission

EHC:

Electrically Heated Catalyst

EVAP:

Evaporative Emissions

FCM:

Fuel Consumption MonitoringFuel Consumption Monitoring

eCVT:

electric Continuous Variable Transmission

GDI:

Gasoline Direct Injection

ICE:

Internal Combustion Engine

ISC:

In-Service Conformity

LIVC:

Late Intake Valve Closing

mHEV:

mild Hybrid Electric Vehicle

PHEV:

Plug-In Hybrid Vehicle

PM:

Particle Mass

PN:

Particle Number

MPI:

Multi-Point Injection

NEDC:

New European Driving Cycle;

NMHC:

Non-Methane Hydrocarbons

NO_x:

Nitrogen Oxide

NOX:

Nitrogen Oxides

N₂O:

Dinitrogen Monoxide

RDE:

Real Driving Emission Test

THC:

Total Hydrocarbons

VSS:

Vehicle Simulation Suite

WLTP:

Worldwide Harmonized Light duty Test Procedure