A review of cost functions for HEV powertrain control

This document provides a review of the latest supervisory control strategies and techniques for energy management in Hybrid Electric Vehicle (HEV) powertrains. The primary calculation required of the supervisory controller is the contribution to the powertrain torque demand provided by the engine and the electric drive(s). Cost functions are used as a high-level representation of the optimisation problem, and two common examples are selected for a more detailed discussion

Cost functions applied to H.E.V. powertrain control

A Hybrid Electric Vehicle (HEV) powertrain controller determines the complex balance of power between the individual sources available in the powertrain. Selection of an inappropriate control strategy can significantly impact upon the potential fuel economy and powertrain performance, so correct control strategy selection for a given HEV powertrain is essential. A Cost Function is used to evaluate the implications of a selected balance of power. There are various methods of achieving adequate control. Dynamic programming, used with Cost Functions for Minimum (fuel) Consumption, is discussed. The aim is to develop an improved Cost Function calculation that is solvable on a standard automotive Electronic Control Unit (ECU) in real time. The approach described in this paper is an improvement on the Local optimum solution by employing knowledge of the average operation. This then provides more informed Equivalent values to solution of the Cost Functio

A novel structure for comprehensive HEV powertrain modelling

Current software packages for Hybrid Electric Vehicle (HEV) modelling do not offer the comprehensive functionality to perform the wide variety of analyses required by both manufacturers and customers. The functionality is determined by the modelling structure, and often several structures must be employed to cater for all types of analysis. A new modelling structure for HEVs is proposed, employing an approach which overcomes the causes of limited functionality. It makes possible a wide range of investigations, the results of which offer quantification of the benefits that can be achieved in terms of, for example, tank-to-wheel analyses, emissions, and performance. The accuracy of calculations made with a software employing the new modelling structure is shown to be comparable to the accuracy of data supplied, satisfying the intended purpose

Cost benefit analysis for the development of hybrid electric vehicles

The financial justification of the decision to purchase a hybrid vehicle in place of a conventional one is difficult given the generally overly simplistic approach that is typically adopted in the decision-making process. This paper brings together the large number of factors necessary to present a clear view of both the costs and benefits that should be taken into consideration when assessing the viability of hybrid vehicle developments and subsequent purchase. Elements are highlighted, such as, fuel savings, residual values, insurance costs and disposal costs, together with a detailed justification of the reasons for their inclusion. This enables the potential life cost differences for customers to be established. The associated costs for a vehicle manufacturer in the development of hybrid electric vehicles are considered. It is explained how the calculation of the potential savings a customer may make, identified through profiling a notional customer, can support forecasting the premium a customer may be prepared to pay to purchase the vehicle. This information can be used in the manufacturer's business case for the development of a hybrid electric vehicle

A randomized double-blind multicenter phase III study of fixed-dose single-administration pegfilgrastim versus daily filgrastim in patients receiving myelosuppressive chemotherapy

Background: We evaluated the efficacy of a single fixed 6 mg dose of pegfilgrastim (a pegylated version of filgrastim) per cycle of chemotherapy, compared with daily administration of filgrastim, in the provision of neutrophil support. Patients and methods: Patients (n = 157) were randomized to receive either a single 6 mg subcutaneous (s.c.) injection of pegfilgrastim or daily 5 mg/kg s.c. injections of filgrastim, after doxorubicin and docetaxel chemotherapy (60 mg/m2 and 75 mg/m2, respectively). Duration of grade 4 neutropenia, depth of neutrophil nadir, incidence of febrile neutropenia, time to neutrophil recovery and safety information were recorded. Results: A single 6 mg injection of pegfilgrastim was as effective as daily injections of filgrastim for all efficacy measures for all cycles. The mean duration of grade 4 neutropenia in cycle 1 was 1.8 and 1.6 days for the pegfilgrastim and filgrastim groups, respectively. Results for all efficacy end points in cycles 2-4 were consistent with the results from cycle 1. A trend towards a lower incidence of febrile neutropenia was noted across all cycles with pegfilgrastim compared with filgrastim (13% versus 20%, respectively). A single fixed dose of pegfilgrastim was as safe and well tolerated as standard daily filgrastim. Conclusions: A single fixed dose of pegfilgrastim administered once per cycle of chemotherapy was comparable to multiple daily injections of filgrastim in safely providing neutrophil support during myelosuppressive chemotherapy. Pegfilgrastim may have utility in other clinical settings of neutropenia

Factors affecting the germination of orchid seeds

The effects of sugars and other carbohydrates, vitamins, hormones, complex additives, temperature, light, pH, atmosphere and its components, and moisture are reviewed. Orchid mycorrhiza, symbiosis and asymbiotic nutrition are also reviewed